Tappet rotation (not)

[veggie]

The intake tappet and pushrod on my new 6/1 is not rotating.
What needs to be done in order to correct the problem?

Cheers,
Veggie

[mbryner]

It's times like these where all that old info from listerengine.com would come in handy.....

Do the guide turn trick first.   It only took about 1/8-1/4 turn of the guide to get mine spinning freely.   Really simple.

Marcus

[XYZER]

veggie,
The tappets are ground flat.....the cam is offset to induce turning. Marcus has the right idea...I loosen the clamp and rotate the guide tighten the clamp while it is running and see what happens it might take a couple of times until you find the sweet spot. Both of my 6/1's had the same diease and the fix worked on both.

[Ronmar]

Jens hit the high points.  The tappet face must be perpendicular to the tappet shaft, and the tappet guide bore must be perpendicular to the lip of the guide that sets on the engine case.  Crap under this lip can cause the guide to set at an angle and mess with rotation.  Indian machine work being what it is,  The tappet face and the guide bore do not always come out true.  Rotating the guide may bring the sum of these machine errors into alignment.  You can put a little downward pressure with your finger on the adjuster screw/nut on top of the rocker arm while the engine is running to help get things spinning and gauge how effective the rotating of the tappet guides are with helping the rotation to occur.

Drag in the system also plays a factor.  Mine don't like to rotate till I get the engine up to a good huffing load and full op temp.  This loosens things up a little bit and they rotate a lot more freely when warm.  I also had issues with my push rods seating too tight in the cups on the top of the tappets.  I had to polish mine with lapping compound to free them up so they would rotate easilly.  A little drag here can impede the rotation as the rod comes under compression working the rocker arms.  To polish the cups, put a dab of lapping compound into the cup on top of the tappet and the cup on top of the pushrod and install the pushrod.  You can adjust the valve adjusting screw and nut to put a little preload on the pushrod.  Wrap a shoelace around the pushrod a few times and pull back and forth on the ends of the laces to rapidly spin the pushrod and this will polish the cups and ball ends so the pushrod spins freely in the cups.   You may have to start out with almost no pressure on the pushrods to get them to turn in the cups. You may also have to gently clamp the tappet shaft to keep it from rotating.  Occasionally remove the pushrod to get fresh lapping compound down intothe cup.  When done throughly clean out the lapping compound and re-assemble the pushrods with fresh oil.

I have a little over 80 generator hours on mine now, and they still never set into a truely free rotation regardless of guide position.  I wound up adding a small spring set on top of the valve spring cap that gently pushes up on the bottom of the rocker arm.  this keeps a gentle pressure and tension throughout the rocker/pushrod and tappet assembly and allows the tappet to follow and get rotation force applied from the backside of the cam lobe.  

I can put up a pic of this spring if you like.    

[BruceM]

I'd love to see your spring arrangement, Ronmar. 

I have good tappet rotation, but the tappets are clacking down on the cam very loudly- they do not follow the cam well.  The clack-clack of the tappets is the loudest sound of my engine.  Perhaps your spring arrangement would help with this.

[Ronmar]

When I initialy put a little downward pressure on my pushrods, they bound up in the cups.  The cup bottoms were poorly machined, a little tight and not smooth.  The rod ball ends were not too bad.  I was able to polish the cups smooth and get free rod rotation in about 10 minutes each using the shoe string and lapping compound.

Bruce, I will post a pic a bit later.

[XYZER]

I have found the Indian supplied clamps with the mushy gaskets will induce a tilt in the lifter guide causing no rotation. If you over tighten the supplied clamp it will apply preassure on the inside edge causing the guide to tilt. The preassure needs to be on centerline so as not to tilt the guide......a dab of paint on the lifter will give you a visual of rotation....

[Ronmar]

Bruce
   Here is a pic, sorry it is a little blurry, I think the camera had a hard time autofocusing on the shiny surfaces.



Dave
   I don't have gaskets under my tappet guides.  They set metal on metal, but The stamped clamp plates do leave much to be desired.  I believe several have re-engineered those clamp plates.  I know Ihave thought ablut doing it, but everythig is working pretty well now, so it is a lower priority for me...

[BruceM]

Ronmar- How are your load springs held in place? It looks like a delightfully simple solution to my tappet clacking. Nice!

[Ronmar]

They are just wedged in there...  There are two springs, one inside the other.  I had one set, but they were a little weak.  Tje second set I bought was also a little weak.  I put one inside the other and that was just right:)

[BruceM]

I thought I saw something inside the outer springs in your picture!
This looks like just what my clacking tappets need, and your fix couldn't be easier to implement. 

Thank you Ronmar!

[dubbleUJay]

Ronmar, this idea of yours is great, I also heard the clanging on mine and if I applied pressure by hand downwards on the rockers, it goes away.
What bothers me though is the side pressure the springs are putting on the valves and also that the springs might wear into the rocker.
What about a single spring on the outside between the two push-rods, connected at the bottom to the nut holding the "cradle" and at the top to some sort of T-piece resting on both rockers?

I'm not shooting you down, just some "preventive maintenance" 
I will definitely do this mod some time when I get a change.

dubbleUJay

[Ronmar]

I don't think there is any real side load on the valve as the spring is nearly vertical.  The added spring pressure is also just a fraction of the valve spring force.  How much hand pressure does it take to quiet your rockers?  Those springs are only providing that much force...  I had tension springs initially setup like you described connected from the rocker arms down to the tappet guide cradle bolt.  That worked also, and was my initial test of how this worked. But it put a little side load on the rockers and that concerned me.  That is where i came up with putting it under the rocker as it caused no side load.  I am not sure how a single tension spring with a cross bar would hold up under the alternating rocker action. I had thought of making a different hold down bar for the tappets.  It would be an easy thing to add a tab right under each rocker so you could add a tension spring that is in line with the rocker and pushrod.

I don't think the springs will wear much on the rocker where i put them.  I don't think there is any real movement between the top of the spring and the bottom of the rocker.  I only have about maybe 5-6 hours  with the springs in place, but they have not moved any

[cujet]

My tappet surfaces were horrible. The reason they did not rotate is that the surface was off by about 40 thou of an inch! I ground the tappets flat on my lathe, using an air powered long nose die grinder. Here is a video of my grinding process. It worked perfectly and my tappets rotate like they should.

http://www.f1-rocketboy.com/images/743375941_ORIG.mov

[veggie]

My tappet surfaces were horrible. The reason they did not rotate is that the surface was off by about 40 thou of an inch! I ground the tappets flat on my lathe, using an air powered long nose die grinder. Here is a video of my grinding process. It worked perfectly and my tappets rotate like they should.

http://www.f1-rocketboy.com/images/743375941_ORIG.mov

Thanks for tip on grinding. I do have access to a machine shop so upon inspection, I too may end up grinding the faces.

Cheers,
Veggie