Longer pushrods, or can I use lash caps?

Setting preload on my roller rockers, and on EXHAUST only, I bottom out before the pushrod/rocker/valve is all making contact. I have about .010 space left in there. I tested it by sticking a .060 spacer between the valve and rocker and it worked almost perfectly.

Can I use lashcaps (or do they even still make those things)?

Or will I need to order 8 pushrods .060 longer than the rest?

Intakes all preload perfectly.

 

You should first find out why this is happening. Something has to be wrong. These are inline valve heads and if everything is set up properly, you would only need one set of valvetrain components.

Are the exhaust valve stems shorter than the intakes?

 

On this first page alone you have 7 threads open plus all the rest on the other pages.
It must be a record now!
Why not pay some one to build the motor and enjoy it for more than 6 months before something happens again?

 

No offense, but If you're gonna own a hot rod or what ever, you should build it yourself. there are only a couple of things I am going to farm out, like the body work, but even that, I may try.

Scott, keep plugging away at it. Are you sure all the rockers are the same, they didn't mis box them on you? did you compare all the rods to make sure they were the same, ore they for the heads that you are using? I'm not real sure, you are a lot deeper into your build than I was, I used all the stock parts, but gasket matched and polished the crap out of the heads and intake, so I knew everything that came out of the valve train would work. I do need to step up my springs though, I have a fairly hot cam and I think I'm floating the valves around 5500. Just keep going buddy, there's always a reason why things don't work the way they should

Shaun

 

i see "you don't understand" either...

...ILMAOD...

 

Maybe I should ask the question again...I guess I wasn't one of those special few who was born with all the knowledge needed to build an engine...

This is not a head question, this is a valvetrain question. Both heads are done and ready to install as soon as the paint is cured. There will be no more questions regarding the heads. You guys are welcome to keep bringing up the head question posts if you like. One is already 7 pages and growing, and half say use mixed heads, the other half say spend $2000 or wait until you can... It is my job to follow the 50% of the experts that are suggesting what is in MY budget.

 

AND...back on topic...

This is on the same head and rockers i used last time. Pushrods are new hardened stock 5.0 roller length, cam is new, lifters are used/new. So there are lots of NEW variables here. I have swapped the rockers and pushrods around and always end up with the same play on just the exhaust rockers.

I have no problem getting new pushrods. I have so many frankenstein parts here that there is no telling which part(s) have changed my geometry...

Fred, I will measure the valve stems first thing...I notice the exhaust valves that are in there have a small welded on cap (these are the GT40P valves), I am assuming a hardened piece on the end. I also notice that the springs lock on a little lower on the exhaust valve, but I think that is normal.

 

you could save...time and money if you would...ask... what part fits?
not...get a part and then ask...why it would not work?

...ILMAOD...

 

I did. I researched the part number/size, then upgraded to hardened Comp brand, put them on and there is play. THEN I asked this question.

Now, back on topic again...

Would a .060 longer pushrod fix this?

Or should i specifically look at something that might be wrong? I only have had one suggestion so far, and I am on the way out to measure the length of the valve stems.

 

Valve stems are exactly same length.

There is an extra .080 distance between the lock groove on the exhaust valve, but that shouldn't affect what is going on here. That just compresses the springs a little more on the exhaust valves.

 

Maybe you have a dual pattern cam. Very common. Exhaust usually is higher lift than intake.....so??????

 

I don't have my parts interchange book here so I can't check why that is, but I'm sure it's nothing significant. did you have new seats put in by any chance? I'm reaching here, without seeing it, I don't know, but it sounds like you have a very similar backround to machine work as I do.

 

Everything that affects preload needs to be considered. Things like valvestem height, rocker studs/stud bosses, rockers, pushrod length, lifters and base circle diameter should be investigated until you find the issue.

 

Very well could be the cam profile, Fred....it was a free cam from Rick Book. He used it on a nitrous 5.0 mustang and it was a custom grind and has pretty odd numbers. The problem is that he did not have the exact dimensions. I am getting a degreeing kit in a few days in the mail and will verify EXACTLY what I am working with.

That motor failed on him...wonder if he used stock components (pushrods) on this cam and had the same problems I am having without knowing it. His problem was lifter related...according to the conversation I had with his mechanic.

Thanks for the suggestions on where to look. The cam profile sounds like it has a very good chance of being the culprit.