Shimming Hydraulic Tappets - Thoughts?

[tasmania]

Had a guy call ref my 4.6 V8Devt motor which has been for sale.

Engine has competition hydraulic followers, Ray's top draw Hydraulic related cam, etc.

The chap interested asked if the followers been shimmed and was adamant they needed to be! I thought the followers sat directly on the cam and the push rods sat in the followers, which is why the rods to followers and followers to cam have to always be replaced as removed.

Also often the issue on V8's is the cam followers stop rotating and the cam wears a groove in them!

Never heard of shimming a hydraulic engine - am I mistaken?

TaS

[pistolar]

when i did the cam and followers on my 400, with the kit i had shims but they went under the rocker pillars



dont know if this helps

[dickymint]

Pretty sure that they need to be shimmed. Mine were when I had upgraded cam fitted on the 350. RPI have a good article on it here...www.rpiv8.com/engine-4.htm#pre-load

[number 7]

The pre-load needs to be set on the hydraulic followers, so shims are used to pack under the rocker pillars. Obviously need to use the same under each pillar, although this may result in some small differences in actual preload across all of the followers. I presume you've also got Rhoades or similar Hi-Rev followers - just delays the point at which they start to pump up.

7.

[deetes]

Hydraulic tappets have no adjustment. The only type of engine that would require shims for valve clearance adjustment are OHC engines with bucket and shim cam followers.
Methinks the guy that asked you about the shims has been misinformed, possibly by someone by someone who had also been misinformed.

[dickymint]

Shims go here!!

[GreenV8S]

dickymint said:

Shims go here!!

What he said.

[tasmania]

Cheers
Makes sense and not quite as it had been explained as it was suggested they went between the cam and follower!
Rocker pilar as shown is as per Ray's work.
Ta Muchly.
TaS

[Boosted Ls1]

You only fit shims if you need to. Stock engine with all stock parts won't need shims. Soon as you skim the heads, fit different gaskets or pushrods or anything like this then you should measure plunger clearance in the lifters.

Boosted.

[grahamw48]

Now that's what I call a quality thread.

[rev-erend]

Boosted Ls1 said:

You only fit shims if you need to. Stock engine with all stock parts won't need shims. Soon as you skim the heads, fit different gaskets or pushrods or anything like this then you should measure plunger clearance in the lifters. Boosted.

I was wondering why you would need to shim - great reply .. really obvious really..