Roller camz on the street

[Chuck Leeper]

In the FWIW dept: A bit of input from the folks at ISKY cams about running mechanical roller cams on the street. Due to the longer run times seen street driving, the roller brgs do not live as long as some think they will/should.
As a result of seeing this problem crop up in their products, ISKY has developed a roller w/ pressure oiling directly into the brg. They report dyno testing has shown 2 to 5 times longer life. The product has not been released yet. It is a "guesstimate" that the price will be in the $500.00/set range. [I'm betting they are referring to a V-8 set]
They advised us to run a new/rebuilt set of their current design lifters 2000 to 3000 mi. and then pull them for rebuild.
We did this "investigation" as there was comment made by our engine guy referring to a odd fire setup in a COBRA that's street driven.

HTH,

 

[TurboTR]

re:

Sounds like a good idea to me. Keep us posted please Chuck.

TurboTR

 

[REEDOG]

Are you saying that roller lifters won't live in a street motor? Or maybe you're refering to solid rollers only? What about all the Ford and Chevy V8s factory equiped with roller cams, I know some Chevy trucks with close to 300,000 miles on the stock roller lifters.

 

[NOSjohnWE4]

rollers

i believe those are "hydraulic rollers" ....HTH


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[Chuck Leeper]

Roller cams on the street

The post made reference to mechanical lifters, not hyd. You are correct, the hyd's do live on the street.....

 

[Bob Mustic]

Chuck

I've been thinking about this Solid Roller lifter problem. Ron T. and I had talked about the benefits of the Rev Kit on the problem.

As you know, but others might not, the theory is that the valve lash is what hammers on those little rollers. ie .024 clearance on my cam in effect is like a hammer blow on the needles. I've been told that Valve float is the biggest reason for the roller to fail. Then comes idleing. Now why would idleing do it? IMO, it has to be because without the rev kit the roller would bounce off the lobe by the amount of the valve lash. There would be nothing to hold it down. But with the rev kit the roller can't bounce. The "Jesel's" would have to aborb the "impact"...

The problem of lack of oil will be fixed with the "bore notcher" and the new Isky lifters. I'm going to run mine for this season coming up and then put in a new set of Isky's, keep the rev kit and make sure the rev limiter works. I think that should allow for at least a couple of years between roller replacements. "Maybe"

Bob

 

[blue-t]

dont forget about spring pressure 140# for hyd roller and 225 for solid , solid eats up springs and then you get roller chatter thats what beats up the lifters on the street .

 

[DeltaT]

Roller Cams and Idling

My understanding about why rollers don't generally live well on the street has more to do with how little oil they get when they're at idle and just-off-idle. There isn't enough oil splashed up to lube the roller bearings.

Comp Cams, and a couple other places, has come out with their Endure-X roller (or something similar) lifters with 2 machined grooves coming down from the oil-containing area of the solid roller to the edge of the roller itself. Each groove goes to one side of the roller. This is to get pressurized oil directly to the roller bearing.

They tested these things in a number of ways including 2 Power Tours with Hot Rod Magazine around the country. The grooves seem to solve the durability problem; no one experienced a roller-related failure in the tests or the tour.

I also understand that in solid roller cam design, there is both a lash take-up ramp and a lash take-down ramp designed to NOT hammer the roller bearings at any speed.

I just received my custom, solid roller cam from Comp, for my 383 I'm building. Since I'm going to run a small (6-9 pounds) supercharger through it, and it's in a 'sleeper' Malibu (81), I kept it modest: 268/274 advertised duration, 230/236 at .050", net valve lift (these are low lash lobes with lash between .014"-.018") of I:.575, E:.589 with 1.6 rockers. I had them cut the cam with the late model 'step' on the nose to handle the block retainer plate.

I'll post later to see whether I like 'em, whether they're noisy, etc.

Jim

 

[HRpartsNstuff]

Crower has athat design too, and looks to be the best. They EDM a small hole from the oil gallery groove on the lifter, down to the roller pin. This actually forces the oil between the roller & the pin, not just getting it close. Sounds like they all cure the low rpm lack of oil problems. Not sure if they all have them for the Buicks right now, but great design.