Thread: 3.9 Lifter/Pushrod Preload

I looked at the kits available from OS when I did my build and then decided to make mine. Not that hard.

Anyone know of a source of rocker pedestal shims in Australia?

You can easily make them yourself if you buy some brass shim material .
You cut a shim the same size as the bottom of the pedestal , which is about 25MMx 12MM. You have to then drill 2 holes or an oval hole to allow the oil to go up the back or front pedestal.
When drilling brass shim, sandwich it between 2 bits of ply.

I have done it many times , and as long as preload is over say 010 they tappets will be quiet. The bigger the preload the more likely they are to "pump up" at 5000RPM plus unless you use crane anti pump up lifters.
BUT even 50-60 thou should be no problem.

Re dry vs wet. I love this one, as who EVER puts lifters in dry? It doesn't matter as you will always be doing them cold in which case they will have leaked down any excess. The pre load will be greater with oil but IMHO it does not matter.
Regards Philip A

I did this a while back... see Adjustable push rods / roller rockers on 4.6 V8? post #8.

The original preload measurements were taken on the assembly with lifters straight out of the box. I then dismantled the rockers etc and put the required shims under the rocker posts. The lifters were then bled and the valve gear reassembled.

Don't forget all rocker posts on the same bank have to be shimmed the same.

good luck with it!

Originally Posted by PhilipA

You can easily make them yourself if you buy some brass shim material .
You cut a shim the same size as the bottom of the pedestal , which is about 25MMx 12MM. You have to then drill 2 holes or an oval hole to allow the oil to go up the back or front pedestal.
When drilling brass shim, sandwich it between 2 bits of ply.

I have done it many times , and as long as preload is over say 010 they tappets will be quiet. The bigger the preload the more likely they are to "pump up" at 5000RPM plus unless you use crane anti pump up lifters.
BUT even 50-60 thou should be no problem.


Re dry vs wet. I love this one, as who EVER puts lifters in dry? It doesn't matter as you will always be doing them cold in which case they will have leaked down any excess. The pre load will be greater with oil but IMHO it does not matter.
Regards Philip A

Where did you get your shim material PhilipA?

Most bearing retailers will have shim material in varying thicknesses .

Landy mates,
Took the wuss option and ordered shim kit from Rimmer bros. Made some probes in sizes 20 thou to 80 thou and set to with adjusting preload. Really hard to get in there with a hooked bit of wire and accurately see the gap - some say gap between circlip and top of lifter piston. Others say bottom lip of recess for the circlip to the top of the piston??? Don't know how anyone gets it that accurately anyway.
Could not get a shim thickness that brought all lifter clearances within limits on the first bank tried - two were still too large a gap.
Looking more carefully and found the cam lobes worn half down on these two and hardly any lift at all! @#$%! New camshaft and rest of lifters to make a full new set on its way.
So hard to believe the wear on the cam lobes and some of the lifters when all was replaced new, including pushrods, rockers, shafts, valves, timing chain and sprockets only 55000km ago. And me a religious oil changer with Castrol every 5000km. Must have been the overheat and few hundred ks running before leaking head gasket became apparent. Hate to think where all the swarf worn off the camshaft went - into the main and conrod bearings metal?

Originally Posted by aRRon

Landy mates,
Took the wuss option and ordered shim kit from Rimmer bros. Made some probes in sizes 20 thou to 80 thou and set to with adjusting preload. Really hard to get in there with a hooked bit of wire and accurately see the gap - some say gap between circlip and top of lifter piston. Others say bottom lip of recess for the circlip to the top of the piston??? Don't know how anyone gets it that accurately anyway.
Could not get a shim thickness that brought all lifter clearances within limits on the first bank tried - two were still too large a gap.
Looking more carefully and found the cam lobes worn half down on these two and hardly any lift at all! @#$%! New camshaft and rest of lifters to make a full new set on its way.
So hard to believe the wear on the cam lobes and some of the lifters when all was replaced new, including pushrods, rockers, shafts, valves, timing chain and sprockets only 55000km ago. And me a religious oil changer with Castrol every 5000km. Must have been the overheat and few hundred ks running before leaking head gasket became apparent. Hate to think where all the swarf worn off the camshaft went - into the main and conrod bearings metal?

1. Doesn't say much for Castrol oil, never heard good reports on it for flat tappet engines, I've always used Penrite oil, which is high in zinc. I don't have worn cam problems.
2. There's this thing called an oil filter on your engine, it's supposed to filter all the oil before it gets to the main bearings. Depends on how good your filters have been.