Clevite 77 engine bearings [Merged 3-8]

[92GS-T'd]

I am going to start rebuilding my motor tommorrow. But i got a question on Clevite 77 engine bearings (not rod bearings). There are four bearings with grooves in the journal, four with flat journals, and two larger bearings with lips (pretty sure these are the thrust bearings. My question is does anyone know the order these bearings go in? I chiltons book and they dont cover the subject. Any help would be great!!!

 

[92GS-T'd]

Anybody??? Somebody???? Please!!!!

 

[greathuskie]

please only people with experience on this, which bearings would you go with?

 

[gritsak]

and also please reply to the thread and tell why you chose which...im noticed alot of people using the clevite..are the oem not that good?

 

[bigfoot]

I think the Clevite's were cheaper. They have been making aftermarket bearings for a long time. And it was Mitsubishi that brought us crankwalk.

 

[Victory]

Another option we find works extremely well are the Federal Mogul Bearings. They're not as hard as the Clevites which don't provide much dampening. No dampening frequently means catastrophic engine failure.

 

[NDgsx]

I run clevites, they're cheap and they work fine.

The crank should be spinning on a film of oil, if the bearing needs to dampen something you've go other issues, run a larger tolerance. IMO.

 

[Defiant]

Originally posted by NDgsx
The crank should be spinning on a film of oil, if the bearing needs to dampen something you've go other issues, run a larger tolerance. IMO.

Ooof! If the crank ISN'T running on oil -and it's a hydrodynamic wedge, not a film- it'll last a few hundred revolutions before the oil overheats, cokes, melts the bearing and destroys itself. The bearing clearances are determined by the factory and about a hundred years of experience, do not deviate from their specs. Bigger is NOT better in terms of engine longevity.

As for manufacturer, I've not heard of a "black sheep" bearing maker for any known-name on the street.

 

[germain101]

i've experience with all three bearings...here’s what i've come up with...

Mitsu OEM bearings= crankwalk

Cleavites= currently in my 6bolt no signs of crank walk 13k miles...

Federals= currently in my friends 6bolt that i just rebuilt, 550 miles and no signs of crank walk...

the only thing i’ve noticed that was different between the three was, the mitsu bearings have a channel on the journal side of the thrust bearing coming off of the oil holes...the federals and cleavites don't have this channel...

 

[gritsak]

Originally posted by germain101
i've experience with all three bearings...here’s what i've come up with...

Mitsu OEM bearings= crankwalk

Cleavites= currently in my 6bolt no signs of crank walk 13k miles...

Federals= currently in my friends 6bolt that i just rebuilt, 550 miles and no signs of crank walk...

the only thing i’ve noticed that was different between the three was, the mitsu bearings have a channel on the journal side of the thrust bearing coming off of the oil holes...the federals and cleavites don't have this channel...

do you have experience with mitsu bearings in a 6bolt walking vs. others in the same setup not walking? if its on a 95+ 7bolt that you had mitsu bearings and it walked thats hardly reason to suspect that it was the bearings themselves that led to the crank walk.

 

[germain101]

i could give a sh!t what LED to the bearing failing, the fact of the matter is it failed and that was my EXPERIENCE with mitsu bearings...

 

[gritsak]

Originally posted by germain101
i could give a sh!t what LED to the bearing failing, the fact of the matter is it failed and that was my EXPERIENCE with mitsu bearings...

why do you have to be a f*ckin #### about it...all i was asking it you know for a fact it was the mitsu bearings that caused the problem or what....when you have a 95+ 7bolt motor that had facotry bearings and crank and it walks...then rebuild a 6 bolt with aftermarket bearings and it doesnt walk, it really doesnt prove a damn thing except you switched to a 6bolt which obiously is much less walk prone....

give me a motor that had problems with one set of bearings (bearings A) then rebuild the SAME motor with different bearings (bearings B) and have it last, then it will be reason enough to say bearing B is better then A.

 

[ProStreet01]

Stock mitsu bearing: Using my current setup and 20psi on pump, all 4 of my rod bearings on the rod side,(not the cap side of the rod assembly), were significantly scuffed. the cap side of all my main bearings showed mild scuff. This was with non-synthetic 10w30 changed every month. Motor had 7k on it.
Clevite: Under the same circumstances rod bearings showed very very little scuff. the mains appeared to have nearly none after 5k.
I've seen this trend consistently.

 

[NDgsx]

Originally posted by Defiant
Ooof! If the crank ISN'T running on oil -and it's a hydrodynamic wedge, not a film- it'll last a few hundred revolutions before the oil overheats, cokes, melts the bearing and destroys itself. The bearing clearances are determined by the factory and about a hundred years of experience, do not deviate from their specs. Bigger is NOT better in terms of engine longevity.

Thanks for reminding me I'm not an engineer, great correction.

Right, there's a section of the manual that lists a certain thing called tolerances. See there's actually a specified range of acceptable clearances and you can decide where in that range you want your engine to be when the mains are align honed (or bored) and the rods are resized.
We're not worried about getting 200k out of our engines here. Most people are more concerned about having their engines survive while making double the factory hp. Typically on any high output engine bearing clearances will be set slightly larger than on a standard rebuild. If you're worried about not having enough film pressure, er hydrodynamic wedge, then tighten up your rod side clearance. Luckly most forged rods start out a little wide already.

 

[Groomz]

Most of the engine builders I've talked to about Mitsu's factory tolerences said that they are very tight from the factory and that the range is also very tight. Based on what I have read and seen, and by what people who have built motors before have recommended, going w/ slightly more clearance than factory would be beneficial to the bearing life , if not it would not harm the motor in any way.

 

[hose101772]

Well i've tried to use 2 sets of federals and in both sets the thrust faces looked like they were sized with a pocket knife-ahhhhh pass.New engine (2.4)will be using toga bearings from importperformanceparts.com if they look good when they get here.In my last engine i used clevites(2.0),though scuffed, the rod bearings didnt deform and spin.I dont really think i want "soft" bearings deforming at 7k and nuking my high dollar parts.Cranks can be turned,holes in blocks cant.Oh by the way,detonated bad enough to blow big chunks out of head and block between 3 and 4.

 

[keltalon]

well i think i will try these maybe everybody should look into them.

]http://www.importperformanceparts.net/toga/togabearings_mitsu.html

 

[2-0turbo]

Originally posted by Defiant
Ooof! If the crank ISN'T running on oil -and it's a hydrodynamic wedge, not a film- it'll last a few hundred revolutions before the oil overheats, cokes, melts the bearing and destroys itself. The bearing clearances are determined by the factory and about a hundred years of experience, do not deviate from their specs. Bigger is NOT better in terms of engine longevity.

As for manufacturer, I've not heard of a "black sheep" bearing maker for any known-name on the street.

I don't have proof, just a few points of discussion. I have TRIED for quite some time to get in contact with a powertrain engineer at some manufacturer to pick his/her brain on this subject. I am an engineer and have debated this subject heavily with my co-workers and fellow gear heads.

Based on research I have done to this point, I honestly believe that larger tolerances are better, provided that the oil pump can deliver the volume. The pressures inside a bearing are much higher than the 80 psi oil pressure you are running. Going from memory here, the viscosity of oil at 300,000 psi approximates Nylon. Not that you are always running pressure that high in your bearings, but put a film of oil in there and smack the other end with 1000 psi and the pressure in the bearing will rise.

So, in my opinion, spun bearings are caused by one of two things: 1) What Defiant said about the oil coking, overheating and spinning the bearing and 2) Excessive heat due to inadequate flow. For this reason, on my engine rebuild, I am more inclined to use a high volume pump (same stock pressure) with a reasonable oil viscosity (10W-30) and looser clearances. I am leaning away from higher weight oils due to the flow reasons. There is a balance somewhere; higher viscosity has higher film strength, but you get less flow with a given bearing clearance.

The oil pressure in your engine is a function of only two things: oil viscosity and the engine bearing clearances. This is provided your pump is in good condition. Remove a balance shaft and don't block off the bearing and your oil pressure is going to be LOW, regardless of how high a pressure pump you are running. Run very tight clearances and your pressure will be very high, but your FLOW through the bearing could be quite low. Low flow through/around the bearing could cause excessive heat buildup and a spun bearing.

I am kind of thinking out loud here, rambling just a bit and I have totally hijacked this poll. I am very interested in others TECHNICAL thoughts on this subject.

*edit* grammar

 

[NDgsx]

Another thing to keep in mind is rod side clearance, that will affect the pressure of the oil on the rod bearings and the amount of time it spends there. I found one set of eagle rods to be on the very tight end of stock tolerance (.0045").
On my 7 bolt that I am running right now (stock pistons, just flexhoned with new rings) and clevite rod bearings my clearance is .0018". It has been working great for me, but I haven't torn the block down to inspect the bearings (if it ain't broke don't fix it ).

 

[hose101772]

Got the togas,finally.Flatlander got the street number reversed,no biggie.I have to say these are best looking bearings I've ever seen.Havent measured them yet so I'll get back with that info.

 

[98TsiAWD]

Originally posted by hose101772
Got the togas,finally.Flatlander got the street number reversed,no biggie.I have to say these are best looking bearings I've ever seen.Havent measured them yet so I'll get back with that info.

Yes let us know, I need to order some bearing very soon.

 

[ArticNemesis]

main, main, thrust, main, main.


Thrust bearings go in the center main cap.

**edit: didn't mean to dig it from the grave, was sifting through info on bearings, and figured i could help him out, without looking at the date of his post.. my bad.

 

[skier_du]

this may sound silly. but does anyone know a place where I can get Clevite bearings. I can't seem to find a site with them listed. Thanks

 

[Groomz]

www.diamondstarmotorsport.com

 

[ArticNemesis]

Your local Napa or autozone.

**edit**
I actually ordered a set of the Clevite 77 Main bearings from Napa last week.. $59.99 + tax, arrived in store the next business day..