Going the miles with a high lift cam.

[TheSilverBuick]

Knowing I put 10,000+ miles on my car a year, what is the practical limit of lift to keep valve springs, etc from becoming regular service items?

Assuming roller lifters and rockers. My case is for big block Buick's for what it's worth.

[TC]

IMO low .600 lift is about all I would want to go on a street driven vehicle........ The hydralic roller I'm looking to put in my '99 Camaro has .612 lift, seems even a lot of the smaller ones have lifts in the high .500's........might depend on your valve/rocker geometry..........Longer rocker, less lift on the cam to achieve the same lift........

[TheSilverBuick]

I guess I should add the caveat that I likely won't have beehive springs, which from what I gather last a ton longer in high lift applications, or at least when OEM's run greater than ~.550" or so. Squirrel runs around .550 iirc, because I've asked him this question before

[JeffMcKC]

Good springs and spring oilers, Lift does not kill springs its the ramp to the lift that kills them, but springs have came a long ways. I change mine out of sorrow for them, not a loss of pressure anymore

[TC]

I guess I should add the caveat that I likely won't have beehive springs, which from what I gather last a ton longer in high lift applications, or at least when OEM's run greater than ~.550" or so. Squirrel runs around .550 iirc, because I've asked him this question before

I'd rather run duals than singles(beehive), if one breaks with duals you don't drop a valve........And it's not the lift that kills the springs its the ramp speeds.........

[squirrel]

You probably need to talk to a cam company...but they might not know the answer either.

There's more to it than just the springs, too. Higher spring force usually means more wear on the valves and guides, along with the rest of the valvetrain. And the need for higher spring force is related to both valve lift, and rpm. And valve lift is related to cam duration, which is related to rpm.

How fast do you want to spin it?

edit: I don't know about ramp speeds, but I do know that fatigue strength is related to the alloy, and how close to the yield strength you are operating. If you are far enough away from yield strength, the metal will last an almost limitless number of cycles.

[BKBridges]

Ive got about 45K miles on my Crane .548 lift fast rate hydraulic roller set-up in my BB mopar. The only thing Id do different is to use a set of steel roller rockers instead of the aluminum crane golds. No maintenance so far at about 10K miles a year. I did bust an adjuster at the track when I first set it up. Crane made good and sent me a new set, then went bankrupt. Im thinking hyd roller is the best option for an EFId street car. Im running the springs that came in the Edy heads. They seem to be holding up well. My rev limiter is set at 5700rpm. The only valves Ive dropped were on my high revving 273 V8 with mechanical Schneider cam. It went about 150K miles before that happened though. Then it did it twice in 100miles before I got smart and replaced the springs.. Duoh. Things fatigue in different ways.

[anotheridiot]

thats alot of miles for a high lift motor. lots of horsepower is found in longer duration cams that dont need so much lift and less wear on your springs.

I'm just guessing since you are driving it so much you arent really beating on it hard at high rpm's? thats really where you start to get float with dead springs. Thing is you go back to the glory days of GM from 67-69 and you look at stock lifts on big blocks that were at 1 horse per cubic inch, then figure the springs you buy today for those motors are probably a bit better made.

[TheSilverBuick]

I'm not going to get as fancy as spring oilers. RPM's will be under 6,000, and I try to keep it to 5,500 rpm. Being a roller lifter (although it is hydraulic) the ramp can be relatively fast. The analogy I got was that a hydraulic roller lifter uses the same spring pressure as a solid lifter, and I'm guessing that's from a combination of higher weight and quicker ramp rates.

I'd like to say in the "limitless number of cycles" area

Rebeldryver Scott was telling me about the cam in his 454 Caprice and that it was all lift and little duration for a stump pulling torque engine. Not necessarily the route I want to go, but it did intrigue me.

[milner351]

In all of your instrumentation - do you monitor oil temperature? I would think keeping good oil (not going to open the synthetic / dino debate here) quality filters, and maybe adding an oil cooler would go a long way to keeping all your engine internals happy with the long highway runs you drive so often.

[TheSilverBuick]

I only monitor the oil pressure and can tell when the oil is cold, normal temp and hot. After a couple back to back spirited blasts on the highway normal cruise pressure drops by five or so psi for some length of time (5-10 minutes?) before creeping back up, but always does come back up. It would be easy to add an oil temp sensor if I pulled the pan, but I don't want to pull the pan =P

[milner351]

can't blame you for not wanting to pull the pan!

I was thinking of an add on cooler set up - one of those that goes onto the oil filter boss on the block, then you put your filter on top of it, it would also add a bit more oil capacity to the system, not a bad thing.

[squirrel]

I think your engine is pretty far from needing the type of springs that you have to replace very often. You should be ok with about 5 years between overhauls, if you can get it to keep working that long (and I think you've got it sorted out well enough now that it shouldn't be a problem). And the overhauls would be to inspect stuff, do a valve job, and replace normal wear items like bearings, rings, valve springs, etc.

But that's just my opinion....

[TheSilverBuick]

I think your engine is pretty far from needing the type of springs that you have to replace very often. You should be ok with about 5 years between overhauls, if you can get it to keep working that long (and I think you've got it sorted out well enough now that it shouldn't be a problem). And the overhauls would be to inspect stuff, do a valve job, and replace normal wear items like bearings, rings, valve springs, etc.

But that's just my opinion....

With the current setup I whole heartedly agree with you. I should, and probably will, just leave well enough alone. But I keep wondering 'What if' I went more agressive on the cam, because frankly it's pretty tame behaving and I have more tolerance for grumblyness than it currently has.

[Barry Donovan]

Good springs and spring oilers, Lift does not kill springs its the ramp to the lift that kills them, but springs have came a long ways. I change mine out of sorrow for them, not a loss of pressure anymore

I learned that first hand.
funny enough, the gentle ramps are the bigger cams.

the pointy snappy twackers they had on solids was as ass first as an egr on a boxer.

this question should be "no problems" to answer..but stuff still happens.

cooling, strong grounds.. even interferences..all those things go with big fires from startup. "springs and things" are the simplest of problems.