Timing has a great effect on fuel efficiency, more than I expected.
With the original cam in the first 1000 hours fuel consumption was close to one litre/hour.
After repairing a loose cam gear consuption was as high as 1 1/4 litre/hour. After retiming it was back to normal one litre and stayed there until the damn camshaft broke after 300 hours.
Now. To my big surprise with a new camskaft from Stationay Engine Parts it only consumes .85 litre an hour with the exact same constant loads of 2500 watts!
Am I wrong or..........is this possible?
Quote from: oiler on May 06, 2010, 01:39:44 AM
Am I wrong or..........is this possible?
It's possible, provided you're not exceeding the energy capacity of the fuel. Whilst timing is important, probably equally important is the cam profile, which will determine the valve overlap, max valve opening, dwell, and so forth, all of which will make a difference to fuel consumption.
That might explain why the new cam is better.
My twin has a significant camshaft timing issue with the injection pump lobe on #2. In fact, it's so bad that #2 cannot produce anywhere near full power. I can get the injection timing correct on both cylinders, but because of the lobe problem, #2 has very little total lift, obviously limiting the total output. If I adjust the pump for more stroke, the cylinder knocks like crazy.
So, I have concluded that the lobe is likely advanced by 30 or 40 degrees from where it should be.
I have a spare camshaft, so I'll take the time to "degree the camshaft" measuring the lobe timing on each lobe. I'll bet a dollar all of the cam lobes are positioned significantly away from the ideal. I'd expect nothing less from these engines. I'd also expect that a properly set up camshaft will result in significant economy and HP improvements.
Chris
My plan is to make myself a new shaft from a better material than the original.
Then position the lobes in accordance with my original Lister Startomatic. Hopefully this could improove both fuel efficiency and give me a longer lasting camshaft.
Any suggestions reg. materials?
Torsten
Quote from: oiler on May 06, 2010, 05:52:15 AM
My plan is to make myself a new shaft from a better material than the original.
Then position the lobes in accordance with my original Lister Startomatic. Hopefully this could improove both fuel efficiency and give me a longer lasting camshaft.
Any suggestions reg. materials?
Torsten
What are the specs on a Genuine cam?
I bought an OEM NOS twin camshaft from England and shipped it and an Indian cam down to a camshaft maker in Tennessee. His comment on the Indian cam was that it was guaranteed to break because of the cam positioning and off-centre drilling and that any engine that had it installed would not get full power out of both cylinders. He compared the English cam and determined that even that one was a few degrees out on #2 cylinder. He has done all the measurements for me and is willing to build a cam to exact specs, in fact there are a few prototypes ready now. I am shipping some engine pats down to him so he can install a cam into an Indian engine and prove his work. After that I should have some cams available that will have the lobes exactly where the need to be. As soon as they are ready I will let you all know. Price is likely to be in the $300 range, a bit high but if they are as good as I hope, they will likely allow long-term use of the twins, something I have been reluctant to predict in the past.
John,
It would be interesting to know whether the lift, duration, overlap, timing, etc of an Indian 6/1 camshaft is anywhere near that of one from a Brit 6/1, too.
Quinn
Guaranteed......no two camshafts are alike. I own 2 Injun oids. 1 is very smooth and quiet....the other suffers from sever intake noise and is imposable to get the correct valve timing. Many of us went and got intake silencers from McMaster Car to hide our problem. It will take a fine piece of tooling to locate the lobes using the tapered pin method. I have been tempted to take my quiet cam and have the noisy one ground the same.
Many years ago, I raced a go-cart or two powered by the old flathead Briggs & Stratton.
In setting up the engines, SURPRISE!! they don't grind their camshafts to anywhere near the same specs either!
Ron
Sounds like maybe there's a market for aftermarket "hotrod" parts for these engines, John.
Quinn
Quote from: quinnf on May 06, 2010, 12:28:13 PM
Sounds like maybe there's a market for aftermarket "hotrod" parts for these engines, John.
Quinn
Offset idler bolt
Bronze idler gear
polished lifters
real camshaft
roller bearing :fuel pump lever
Hollow dipper (non-fatigue version) & matching bearing shells
What else is there???
If I remember correctly, The cam on the twin only needs one lobe removed for camshaft removal. Meaning, I could possibly TIG weld the other lobes in the proper position.
It's not unusual to see welded or brazed in place cam lobes on industrial engines. That way, the same lobe can be used for many positions. Even some modern cars and bikes do it to some extent.
Chris
Quote from: mike90045 on May 06, 2010, 01:33:30 PM
Quote from: quinnf on May 06, 2010, 12:28:13 PM
Sounds like maybe there's a market for aftermarket "hotrod" parts for these engines, John.
Quinn
Offset idler bolt
Bronze idler gear
polished lifters
real camshaft
roller bearing :fuel pump lever
Hollow dipper (non-fatigue version) & matching bearing shells
What else is there???
Chrome valve cover and dipstick! ;)
I dont know whether you could get away with tigging all the other lobes without having too much distortion issues. I think the ones that are welded in manufacture by welding may use rigid jigging and post weld heat treatment. Depending on shaft material field welding may leave a very brittle zone at the weld borders. That would be a concern as a stress riser in an item that has high stress reversals in both lateral and torsional directions. It is a common failure point with welded on gears etc.
If you are down in the range of .20% or less carbon, brittleness would not be a factor but since the shaft is also run in bronze bearings it would be better for wear if it were higher. If you were making a camshaft with integral lobes then it would have to be of a material that would accept flame or induction hardening of the lobes so something up around 40 or 50 points of carbon.
The pinned on cams have the advantage of keeping the heat treating of the lobes separate from the shaft but the need to have them slip fit for assembly puts all the force transmitting solely on the pin and the drilled shaft hole, making for a bad stress riser to initiate fatigue failure. I dont think there is a quick and cheap fix!
Anybody know what a British cam looks like? Pinned lobes or one piece?
Quinn
Look in the parts listing book?
Regards, RAB
hey us yanks, don't have no stinkin parts book!
hell we would be doing good to have an original lister over here :)
bob g
I've got one 6/1 that is a real "hopper". It is so bad that it broke the camshaft after 700 hours of use - that's absolutely no good to me. I'm going to have a couple of single cams made up to see what difference it makes but I'm beginning to suspect that this particular engine has a bent crankshaft or something similar. It has been a problem child ever since I put it in to replace one with over 26,000 hours on it - wish I hadn't! When I put the new Injun shaft in it seemed to be a little better, but not nearly as good as the Fergenmonster (That's a 6/1 lower end with a 10/1 piston, sleeve, barrel and head attached. It runs at 650 rpm and gives a "bit" more power than the standard 6/1, not enough to make it worth anyone's while to do it) I just did, well, "'cause I could".....and I was bored that day......
I've just sent a bunch of Injun lobes down to my cam maker, hopefully will see something soon. The down side is that they came already drilled, but I think my guy is going to re-drill a hole 180 degrees off from the original and use a much smaller pin. The English one I got had pinned lobes.
Tig welding the camshaft lobes won't be a problem. I already weld the pins in the lobes. Same for 2 stroke crankshafts, the hardened pin welds just fine.
Quote from: cujet on May 07, 2010, 09:05:05 PM
Tig welding the camshaft lobes won't be a problem. I already weld the pins in the lobes. Same for 2 stroke crankshafts, the hardened pin welds just fine.
Cujet, I agree that TIG welding would be the way to go but I think there would be serious concerns with distortion or weld zone embrittlement if you circumference welded lobes to the shaft under field conditions. I have seen welds pull out intact from high carbon steel and seen fatigue fractures start at weld edges. Certainly to fabricate a camshaft assembly by welding on all the elements instead of pinning you would no longer have a straight shaft and it is going to play hell with the support bushings. It could be done but lots of unintended consequences to deal with.
I got a bit of back grounding on this in stress relieving piping welds. The training demoed grain structure of weld cross sections that had been polished and etched as welded with no pre and post heat, ones done with proper procedure and also after total stress relief heating. Quite dramatic difference. Two gas pipeline blowouts occurred north of me a few winters ago. Cause? you guessed it.....! weld failure at heat affected zone from lack of preheat.
If I was having a pin shear problem on a single I would tend to silver solider them......maybe. Then have the lobes re-ground for correct timing whatever that is. Solid shaft for a twin.........
Quote from: XYZER on May 08, 2010, 09:49:28 AM
If I was having a pin shear problem on a single I would tend to silver solider them......maybe. Then have the lobes re-ground for correct timing whatever that is. Solid shaft for a twin.........
That would take the torque transfer off the pin for sure. How about the hardness of the lobe surface? would that have to be re done?
I think a good part of the problem is the slack fit of the cam piece. If they could be placed hot and shrunk on like the crank timing gear they would be a better assembly. Or how about machine a shaft so it was oversize at those locations so the lobes could be press fit cold, yet proper shaft size at the bearing locations? Just think of the cost that would add though!
I wonder what construction method John F and his camshaft man are contemplating on the new design. Single or double also?
One of my thoughts was to simply tack the lobes in the proper position. Then run the tapered reamer through. If the mismatch is not too bad, the reamer should true the hole and allow the use of a stock pin. Which would be tack welded in place too.
FWIW, I don't expect any significant distortion using this method. The way we weld crankshaft pins produces so little heat, there is no warpage of note, and that was the basis for my thoughts. I'm not talking about a large weld bead, simply a TIG weld, done on a lathe with little to no filler.
But, it remains to be seen. So, I guess, it's "wait and see".
JohnF,
Please continue to post updates on your cam shop down in Tennesse. I and at least one of my friends has also expressed interest in a precision / accurate camshaft for twins. Even at $300 or so, this may not be that expensive when one calculates all the damage that acn be caused when a camshaft fails and trashes the rest of the engine. So to maximize fuel efficiency and power output while almost guarenteeing the absence of a camshaft failue, it is worth it to me.
Please keep us posted on your progress.
Bruce
For this run we will be using Indian cams fastened on to a North American shaft. The jig has been set up and the cam degrees of separation exactly measured. Each cam will be fitted/ground as necessary (we did find that the Indian cams had a pretty good Rockwell hardness index but the shaft did not) then pinned to the shaft with much smaller pins. For this set I ordered enough cams for about 20 assorted shafts (single and double). I'm not completely sure that the singles will improve much with the new cam, the Indians seem to be able to get it "close" for a one cylinder, although I have one very bad "hopper" engine here that is going to be my test bed on that issue. I have just sent a couple of twins plus some old engines down to Tennessee, my guy down there will re and re the cams after testing with the originals in place and do some real-time data logging.
I sure hope this works with the twins, I had stopped importing them because of this problem. However, this is a relatively easy fix (if not cheap!). If it works, so it will open up the possibility of bringing in the twins again for me.
The cam maker does not want to TIG or MIG the cams, I haven't discussed why with him, he's the expert!
Cujet, I agree that several small tig tacks equal in size, opposite, and laid down in opposing direction, would not likely be a problem for distortion, but as little heat as you can use will still far exceed the transition point though and if the shaft is anything other than mild steel it will leave a hard spot that is a stress riser seed for potential crack propagation. I think John F considers it likely that the drilled pin hole in the shaft is effectively creating a notch that leads to breaking from gradual crack propagation from this point. My guess is that is why a smaller through pin is being considered. I have heard of pins shearing on the timing drive gear so there may be a limiting factor then with how small you can go with the pin size.
There is a big difference in toughness in different alloys especially in regard to fatigue resistance so John can likely make a big difference there in potential life of the camshaft assembly.
Torsional resonance phenomenon may be a factor and the sharp power pulses of one and two cylinder low speed engines could be initiating forces at just the right frequency to create a problem. Do a google search on torsional resonance for some interesting reading; that is at the root of a lot of shaft failures. Cummins had the problem 20 or more years ago with breaking crankshafts. If you held them at just the right frequency they would break in short order! I think I have seen Mobile Bob post about that. I ran into it in some prototype logging equipment being tested and it took a while to sort out that it was not operator abuse causing the drive shafts to wind up.
I suppose any heat applied will introduce a problem......I remember when I was a young know it all I had a Ford 1/2 ton with the pressed on collar that helped hold the bearing on the rear axle. I had a iffy one and just put a minute tig tack on the collar to hold it on the axle.....boy that was a long hike!
Hey Johnf is there enough size on the cam lobes to bore them out and go to 7/8" dia? Stock is 3/4" i think.
The right way to do this imho is for the cam grinder to locate a cast iron blank that can be modified to fit and grind that.
When I spoke with my local cam grinder about it, he figured he'd be able to find something that could be modified to fit.
No pins, no welding, hence no stress risers...
Short of finding the correct blank, I'd key the shaft and lobes for the correct location, and put a snap ring on either side of the lobes to hold them in place. Yes, it would be a bit of a challenge to figure out, but it would solve the problem for good I would think.
I would submit that the only reason those lobes are being pinned is to save money.
These cams just don't have that much force on them when compared to modern V8 engines so I think it would work fine.
Just my $.02,
Steve
I am a bit puzzled why it appears to be hard to find a cam manufacturer who cannot duplicate what has to be the most simple engine camshaft in the world, and one that operates at very low stress and lifter contact load. I'll bet you could make one yourself on a wood lathe and disc sander in one piece out of hard white maple or even teak that would last for a while.
What's wrong with these Indian engine manufact-errors? If their product line required more different grinds than just two, one for all the singles and a different one for all the twins, then the slide on hardened lobe secured with a pin and pre-cracked at the factory with a oversize hammer precisely applied by an uneducated laborer might make some sense. They could make a case for stocking only one bare shaft for each engine line, adding the lumps as needed. What they do now is supply custom timing profiles, not by design but by incompetence. ???
Perhaps we need to inspire the interest of one of the well known North American cam houses like Isky or Crane to make a limited production run of one piece camshafts for these engines.
i know we can get a foundry to cast up some cast steel or cast iron blanks
you just need a pattern, which is generally made of wood
our local foundry will do short runs, if one is not in a hurry and can wait till they run another project
they will then finish up with the small projects
they do mainly cast steel i am told.
bob g
you don't even need to carve one out of wood....just sit down with some bees wax and give an original some beef where you want it and some draft where you need it and walla you have a master.....cast 5 or so in aluminum and you are in production....
I'd be willing to buy an accurate camshaft for a twin in the $300 range. I'll bet there are hundreds of people around the world wide willing to do the same with most of those willing to buy in the US. Other places probably dont care about having a precision camshaft, for a couple hundred dollars they just buy another engine. Anyway, I'm interested but only if the price can be held down to say $300, any more significantly reduces the potential sales market.
JohnF, I hope your cam guy down here isn't under water!
Ron
SOOOOOOO..... whats the Update on this?? OH
and since Im here.. Im a new member.. I live in Alaska. My father and I both have Listeroids. his is a 12/1 Powerline. And Mine is a Metro 12/2. Anyways Im interested in the Camshaft bit for my twin, Also Im interested in someone that can lead my to find a Offset Idler gear bolt.. ANYONE??
Anyways Im Robert, Dads, Frank.
Your looking for a member here called XYZER he has a post on the forum here most likely in the "things for sale" section Wherehe was asking who wanted one. here's a link to those posts It's actually in the parts wanted section of the forum. http://www.microcogen.info/index.php?topic=936.0 My understanding is the cams are under going testing if the cam guy is not under water from the recent floods. I too am interested in them.
Scott R.
Great thanks much
didnt think he was going to make another run from what things I HAD read. I left him a message Hope he makes more...
he also makes hollow oil dippers for use with con rod bearings that do not have the groves in the top shell, the grooves in the top shell reduce the abillity of the top shell to resist the load placed upon them in running & prevents debris from getting into them from the oil running down the con rods & into the oil holes normally used to supply oil to the bearings. I'm hoping he'll make a run of dippers soon too.
Scott R.
My cam guy isn't under water! I do have a slight delay,the Indian manufacturer didn't send me any cam gear weights in the spares order so they are now on the way. Meanwhile I have a few spare weights around from previously destroyed cams that we should be able to make up 3 or 4 shafts. I have several spare twins of various ages down in Tennessee so they will be the test engines, my guy is doing heroic work in measuring and recording data - he's much better at that stuff than I am.
Quote from: lowspeedlife on June 04, 2010, 09:10:58 PM
he also makes hollow oil dippers for use with con rod bearings that do not have the groves in the top shell, the grooves in the top shell reduce the abillity of the top shell to resist the load placed upon them in running & prevents debris from getting into them from the oil running down the con rods & into the oil holes normally used to supply oil to the bearings. I'm hoping he'll make a run of dippers soon too.
Scott R.
so where do you get these NON-oilgroove bearing shells?
Yes I hopo he will make some more Dippers as well Id like a set for my twin.
`I have a few non-oilgroove dippers left in stock, they were a special order. If there is enough interest I can look into getting some more. The upper shell is completely plain, the lower shell has the same grooves as a standard dipper. If anyone is interested, PM me.
Non oil groove Bearing shells you mean?? upper and lower if thats correct then how much and Yeah I think Id want a set for a twin so 2 sets. upper and lowers.
Like this but better focused!
ok what ya want for'em...
these are supposed to be better, from what ive heard they dont harbor fine metals in the grooves and and better metals, correct?
I suppose I should be getting hollow dippers for these as well, Hope I can find those...
The upper shell is plain - no grooves or holes. The lower shell is the same as a standard one (but likely better made!) These shells CANNOT be used without a hollow dipper - that is how the oil gets into the bearing. I don't want to pee off the admin of the board, so please send me a PM to John@woodnstuff.ca
pm sent
Quote from: Crofter on June 07, 2010, 03:09:01 PM
Like this but better focused!
Thank you for this Crofter big help..:)
so is there any new news?????????????????????????????????????????????????????????????????????????
I want one...
hmmm I guess this camshaft thingy drowned....bummer.
There are two twin camshafts being tested right now. I just sent down the components for 30 more, but also have to bring in cam weights (Indians forgot to put them in the order) from India. Hopefully we will have all the component parts under one roof in a week or two.
Thanks for the update. many are watching
Quote from: JohnF on June 29, 2010, 03:55:55 AM
There are two twin camshafts being tested right now. I just sent down the components for 30 more, but also have to bring in cam weights (Indians forgot to put them in the order) from India. Hopefully we will have all the component parts under one roof in a week or two.
very good John,
thank you for this update very interested. also is there any update on a possible run of Hollow Dippers???
anyways thank you for all your efforts on all this John...
Rob
Quotevery good John, thank you for this update very interested. also is there any update on a possible run of Hollow Dippers???
anyways thank you for all your efforts on all this John...
And then we need a run of plain bearing shells to go with them. Having not opened my up, is the top shell (with oil holes and grooves) not interchangeable with the bottom shell ? Does a oil hole come pre-drilled in the plain bottom shell, or does that have to be done? any oil groove need in the bottom to spread oil around, or only for the top in gravity drip mode?
Quote from: mike90045 on July 01, 2010, 11:40:27 PM
Quotevery good John, thank you for this update very interested. also is there any update on a possible run of Hollow Dippers???
anyways thank you for all your efforts on all this John...
And then we need a run of plain bearing shells to go with them.
i second that.
Mike;
The plain bearing shells are not interchangeable top and bottom. The top is completely plain, no holes, no oil grooves. The bottom one looks pretty much like a standard bottom shell, it has the oil hole and the oil distribution grooves. It is those grooves that force the oil up into the top shell.
any new news???? were dying to hear how this is going.......?? ??? ??? ??? ??? ??? :P :P :P :P :'( :'( >:(
ummmmm.? ??? ??? bump :-\
Slowed down a bit due to the fact that the Indians did not send me all the parts (grrrrr!). I have everything except the little collars the governor arm rides in.
But, while we were spinning our wheels, we had another engineer have another look at the firing sequence of the twins vs. the cam positioning. He tells us that the ideal degree of separation between intake and exhaust cams is 102 degrees. However, on the camshafts provided (the 2 or 3 he has looked at) the degree of separation on cylinder #2 is about 97 degrees. Doesn't sound like a lot UNTIL you realise that this means the second intake cam is opening against the pressure of the compression stroke from cylinder #1. Add that to all the other little problems (camshaft it self too soft, centre bearing too sloppy, end bearings marginal) and he says the camshafts "don't stand a chance". The shaft is being flexed badly every time it turns, this is also leading to excessive wear on the gear train (it is likely not the bad positioning of the idler, although that does play a small part).
Now I just have to get all the bits under the same roof and we can get going on this...
Very interesting 102 degrees vs 97 degrees, please keep us posted on your progress. I enjoy reading your analysis.
I am interested in seeing how "6 degrees of separation" affects fuel economy, not only longevity.
Ron
Yeash thats alot off,, no wonder we have such problems with the twins geartrain,,,, Sure hope you can get a solution to this mess... Keep us posted, and thank yous o much for your efforts..
BUMP!!
I was thinking that Indian cam lobes could be correctly positioned on a local, undrilled steel shaft, and furnace brazed on. Then structural integrity and cam timing would be assured. Just the last lobe needs to be pinned on for the twin, the fuel pump cam.
My first choice is still John's cam. I could go $300.
I have 2 6/1's. One has a noisy intake and can not be timed correctly to the crank. The intake valve opens early or late and won't start late. It is off maybe 4 degrees. It also has the typical air intake noise. The intake is almost as loud as the exhaust. My other 6/1 is timed spot on and has a quiet intake. Just runs smoother. Someday I will pull both cams and get my bad one ground to match the good one. I am thinking it would be easier to do if I have a master or a known good cam.
XYZER, I see from photos of my cam that the injection pump lobe has much greater duration than the valve lobes: I wonder if there could have been a screwup and a wrong one installed for your intake?
Frank,
I have never had them side by side to compare. The bad cam could have several things wrong. The gear could be off or the intake lobe could be off. I never checked the exhaust. I don't believe the injection pump lobe was swapped. I believe they did a typical throw the lobe on the get er close and drill it and pin it. If there fixture is a little sloppy they will play hell getting all the lobes and gear to stay at there correct position in relation to each other while they drill and taper pin it. If I had the cam specifications I would grind to that but those numbers are a bit unknown. I am happy with the way the good cam works (much quieter) and one of these days I'm going to talk to a cam shop and see if he can grind my bad cam using my good cam as a master. Many people with Listeroids have complained of noisey intakes and we used an intake silencer to hide the problem. It might even be caused by the timing gear on the crank........
Yes, if the crank gear were off a fraction in placement you would have at best a compromise for valve timing. Also with the injector pump; ff the camshaft timing is off a bit you can shim the pump to get the correct initial spill timing in degrees but the map of the fuel delivery could vary hugely because of a variation in where the plunger contacts the lobe.
It is too bad regulations dont bode well for a big number of future sales as that cam and valve train would be worth a good rework. It is a shame because it is such a simple engine to work on. Just a bit more attention to detail would make a big difference in its predictability.
Jens, does it appear the two holes in the lobe are not 180 Deg. apart or is the hole in the shaft off center?
they are all off center, and as such shouldn't be a problem so long as they aren't off center a bunch
the reason they are off center is to assure that if the lobe is removed for whatever reason it can easily be put
back in the correct location and not 180degree's out.
i think the biggest problem is they beat the living shit out of the taper pin and in doing so set up stress risers which lead to early failure
bob g
Hi Jens !
I think what Bob is saying is that the holes are deliberately off center so that the lobe can only be mounted in the correct orientation....only one way. It's not the pin that is being discussed, but rather how and under what circumstances the pin holds everything together.
And yes, the pin probably had the crap beaten out of it when it was installed originally. Accurately indexing the lobe to the shaft, the drilling of the holes and the general assembly techniques employed by the factory certainly leave a lot to be desired. Is it any wonder that the camshafts (in some cases) are hindering performance or at the very least are failing prematurely ?
Have a good day sir.
wormshoe
Jens
the reason i said they are slightly offset is it is incredibly easy to screw up an drive a pin in 180 out if it is perfectly aligned.
not so easy for someone that is experienced with tapered pins, but very easy for someone that has never used on before.
case in point, i have heard of parts being broken because the installer didn't understand the taper system, and tried to assemble
without having the proper orientation, this only happened because the thing could be assembled 180 degree's out of place.
bob g
Is there some conjecture slipping into the picture? Can we verify that the holes in the lobes and/or the shaft deliberately oriented off center? (They should have to be so in both parts) This seems like a very difficult cure of the remote possibility of putting the lobe on 180 off, though I have seen it done on timing mechanisms on hay baler components. I wonder if it is merely sloppy unintentional dull drill dull operator circumstance. I know that it is very difficult to get a true hole perfectly centered and even more difficult to get a true and consistent hole deliberately off centered.
Do new factory cam lobes come pre drilled? do shafts come predrilled or do the holes get drilled into the shaft at assembly time? Lots of questions!
India is in he news his week because they are not ready to host the world for their olympic games, or whatever the hell games it is, even though they have been preparing the olympic facilities for many years. Cement that needs 6 months to cure for safe strength in structures that will support the expected visitors is still being poured this week. Apparently the army of workers who are not being paid minimum wages and have to go to the bathroom anywhere they can find, maybe in that wet cement?, and who are working without shoes has had the heat turned up on them to get the place finished. They have less than a week now before the games are suppossed to begin. I suspect they will be late and their party a disaster. The reason will be given that work could not proceed because a sacred cow was on the road, in the way.
We in the west may be expecting way too much of this pathetic lot if we think they can put a pin in a camshaft correctly.
Quote from: Jens on September 27, 2010, 11:56:06 AM
No, I can not believe that off center hole positioning has been done on purpose in this case. It makes no sense (and weakens the camshaft).
How does it weaken the cam? Seems like if anything, it would be stronger because if you do not drill directly through the exact diameter of the shaft, you're removing less metal -- i.e. by drilling directly on the diameter (on-centre) you'd be removing the most material, and less as you get farther off-centre.
If I had to guess, I'd guess the lobes are placed on the shaft, indexed (to some extent ;-), then both drilled simultaneously. If the hole isn't perfectly centered, then you get the extra benefit of not being able to reinstall it out of phase later.
And I'd also tend to think that if drilling it off centre does weaken it
and it makes enough difference to cause failure, then the material was inadequate or the shaft too small to begin with. It shouldn't be engineered that close to the edge (pardon the pun).
Tapered pin in a straight hole? what happened to the taper reamer operation prior to driving the pin. JohnF apparently has seen unassembled cam lobes, maybe he can vouch for whether or not the holes are 180 Deg. apart and whether they are the same diameter side to side. Can you order a bare cam shaft and if so does it have the holes drilled?
First: The Indians are NOT bright enough to drill holes slightly off centre. It is caused purely by poor work habits - dull drills, not prepping the round surface before drilling.
The cams come with the holes pre-drilled and the ones I saw "looked" to be drilled correctly, but I wasn't measuring that as we do not intend to use the original holes (I've sent them all out so I don't have one to measure). An additional problem with the Indian product is how soft the shaft itself is - there is an amazing amount of flex from one end to the other and neither the centre bearing nor the end bearings are sufficiently tight to dampen it.
All-in-all, the camshaft is a precision part that has fallen way out of spec - and I don't think the Indians know where spec is.
I'm so frustrated with Indian QC right now that I'm looking at China instead of India for new engines, I know of a nifty Yanmar-type 10hp/1000rpm engine that can be slowed down. It has a 23.5 flywheel and may be the way of the future. Myself and a buddy are looking into what we can do to ensure good QC.
Quote from: Jens on September 27, 2010, 03:02:11 PM
Quote from: cgwymp on September 27, 2010, 01:52:54 PM
How does it weaken the cam? Seems like if anything, it would be stronger because if you do not drill directly through the exact diameter of
You are setting up for a stress failure by not distributing the forces in the shaft equally.
I'd have to see the numbers -- so far I'm not convinced.
Quote from: Jens on September 27, 2010, 03:02:11 PM
Quote
And I'd also tend to think that if drilling it off centre does weaken it and it makes enough difference to cause failure, then the material was inadequate or the shaft too small to begin with. It shouldn't be engineered that close to the edge (pardon the pun).
..... which is exactly what this thread is all about and why JohnF is trying to produce camshafts that don't fail
So you agree the hole isn't the problem.... ;-)
Cheers!
Here is a pix of a new camshaft for a 6/1, it is pre drilled and the holes ARE 180 apart. Also shown is a new exhaust lobe. If I slide this lobe on the bare shaft the holes line up.
The drilled holes always line up - even if I slide the lobe on backwards. What will not line up is the tapers if the lobe is installed incorrectly.
flywheel
Flywheel, are you saying that the holes in the shaft and the holes in the lobe are all tapered for only one orientation?
Quote from: Crofter on September 27, 2010, 07:52:40 PM
Flywheel, are you saying that the holes in the shaft and the holes in the lobe are all tapered for only one orientation?
That is correct!
In my experience you will never drill then taper ream shaft then the cams seperatly and ever expect the holes to be in alignment for proper assembly with the tapered pin. Standard process in the machine shop world I have been would be to assemble the cams in the desired location then drill and ream while in location. I have never seen a machined part yet on a listeroid that appeared to have fresh cutting tools. All of the machined surfaces appeared to have been cut with tooling that was way past its last leg. A good tapered reamer done correctly would have a high quality finish with no tears in the surface and the tapered pin would align it and lock immediately.
Today i was tinkering with my genuine lister cs and i noticed that the valve springs are quite a lot weaker than the ones on the JKson. Could it perhaps be that is the reason why our cams are failing?
On the cs i can open the valve with two fingers, on the genuine i can barely open them with two hands!
Coincidense or have someone else noticed this too?
Quote from: oiler on October 08, 2010, 12:17:16 PM
Today i was tinkering with my genuine lister cs and i noticed that the valve springs are quite a lot weaker than the ones on the JKson. Could it perhaps be that is the reason why our cams are failing?
On the cs i can open the valve with two fingers, on the genuine i can barely open them with two hands!
Coincidense or have someone else noticed this too?
Did you mean on the JKson, you had to use both hands?
i see no reason for any more spring pressure than it takes to close the valve and keep them from floating at 650 or 1000rpm
depending on engine, however
those god forsaken wide seats might need the added pressure to help chop up and clear bits of carbon?
not sure how much stress it would take of the cam and idler to reduce spring pressure, or how best to do it anyway, without
replacing the springs with something a bit weaker.
it probably doesn't take much to close a valve on a relatively slow speed engine.
even if you were to reduce the spring tension, and have reduced stress on the cam/idler assembly, one still has the injection pump
and there is nothing you can do to reduce that cyclic load.
at least not easily
bob g
Yes i had to use both hands to open one valve
Bob. You are right, i forgot the pump. ;D ;D
Don't forget that many of the old "Hit & Miss" engines opened the intake valve with just suction. 6 or 7 hundred rpm's doesn't take
much spring pressure.
Ron
A good part of the necessary spring pressure is to reverse the mass of the rocker arms, pushrods and cam followers. Lighten that part of the package and I think you could use much lighter valve springs to affect valve sealing. As Vdub mentions, the valve spring on the hit'n mis intakes are pretty light. Probably the exhaust with lifters, pushrod and rockers are heavier.
We need Xyzer to make us up some titanium or carbon fiber valve train components so we can lilghten the valve springs waaaay up and save the cam shaft breakage on the twins.
Go down to your favorite Wally-world and grab a couple composite arrows, cut to length, epoxy ends on 'em and there are your lightweight pushrods. Aluminum rocker arms and you're all set, wonder if a set of big block chevy roller rockers could be adapted?
Ron
Quote from: vdubnut62 on October 09, 2010, 07:40:17 PM
Go down to your favorite Wally-world and grab a couple composite arrows, cut to length, epoxy ends on 'em and there are your lightweight pushrods. Aluminum rocker arms and you're all set, wonder if a set of big block chevy roller rockers could be adapted?
Ron
Yes, and I think the cam followers could be fabbed hollow. I think the reciprocating mass of the valve train could easily be cut in half. Probably save enough friction to show a minute fuel saving. I think you would want to maintain a reasonable safety margin on valve float in case of incidental governor overrun. The valve keepers are not a very sophisticated fit to the stems or the spring cap so it wouldnt take much to shake them loose with bad results.
Crofter. I see your point, but on a genuine Lister pushrods and rockers are at least as heavy as the ones on an 'oid.
Perhaps valve float could add a little safety in an overspeed situation...
i would rather float valves as float flywheel shrapnel
valve float is a very effective rev limiter
bob g
Yes, for sure the grenaded flywheel would be the greater evil! I dont think you can consider valve float as a viable over speed protection though. I dont know how representative mine might be of typical Listeroid valve retainer components but they sure would not stand any amount of float without getting knocked apart. I had to grind considerable off the outside of the keepers to get them to bury beyond the half way mark into the spring cap. :o
I am sure that the dual springs could be made much lighter or shorter though. There was no attempt to close the top and bottom coils or taper off the last half turn like we are used to seeing on any commercial engine. Brute strength and awkwardness is the rule of the day.!
Jens, sounds like the "mechanic" that mechanicked your engine missed that class of oil groove theory!
My idler shaft was a light drift fit in the crankcase so no problem with it turning. You could machine a slot in the outer end of it. doubled hack saw blades in the frame...... to make a screwdriver slot to hold and reference the oil groove location while you torque the nut. It should have not tendency to turn once firmly seated against its shoulder.
If you do decide to remove and reset the cam bushings make sure you do not cause bruising that will result in localized tight spots or you risk doing more harm than good. If they are loose in the housing you may have to resort to prick punching a dimple pattern on the OD. to stabilize them.
Listeroids are an endless source of fun and surprises!
Yesterday i recieved two sets of genuine Lister valve springs for the 6/1.
They are much easier compressed than the listeoid ones.
Quote from: oiler on October 19, 2010, 12:23:23 AM
Yesterday i recieved two sets of genuine Lister valve springs for the 6/1.
They are much easier compressed than the listeoid ones.
Is it possible that the added valve train tension caused by too resistive springs is causing upstream problems?
At the speed these engines run I can't imagine them needed a really aggressive spring.
R
Quote from: RogerAS on November 17, 2010, 09:20:01 AM
Quote from: oiler on October 19, 2010, 12:23:23 AM
Yesterday i recieved two sets of genuine Lister valve springs for the 6/1.
They are much easier compressed than the listeoid ones.
Is it possible that the added valve train tension caused by too resistive springs is causing upstream problems?
At the speed these engines run I can't imagine them needed a really aggressive spring.
R
I would bet the Indians use the same spring in all rpm engines.....The approriate rpm valve spring would save valve train wear and tear and serve as a rev limiter IMO. I would go with lighter components if it was an 8000 rpm engine for sure.
John,
Any updates on the camshaft project?
Haven't talked to the guy for a bit, will call him this coming week. Last we talked he had a prototype up and running in one of his twins, said it made a big difference.
ok time for an update. dont ya think??
The last of the pieces are being shipped from India this week. There are a couple of test units built and they are working very well. This has been a long and difficult process, more more so by the Indians being very obstructive and only sending partial parts orders. This final shipment is coming from JB Shaw, so I'm confident it will be good.
CS camshaft timing specs... in case it hasn't been posted already.
dieselgman
Any status updates as of late? Thank you for all the work and time to solve this problem.
Sara
At the risk of breaching some sort of forum etiquette, PLEASE RSVP status on this.
Thanks!!
I've been holding my breath too. Anxious to see / hear the results. Thank you for investigating this rather common problem, hope a cost effective solution can be obtained. Standing by.
I do have a few re-jigged camshafts in stock - currently 3 or each (6/1 and 12/2) If anyone is interested please PM me - john@woodnstuff.ca.
Sorry,I must be missing something as I have yet to pull the cam from my Petteroid.
Is it the Lister the Petter or both that pin the lobes to the camshaft?
What would motivate the Indians to use such a round about method of cam manufacture?
$
Quote from: Tom on September 13, 2013, 05:25:40 PM
$
I keep forgetting that. I work in an industry where it is more important to do it right than it is to save $$$.
i can imagine it taking a relatively simply machine to make up cam lobes that are later pinned to a shaft
far easier than the machine it takes to grind lobes on a one piece camshaft.
also there is something to be said for being able to tailor the overlap simply by where you pin the lobes to the shaft.. maybe the same set of lobes fit a variety of applications?
bob g
The holes through the camshaft have been a big problem for the Rajkot twins, only occasionally a problem on the singles.
Drilling a hole in the round shaft seems structurally perilous if it is off center, and also seems more prone to positional errors. We've seen pictures of both here from Rajkot.
I wonder if there is a way to keep the simplicity of separate cams and shaft, but fasten the cams via welding or weldbond?
Maybe the "kits" should include the cams and the shaft but not assembled?