TFS 215s PTV Clearance FWIW!!
07-13-2012, 06:05 PM
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TFS 215s PTV Clearance FWIW!! I recently installed a set of TFS 215s on a bone stock LS1 motor for a customer here locally along with a custom cam I did and a set of Yella Terra "UL" rocker arms. Heads have been milled .027, and cam was verified and degreed in by myself. Here are the PTV results I cam up with:
Cam: 235/239 .620/.623 113+0 (Comp)
Degreed in at: 112ICL and IVO @.050=6*
Head Gasket Thickness: .051
Deck Height: -.008
Results: Intake= .035
Exhaust= .089
Just some information for you guys I cam up with thru my findings.
Joe
Cam: 235/239 .620/.623 113+0 (Comp)
Degreed in at: 112ICL and IVO @.050=6*
Head Gasket Thickness: .051
Deck Height: -.008
Results: Intake= .035
Exhaust= .089
Just some information for you guys I cam up with thru my findings.
Joe
07-14-2012, 01:49 AM
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07-14-2012, 01:13 PM
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I suggest not to run it imo. To close for most applications to run. The cam only guys would be surprised if they took there heads off and seen where the valves were touching the pistons a tad.
07-14-2012, 03:47 PM
#12
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07-14-2012, 08:33 PM
#14
were would you want your clearances at for intake and exhaust?
i have heard about .080 thou for the intake valve.....
and .100 thou for the exhaust valve....
is that info correct...
to the op if it is to tight, i would flycut to be safe....
i have heard about .080 thou for the intake valve.....
and .100 thou for the exhaust valve....
is that info correct...
to the op if it is to tight, i would flycut to be safe....
07-14-2012, 11:12 PM
#15
ever measured a trex in a stock longblock? they are pretty close to .015 on the intake side., most cam only guys dont measure because they simply dont want to know!! and an intake valve will NEVER catch up to a piston if it doesnt hit when checking. Smarter guys than I have spintron tested it and the verdict was "if it doesnt hit at idle it never will". exhaust on the other hand is much more important but .080 is plenty
07-14-2012, 11:20 PM
#16
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ever measured a trex in a stock longblock? they are pretty close to .015 on the intake side., most cam only guys dont measure because they simply dont want to know!! and an intake valve will NEVER catch up to a piston if it doesnt hit when checking. Smarter guys than I have spintron tested it and the verdict was "if it doesnt hit at idle it never will". exhaust on the other hand is much more important but .080 is plenty
Try to sit back and think carefully about the irresponsible comments you are making.
07-14-2012, 11:22 PM
#17
And GRR, I have never seen valve float or bounce at idle, but have seen it on over revs and miss shifts
07-14-2012, 11:52 PM
#19
If you ever look at a spintron trace you can see the cam gets smaller, the higher you rev it.
Deflection is a bitch....that is why our cams have to be so big.....well one reason...so they will be big enough
when everythingis loaded, deflected and dynamic. We have found that if....it clears while rotating by hand..it will have more room when it is running.
Deflection is a bitch....that is why our cams have to be so big.....well one reason...so they will be big enough
when everythingis loaded, deflected and dynamic. We have found that if....it clears while rotating by hand..it will have more room when it is running.
The closest it will be is spinning it over with the starter...quote me on it.....sorry this makes some folks nervous .
Installed a TREX cam and 243 heads and i have 24thousands......talked to thunder racing and they said thats normal
I've run as little as .010 on the intake successfully. I always check it with a dial indicator and clay both for they will give you different reads.
Under running condition it actually opens up to a little more clearance as everything twisting to retard the cam.
Under running condition it actually opens up to a little more clearance as everything twisting to retard the cam.
Pro Stock engines actually set it up with a couple of thousands interference between intake valve and piston.
With full valve train installed I've seen as much as .030-.040 loss of net lift due to cam and rocker flex, toerance take up, etc., plus as you mention, a little retarding of the cam when running. I wouldn't have a problem with .010 static clearance.
Run it. We run 0.35 on the intake and 0.85 on the exhaust at over 10,000. Haven't hurt anything yet
I have had on a couple occasions only .010 clearance with lash.... which results in negative clearance no lash(static).. upon inspection have had no witness.... on the intake.
Not only does the intake valve chase the piston, but you have compliancy in the entire valvetrain working in its favor(dynamic).... You have a timing chain/Belt Drive that will allow the cam to retard even slightly(more intake clearance dynamic), you have a camshaft twisting(more intake clearance dynamic)... and pushrods/rockers that will comply early in the event, which is where your intake PtoV occurs... all of that adds up to more clearance than your static measurement.
All that said, it's a little irresponsible for me to suggest anyone do something stupid like that, not knowing any specifics and not having control over the assembly...But I feel safe in suggesting that .060 is safe, and allow yourself .050 radial clearance....ie, pocket is .100 larger in diameter than the valves.
Not only does the intake valve chase the piston, but you have compliancy in the entire valvetrain working in its favor(dynamic).... You have a timing chain/Belt Drive that will allow the cam to retard even slightly(more intake clearance dynamic), you have a camshaft twisting(more intake clearance dynamic)... and pushrods/rockers that will comply early in the event, which is where your intake PtoV occurs... all of that adds up to more clearance than your static measurement.
All that said, it's a little irresponsible for me to suggest anyone do something stupid like that, not knowing any specifics and not having control over the assembly...But I feel safe in suggesting that .060 is safe, and allow yourself .050 radial clearance....ie, pocket is .100 larger in diameter than the valves.
This is mostly pertaining to the intake side, these are some quotes from some of the best builders in the country, and whom I consulted with my numbers. You can say its bad info or "irresponsible comments", fact is people do this **** all the time and sometimes it works and sometimes it dont. People that get it to work are the ones that take home the trophies! Some people want it super safe, some want as much as they can get, He asked and I said run it as IMHO that is plenty of room from my own results
exhaust valves WILL HIT and DO NEED MORE ROOM, but then again some of the old ford prostock factory engines ran light springs and used the piston to close the exhaust valve, but if the intake doesnt hit at 8* ATDC when checking it never will, plain and simple
, best of luck, but one day you'll learn your lesson, that I guarantee.