Valve train geometry problem...
08-12-2003, 11:47 PM
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Valve train geometry problem... I have a set of A&A Stage 1 heads. They have over size valves and milled .040" and worked well with MMS 224/224 .571/.571 114LSA cam. I am building another motor and decided to use these heads again and had them freshened up. But it didn't pass the clay Piston to Valve test. Without gaskets, the valves actually dented the piston slightly. Very minor dent but it don't think it will clear. Here are the specs on the current set up:
cam: 226/230 .569/.572 comp cam XE grind.
Heads: A&A stage 1 heads milled .040" and freshened up with a .003" cut. Over size valves.
Pushrods: Thunder Racing Heat Treated Chrome-Moly Pushrods, 7.350"
Lifters: Stock OEM.
Bottom end is not touched.
Gasket will be stock GM composite gaskets.
I put the head on a flat surface and measured the valve travel before it hits the flat surface, here is what I found:
Intake: 0.142"
Exhaust: 0.175"
I am suspecting the heads are milled more then I was told, that are your thoughts?
Thanks
cam: 226/230 .569/.572 comp cam XE grind.
Heads: A&A stage 1 heads milled .040" and freshened up with a .003" cut. Over size valves.
Pushrods: Thunder Racing Heat Treated Chrome-Moly Pushrods, 7.350"
Lifters: Stock OEM.
Bottom end is not touched.
Gasket will be stock GM composite gaskets.
I put the head on a flat surface and measured the valve travel before it hits the flat surface, here is what I found:
Intake: 0.142"
Exhaust: 0.175"
I am suspecting the heads are milled more then I was told, that are your thoughts?
Thanks
08-13-2003, 12:24 AM
#2
Re: Valve train geometry problem... When I originally built the heads for Andy, the heads were milled .040". You can try measuring the overall head thickness with a pair of vernier calipers. Measured at one of the ends of the head (valve cover rail to deck surface), you should measure 4.710". Any less than that means that the heads have been surfaced more than .040".
Hope this answers your question. If not, please email me.
Good luck,
Richard
Hope this answers your question. If not, please email me.
Good luck,
Richard
08-13-2003, 12:54 AM
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Re: Valve train geometry problem... Thanks Richard, I don't have a vernier caliper but a dial caliper. It measured 4.720", which indicates my caliper is off 
I am not questioning your work as the heads were fine with the 224 cam. It's just with this new 224 cam and the refresh deck of .003" I am having problems.
I am not questioning your work as the heads were fine with the 224 cam. It's just with this new 224 cam and the refresh deck of .003" I am having problems.
08-13-2003, 09:22 AM
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Re: Valve train geometry problem... I put the head on a flat surface and measured the valve travel before it hits the flat surface: Intake: 0.142"
Exhaust: 0.175"
Is that enough distance?
Exhaust: 0.175"
Is that enough distance?
08-13-2003, 10:06 AM
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Re: Valve train geometry problem... Good thing you checked PVC. I suppose you could always flycut the pistons...
One of the sponsors has a special head you can rent with no seats that is used with a cutter tool. this can be done with the motor in the car.
search here for posts on this....i think it was a popular topic when i did my milled heads about 4-5 months ago.
One of the sponsors has a special head you can rent with no seats that is used with a cutter tool. this can be done with the motor in the car.
search here for posts on this....i think it was a popular topic when i did my milled heads about 4-5 months ago.