I'm putting together a build next week, and I've been putting together parts for it.
A couple things I'm uncertain of:
I bought some 302 parts from a fellow who built a 1990 engine with gt40 heads, exactly the same as mine, so I figured they'd be compatible but I double checked and I had a question.
He had some brand new, PBM performance products chrome molybdenum pushrods. They are 5/16" x 6.350.
When I looked up pushrods in rockauto, I'm supposed to have 6.250
Well, I already bought these from him, and I like the idea of installing heavy duty pushrods just because I can: will 6.350 work?
Will my hydraulic roller lifters take up the tenth of an inch difference, or will I cause problems for myself, collapsing lifters or holding valves open, etc.?
whatever the benefits of chrome moly pushrods, if these are not a workable size I don't want to use them. But, maybe they are.
Second question.
I chanced into some brandy new ford racing 1.6 ratio roller rockers.
I'm still running stock rockers, which I believe I simply torqued the bolt down to 25 lb feet or something like that.
I'm confused, though, on how this works... the hydraulic lifters have a range, and are designed to bleed down or pump up to just take up the slack/lash in the rockers and no more (or they'd hold a valve open), no matter what the height, within a range.
So the instructions supplied with ford racing seem to tell me to just torque it down until the pushrod is clamped tight, then back off until I can rotate the pushrod? Without oil pressure to pump up the lifter, I'm really not sure how this works... I'd like some guidance with the proper way to install and possibly shim, roller rockers. Pedestal mount (stock gt40 heads).
Final question.
When I did my gt40 heads as part of a community college rebuilding class, we used a drill-mounted reamer to do the valve guide sleeves. Naturally, they all came out just subtly crooked. When I went to hone the valve seats, I found myself cutting more on one side than the other. So, I sent them to a machine shop, which then reinstalled seats to match my slightly off sleeves so they valve sealed and seated correctly.
This does mean that my valve stem tips, are probably off a little bit with respect to the rockers. The car seems to have been running just fine for the last year.
Will slightly crooked valve tips, do less well with roller rockers than they do with stock stamped steel rockers, is this a serious issue?
My machinist seems to think it'll work out fine, so I'm hoping that's true.
thanks for the answers and advice!
-Bernard
A couple things I'm uncertain of:
I bought some 302 parts from a fellow who built a 1990 engine with gt40 heads, exactly the same as mine, so I figured they'd be compatible but I double checked and I had a question.
He had some brand new, PBM performance products chrome molybdenum pushrods. They are 5/16" x 6.350.
When I looked up pushrods in rockauto, I'm supposed to have 6.250
Well, I already bought these from him, and I like the idea of installing heavy duty pushrods just because I can: will 6.350 work?
Will my hydraulic roller lifters take up the tenth of an inch difference, or will I cause problems for myself, collapsing lifters or holding valves open, etc.?
whatever the benefits of chrome moly pushrods, if these are not a workable size I don't want to use them. But, maybe they are.
Second question.
I chanced into some brandy new ford racing 1.6 ratio roller rockers.
I'm still running stock rockers, which I believe I simply torqued the bolt down to 25 lb feet or something like that.
I'm confused, though, on how this works... the hydraulic lifters have a range, and are designed to bleed down or pump up to just take up the slack/lash in the rockers and no more (or they'd hold a valve open), no matter what the height, within a range.
So the instructions supplied with ford racing seem to tell me to just torque it down until the pushrod is clamped tight, then back off until I can rotate the pushrod? Without oil pressure to pump up the lifter, I'm really not sure how this works... I'd like some guidance with the proper way to install and possibly shim, roller rockers. Pedestal mount (stock gt40 heads).
Final question.
When I did my gt40 heads as part of a community college rebuilding class, we used a drill-mounted reamer to do the valve guide sleeves. Naturally, they all came out just subtly crooked. When I went to hone the valve seats, I found myself cutting more on one side than the other. So, I sent them to a machine shop, which then reinstalled seats to match my slightly off sleeves so they valve sealed and seated correctly.
This does mean that my valve stem tips, are probably off a little bit with respect to the rockers. The car seems to have been running just fine for the last year.
Will slightly crooked valve tips, do less well with roller rockers than they do with stock stamped steel rockers, is this a serious issue?
My machinist seems to think it'll work out fine, so I'm hoping that's true.
thanks for the answers and advice!
-Bernard
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