LS Hydraulic lifter limitations

[Rob Wright]

Originally Posted by Mark Lewis

ON the short travel hydraulic roller lifters what is the best valve adjustment to get the best performance out of the lifter. Assuming not too much spring rate or valve train weight

I honestly cannot answer that. I followed the supplier's recommendations and it wasn't as good as a normal full travel lifter with plunger set half-way down.

Someone somewhere may have found a way to make this all work out but it was complex and risky enough for my situation to cause me to stop looking at it once I saw worse dynamics in an otherwise stable setup that would spin clean-clean to well above 8000 RPM.

[e vassar]

Thanks everybody. To be honest..Ive never even had a valve cover off.
I will get it apart..see whats going on with rockers,springs,etc. check spring pressures and...probably ask for more help.
Rob,Darren .what should I do with the coils? Theyre still on the valve covers.

[GUMP]

That's where I have all mine.

[Rob Wright]

Originally Posted by e vassar

Thanks everybody. To be honest..Ive never even had a valve cover off.
I will get it apart..see whats going on with rockers,springs,etc. check spring pressures and...probably ask for more help.
Rob,Darren .what should I do with the coils? Theyre still on the valve covers.

Unless you have a packaging concern I suggest you leave them on the covers.

I've heard some dreamed up "imagineered" reasons to move them but there really isn't any good functional reason why it would be better to put them anywhere besides where GM put them.

[Adger Smith]

The best reason I can see to leave them where GM put them is the shortest possible plug wire with less chance to arc to something and with less voltage drop.

[e vassar]

Originally Posted by Adger Smith

The best reason I can see to leave them where GM put them is the shortest possible plug wire with less chance to arc to something and with less voltage drop.

Yes after further study under the hood,I think you guys are right. No big thing just unplug the harness and plug wires to remove valve covers. I need to stop trying to outthink those G.M.engineers.
Thanks again

[Albert Lee]

It's an LS. Why would you have to take the valve covers off?

Al Corda

[GUMP]

I need to stop trying to outthink those G.M.engineers.

I don't have the budget for that!

[e vassar]

Originally Posted by Rob Wright

Stock LS7 lifters have the best dynamic stability out of any I've tested, and the earlier-version LS7 lifters with circlip axle retention are the ones to have.

Differences in stability of stock vs aftermarket brand "M" and aftermarket brand "J" is not incredibly significant.....Best to worst (stability-wise) is listed in order and again, they are not vastly different. All of this assumes plunger at mid-travel for preload.

Actually in my experience the WORST performing hydraulics (stability, , on a given cam/spring/rocker/pushrod combination) were limited travel units.

If you're hitting a wall at 7000 RPM, you should look at whether you have TOO MUCH spring force (compressing the lifter plunger isn't necessarily the problem.....), too heavy retainer, spring, rocker, or all three, and more often than not the cam lobe geometry itself.

Proper lobe geometry shouldn't require tons of spring force to run well past 8K RPM if it is packaged with light valves (like stock LS) a light rocker (like the stock LS), retainer (again, stock LS), and spring (like beehive or well thought out dual like PSI LS 1512 ML), along with a pushrod that is stiff enough to avoid deflection/energy storage/energy release. This sequence causes bounce at closing and that's when stuff breaks.

Robin where is a good source for the PSI LS1512ML? What about a beehive?

[SSDiv6]

Originally Posted by e vassar

Robin where is a good source for the PSI LS1512ML? What about a beehive?

Ken Juszczyk at Motorsports Unlimited

https://www.motorsportsunlimited.net/

or

Brian Benson at Dakota Parts Warehouse

http://dpwferreavalves.com/