getrdunn

Anybody run hydraulic rollers at zero lash/zero turns. No preload kinda acting as solids so to speak. Depending on lobe profile I could see this beneficial and “not so beneficial”. I’ve always wanted to try it years ago on hyd flat tappet engines but never did.

I would think it might be hard on a non billet core. Beating the lobes.

GPM

Would you get full lift with no preload ? would the retainer ring pop out of the lifter with no preload ?

getrdunn

My thought was Yes getting full lift with the plunger not bleeding down. Not sure though or about he retainer ring?

fbc25el

If the lifter would pump up it might create a piston to valve problem.

GPM

Lifters, Lash and Preload. What you don’t know won’t hurt you, or will it? - Gwatney Performance

SB

OP. - that does not deal with bleed down issues. If the lifter had this because of design/machining issue or even from too much air entering.

That is what reducing pre-load is trying to accomplish.

A lifter with a lot of preload that ‘pumps up’ would be what smack a valve.

getrdunn

I could imagine how lower quality lifters and heavy weight oil not a good combo. Let alone the cooler oil temps most marine engines run.
(Low quality lifters never an option)

Also makes sense when running tight lash solids on a hyd grind your increasing both lift and duration. Some years ago we did a back to back comp and changed over to solids on a hyd roller and gained not only the HP but raised the peak up 200 rpm.

Rookie

I bought 2 sets of Comp 15854's from the swap forum. Seller said low hour barely used. Pics pretty much backed up claim. Later I found a thread where seller was having issues with them ticking and was not able to adjust out. Hung valves when they did pump up. Finding out these issues after the fact, when I put them in my Panther I only put minimum preload on them and let the "hydraulics" do the work. Pretty much enough to engage the pushrod. They made a little noise at first startup on the engine stand and initial shake down. Quiet ever since. Also, Comps recommended install for short travel lifters is Zero lash - 1/4 turn.
BTW, I'm at 0.004" cold lash with my solids on HR's.
https://static.summitracing.com/glob...ca-15850-1.pdf

fbc25el

Got it. Brain fog.I still don't think it would be a good idea in a marine motor. I know some NHRA stock classes were doing this a while back.