Yoji h 123

What are the pros and cons and differences between the two?

G Atsma

As long as the bearing journals and lobes are within spec, WHO CARES??
You always ask such obscure and meaningless questions.... troll....

79_T/A

iTrader: (1)

The 60mm is bigger

RB04Av

5mm

One would think, if one could, that the larger would be stronger; not sure whether that would ever have any real-world implications except in the most extreme cases, though. I don't claim to have heard everything, or even really very much, but I have NEVER heard of a 55mm cam breaking because it was ground on too small of a core.

We might think of that sort of thing as "a hypothetical solution in search of a problem to validate it".

G Atsma

Just a heads up- OP comes on here once in a while, asks a totally irrelevant question, gets some answers, then rarely shows up in the thread again. If so, ignores any responses given previous to his reappearance.
Plus, impervious to any insults given in those responses.... lol

grinder11

iTrader: (1)

Ain't that the truth. Some of them are so far out in left field, Willie Mays on steroids couldn't reach the fences!!!

68Formula

The 55mm is divisible by 11, and the 60mm by 12. They do share the commonality of being divisible by 5 though.

SlowTBSS

Some smart minds posted about it in here.. if you need more information call a cam manufacturer.
https://www.yellowbullet.com/threads...mshaft.530283/

G Atsma

Yoji h 123 posts here on occasion to ask incredibly obscure questions that have no real relevance to anything.
Then drops out of sight for weeks at a time. Nobody here takes him seriously as a poster anymore as a result.
Just FYI....

SlowTBSS

I figured, I've seen the posts before. My response has more than enough information than he will need should he choose to read it. Only took me a minute to find the bookmark.

grinder11

iTrader: (1)

The only thing I can think of offhand is that, IIRC, aren't there roller bearings available for the 60mm cam journals? Or? Not that it matters, as he's either a bot, troll, or both......

SlowTBSS

60mm roller bearings for 55mm cam core and 65mm rollers for 60mm core. Either way the block would have to be machined for both. I know Cammotion has 60mm cores available for the LS.

grinder11

iTrader: (1)

It seems it would be more of a needle bearing than roller, at roughly only a .098" diameter. I wonder if it would be feasible to run a 65mm bore and run a 55mm diameter cam journal? I would think the bigger, 5mm diameter rollers would be more durable. At any rate, this might be the first time the OP has ever generated any interesting posts!!!

G Atsma

I doubt he'll come back to see it... LOL

jayyyw

Since the topic is out there.... Is there a power gain going to a roller bearing versus the standard bearing type?

Che70velle

iTrader: (6)

Roller cam bearings were designed to hold up under severe load situations from enormous valve spring pressures. You have to run a billet cam core with them, because the rollers are hardened steel…not a big deal these days, as a lot of cams are billet steel. Oil is diverted around the roller bearing shell. They rely on splash oiling to lube. This improves oiling to the rest of the oil circuit. Where a SMALL amount of hp is gained is from the lack of oil that a cam journal is typically spitting out from forced oiling, NOT being present with roller cam bearings, and therefore windage is greatly reduced in the crankcase. That’s the biggest improvement really. You’ll also see a little less oil temp due to less friction being present. Major machining is required to make them work, as the oil circuit in the cam journal has to be opened up (typically) to get the oil to go around the roller bearing shell, after the original oil channel has been machined away. Bearings are frozen and block is heated to install the roller bearings correctly. They are easily deformed if you try to hammer them into the block. Basically they are a race only mod and totally not worth it for a street build, imo.

jayyyw

Gotcha, thank you for the explanation

SlowTBSS

I talked to Chris U. About this once on YB and he pretty much said the juice wasn't worth the squeeze and 99 out of 100 times he would use a babbit bearing instead of roller. The HP gains just wasn't worth the added costs etc. The only benefit is they require far less oil. Supposedly they also create more valvetrain harmonics.

grinder11

iTrader: (1)

Let's hope you're correct!!!

grinder11

iTrader: (1)

Man, you're bringing back memories with the freeze/heat stuff!! We used to heat the parts EVENLY in a convection oven, and used dry ice to freeze the parts to be inserted. I remember sleeving engines like that, and once the sleeve started in squarely, it would fall into the bore the rest of the way......