Thread: OEM bearings vs ACL

How do OEM bearings stack up against the likes of ACL and ACL Race? How reliable are ACL's and ACL race bearings for street driven motors in terms of longevity and prelonged load situations. I'm thinking race bearings are maybe manufactured with frequent replacement in mind?

You can't go wrong with OEM bearings.

I for one went with Calico bearings.

The race bearings have more lead in them. OEMs went away from lead because of emissions reasons. The wear rates on them are similar on stock engines, but lead bearings hold more debris easily without issues. An aluminum bearing is soft, but not as soft, and when they spin there is more damage to the crank, so long as the bearing spins without exposing the steel layer. On higher load engines, the ACL will likely last as long or longer than stock.

The ACL race series can hold up to a lot more stress than stock aluminum/tin bearings. There is one major downside though, since I've used a lot of brands... Price. ACL bearings are not cheap.

really? The ACL offered by Calico cost me about the same as a set of OEM GTiR bearings...

Calico offers the ACL and Clevite brands coated and uncoated. I did notice the ACL were the higher priced, but still very reasonable IMHO.

I havent checked pricing on OEM bearings within the last couple of years, but if someone could get a quote for OEM Main, Rod and Thrust bearings, i would gladly post up the price of the ACL Calico coated bearings.

A couple of engine builders I use/know that do Nissan/Datsun specific work have switched exclusively to the calico coated ACL bearings over the OEM due to overall performance results.

Acls all day.

Stratton.

ACL's all day long. Two completely different types of bearings. The OEM bearings like they said are soft compared to the ACL's. One little dry hit on an oem bearing and the weak tab will break and spin the bearing. Ive seen ACLs on some messed up motors take some dry hits and not spin. You can see the imprint of it on the bearing but yet still didnt break the tab causing the bearing to spin.

Dont get me wrong, with a good clean oiling system and pump OEM's will do just fine but if you want that extra security the standard non coated ACL Race bearings are the way to go. Again harder material, much better wear characteristics and can take a lot more abuse and are usually better designed.

Plus they cost about the same as oem so why not. No figuring bearing size, They come in standard and several oversize for those with line honed bores on the mains or ground cranks. But for fresh cranks and blocks, Standards come out perfect on the oil clearances every time.

OEM here is not cheap. About $120 for big ends and $130 for mains. ACL race by comparison are about $90.

At Gspec OEMs are $15 (2 halves) main and $12 (2 halves) big ends. That's about $75 mains and $48 big ends.

How will I know if the ACL's are coated or not? I'm tempted to go with ACL cause its available, where as OEM takes 2 weeks from Japan via the dealers.

Which ACLs are you running Stratton?

Lastly, OEM comes in different grades and are sold loose, where as most aftermarket bearings I've seen are packaged as the same size for the entire set. How do you get around that issue?

Most people run the ACL Race Bearings in standard size again assuming the crank is in great shape and never been reground and the block never touched

OEMs are specd on sizes. Again not many other manufacturers went into as great of detail on oil clearances as nissan did and probably why the SR's last soo long. But when we are talking a difference in each grade we are talking a difference of .0001-.0003" for each grade. The standards just come in the halfway point of those grades and from what ive seen usually give you a perfect mid spec oil clearance and never had any issues with it.

I wouldnt run the Calico Coated ones as they usually run tighter oil clearances and if there is any problem with your oiling system or ever hits a dry spot it will tear the calico coating off the bearing and you will now have debris in your oil passages and bearings. They are great for full out race motors that will be torn down every soo often and soo on. But the extra benifit from them doesnt outweigh the longevity and more clearance which gives you more of a cusion when it comes to bearing life

I used Clevite main and rod bearings.

Clevites are good. Just a slightly different material than the ACL's but an almost equal quality bearing. ACL's are still slightly stronger.