Curious as to how much cylinders and pushrods expand as the engine temps rise on our Aluminum Harleys..

The only reason I ask is because we all know as metals are heated they expand and as they cool they contract.. Therefore we use hydraulic lifters to be able to maintain a constant adjustment on the valve train to help keep it quiet..

Back in the day, solid lifters were the go to for performance engines... They were much more reliable in rpm ranges above 6200 RPM but as temps built and expansion set in, the valve train would get noisy..

This was evident with my hi rpm SBC's and also when I used solid lifters in my 77 FXE.. With my Shovel from zero lash I would set the adjustment 1.0 flat deeper than zero lash (.031").. It actually changed the starting characteristics a tad when cold but when the motor reach normal temps the valve train noise was acceptable.. If any of you remember the slant 6 with solid lifters you know what I mean..

So now I want to make a comparison between the Solid and Hydraulic lifter.. Not really a comparison but want to look at how much change in lift at the valve can occur between the two.. We all know that with a solid lifter, once set the the lift to the valve will not change but will change a little because of heat related expansion to the cylinders and pushrods..
Now with the Hydraulic lifter and bleed rates and spring pressures and oil pressure, how accurate is the advertised lift at the valve compared to the solid lifter.. We know that a hydraulic lifters main benefit is quieting down the valve train and with .100" of travel to the lifter piston (after setting preload as recommended by Harley) and high spring pressures how can we be sure that we are getting the advertised lift of the cam when running hot..

So I ask, are we actually losing performance? Should we go to solids if we're looking for total performance?

I don't mind a little valve train noise but would like to know if it would be a benefit to go to solids.. I don't have a Dynamometer so I wouldn't be able to support any testing between the 2 but if anyone who does would like to experiment over the winter, I'm sure it would be beneficial to many.. thanks...

 

Go to travel limiters and lower bleed lifters. Best of both worlds.

 

I was actually thinking to do that.. I have a couple sets of limiters.. But I was thinking of putting in 2 per lifter to make it a true solid..

 

If you adjust to 0 lash on a hydraulic, what difference does it make whether you use 0, 1 or 2 limiters?

 

I would be afraid of a lifter pumping up at high RPM and kissing a piston.. it's happened to me before at 6650 rpm.. luckily enough I did no damage but it did bleed out 2 lifters and were noisy for a little till they could pump back up..

 

If you have valve float issues, fix the valvetrain or lower the rev limit.

 

Everything was new, S&S lifters set to .142" and Bee Hive springs 170#/380# good to .650" lift is what I was told with new OEM rockers and S&S pushrods.. I attributed it to Hi rpm and Hi oil pressure. Even though my rev limiter was set to 6200 my Wego III data log showed 6650. I lowered the Rev limiter to 6000 and never had the issue again. It's not like I missed a shift and over revved the motor.. Not only that I'm really not making a hell of a lot power after 5800 rpm so I try to shift at that rpm.. No sense it taking it beyond that. My Dyno sheet showed what I thought was a lot of reversion above 5500 anyways..
This why I am asking about engine growth. I've never run solids in a Harley before.. So If I was to use them I would eliminate any chance of lifter pump up..

 

super +1 mr. max
i run the s&s limiters with rivera adjustables. they are adjusted to just quite the limiters, estimated stem clearance is .030 cold. one thing you MUST consider is NOT letting the lifter cup hit the retaining clip!!
i can crank it and take off, no worries about lifter being devoid of oil and i can take it to the 7.5k ign limiter and not worry about pump up.
way cheaper than hydro-solid lifters.
you must allow the valve to seat on the head for obvious reasons.
there were not many issues with the old hd solids, my ch never suffered and it too from the moco was 7.5k redline. it was rode and put up wet tooooo many times to shake a stick at.
all said and done, if you are just a street machine, no advantage getting away from stock. even then, there would not be much power to be gained.

 

If a lifter pumps up it's because valve train control was lost. High oil pressure will not do it.
Running solids in a Harley will drive you crazy in a street bike. The noise is crazy & the cams aren't
really made for this. On the track it's OK but on the street you won't last a day. Unless you're deaf.

 

What were you using for a rev limiter? What was the motor / cam? what valve bent? Did the valve bottom in the pocket or catch the edge?