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6 bolt Bearing question

503oneG

Proven Member
30
11
Sep 25, 2020
Beaverton, Oregon
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

Moderator
8,342
4,224
Nov 14, 2013
Independence, Kansas
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

DSM Wiseman
1,537
1,079
Jun 12, 2014
Japan / Mexico, Arizona
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

Proven Member
30
11
Sep 25, 2020
Beaverton, Oregon
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

DSM Wiseman
1,537
1,079
Jun 12, 2014
Japan / Mexico, Arizona
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
 
Last edited:

TuskeeTuner

Proven Member
34
6
Dec 16, 2020
Everett, Washington
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

Moderator
8,342
4,224
Nov 14, 2013
Independence, Kansas
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

DSM Wiseman
1,537
1,079
Jun 12, 2014
Japan / Mexico, Arizona
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.
 
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