Question: Mystry question on late 1986 cam for aluminum head '128 vert.

[Enuzio]

Hi everyone...I have a mystry question for you or someone.

Background: The engine in my 1986 vert has aluminum '128 casting heads. The valve springs are orange strip which according to GMPP are supposed to be chrome moly and only used in aluminum head with a roller cam or aftermarket. As near as I can tell they are stock with the exhaust valve rotators.

So the question is, given the valve springs, does the engine have a roller cam?

Can Hib or Grumpy weigh in on this?

 

[vetteoz]

So the question is, given the valve springs, does the engine have a roller cam?

What is the build date?
What is the block # ?
Has been previously mentioned some very late '86 cars may have got the '87 roller cam engine

 

[Enuzio]

Mystery Cam

What is the build date?
What is the block # ?
Has been previously mentioned some very late '86 cars may have got the '87 roller cam engine

Thanks vettoz...I have out of touch with reality for a while...family, work, and contemplating retirement....

The car was built on or about May 20, 1986 at 5:30 pm according to the build sheet....

The block number is covered over by the emissions components...

Cheers,

Enuzio

 

[Hib Halverson]

It is unlikely your engine has a roller lifter camshaft. 1987 was the first year for those.

Aluminum heads (late 86 intro on convertibles only) may have had the 87-spec valve springs.

 

[rayquayle]

It is unlikely your engine has a roller lifter camshaft. 1987 was the first year for those.

Aluminum heads (late 86 intro on convertibles only) may have had the 87-spec valve springs.

Late coupes also got the '128 aluminum heads, but I've yet to see any '86 Corvette block machined for roller cam. My '86 convertible that I bought new was built in July and the engine block is stamped 0627 and as you can see, there is no machining for a roller cam retainer or spider:

 

[Hib Halverson]

Late coupes also got the '128 aluminum heads,(snip)

Now that's something I didn't know. How many coupes were built with aluminum heads and do you know the break point?

 

[rayquayle]

Now that's something I didn't know. How many coupes were built with aluminum heads and do you know the break point?

Hib, You're joking, right?

As for aluminum heads, all 86 Convertibles had them and most late production Coupes had them. With the coupes, the exact break point between iron and aluminum heads is unknown, but Antonick's Black Book has stated for a number of years that "...it is believed that the last 8594 coupes had them."

I know you've reported on this many more times as well. As for break point, I've seen nothing to dispute Mike's assertion. The latest iron head coupe I've ever seen was 5119011.

 

[Hib Halverson]

Hib, You're joking, right?

Well...:duh...the easy way out would be to say, "Yes".

I know you've reported on this many more times as well. As for break point, I've seen nothing to dispute Mike's assertion. The latest iron head coupe I've ever seen was 5119011.

I have written so much and researched so much, I've forgotten some of those, old mid-'80s factoids. Thanks for reminding me, Ray.