valve lash question

[396_WAYS_TO_SPIT]

What if you set your valves a little too tight? What does for the performance?
What if you set them a tad loose? Just trying to get an understanding.

[Fiat48]

Lossening valve lash basically shortens the cam profile (possibly more low end power) and tight valves increase the cam profile (possibly more top end.)

[DetroitJim]

Tighter lash will increase duration a bit, if you pick up power then you could use a bigger cam. I go as tight as 0.008 checked on a fully hot engine. No reason to go looser than the spec, it just beats up the valve train.
DJ

[396_WAYS_TO_SPIT]

I was just curious cause my motor ran differently when the valves were a little looser. When I ran through them it ran a bit different.

[steelcomp]

Tighter lash will increase duration a bit, if you pick up power then you could use a bigger cam. I go as tight as 0.008 checked on a fully hot engine. No reason to go looser than the spec, it just beats up the valve train.
DJ
This is basically a myth. One of the biggest HP robbing problems in an engine is valve bounce. There's really no reason for the excessive valve lashes designed into cams today, since the lash is simply there to compensate for expansion of parts once they heat up. It assures that the valve will always sit on the seat, adn anything more than that is not necessary. With the excessive lash settings, you have rockers "hitting" the tops of valves causing harmonic vibrations which can add to the valve not sitting down on the seat, but instead, bouncing, sometimes as much as .030"!! (This usually results in broken valve train parts, specifically, the valve) When you tighten up your valve lash, it's been proven to actually help smooth out the harmful vibrations, and help reduce valve bounce. Reduced valve bounce = more HP. Noticably more HP. It dosen't necessarily mean you need a bigger cam. :D

[steve d]

This is basically a myth. One of the biggest HP robbing problems in an engine is valve bounce. There's really no reason for the excessive valve lashes designed into cams today, since the lash is simply there to compensate for expansion of parts once they heat up. It assures that the valve will always sit on the seat, adn anything more than that is not necessary. With the excessive lash settings, you have rockers "hitting" the tops of valves causing harmonic vibrations which can add to the valve not sitting down on the seat, but instead, bouncing, sometimes as much as .030"!! (This usually results in broken valve train parts, specifically, the valve) When you tighten up your valve lash, it's been proven to actually help smooth out the harmful vibrations, and help reduce valve bounce. Reduced valve bounce = more HP. Noticably more HP. It dosen't necessarily mean you need a bigger cam. :D
Do you think excessive valve lash on a roller cam would be responsible for for the eventual groove starting on the back side of the lobe? Could it be cam material? Seems to have the same indications on ramp up also. Does too much valve lash =broken roller lifters--seems like this is going around lately....Thanks Steve

[Moneypitt]

Rollers will loose contact with the lobe. The fix is a rev kit. I see valvetrain failures all the time without the addition of a rev kit, very seldom with one......Seems like the cam guys are saying they are no longer needed, Why? What changed? Keeping roller contact with the cam is a way to make them last a long, long time, and also is alot less abusive to the rockers, valves, and retainers. I think Comp cams still offers a rev kit, look into it..............MP

[Snowboat]

Both Comp and Crane offer rev kits. Any idea which one is better?

[Moneypitt]

Ken, I am sure they will both do the job. A rev kit isn't that complicated, it is soley to keep the roller in contact with the lobe, thats it. Using one will make head instalation a little tougher because the head is what preloads the spring against the pushrod,(Engle style). They do make head removal easier though! I would check out what ties in with what to get the spring loaded. Engle pushrods have a cut with retainers and keepers, but they are also getting away from the rev kits for BBCs. (still used on SBC)......Ray
PS: Is all OK from over there??????

[Snowboat]

So far, no news of any deaths. Thanks for caring.

[396_WAYS_TO_SPIT]

So far, no news of any deaths. Thanks for caring.
WTF??? :confused: :confused:

[INEEDAV]

WTF??? :confused: :confused:
Ken's son is over there(Iraq), read the post above Kens.