Dueclaws

What RPM are you turning your hydraulic roller engines?

I've always tried to keep mine 5,900 or less because of fear of valve float. I read in a Hot Boat where they dyno'd an engine with a HR cam and they were turning it 6,500.

Do any of you turn yours that high and what problems if any have you had?

Cord

I was told to NOT exceed 5500 rpms with mine. Even then, I was told not to hold the engine at 5500 for any length of time.

Dueclaws

My engines had 65 hours trouble fee, but admittedly I seldom ran at full throttle and even then just for short runs.

The engines are at the shop now for freshening and they haven't found any failures. But they're replacing springs and roller lifters anyway

traviss

I spun my motor 5500-5600 rpm most of the summer. around 45 hrs. When I dissassembled my motor a few weeks ago the hydraulic rollers looked great. This is a 383 small block with 170 lbs on the seat and 472 lbs open. And keep in mind these were stock GM roller lifters, with this .600 lift cam. I replace them every year no matter what.. For $180 I get all the lifters, the 8 guideplates and the retainer plate, pretty cheap insurance.

Travis

Adivanman

I spin my HP500 EFI to 6,000 all day with no issues and have taken it to 6,500 with no ill effects. When I spoke to Crane, they suggested that it be kept below 6,800. Most other sources gave a range from 5,500 to 6,500.

Dueclaws

Adivanman
Are you using stock HP 500 springs, etc.?

I think my custom Cranes are much more radical than the HP500, so this might be an issue for my too.

John

Adivanman

Stock HP500 EFI Cam, Lifters, Springs and Rocker Arms. No problems, no issues, no concerns.

In my humble opinion, if you are looking at camshaft profiles more aggressive than the HP500 EFI and beyond the Crane 741, a hydraulic roller is a compramise anyway.

If you want an aggressive camshaft and you want to rev, a solid roller is the way to go....unless you want to move into some competition grade semi-hydraulic lifters...

Dueclaws

I agree. In retrospect, I probably should've used solid rollers.
Thanks

Infomaniac

A lot of the manufacturers say it is OK to run a solid roller on a hydraulic roller cam. Comp especially. Just run .004 - .005 clearance.

You can also run 150 # on the seat with new springs on a hydraulic roller. Just make sure you have very good oil pressure.

Cord

You sure about that? The 500efi's have a limiter that will kick in before then. I believe they go into valve float around 6k.