In light of the other thread....

How often do you have to adjust the valve lash on a solid roller?

Second, is a solid roller cam really beneficial on an LTx motor? It seems from what Ive read, the opti won't live at higher rpm....what is the safe cutoff? 7k rpm? 7500rpm?



Thanks.

 

A solid roller will need the lash set at least weekly if you are racing the car regularly. On the street I have went an entire summer without having to reset the rockers but I used polylocks. A solid roller is a powerful cam but is not really too practical on the street, it will behave okay but the lobes are such a design that they will wear out springs & guides quite often. I ran a solid roller in my Chevelle Pro Street two years before I got rid of it and all I had to do was set the lash every spring. I was just getting ready to pull the heads to check out the guides & replace the springs when I got rid of it. If you don't mind the added maintenance & parts replacement then a solid roller will give the power you want but a hydraulic roller is much easier on parts.

 

I ran solid rollers in circle track engines and once everything was broken in, all components were of quality manufacturer there was little maintenance on the solid roller cam - we checked lash over the winter when getting everything ready for the season, then only once mid season if we didn't have to do any other work. As for the guides wearing - proper valvetrain geometry is important as the high spring rates will really exaggerate the wear issues of improper geometry.

I've got one circle track engine with a solid flat tappet cam that I've only set the lash once after the initial breakin and that engine has been 4 seasons in a street stock, been run a total of 1 season as backup engine in a modified (over 3 years) and routinely ran 6200 in the street stock and 6600 in the modified and has never needed them adjusted again (even when we swapped intakes to run it in the modified all we did was check a couple and call it good...)

 

First - lash adjustment really depends on the quality of your valve train componets and the lobe desgin.

A properly set up street roller will go 5-7K miles before needing adjustment. That's 2 oil changes in a street car. All you have to do is bump the motor over and check the lash, correcting tight ones as you go....

A radical but properly set up roller will go alot longer than you think. We check the lash on our 10.5 outlaw car every weekend. We are talking 298@.050 and .900+ lift in a 632 inch motor that turnes over 9000RPM - it rarley has 1 or 2 valves that are tight by a few thou. We run a 16 car field and run well, so the car makes 3 qualifying passes and usually 3-4 1/4mile passes every week.

Some of the bracket engines we build can go a month or more and when the customers finally bring the car to me to check the lash it's rare for me to have to do anything but check the lash and double check that adjusters or poly locks are tight. These cars run local tracks across the South East with car counts of 30-40 cars a night and buy back's in the first 2 rounds.... That's alot of passes.

I like mech rollers. Most of my engine building experience has been with them. That said my personal LTX has a hyd roller. It was something I just wanted to try out for my personal education.... (and it's been a real learning experience over the past 2 yrs) - It's a custom grind with inverse ramp lobes from Mike Jones. It makes peak power at 6800RPM and does not fall off until 7400RPM. I'm turning it 7200RPM on the gear change. I don't worry about the Opti. I have the MSD and it's working well so far.

I can tell you that if I ever build a second LTX for myself it will be a mech roller. It's too easy to make power with a mech roller. It's really hard to make power even in the same ball park with a hyd roller.

On the subject of Opti failures at "high RPM:, I see the same failures everytime. Broken rotors and worn out brgs. IMO provided the rotors were tight that leaves 2 possible causes.

1. Too much thrust end play in the cam allowing the cam nose to push against the opti destroying the brg/rotor/cap.

2. Poorly engineered/sorted valve trains with out of control harmonics at certian RPM ranges. Since the Opti drives off the cam directly, these vibrations are transmitted directly to the Opti causing failure.
Will

 

Wow, thanks Will. I appreciate it.

 

New motor may adjust it once or twice til things take a set then leave it and enjoy. Never go back to a juicer cam again they just run/rev too good and the sound is addicting. The exhaust note is what sets it off you can def. tell a difference between a SR and HR motor;pure sex

Have an inverted flank SR now, changing to a gentler ramp with a tigher lsa...more revs

Just learned the hardway about the needs with them wanting a GOOD pushrod lol.
Might step up to a 3/8

THink too many read the internet stories too much or judge something being too big via specs.
A grandma could drive mine the manners were so good;they make much smaller ones also a SR doesnt have to be big. Maybe on a BBC with high rpm/heavy valvetrain you may hear about issues but have spoken to many that have logged 10s of thousands of street miles on a SR without issue. With a large HR springs should be checked occasionally so whats the difference may as well have the power to go with it.

 

For a high powered high RPM street car solid roller is the way to go. (I define high RPM as making power above 6500 RPM) If you are planning to run your LT1 to 7000 RPM on the shifts then you will make more power with a solid roller and you will not have to set lash more then once a year after initial breakin. If you plan to shift at 6000 RPM or less at WOT then use a hyd roller.

I run a solid roller in my 555 BBC with .808 lift , 288 duration, 250 LB seat pressure with more then 1000 lbs over the nose, and I only have to set the lash at the start of the season. I check it at mid season and it is always fine. On the street I can run 10,000 miles before I check it and it is usually requires little to no adjustment.