Hello.

i´m rebuilding my 1931 45" scout engine.

i´m in need of the clearances for the push rods in the push rod guids an from the valve lifters on there shafts.

thanks in advance, for your help.

Thomas from bavaria (germany)

Bob Sneberger wrote:

I am unable to find this information, but if you want to use the Ford model A engine as a reference which was built from 1928-1931, the lifter bore clearance is 0.0015".  Since both the Ford and Indian are from the same era, I would guess that the clearance is also close.  I don't know if this helps, and good luck.

Bob

Thanks Bob

I think it would be good, to put those Infos in the B&O

Greatings Thomas 

Military manuals for 741 and sport scout give 0.002" for clearance. I would call that bare minimum, total loss motor running a good bit hotter.

A little more isn't a disaster, considering  age and potential mileage. Oversize lifter shafts available.
All that is likely to happen in the short term is a little more noise 

Bob, for reference, Model A watercooled, so operating temp likely to be a fair bit lower.
Replacing guide blocks is a last resort, imho, never seen replaced guide block not leak oil around base. Have seen several broken cases where guides have been removed carelessly.

The guide will most likely be worn into an hourglass shape wider at the top and bottom. Oversize pushrod might go well with a light hone of guide.

As we are not dealing with Nascar level of tech, it may be better to leave well alone. What clearances do you have now ?

Have heard of helicoil like guide liners available, never seen in action, assume designed for valve guides of softer material, anyone have any direct practical experience of these ?

Exhaust pushrods have a groove to allow for lubrication. There were some nice repro ones availabe with a spiral groove for improved oiling, not sure if they are still availabe anywhere. Does anyone know?

T

Tim Raindle wrote:

Military manuals for 741 and sport scout give 0.002" for clearance. I would call that bare minimum, total loss motor running a good bit hotter.

A little more isn't a disaster, considering  age and potential mileage. Oversize lifter shafts available.
All that is likely to happen in the short term is a little more noise.

Thanks for all the input.

I go for a 0.0015 clearance on the push rods

i´m still unsure on the clearance from the valve lifters on there shafts.

Here is a quote from Jim Mosher's Web Page: (i hope he dosen´t mind)

Most people don’t have the luxury to be able to remove their push-rod guides like me, but when I do, I always rotate the guide so that any inside groove would be pointed outwards to the right. This is to keep a push rod edge out of any groove. It’s for better alignment, and it will extend wear. Then hone the guides for a new over-size “spiral groove” push rod set for a “loose .001” clearance. Make sure your valve adjusters are new, or in good shape. They are going to be working harder!

   Before you install the lifters into the motor, soak the lifter rollers in a small cup of 50Wt. oil to get some more oil in the roller needles. Roll them through a few times. Then use common grease on the pivot pins and holes, then on the Arched Pad, and the push-rod guides. Grease is good to break-in new parts. Important! Any time you wash your motor, always start it for a minute, or kick it over several times. Scout valve covers don’t seal out water. A drop can, and will, run down against the cam lobe, and rust the edge where the roller meets the cam. Both pieces are probably ruined.    I’ve done it.