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Engine build help

GSTwithPSI

Well-known member
Joined
Jan 1, 2012
Messages
3,445
Location
SoCal
I disassembled my motor and took some measurements for the rebuild. I have a used crankshaft that I'm planning to put in the car, and took some measurements just to verify it is good. The strange thing is that the measurements I took on the new crank are identical to that of the old one. Simply, the smoked crank that's in the car right now measures out to be identical to the used one I have. That wouldn't be strange normally, but both cranks are identically under factory specs. Here are the measurements:

Old crank (smoked)

Main Journals
1= 2.234"
2= 2.234"
3= 2.235"
4= 2.234"
5= 2.235"

Rod Journals
1= 1.762"
2= 1.762"
3= 1.762"
4= 1.767" (This was the burned journal)




Newer crank

Main Journals
1= 2.235"
2= 2.234"
3= 2.234"
4= 2.234"
5= 2.234"

Rod Journals
1= 1.762"
2= 1.762"
3= 1.763"
4= 1.762"

Rod Journal OD spec = 1.7709-1.7715
Main Journal OD spec = 2.2433-2.2439

It looks to me that BOTH cranks have been cut down .010" on both the main and rod journals. It's just blowing my mind that both cranks are measuring out under specs, but are measuring out exactly the same? I know my mics are reading right, and I double checked each mic measurement with my dial caliper just to be sure. What are the chances of that? Additionally, the bearings I pulled out of both the main and rod journals say .25 on them. I thought this was a standard bearing, but now I'm not so sure. Does .25 usually identify a standard bearing? Any help or input is greatly appreciated.

Here is a pic of the bearings.

The main bearing is engraved: M1-1085 .25 NDC

The rod bearing is engraved: C1-1085 .25 NDC

 

rdomeck

Well-known member
Joined
Jun 1, 2011
Messages
620
Location
Indianapolis, In.
By your measurements and the bearings saying .25 you have a crank that has been turned down. These cars have nitrated cranks in them. Meaning that the journals are ground to size and then hardened. If there is any way you can find an uncut used crank you will be better off. Chances are your crank was not ground correctly and that is why you have a burned journal!
 

G

Staff member
Joined
Feb 24, 2004
Messages
8,896
Location
zompton
Ndc is the bearing manufacturer. They make a lot of oe bearings and private label for mahle. So if you buy some clevite bearings the part numbers are usually the same as ndc. Look on pg. 26 click and pg.s 45 and 46 here click To see if m1-1085 is there. I'm assuming that one is the lower bearing? .25 is definitely the size. Probably from mitsubishi. If not then email these guys for help >> [email protected] [email protected] [email protected] [email protected] click

As far as the crank goes, if you send it to castillos crankshaft he can fix it. He can re-polish and harden and or add material and then polish and harden.

I just checked some that I happen to have laying around. The oil holes look different than yours. This one is a lower crank bearing. m1-1164 L (lower) std (standard) from the ms-1821a set.

img6721i.jpg


img6725l.jpg


img6726l.jpg
 
Last edited:

GSTwithPSI

Well-known member
Joined
Jan 1, 2012
Messages
3,445
Location
SoCal
Thanks G. Your post definitely confirms my crank has been cut .010 under. I took the crank I was planning on using to the machine shop today and the machinist said it was too grooved to be polished, and that it would have to be cut. It's already .010 under, and I'm not comfortable going more than that. I guess I'm in the market for a new crank now.
 

G

Staff member
Joined
Feb 24, 2004
Messages
8,896
Location
zompton
Castillos can fix yours and bring it back in to spec for the cost of a used one that may or may not be at the tolerances you want. If you don't want those cranks lmk i'll take em'.
 

G

Staff member
Joined
Feb 24, 2004
Messages
8,896
Location
zompton
La Mirada, CA. Castillos crankshaft.
 

89Mirageman

Well-known member
Joined
Jul 5, 2006
Messages
2,502
Location
Stantonsburg, NC
Even the na 89-92 Galants and the na 90-92 dsm's had the same crank. You should be able to find one fairly easy in the local junkyard for $50 or less and an afternoon of work pulling it. Even less if you get lucky and the trans is out. You can even drop the pan and pull the caps to check its condition. I did this a few months ago with an 05 Galant.
 

donniekak

Well-known member
Joined
Jan 1, 2009
Messages
748
Location
surprise az
Go get another crank. There are to many 4g63 cranks out there to dump cash into fixing one. Pull one at a junkyard for $30-$50, pay another $40-$50 to have it polished, and be better off.
 

EMX5636

Well-known member
Joined
Jun 28, 2008
Messages
1,631
Location
Bucks County, PA
The normal stroker is the 100mm crank. But I would pick a checked/polished Mitsu crank over an Eagle every day of the week.
 

boostin4door

Well-known member
Joined
Oct 7, 2006
Messages
150
Location
Chicago, Il.
"Go get another crank. There are to many 4g63 cranks out there to dump cash into fixing one. Pull one at a junkyard for $30-$50, pay another $40-$50 to have it polished, and be better off."
"But I would pick a checked/polished Mitsu crank over an Eagle every day of the week."

^ Agree w/both.
 
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