Probably a simple rocker question...

[Dablaze]

Hi,

I am working on a friends '58 and found that the intake rocker is tapping the inside of the cover. I believe that I heard that this is common. The rocker itself has a touch of weld (pushrods end) that seems to be the culprit. Two questions, what would be the reason for the weld and is the solution to just take this down some?

Thanks,

Craig

image.jpg

[Jerry Wieland]

Culprit is not the weld but either you have a short stemmed valve or the rocker arm at the valve stem has excess wear. I've seen both be a problem.

Jerry

[Dablaze]

Ok, good point, but it does seem to have a pointy tag that's not illustrated in the lousy pic.

I will go through every thing though. Thanks!

What's the reason for the weld, there's a blob on every rocker. On the pushrods side.

Craig

[Robert Luland]

oil passage.

[motorhead1]

Culprit is not the weld but either you have a short stemmed valve or the rocker arm at the valve stem has excess wear. I've seen both be a problem.

Jerry

True. Also consider that the rocker arm pad could have been ground to clean up the valve stem wear and too much was removed. A problem I see a lot is when someone has tried to compensate for valve seat recession by installing an oversize head valve and not cutting the seat to get proper stem protrusion. You can tell if this is the case by measuring the installed height of the spring assembly. While they wont be exact on a worn engine, both spring heights should be very close.

[larry]

You can file it flat but not through to the passage.

[Dablaze]

Thanks all!

It's a rider, put together from used parts and aftermarket stuff, so nothing special. Most of the engine looked pretty new.

Could we just ball pecan a little clearance into the cover until it's time for a rebuild?

Craig

[BigLakeBob]

Thanks all!

It's a rider, put together from used parts and aftermarket stuff, so nothing special. Most of the engine looked pretty new.

Could we just ball pecan a little clearance into the cover until it's time for a rebuild?

Craig

Sounds like it is time for a head rebuild, not like you have to do the whole motor. You're in there, why not fix it right? It will haunt you down the road IMO.

[Dablaze]

Pulled the head, everything is fresh, good seats. I had the owner helping me out and at one point I looked at him and he had the pushrods in his hands and he was holding one of them upside down. I am guessing that that one might have been in the motor that way, which I think is the issue.

Craig

[motorhead1]

Craig, the photo you posted clearly shows the pushrods installed correctly, so that is not your problem. Remove the intake spring and check the stem protrusion. The specs are in the manual. If it's good then you have a rocker arm issue.

[billpedalino]

Craig, the photo you posted clearly shows the pushrods installed correctly, so that is not your problem. Remove the intake spring and check the stem protrusion. The specs are in the manual. If it's good then you have a rocker arm issue.

If the rocker arm is hitting the inside of the pan cover, my money is on an excessively deep valve seat. The service manuals for each model give the maximum valve height measurement from the top of the installed stem (no springs or collars) to the base of the valve guide. Being too lazy to pull out my books right now and without looking, I believe that the correct maximum distance for panheads is 1.75", but check that. If its more, the rocker arm will most likely hit the inside surface of the pan cover.

[Dablaze]

Ok, pulled the head, the valves sit nice and freshly proud, it's definitely a fresh build. I am not sure from the pic, but I am very certain that when I went back to the pushrods (I leave them in the tubes and sit them in the order I take them out) one of the rods was large ball up and one was small ball up. They are mated to adjustable tappets (I am assuming that this was a conversion kit, probably from Colony?)

The valve stems on the same head measure up the same out of the head, but that is measuring one exhaust and one intake...is that correct?

If I am wrong about the pushrods being upside down then it has to be the face of the rocker where it meets the valve, correct? Any way to determine this other than process of elimination?

Thanks again for all the help!

Craig

[Rubone]

If the rocker arm is hitting the inside of the pan cover, my money is on an excessively deep valve seat.

That only occurs on the valve end of the rocker, his is hitting the pushrod end, which generally indicates too little valve stem protrusion, the opposite problem.

Craig,
Check the stem protrusion. It involves removing the springs and collars, but is an important measurement. Just because the parts are new doesn't make the job right.

[larry]

Photo of pushrods and adjusters?

[billpedalino]

That only occurs on the valve end of the rocker, his is hitting the pushrod end, which generally indicates too little valve stem protrusion, the opposite problem.

Craig,
Check the stem protrusion. It involves removing the springs and collars, but is an important measurement. Just because the parts are new doesn't make the job right.

You're correct Robbie - I didn't see the photos and didn't realize that the interference was on the right side. Sorry for the misinformation Craig, short valve stems would be a first guess.