6 bolt Bearing question

[503oneG]

So I went out on a limb and bought a “drop in ready” 6 bolt 4g63 on marketplace. Had it in the car and was eating for a pan gasket. Went to install the pick up and found that the main stud that mounts it was in the wrong spot. At that point I was kind of annoyed I had to “un torque” a main cap. Once I did I realized al
The mains were finger tight. As well as the rods.. I re torqued the entire bottom and it would no longer spin. I’m pissed that this point. Pull a main and rod cap, both oversized .25, plasti gauged mains shows .0020 which is serviceable. The rods were less than .0001 and that’s why the engine wouldn’t spin. So, my question is. My bearings are oversized, I bought some std bearings with the .0010 for oil clearance and it was .0040 of clearance. I don’t know what to do at this point. Do I need a new crank? Thanks, Seth

 

[1990TSIAWDTALON]

You can polish the rod journals until they give you .0015-.0020" with emery cloth but you really have to have the crank out to do that as it will need cleaned. Sounds like someone just slapped parts together without knowing what they were doing. If the crank has to come out you might as well just figure on rebuilding it all from what you are finding. Sorry about the sour deal.

 

[DSMPT]

So I went out on a limb and bought a “drop in ready” 6 bolt 4g63 on marketplace. Had it in the car and was eating for a pan gasket. Went to install the pick up and found that the main stud that mounts it was in the wrong spot. At that point I was kind of annoyed I had to “un torque” a main cap. Once I did I realized al
The mains were finger tight. As well as the rods.. I re torqued the entire bottom and it would no longer spin. I’m pissed that this point. Pull a main and rod cap, both oversized .25, plasti gauged mains shows .0020 which is serviceable. The rods were less than .0001 and that’s why the engine wouldn’t spin. So, my question is. My bearings are oversized, I bought some std bearings with the .0010 for oil clearance and it was .0040 of clearance. I don’t know what to do at this point. Do I need a new crank? Thanks, Seth

I think the rod journals have already been polished and .001 material have already been removed.
To me, this sounds like that the vendor ordered a wrong rod bearing set or didn't realized that he received a wrong set. This is a kind of common confusion and mistake. The vendor should have had xxx-.025 bearing set instead of xxx-.25.
So do you mean the rod clearance is .004" with STD +.001" extra clearance bearings? If so, and if the numbers you mentioned above are accurate, what you would need is a xxx-.025 rod bearing set, this set would give you .001" "less" clearance than STD. So, you should have .002" less than now. Technically it would be approx .002" clearance for rods.

But I would strongly suggest to disassemble and inspect everything. IMO, you can't trust what this vendor said. And to know accurate clearances, you would have to measure by a dial gauge and a bore gauge.

 

[503oneG]

I think the rod journals have already been polished and .001 material have already been removed.
To me, this sounds like that the vendor ordered a wrong rod bearing set or didn't realized that he received a wrong set. This is a kind of common confusion and mistake. The vendor should have had xxx-.025 bearing set instead of xxx-.25.
So do you mean the rod clearance is .004" with STD +.001" extra clearance bearings? If so, and if the numbers you mentioned above are accurate, what you would need is a xxx-.025 rod bearing set, this set would give you .001" "less" clearance than STD. So, you should have .002" less than now. Technically it would be approx .002" clearance for rods.

But I would strongly suggest to disassemble and inspect everything. IMO, you can't trust what this vendor said. And to know accurate clearances, you would have to measure by a dial gauge and a bore gauge.

Thanks for the help. And I’be been looking for those bearings you mentioned with no luck. I appreciate everyone’s help on this, what a pain. Where is the best place to those bearings?

 

[DSMPT]

Thanks for the help. And I’be been looking for those bearings you mentioned with no luck. I appreciate everyone’s help on this, what a pain. Where is the best place to those bearings?

Please refer the part numbers below. These are the 6 bolt .001" (0.025/0.026mm) oversize rod bearings that you want when you polish STD journals.
(But please note that what I said above is according to what you mentioned. To know the exact clearance, you need to measure by a micrometer and a bore gauge)

ACL Race Series : 4B1146H-.025 or 4B1146H-025
King XP Series : CR4481XP.026

(Select .001 oversize)
https://www.extremepsi.com/store/AC...ring-Set-Mitsubishi-Eclipse-6-Bolt-4G63T.html
https://www.extremepsi.com/store/Ki...ring-Set-Mitsubishi-4G63-4G64-6-Bolt-DSM.html
https://www.maperformance.com/produ...earings-6-bolt-dsm-4b1146h?variant=9311789955
https://www.maperformance.com/products/king-xp-series-rod-bearings-dsm-evo?variant=42304241219

 

[TuskeeTuner]

Not trying to jack the thread but I just did a search for "bearing clearance" and this one popped up. I seek the same info as the O.P.

I want advice on bearing size and clearances as well. I have a crank that the shop says has been cut 10/10. Does that mean .0010/.0010 for the main/rod journals? Seems that .010 would be a LOT of material to remove so that can't make sense.

Block has not been to the shop yet, so the main caps (6-bolt) are not cut as far as I know. I had some problems with this engine after 23000 miles (along with wrecking the car).

What would happen with STD sized bearings and a cut crank? I'll dig through the factory service manual PDFs later and get numbers, but I know some of you know off the top of your head how things should look.

 

[1990TSIAWDTALON]

Std bearings on a cut crank leaves a bunch of clearance and no good will come out of it.
The first cut of a crank is usually .010" and most of the time is marked on the crank somewhere.

 

[DSMPT]

the shop says has been cut 10/10. Does that mean .0010/.0010 for the main/rod journals?

In general, if they say "10", it means .010" (0.25mm), like Marty said above that usually .010" is the first cut. So, if the main and rod journals have been cut .010", which means you would need .010" oversize bearings to keep proper clearance.

What would happen with STD sized bearings and a cut crank?

It would be way too loose. With that much clearance, oil wouldn't function as expected between bearings and journals, and then would cause something you don't want sooner or later. Don't do that, a bad idea.

 

[pauleyman]

Std bearings on a cut crank...hmm i give that less than 5 minutes before it seizes.

 

[TuskeeTuner]

Starting my engine blueprint; merely hand-written notes in a 3-ring binder right now. So far just comparing my actual measurements to the FSM specifications. I understand the crankshaft cut numbers (10/10) and need to decide on bearings next.

Any suggestions for bearings based on 400 WHP gasoline? Turbo: KTS D645 compressor wheel+TD06 turbine and $thousands in parts with no car or engine yet...

 

[motomattx]

Factory bearings are some of the best that you can get, they can be pricey is the reason that many buy aftermarket, but I would say that the factory bearings are the most precise size wise, most times when your removing factory bearings they dont even show much wear on them even after 200k miles.

 

[TuskeeTuner]

Factory bearings are some of the best that you can get, they can be pricey is the reason that many buy aftermarket, but I would say that the factory bearings are the most precise size wise, most times when your removing factory bearings they dont even show much wear on them even after 200k miles.

I did a quick Google search for OEM bearings; don't see any .010 Undersized, and have no reason to buy an aftermarket crankshaft right now. Guess I'll keep searching for the next best thing.

 

[DSMPT]

I did a quick Google search for OEM bearings; don't see any .010 Undersized, and have no reason to buy an aftermarket crankshaft right now. Guess I'll keep searching for the next best thing.

Any suggestions for bearings based on 400 WHP gasoline? Turbo: KTS D645 compressor wheel+TD06 turbine and $thousands in parts with no car or engine yet...

If the car would be mostly used daily on the streets and you are not planning to use the car for racing often, I would go with Mahle clevite or ACL Aluglide. Of course you can use racing bearings such as ACL Race or King XP but just keep in mind that the most important thing is the quality of assembly. Since you cut the journals, pay extra attention to surface finish, roundness, taper etc. That would be more crucial than manufacturer or material of bearings.

 

[TuskeeTuner]

If the car would be mostly used daily on the streets and you are not planning to use the car for racing often, I would go with Mahle clevite or ACL Aluglide. Of course you can use racing bearings such as ACL Race or King XP but just keep in mind that the most important thing is the quality of assembly. Since you cut the journals, pay extra attention to surface finish, roundness, taper etc. That would be more crucial than manufacturer or material of bearings.

I wanna thrash on the car, just like I did back when I built my first DSM...base model with a 4G63T swap. It probably won't see much (if any) drag racing; maybe some SCCA, autocross, and road race courses. It does need to withstand 400-430 WHP and any minor accidents while tuning...

 

[motomattx]

You wont find undersize oem bearings for the six bolt because your not supposed to grind the six bolt crankshaft.