Cam&Lifter& valvelash?
 

I've been wondering if I can do this: when nhra opened up the lifter rule allowing solid lifter in place of hyralic's, I thought it would be a good idea to try them on our 305.She turns it quite a bit higher that 7000 so I thought their might be something there.I was concerned about running them on the same cam but in the Comp master lobe chart it said the lobe profiles we were running would work with solid or Promagnum hydralic lifters.Since most of today's racing hydralic lifters are basically solid I thought I would try it out.It seemed to help with top end mph Quite a bit.My question is does anyone think I can zero lash the solid lifters? Since I zero lash the hydralics I can't see how it would hurt to try it on the solid's.Called comp today and they didn't seem to think It will work, but why would they put it in their catalog chart saying you could run both.I'd appreciate any thought on this.

Re: Cam&Lifter& valvelash?
 

When you zero lash the hydraulic lifters is there any travel left in the lifter or is that bottomed in the lifter? If there is travel left in the lifter, there is your lash. I would think if you zero lashed a solid lifter when everything heats up it would wind up holding the valves open a little. I may be thinking backwards, it is pretty late. Derek

Re: Cam&Lifter& valvelash?
 

I think Derek is right. If you put the lash at zero with a solid lifter, when things warm up and expand, you will either bend pushrods or hold the valves open. Lash exists to allow for the clearance change that occurs when things go from cold to hot.

Re: Cam&Lifter& valvelash?
 

While on this subject, new to me is hyd. lifter combo, 255/350. With Shubeck hyd. lifters, what procedure is recommended to set valves with respect to preload. Always ran solid lifter B/B before, many thanks for any response, Tony Tosto.

Re: Cam&Lifter& valvelash?
 

Bill, the lash tightens up .002-.003 on an iron head/iron block SBC (cold to hot), so keep that in mind. -Al

Re: Cam&Lifter& valvelash?
 

Thanks guys for replies,I' tried lash settings from .008 to .012 and was wondering just how close I could run . I noticed when checking cam lift that I lost a noticable amount of lift by running that much lash so that's why thought about tightning it up.(ex. .010 x1.5= .015 lift lost).It sure is fun doing crazy stuff like this but I believe it's going to fall by wayside in not too distant future.

Re: Cam&Lifter& valvelash?
 

I've been running .006" cold with Shubecks. They tighten up .003/.004 hot so I still have some lash.

Jim Mantle V/SA 6632

Re: Cam&Lifter& valvelash?
 

Some variables exist between motors,even of the same brand and even configuration. Valve lash can be affected by numerous things. Probably the best way to weed out some variables would be to carefully set valve lash cold,knowing exactly where you set it, running the engine to operating temp, then checking it hot. Now, operating temp at the end of a hard pass would be hotter than a 10 minute warm up.That would affect exhaust valve lash more than intake because of the greater heat of the exhaust gas passing the valve.The important thing is to know exactly how much the lash tightens up between temperature extremes. The main thing is to still have .002-.003"lash at the heat extreme.
You definitely need to find the fine line between loose valves and lost lift,and tight valves, lost power and compression loss due to valves not seating at the finish line. If adding that much lash caused that much loss of lift, maybe you should try a set of pushrods that are .030"-.050" longer. That would work with the engine's valve train geometry to bring the lift into an optimal setting. Also, too much lash with Schubeck lifters kind of scares me with some of the stories about the ceramic base of the lifters failing. You need to compare cold lash with hot lash on that particular engine you're racing and working on in order to determine exactly what works. A good motor is like a good woman. It will talk to you and you can figure out exactly what it wants. They can both get quite loud at times,however.

Re: Cam&Lifter& valvelash?
 

Setting valve lash with a "feeler" gage can easily be all over the map when it comes to accuracy. Depending on valve train deflection, a racer might want to more precisely set the valve lash with either an old P&G valve gapper or one of the more recent pieces from Precision Measurement Supply in San Antonio.
Regards,
Dissident:)
Hope the pics attached ok.

Re: Cam&Lifter& valvelash?
 

Wondering about the loss of lift running solid lifter. If you have to run lash but the cam is checked at zero lash by NHRA then you would have to lose some lift using solids. Question is, do you lose lift with a hydraulic lifter at zero lash or with some preload, and how much? Then is a solid lifter really the way to go?