Pepsi or Coke?

SupraDupra · 03-11-2007, 08:00 PM

I have two crankshafts for my '88 7M-GE. They have the same sizes on all bearing surfaces and are almost perectly identical ,except every 3rd counter weight is in a different location. Which one is correct? Here is my poor artistic representation of what's cast into the two cranks.

jfunez · 03-11-2007, 08:52 PM

I think as long as you are sure both are 7m ge , the location of the counterweights is of non importance..since they are placed on the crankshaft in order to balance them and since no 2 crankshafts are balanced the same...it would'nt matter....

SupraDupra · 03-11-2007, 09:08 PM

I got my camera to cooperate for five seconds ,here's a pic...

mrnickleye · 03-11-2007, 09:40 PM

It looks like there is more 'mass' on the crank to the right side of photo.

Where did you get 2 cranks??
Which is the one outa your car???

I believe I read somewhere (here, or SM forum) about a crank update in '89, that was for better balance, and less vibration.

Perhaps one of those is an updated version.

SupraDupra · 03-11-2007, 11:04 PM

The one on the left is out of my engine ('88),the one on the right I bought used (exact year unkown) . All the tolerances are dead on and the working parts seem to be in the correct locations. That'd be nice if it is a lower vibration version.

IHateHacks · 03-12-2007, 02:06 AM

Well Mr. Nickleye, I got this out of one of your threads in the FAQ's:

And I quote: In 1988 "Toyota began using the "7M" crankshaft mid-year, with dual counterweights to improve smoothness. The extra weight also caused the redline to drop from 6500 to 6250."

"The 86.5 Supra had a new block under the hood, although it used the crankshaft from the JDM MKII's 6M-GE"

So from 86.5-88.5 ALL supras came with cranks from MKII JDM 6M-GE's.

And from 88.5 on they came with true 7M cranks.

03-11-2007, 08:00 PM	#1
SupraDupra 3" Exhaust Join Date: Oct 2006 Location: Cleveland OH Posts: 129	More crankshaft curiosity I have two crankshafts for my '88 7M-GE. They have the same sizes on all bearing surfaces and are almost perectly identical ,except every 3rd counter weight is in a different location. Which one is correct? Here is my poor artistic representation of what's cast into the two cranks. Attached Thumbnails __________________ 1988 Supra - N/A 5 speed 1974 'Cuda - 318 2001 Cherokee Last edited by SupraDupra; 03-11-2007 at 08:52 PM.

03-11-2007, 09:08 PM	#3
SupraDupra 3" Exhaust Join Date: Oct 2006 Location: Cleveland OH Posts: 129	I got my camera to cooperate for five seconds ,here's a pic... Attached Thumbnails __________________ 1988 Supra - N/A 5 speed 1974 'Cuda - 318 2001 Cherokee

03-11-2007, 09:40 PM	#4
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	It looks like there is more 'mass' on the crank to the right side of photo. Where did you get 2 cranks?? Which is the one outa your car??? I believe I read somewhere (here, or SM forum) about a crank update in '89, that was for better balance, and less vibration. Perhaps one of those is an updated version. __________________ Had a Red 1989 N/A. Automatic. Sports Pkg. w/wing. TEMS, and some nice MODS. Sold to a friend 10/08/08. Last edited by mrnickleye; 03-11-2007 at 09:43 PM.

03-11-2007, 11:04 PM	#5
SupraDupra 3" Exhaust Join Date: Oct 2006 Location: Cleveland OH Posts: 129	The one on the left is out of my engine ('88),the one on the right I bought used (exact year unkown) . All the tolerances are dead on and the working parts seem to be in the correct locations. That'd be nice if it is a lower vibration version. __________________ 1988 Supra - N/A 5 speed 1974 'Cuda - 318 2001 Cherokee

03-11-2007, 08:52 PM	#2
jfunez 12psi boost Join Date: Oct 2005 Location: georgia,usa Posts: 338	I think as long as you are sure both are 7m ge , the location of the counterweights is of non importance..since they are placed on the crankshaft in order to balance them and since no 2 crankshafts are balanced the same...it would'nt matter....

03-12-2007, 02:06 AM	#6
IHateHacks 20psi boost Join Date: May 2006 Location: New Haven/Hamden Posts: 793	Well Mr. Nickleye, I got this out of one of your threads in the FAQ's: And I quote: In 1988 "Toyota began using the "7M" crankshaft mid-year, with dual counterweights to improve smoothness. The extra weight also caused the redline to drop from 6500 to 6250." "The 86.5 Supra had a new block under the hood, although it used the crankshaft from the JDM MKII's 6M-GE" So from 86.5-88.5 ALL supras came with cranks from MKII JDM 6M-GE's. And from 88.5 on they came with true 7M cranks.