Thread: OEM bearings vs ACL

^^^
good to know. Thanks

I have to respectfully disagree with your outlook on coatings. The purpose of coatings is to increase longevity by eliminating metallurgical stress/strain and effects created from thermal cycling (caused by adverse gradients created in operation and from random exposure to heated lubircants, etc..)

In no way, shape, or form should anybody think that a coating will increase the hardness or any other metallurgical property of the metals in a bearing (and I dont think you were suggesting that at all). But what you were suggesting is that in the event of some kind of FOD or oiling anomoly the coatings will catastrophically fail as a whole and create more FOD. Engine component coatings are damn near rock hard and their bonds are stronger than the average metallurgical bond between layers of dissimilar metals. They not laminar in structure, like say a composite, so they wont "peel" or "rip off" like paint or something like that...that seems to be the picture you are suggesting and I have to completely disagree from a materials engineering standpoint.

Is the situation possible that some kind of FOD strike can remove the coating significantly, YES...but not likely...has it happened before, have you possibly even seen it..sure...not doubting that, but if you have seen it multiple times and consider it a trend I can promise there is another problem causing that kind of destruction/degradation
When making a design/selection decision based on an anomaly that cannot be equally predicted for two separate candidates, one would just be playing the old horseshoes and handgrenades game....

My concern would be if you fear fod or imbalance conditions that are going to be "ripping off" coatings that are rock soild and well bonded...you either built that motor in a dirty ass room with piss-poor practice or you have other underlying preparation or contamination issues.

Its for this reason specifically that engines are flushed multiple times after machining, assembled in clean rooms and should receive oil changes/flushings excessively during the first several hours of operation...

If someone is anticipating so many problems with your oiling system then its just a ticking time bomb anyway. I would have to ask- are the oil galleys and block not being flushed after machining? Are old oil-related seals, hardware and components being re-used and not cleaned ultrasonically (oil coolers, lines, valvetrain, pumps, chains, guides, etc.)? All that can introduce havoc-reaking FOD, none of which is any bearings fault-nor should any bearing be designed to deal with that LOL

I will agree that in order to compare apples to apples we should compare a non-coated ACL to a non-coated OEM bearing....and I would again agree that the ACL bearings are superior.

With that said, if you are not building a high output motor then the extra money you will pay for the coatings (which does add up if you get the rod, main and thrust all coated) is not necessary. It wont hurt to have it, but you honestly wont notice the difference either.

To the OP, I say: considering the savings and availability, I think you should feel comfortable getting the ACL bearings.

I remember buying ACL bearings a while back and main/rod set was almost $200. That's what I remember paying for the Race bearings.

Thanks for the feedback guys. Just to confirm, when you say ACL you only reffering to the ACL RACE. Not the regular acl's right? I see you get both a blue/yellow ACL Race packaging and then there's the black/gold sets also labelled ACL RACE. So which is the right one?

And I'll be using a bone stock DE crank for my rebuild. So I'm assuming STD size ACL's is the way to go, regardless of the grades on the block and crank. I see ACL also offer a STD size with 0.001" extra oil clearance.

@ coheed I see complete sets of main, rod and thrust for about $130:

http://cgi.ebay.com/ebaymotors/ACL-Race-Main-Rod-Thrust-Bearing-Nissan-SR20-SR20DET-/190552375760?pt=Motors_Car_Truck_Parts_Accessories&hash=item2c5dce81d0

I never understood how ACL bearings could go with "one size fits all" when the OEM bearings have the different grades. Is ACL just happily accepting the big swings in tolerances? That never sat well with me.

The OEM bearings for our engines are still lead. They haven't changed the design to aluminum just because the newer engines use aluminum.

The ones in the black and gold packaging are the ones you want.

Again ben its not really soo much as a one size fits all. Again the differences in each grade are only .0001-.0003. Not much at all. So to go with the mid of things is perfectly fine. Again they have been out for years and i cant recall anyone ever having a problem with clearances with ACL's and spinning bearings. The ACL's are by far much stronger than oems and will take much more abuse and even dry impacts than the oem's will. Last thing you want is the bearing to spin, You would rather have dry impacts and scuffs on the bearing than for it to break that tab and spin.

I used to only use oem's until i did more research on the ACL's and then used them and found them to be a far superior bearing. And ive broken down heavily abused motors with oem bearings and ones with ACL's such as my motor and the crank and bearings were all by far in better shape than the ones with the oem's. OEM's were showing signs of wear while the ACL's were still in perfect shape as well as the crank.

Its a no questions asked hands down that ACL's are better than the OEM's. When you are talking about having the grades that accurate, it really isnt that important. As long as your oil clearances fall within specs you are good. And if your spec is right in the middle with the matching grade oem bearing you could use a grade or two up or down and still fall within the oil clearance spec given. Again its that small of a difference between grades.

One more thing, when is the single hole main bearings appropriate and when are the 5 hole main bearings appropriate?

Also, when do you need that 0.001" extra oil clearance that ACL race offers?

If this is a ve or gtir motor you can get the 5 hole or single hole, it doesnt really matter. The 5 hole allow more oiling to the rod bearings being the oiling hole on the main journal of the crank is seeing the oiling hole 3/4 the way around that upper half. So its up to you. Im going to use the 5 hole mains this time around on my build because i want all the oiling to the rods that I can get. The ve and gtir have the 3/4 groove on the block that the 5 hole bearings are associated with. You have to mod de/det blocks to use the 5 hole bearings.

As for the extra .001, that is not really necessary. Its for big full out race motors running very heavy oils as well. Again its just for the extra cusion if you have a proper oiling system for it. Even on my motor im going to run the standard sizes. Havent had a problem yet and dont forsee any by sticking with them.

Yeah it's for the VE rebuild. Will see if I can get hold of the 5 hole ones then.

Thanks again. Also just read through the sticky on bearing sizes. Good info between these two threads.

Yep, yeah the 5 hole bearings are a tad more than the single but in my opinion worth it again as long as you have the gtir or ve block to start with.

Good luck on the build. Again just make sure to spray out all your oil passages on the block, crank, pickup tube and head with cleaner before assembling. Dont want debris in there.