Solid lifters in Stock

[Mark Yacavone]

Minus 4 thou lift not a big issue to me .Probably lose that much on the other side with hydraulics.
Last year, guys were talking .010.
Any more real world, hands on reports about lash from last season?

[Nmbr1GMfan]

I am in the process of switching from hydraulics to solids on the same cam (originally ground by crane who was of little help to me) (maybe I talked to the wrong guy). Called Bullet, they were very very helpful and instructed me to swap to an "EDM" lifter @ .008 hot. I'm going to tighten the lash from there on the dyno to see if there's any + or - results. I hope there is a peformance improvement for me with lifters, pushrods, rockers and properly setup springs.

[Pat6868]

Treating your cam , Nitride or Cryo is worth looking into.

[Greg Reimer 7376]

I worked with a guy some time back who was our shop foreman. He was a Mopar wedge guy, and he knew Torqueflites inside and out. He was a self taught rocket scientist. He experienced a tendency toward lifter pump up on one of his rather radical streeters, he attributed it to not so much as valve float over the nose of the cam, but due to the long duration cam he had, the exhaust valves had trouble closing quick enough, and the lifters would tend to pump up. He got a set of solid lifters,16 adjustable push rods, and dropped them in on the hydraulic cam. He adjusted valves around .008" on both valves, then buttoned it up and went for a ride(ha,ha).The car liked it. It had more RPM in all three gears, it ran smooth at a steady speed, seemed like a win/win. He said that when he got off the freeway after a run of a few miles or so with a fully warmed up engine, it would steadily start idling worse and worse, and one time it stalled in traffic at the bottom of the offramp. Attempting to restart the engine, it cranked like it was low on compression (which it was).After a bit, it restarted, and in regular traffic, it seemed OK. What was happening was that the cylinder head temperature climbed at a hot idle, the valve stems and valve train components expanded due to the heat, and it took up the valve lash to the point where the exhaust valves weren't closing since the lash disappeared. After it returned to ambient temperatures, lash reappeared, the engine ran fine. We don't heat soak a stocker motor like that, so .008" or so lash wouldn't do this, but it might be a thing to consider. Another thing--a hydraulic lifter with a lot of spring pressure running at 6000+ rpm, would it be possible for the lifter height to decrease, allowing the maximum lift at the finish line to be less than the lift at a lower RPM? Is it possible for lash to open up at RPM like that due to the lifter starting to possibly retract the plunger?There's no way to adequately measure this while the engine is running, but the non-collapsible lifter might result in a little more lift at RPM's than we had with hydraulics. Just a speculation.

[Rich Biebel]

A very common problem on small air cooled engines with solid lifters. They run fine cold but start running bad and stall and won’t restart. Not enough valve lash on the exhaust side. It quickly gets worse when the valve is not able to touch the seat and shed some heat. Onan old style flathead opposite opposed twins did it all the time. Lash spec was .013” on exhaust side. Valve face wears and lash gets tighter. Eventually the hot engine runs bad/no restart scenario. Drives you crazy until you figure it out! One of many odd scenarios heat related I’ve dealt with.

[Mark Yacavone]

Originally Posted by Rich Biebel

A very common problem on small air cooled engines with solid lifters. They run fine cold but start running bad and stall and won’t restart. Not enough valve lash on the exhaust side. It quickly gets worse when the valve is not able to touch the seat and shed some heat. Onan old style flathead opposite opposed twins did it all the time. Lash spec was .013” on exhaust side. Valve face wears and lash gets tighter. Eventually the hot engine runs bad/no restart scenario. Drives you crazy until you figure it out! One of many odd scenarios heat related I’ve dealt with.

Interesting.
Kind of hard to explain motorcycles though.
Many were routinely set up with 2- 3 thou. lash with adjusters or shimmed valve caps on the DOHC's.. They'll run fine, hot or cold , until all the lash goes away and need to be re-shimmed. When they get quiet, ..time for some maintenance.