cam lash

347 · #1 (**permalink**) 05-30-2003, 07:54 AM

do comp cams or other cam manufactures make tight lash .012 or there abouts,solid cams for small block windsors?
And having more lift in a said cam what will that do to engine performance?

BB427 · #2 (**permalink**) 05-30-2003, 08:29 AM

that would be a very tight lash for a solid camshaft .020-.030 is more common.

As far as the performance gains of a camshaft: all engines are air pumps. The more air they pump the better they run. The problem with one performance modification is that you usually increase the air flow in one area but not in others. Think of them as funnels, just because you increase the top of the funnel the bottom hole will still flow the same ammount it did before. Sometimes a larger camshaft will hurt performance.

coyled · #3 (**permalink**) 05-30-2003, 09:12 AM

You can get radically different lash readings when the motor is cold versus hot. Lash tends to be .015 or better hot, but tends to be much tighter cold which is one of the reasons they recomend plenty of lash. As far as performance goes, more lift generally helps performance at all rpm's. More duration tends to rock the torque curve up in the rpm band. Solid rollers allow for a steep ramp which limits duration but gives you tons of lift,ie. the best of both. Any minor lash adjustments away from cam specs can help the intake or exhaust side of the equation whichever is weaker. Usually, you are better off working on air fuel and timing for more performance, not much to be gained from lash adjustments as the cam manufacturers have it figured out. Scott

SFfiredog · #4 (**permalink**) 05-30-2003, 12:43 PM

Hello 347,
I am using the new tight lash Comp Cams lobes on some FE engines I built recently and really like them. The ramps are very agressive with a quick action for the amount of duration used.
I'm not sure if Comp is offering these lobes on off-the-shelf cams
as I have most of my cams ground to my specs. One draw back to these tight lash cams is increased wear of valvetrain components and somewhat shorter cam and tappet life so I wouldn't recomend them for a daily driver.
The latest cam I had ground was for a 483ci. 427 tunnel port.
Specs are: 252/260 degree @.050, 290/298 degree advertized (compare the two, that's quick ramps!) .616" lift on a 112 degree lobe center, installed at 108 intake centerline. Lash hot is .014 intake, .016 exhaust
HTH,
--Mike

347 · #5 (**permalink**) 05-31-2003, 01:42 AM

when you have lash of .026 etc what are you loosing lift, duration?

750hp · #6 (**permalink**) 05-31-2003, 03:41 AM

Comp Cams specified a custom "tight-lash" solid roller for my motor. MIKE - do you think the wear would only be higher in a flat tappet camshaft? The solid roller cams shouldn't have any increased wear, should they? Please say no!!!

347 - do you have a part number for your camshaft? If so, CompCams will tell you instantly what hot settings you need.

347 · #7 (**permalink**) 05-31-2003, 06:19 AM

its a 294s........i know what the lash is for my cam
i am working out(trying)what,if any cam can give me more hp/torque without going too much bigger

SFfiredog · #8 (**permalink**) 05-31-2003, 11:02 PM

Hi Craig,
Your "tight lash" solid roller does not suffer the same wear issues as the flat tappet "tight lash" cams do. Logically, I would think the
tighter lash would help prevent the roller lifter from "dragging" or "stalling" across the lobe when coming up off the heel of the lobe. You might even be able to stretch out the intervals between lifter rebuilds.
Cheers,
Mike

Mr.Fixit · #9 (**permalink**) 06-02-2003, 01:51 PM

Valve lash should not be adjusted to compensate for poor cam selection. Set it to what the cam grinder told you to.

347 · #10 (**permalink**) 06-03-2003, 03:32 AM

did i mention i was going to play with my lash? you dick head!