KAAMA

Yes, that is a good point you make and I agree with you,....but does that mean your response is good and valid enough to nullify the curiosity of my question and moot enough to make it unworthy of discussion? Or am I a rebel without a cause?

Actually, I am really hoping to use these Isky needleless lifters----my engine blocks will be on the stands by the end of this week ready for assembly and it is time for me to make a decision, it's just that I'm still curious about this needleless lifter.

So far, Haxby looks like he's the best test bed thus far at 227 hours in a pair of 1300hp engines turning 7000rpm before thinking he must rebuild them at roughly 275 hours and I think that is impressive info so far. For as expensive as they are, I just thought for sure, after 7-8 years of production of these Isky needleless lifters, would have seen use up to 400+ hours by now in a pair of supercharged, Big Block Chevy offshore marine engines before rebuilding the lifters. Perhaps there is someone out there with the answer yet---I was just curious to know.

Cole2534

Kaama, that level of testimony is going to be hard to come by.

Black Baja

I think you will be hard pressed to find that kind of information for a couple reasons 1 not many know how to setup a valvetrain properly. In this case a catastrophic failure occurs and the blame is placed on anything and everything besides the real problem (piss poor setup). 2nd reason being that I could see is when you start playing in the big leagues pushing rpm's and cylinder pressure at this level I don't think people are going to neglect there engine for 400 hours. Every piece in the engine has a service limit and in my opinion at 400 hours you are way past the limit.

HaxbySpeed

X2. 400 hours is way past the service life of any component in a supercharged bbc marine engine that is being used for what it was intended. Some of the components may still be ok, crank, rods, etc. but that doesn't mean they shouldn't be taken apart and inspected. Lifters are a wear item, just like valve springs. Nobody would try to get 400 hours out of a set of valve springs on one of these engines, and you shouldn't expect it out of the lifters either. It's not a lot of money to have them rebuilt, and the benefits of the bushing design far outweigh the cost difference of a needle bearing.

KAAMA

Thanks for all your input guys, much appreciated

ThisIsLivin

I looked at the bushing style before I bought the Morels. My concern was on startup when the oil is cold the rollers would slide up the ramp rather than roll due to oil viscosity and high shear at those low tolerances, especially on the steep part of the opening ramp. The shear surface between the roller and bushing is significantly greater then the contact point between the roller and cam lobe. I suppose I could calculate out the shear force at the bushing diameter and the leverage the roller diameter offers to know what the ratio of forces really are. I guess my question is, has anyone seen excessive wear on the ramps of the cam with bushed rollers verses needles?

Black Baja

I understand your theory but my question is does it really matter? I know that they have experimented with different bushing materials and since going back on the market with the bushing lifter they have changed the material a few times.

BenPerfected

This is exactly why we did not used the Isky bushing type lifters a when they first came out. Does anybody have any test or a true comparison on which type of roller lifter is best in an endurance application? Is the NASCAR Truck Series still allowing roller lifters? If yes, what lifter were the Truck teams running in 2014?

Black Baja

Ben, I'm sure they have the bushing material nailed down by now. Isky isn't a fly by night operation they have been around forever. With that being said it seems to me everyone is producing bushing style lifters except Jesel. I don't think there is any "magical" lifter out there. As long as the setup is right and proper maintenance is done there shouldn't be any failures.

ThisIsLivin

My point is, regardless of what the bushing material is, even if it has zero friction, the shear of the oil in such close tolerances could be sufficient to cause the roller to slide up the ramp, especially in high lift aggressive cams that most of us are running. There is so much side load on the roller and the roller contact area is so small compared to the bearing area that it may be easier for the roller to slide up the ramp than roll over it. My concern is mainly when the oil is cold. It would not be out of the ordinary for me to pull the boat out in 40 or 50 degree weather with water temps in the upper 30's or low 40's. My 20w50 Amsoil is going to be just a little thicker than when it hits 200+. If bushings are the best thing since sliced bread, why are engine builders going to needles on cams? Not to diverge, but my 14,000 rpm 2 cycles were all needles on everything, granted when they went, it was catastrophic.