Roller Cam Bearings?
 

Just wondering if anyone has any real world experience with roller cam bearings? Good or bad... Brand used ect. ect.

I fell across a deal on a new block I couldn't pass up. Unfortunately I already purchased a cam and it will not fit in the block unless I go to a roller bearing. At this point that's what I'm doing just wondering if anyone has any usefull experience with roller bearings in a marine application.

We use roller cam bearings. Don't see or have any issues. They may make a small amount of HP but ther aren't generally used in a normal marine application. Roller cam bearings are generally used if you are going to run a 55mm to 60mm cam core. Not sure that standard cam bearings are even used with the larger cam cores. The larger cam cores are stiffer and allow you to be more aggressive on lift (and maybe duration?) and still provide valve train stability. The right push rods are the key to long term valve train stability. I am not an engine builder, but just smart enough to hire experts.

Do you know what brand bearings they are using? Coated or uncoated?

I would talk to a couple of engine builders, they are really designed for drag race pro stock style engines looking for every HP. Not sure how that would work in endurance apps, also may not oil the rockers/springs enough to keep from killing springs due to overheating...but just speculating here...

What do the cam bearings have to do with oiling the rockers and springs?
I have rarely seen roller bearings in a drag race motor. Most of the ones I've seen have been in circle track stuff.

[QUOTE=Black Baja;4386830
I have rarely seen roller bearings in a drag race motor..[/QUOTE]

I see them in an SBX small block all season,actually,3 seasons and before that in an SB2.2 engine.
If the cams bearings are hard enough,I see no reason why the roller bearings won't last.Think of all the 2 strock cranks and rod bearings that are out there.

How many millimeter are you talking? I don't see why a machine shop could not make a sleeve to step it down to a Babbitt bearing. Probably run the roller bearing since it is machined for it.

2.478 new block housing bore
2.282 old block housing bore
Before I got into shimming cam bearings I would just spend the money on a larger cam. At this point I really don't see any downside to using a roller bearing and I already have the cam. Roller bearings are a little extra money but it is what it is.

Probably oil bleed off I would have to think, like the rest of bearings oil is limited to them, not sure how that works with roller cam bearings though as far as keeping oil in them and still provide for rockers and springs.

Why changing the block to the new one?