I'm currently fixing a rod knock issue on a friends 7mge-t. I sent the crank off to the machine shop to get cut(.010 mains and rod), and the rods to get reconditioned with arp bolts. Well I pick the stuff up and when I get back to the shop I noticed the crank says 6m on it, now before I get pissed at the machine shop is this going to cause a balancing issue? sorry if the question sounds stupid but I did 2 hours worth of searching and the only thing I found out was the 6m crank is a little lighter.
Need a ? answered (machinest inside)
- Thread starter sagillman
- Start date
Early 7M's had the 6M crank after 89 they got the unmarked fully counterweighted heavier 7M crank that looked to be practice for the Jz crank.
IJ.;1289042 said:
ok, I did not have the pleasure of pulling it apart(just putting it back together) or I would have noted what was in there. its not the original motor to the car though. is there anyway to tell when the block was made to make sure it's pre 89 so I have piece of mind that its suppose to have 6m crank in it?
The cranks are fully interchangeable, so don't worry about what block you have. If you still want to know if its an early or late block, do a search. The later blocks have more reinforcements if the form of more ribs.
I ran both cranks to 8300BLACKCAT;1289043 said:
See the pics below>>sagillman;1289046 said:
Block differences are in the pics below click them to enlarge I've written what to look for on em, the light block is an 87T the Heavy is my New 93T from Toyota.
[thumb]http://ij.supramania.com/blocks00.jpg[/thumb]
[thumb]http://ij.supramania.com/blocks01.jpg[/thumb]
[thumb]http://ij.supramania.com/blocks02.jpg[/thumb]
[thumb]http://ij.supramania.com/blocks03.jpg[/thumb]
sagillman;1289046 said:
What year car was this motor pulled from...that will tell you if it's supposed to be a 6m crank.
thank you IJ I'll take a look at the block tonight. gaboon the car is an 88 but he told me his dad had to swap another motor in 2 years ago because he said it was cheaper then taking it somewhere for a blown head gasket repair (before he met me), and doesn't remember what year car it came out of. I'm just trying to be thorough before I put it back together, which will be fun seeing how when I asked for all the bolts to put it back together he handed me a gallon bucket half way full of assorted bolts no labels or anything:aigo:.IJ.;1289256 said:I ran both cranks to 8300
See the pics below>>
Block differences are in the pics below click them to enlarge I've written what to look for on em, the light block is an 87T the Heavy is my New 93T from Toyota.
[thumb]http://ij.supramania.com/blocks00.jpg[/thumb]
[thumb]http://ij.supramania.com/blocks01.jpg[/thumb]
[thumb]http://ij.supramania.com/blocks02.jpg[/thumb]
[thumb]http://ij.supramania.com/blocks03.jpg[/thumb]
If I remember IJ's past comments correctly, the 7M was smoother, while the 6M revved faster, but 'thrashier'
Yep after about 6000 they both felt much the same, the initial acceleration of the engine was much quicker with the 6M but it was harsher from idle to 6000.
This is what lead to my lightened 7M.
This is what lead to my lightened 7M.