65Z01

If the roller is below the sides of the rocker tip they are NOT self-aligning, as my CC catalog indicates.

So you need hardened guide plates (4802-8, raised or 4810-8, flat) for 3/8 studs & hardened pushrods (7808-16).

corvette1990

Thanks, I am straight now. As I see they are non-aligning and need the str0nger guide plates. I already have the COMP HD pushrods. where did my xmas summit catalog go? Oh its online...nm..... :party:

blk90rdstr

So let me get this striaght. The factory installed guide plates would be in adequate to use non-self-aligning RR?
If so what size pushrods does a 90 have?
And will I need to change studs for guideplates?

LD85

I agree with the short pushrod scenario

86Moon

I have talked to the original owner. I am not clear as to why, my understanding is that he was attempting to reduce some valvetrain noise, but he hogged out the the rockers wiht a dremel. He also told me that this had been discussed with a builder who had seen this or done this to a greater or lesser extent. Apparently it didn't help and he never got around to changing the rockers out. I don't know why the poly locks were so short.

I have the new Promags and hope to put them in and have them adjusted ove the weekend. We will check the pushrod length at that time. Assuming we get that done I have a few other small things (hopefully) to button up and will tow it to the mufffler shop on Tuesday and drive it home from there :rolleyes:
We shall see :skep:

65Z01

blk90rdstr, yes neither your OEM pushrods nor the guide plates are hardened. When you pull the guide plates you will notice that they are not scuffed, because the push rods have not touched them. They were used only during assembly to roughly index the pushrods.

So you need to pull the rocker studs to install hardened guides.

Your OEM pushrod length is 7.195" x 5/16" dia.

I wanted additional valve train rigidity so I installed 7/16" studs (stock are 3/8"), hardened guide plates and ProMagnum RRs for 7/16" studs.

JAKE

Sorry to read about your problem.

Who set up the valve train geometry on the engine?

Where'd you get the rocker studs, lifters, pushrods?

Others have already said it, but you never use self-aligning rockers and guide plates at the same time. One or the other, and the ones that came on the engine aren't realy guide plates, they're only used during assembly and should be discarded and actual guide plates installed if you opt to go that route.

Jake


[Modified by JAKE, 1:19 AM 12/27/2003]

86Moon

Jake, I bought this motor from a forum member and it has about 10,000 mi on it. http://forums.corvetteforum.com/zerothread?id=622923 It was in the car running at the time I purchased it. I had someone I trusted meet the guy and drive the car. There were no extensive diagnostics done at the time. I have reciepts for many of the new parts and machine shop labor. It's not clear to me who set up the heads after they were received from AFR.

JAKE

I just visited the link. Sounds like a really nice engine with some excellent parts.

Seems that it was just a matter of the geometry not being set correctly. Shouldn't be difficult to straighten that out.

Valve train geometry is one of those areas that far too many people fail to pay attention to; not at all uncommon.

Jake

Trog

Just another $.02... When I origionally installed my non-self aligning 1.6 rockers, I installed new 7/16 studs & used the stock guide plates for about 2 years. They worked okay but because those guide plates weren't hardened they began to wear. At the rebuild, I replaced w/ hardened & all is well again.

86Moon

Damn, things sure move fast around here! Last post on page two already! Thanks everyone for your help. :flag Turns out the guys who said they were running both recanted after further investigation, but they did get the rockers in for me. The springs had been hitting on the bottom at some point as well. The engine sounds good. Hope there is no major damage.



She's gone to the exhaust shop today. :D