Tappets Tap

[Dellb]

Hi All
I am trying to pick the brains of all you SBC buffs. Here is my situation.
I have been enjoying the weather and taking her out. Absolutely wonderful, a beauty to drive. There is however one thing that is bugging me. In my last mail about the gearbox, I mentioned that I was converting her to hydraulic roller cam. This has been done, with the fitting of a mild street Lunati voodoo setup, complete with new rods and comp cam roller (1.5) rockers. I was very fastidious
about setting the valve preload. But after a run, she is very tappety. All appears fine, I even put up with the mess to see oil coming up and out of each rod.
I have come to the conclusion, that the only way this could happening with an all new setup is by the rocker studs moving.
My heads are 1970 vintage ( Casting no’s 3947041) in superb condition With press in studs.
Has anyone come across this before, and is pinning a viable solution.

regards

Delb

 

[Oneball]

Have you reset the pre-load since your initial setup?

Did you set the tappets individually or using the 8 at a time method?

 

[Dellb]

No I have not fully reset the tappets. When I set then I did them individually to ensure the roller was on the base circle.

 

[Oneball]

I’d reset the tappets and see what it’s like.

Have you got self aligning rockers or push rod guide plates?

No experience of roller rockers on hydraulic tappets but used them in lots of race cars on solid flat tappets and they are noisy in that application.

 

[Dellb]

Those early heads do not need guide plates. There is a narrow slot, not a hole in the casting for the rods. The rockers are not self aligning, but I got a good mark on each valve stem.

 

[Oneball]

Doh! Forgot that about the small holes.

As you’ve changed the cam it’d be worth checking that the pushrod doesn’t catch on the sides of the pushrod holes as they move through their range.

 

[Roscobbc]

Setting pre-load on lifters is always a faf. Doesn't help when it takes so long to do it and the engine has cooled down. The cam on mine although a flat tappet hydraulic is more like a roller cam and fairly noisy. What does manufacturer say about preload? - is it zero clearance and 1/4, 1/2 or 3/4 turn before locking-off?

 

[Roscobbc]

Try this method - problem is that it works best when engine is hot and oil hasn't drained out of lifters - so by the time you've removed all the plugs (to make rotating engine easier) the engine is starting to cool off........and once you do the last couple of valves its definately too cool.....so you do it again. And again if need be. You'll soon know if you need to as the 'clickity, clickity' will tell you.