PavelCZ

Hi, I would like to find out if my corvette have flat-tappet cam or roller.

I tried to find the answer here at forum, but I found different informations there.

First I found that roller is from 87 and everything until that is flat-tappet.

But than I found that 86 with aluminium heads is already roller, so I don't know wich information is correct.

I attached my building sheet, maybe it can be found there, but I don't know where.

Thank you, Pavel.

WVZR-1

An '86 that is "untouched" is NOT a roller.

Your engine code on the build sheet is the ZJW - if that's on the block pad in front of the RH cylinder head you can assume that it's original to the car.

kenmohr

What year did they start the rollers

WVZR-1

For the 5.0/5.7 SBC - '87 but other GM had it earlier. All '87+ SBC weren't either. They were quite application specific.

PavelCZ

That means I should add zinc into oil to protect flat tappet cam?

WVZR-1

Yes I'd think but amount gets debated/argued from time to time. How difficult to source correct lubricants there in CZ? Is that the correct Country Code or is it CZE?

VikingTrad3r

pavel, i use quaker state defy, it has elevated zinc levels. there are others with higher zinc as well but this is local to me so i use it. you might not need an additive if you use an oil with it already in. cheers.

vader86

All 86 have hydraulic flat tappet cams, early or late head model. 87 got the roller cam.

I did not ever add any specifically-labeled high-zinc oils or any additives to my 86 and the cam was fine when I finally took it all apart for the new engine at 160K. I used Castrol GTX when I bought it and Mobil 1 Synthetic after that.

KSA Aaron

I thought the late '86 convertibles got the aluminum heads and the roller cam.


Hmmmm.....

vader86

Negative. '128 head only. No roller.

Benny42

Mine has a flat tappet cam and no provisions for the roller hardware. I swapped cam & heads last fall from '128s. I've heard the legends too, but I know what I found in my '86l.

PavelCZ

Ok, and what amount would you recommend?

I tried to find some zinc additive at Czech e-shops with oils and I wasn't successful. But I will try to ask for some additive or ZDDP oil in local oil shop.

CZ is good.

KSA Aaron

I believe your car is a coupe, so still supports my theory.


1986L convertibles only had the roller cam and aluminum 128 heads.

WVZR-1

OP - looking at the RPOs it appears to me that "maybe" your car was actually intended to be exported by the buyer. Do you know for a fact that it was purchased and shipped from the US to "somewhere" when new. It would be unusual for a UL5 RPO for anything other than a car intended to ultimately end up in an other than US market.

That's the more unusual thing that I noticed from the build sheet.

I don't know that in the mid '80s there would have been good reason to maybe "DELETE" any radio option. It's certainly interesting.

The car "for sure" I'd say wasn't for a dealer stock order.

Benny42

Not to get in a wee-wee contest with you or anything, but the convertibles weren't the last 1000 cars off the line in '86 or anything like that. Last six digits of the VIN is the sequence number. Mines 21,620 what's yours?

PavelCZ

I bought this Corvette 9 months ago in US and shipped to CZ by myself.
From history that came with the car, I can deduce that it was in US until I bought it and that the first owner probably made the order directly for himself.

Only explanation is that he may already knew that he will install radio with CD. Because in car is now system from blaupunkt with CD, that actually looks like for mid '80s.

ghoastrider1

my 86 has alum heads and flat tappet cam

Ray Quayle

My '86 Convertible was built near the end of production and had a non-roller block and '128 aluminum heads.

KSA Aaron

Now this actually refutes the theory. Interesting!


You have the aluminum heads, but not the roller block.

KSA Aaron

The legend was never about the later Vettes off the assembly line. It was always the '86L convertibles.


And I have no idea what sequence number my convertible may be, but being as I know it was built very early '87 model year, it really is irrelevant.