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Nice generator

Started by WGB, October 06, 2009, 05:04:01 PM

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WGB


mobile_bob

those are nice units, a bit on the noisey side, but well engineered
far better engineered than just about anything on the market today in my opinion
at least in the 12.5 to 20 kwatt class

downside?
that engine is probably one of the most complex diesel engine's ever made, elegant in design
but i would bet it has more parts in the cylinder head than a complete lister has in the whole engine.
it takes a rather special mechanic to get into one of those engine's, not a diy'er project at all!
it also require many very specialized tools to do even the simplest of things, such as loading a piston
back into the liner.

for instance, to rering (which is probably a bad idea to start with, but can be done)

the piston cannot be installed from the top, such as is typical, not because it won't fit but because
the oil control rings are not to pass the intake ports in the liner. so...

you use a special funnel shaped steel loader, that has a wire edge at its bottom to locate it properly
on the bottom of the liner, the piston assy is pushed down through into the liner,, then the whole assembly
is installed into the block,  the liner btw is a dry liner on the 71 series.  that liner loader was about a C note
30 years ago, who knows what they are now?

thats probably the simplest part, setting the valves requires go/nogo guages, .015/.017" for the exhaust valves
the injectors require a timing pick to set them, 1.484 being popular, as well as some that took a 1.460 and 1.470"

then there is the blower, that is almost a specialty all in itself, rebuilding one of those is not a job for any diy'er period.

governor?  two parts to that , the flyweights are driven off the blower and form the lower section, the bias levers, high/low
springs etc are all in the upper houseing,,, and you better know what you are doing there or one of two things will happen.
either the engine will not pull the load, or it will runaway to 4grand plus.

don't get me wrong though, those engines were the ferrari's of the diesel world back in their day.

btw, i still have all my service manuals, my liner loaders, and blower tooling, and yes those gensets really have a wierd attraction to
me.

having a pair sitting side by side in an engine room singing their song would be really cool in my opinion

but i am a bit strange they say

bob g

Henry W

I was looking at those a while back. And after Bob went through what he just wrote I decided to stay away from them.

But I love so sound of 2 cycle Detroits. 8)

Henry

WGB

I just threw that out there because I've never seen them before.
I will admit I thought about looking into them.
Thanks Bob, now I'm still looking lol.

prof.blink

mobile b, somewhere in the forums,recently you made a comment to the affect that at one time a 12-71 core had high value, we just listed a 125k delco w/12-71 w/less than 900 hrs w/ all ancilairies, bidding stalled @ $1700.00. what do we do with all this stuff-----wave it over the scale for #money? are things the same way on your end of the continent?  blink

lowspeedlife

These are pretty sweet units, someone had a couple of tractor trailer loads of them for sale on E-Bay last year. those had not been reconditioned, these may be the same units. The one's on E-Bay were railroad refer car sets. Gotta agree with Bob, adjusting all those exhaust valves is a bitch & the blower is certainly not a DIY'er job, but the last i remember you could get the piston/liner/con rod as a pre-assembled unit & just drop them in place. i'd like to have one as a back-up for my back-up, but i didn't see a price.


  Scott R
Old Iron For A New Age

Henry W

Are parts starting to get a little hard to find for the Detroit 71 series or are parts still abundant?

Henry

mobile_bob

my understanding is some of the parts are getting a bit hard to get, the usual overhaul parts
will probably be available for many years to come, but
darn few people can overhaul one of them and get a useable result

bob g

Henry W

Thanks Bob,

I was not planning to by one. I am having to much fun with what I have.

Henry

Wizard

mobile_bob,  ever detroit -53 -71 series ever produced in 4 cycle version in simpler designs instead of 2 cycle associated with complex rebuild procdures?

Oh, how is cooling of the dry liner of -71 is done?  Any diagram of one so I can see how it is done?  I am aware that press in cylinder liner is not possible due to need to able to pull liner along with piston as matter of maintaining reasons in the field.

Your insight and real-life experience is golden and that helps to know because I was dreaming of building 2 cylinder using liner & pistons assemblies.

Cheers, Wizard

mobile_bob

the 53, 71, 92, and 149 series all were only built as 2 cycle engine's

of the 4 engine's only the 71 series was a dry liner engine, the other 3 were wet sleeve much like
any other wet liner engines that use orings to seal the water.

the 71 dryliner is basically just a bored cylinder in the block, that has slip fit liner's
they are fitted so they slide in with a bit of drag and they need to be fairly close fit to get good heat trasfer.
the bore in the block needs to be clean of any corrosion (uncommon) or carbon (more common) and the old
liner inspected to make sure that there was good heat transfer before the teardown as evidenced by
an oily outside but no large patches of burnt or carbonized oil which would insulated that area of the liner
and cause a hot spot.

interestingly the original new liners have their part numbers electroetched on the out side of the liner
in three places, up under the lip of the liner, or above the port, or below the port. that was known as
first, second and third fit respectively.
first fit was the smallest od and still be within tolerances, the second fit was mid way  within tolerances, and
the third fit was the max od and still be within std tolerances,  the problem was there was no designation on the outside
of the cylinder kit box, so you had to open the box to check which fits you were getting,,, something parts guys rarely
would allow you to do.  i can't imagine today that they would let you check at all.

the inline engines had a number 1, 2, or 3 stamped by each cylinder, this tells you which fit liner goes in that hole.

the V series engines had no such marking from the factory, so you had to hand fit each of 3 new liners to see which
fit the tightest.

this allowed for such time as you had a cylinder bore and liner that upon inspection showed some signs of carbonization
and hotspotting, you would then carefully hone the block bore, and select a #3 fit to fit that hole, so you would get back
to good heat transfer.

90%+ of all mechanics that worked on detroit 71 series either had no clue about fitting liners, or didn't care, because
it took extra time to fit them properly.

this attention to detail made the difference in an engine that might make another 200k miles or one that would run near
the original 400k miles before needing another overhaul. many detroits had troubles makeing 150k miles due to sloppy
procedures, lack of cleanliness and just not careing enough to take the time to do it right.

cleanliness is very important to any engine, particularly diesels and most especially detroits, being two strokes with a blower
they moved 2 to 3 times the air that any 4 stroke would of similar displacement, so clean air was mandatory, and attention
to detail when it came to cleaning out the airbox section of the block made all the difference in the world. this was something
that was sadly neglected in most inframe overhauls, because it was a nasty, difficult and time consuming job.

then there was the new engine idleing problem, if you idle a detroit for as little as 20 minutes after an overhaul, it will then
and forever after blow oil out of every possible part of the engine. So it was a must to get the thing running properly as quickly
as possible, up to speed and under a load so that the engine could break in properly, otherwise glazed rings were the result.

neat engines for the anal retentive type that is obsessed with cleanliness and who's attention to detail probably would make him
a better aircraft power plant mechanic to start with.

that was always the problem in the shops, the requisite attention to detail made rebuilding one of the engine's a significantly longer
prospect than building a cummins or cat engine. shop foreman and management never understood that and were constantly bitching
about the extra time needed to properly rebuild one, frequently stating "joe can build one in half the time" or somesuch
never understanding that "joes" engine's never lasted much past warrantee.

and that is how detroits got a bad name as being an oily pig, that leaked everywhere

build them right and they did a good job, and didn't leak that bad or any worse that other engine's
build them wrong and they were a mess, more got built wrong than got built right (even by detroit diesel shops)

bob g

mobile_bob

now in fairness some plusses

the liners if oem manufacture are very hard, so wear properties are quite good
the compression rings (4 of them) are stainless allow, the top is also teflon coated on the sides
there were multifuel injectors available for the engine's that would inject and burn just about
anything flammable,
the unit injector is capable of 20k psi injection

the piston crowns are oil cooled, there is a gear pump for pumping fuel
the camshaft lifters are roller tipped

the quality of castings and machinework are second to noboby in my opinion.

i suspect a good rebuilt 2-71 running in a stationary application at 1200rpm
and that is fed clean fuel, clean air and has its oil changed on schedule will make
10k hours no problem and likely many more with little more than the overhead being run
maybe every 3k hours

if the engine was rebuilt using genuine detroit parts (most especially the liner) i wouldn't
be afraid of it as long as i knew it was taken completely down and cleaned properly.
and the engine was broken in properly, which it should have been because it has a genhead
attached to it.
bob g

Wizard

Well, I was thinking of doing a 2 or 4 cylinder 4 stoke around 60-100hp if enough rpm can be attained (2 to 2.5L range) for engine conversion in a vehicle.  Complete wrecked or good car with VW 1.9 TDI is hard to find at reasonable price point.  I'd rather a mechanical injector pump type with advance mechanism.  Googling and looking at websites, I find some but not much info.

Can't hurt to dream and see what others thoughts chimes in.

Cheers, Wizard