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06-12-2011
I have stock heads SI oversized valves, manley retainers, comp cam keepers, and crow cam springs everything is supposed to give a 1.8 install hieght and its coming up to 1.750? anyone run into this?
I was told by SI vavles that the valve may need to be sunk more into the seat and my machinist laughed and said he has never seen that before?
06-12-2011
Are they ,(SI), suggesting you remove material from your valve seats to gain the correct installed spring hieght?
06-12-2011
manley valves or ZZP's?
If manley, intense claims:
Overall valve length is the same as stock and the keeper groove is in the stock location.
06-13-2011
Yes they are SI valves and I was told they are the same length and my machinist measured them but they come up short. SI told me he has to take more out of the valve seat which he is totaly against he said they will be way to thin and he as never had to pull that much out of a seat in the 30 years he has been doing race motors.
06-13-2011
the valve are exactly the same as stock valves as far as lenght retainer location everything other then they are oversized so the head diameter is bigger of course
06-14-2011
Here's a bit of info that I found out when having a set of worked heads checked out.
Stock spring installed height is ~1.72X" with stock retainers
Spring installed height with LS retainers is ~1.78X"
LS springs say they have an expected install height of 1.800"
The heads are 3800 heads, the springs are LS type springs. To get the correct install height of the spring, you have done the proper work and ensured the valves are the right length. Knowing this means that even stock your install height was wrong for the spring spec you have. Therefore the fix is to machine down the spring seat. This can and will correct your heads for a spring install height issue if the valves are confirmed to be correct.
It appears there is some confusion between spring install height and valve seal clearance. To gain clearnace on heads meaning for the valves to open further you can and commonly on our heads we miss the valve guide down to increase the distance from valve seal to valve spring retainer. This allows us to lift up into the .6xx's"
06-15-2011
But according to everything I read all the items I am using should come up to a 1.8 install hieght that is what I was told was stock on these motors and its coming up 1.750 and my machinist never milled any of these valve spring seats so he isn't even sure if there is enough material there to machine with out hitting a cooling port or ect.
These springs INTENSE-Racing.com: Crow Cams 130# Valve Springs
These retainers INTENSE-Racing.com: Manley Performance Valvespring Retainers
These keepers and or locks INTENSE-Racing.com: CompCams High Performance Valve Locks
These seals and machining the guides down a bit INTENSE-Racing.com: Viton® Valve Seals
These valves biggest ones they make for exhaust and intake ZZ Performance
This cam ZZ Performance
06-15-2011
That's all cool, I don't see where it says those retainers will ensure a 1.800" install height. I went to a machine shop with a set of heads with a set of the retainers in your link and I got 1.78x" from the spring seat to the retainer. In chatting with others, I heard teh same measurements that I found.
I'm not positive on which seals give more clearance, but I've heard the ZZP ones do. And those look just like FelPro seals.
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