Toyota Celica Supra Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
151 Posts
Discussion Starter #1
Will the underdrive pulleys for the mkIII work for us...I don't have time to check it out right now can't hit boneyard till next week and unorthodox racing only offers '86 and up..(Big surprise). Need to shed a few pounds.

TEMPEST

be original.....offer a product for the MKII
 

·
Super Moderator
Joined
·
8,395 Posts
No. It will physically fit on a 6M crank, but the pullies are different between 5/6 and 7M motors. The snout is smaller diameter on the 5M crank so it won't directly fit at all.
 

·
Super Moderator
Joined
·
8,395 Posts
snout=end of crankshaft where the pulley, timing cogs, etc slide on. Common engine lingo.
 

·
Registered
Joined
·
9,445 Posts
In addition to this......

Some of those UD crank pulley's DO NOT have a harmonic balancer attached to them... At certain rpms, the engine does get harmonic vibrations, not good in the long run for the motor at all.... Several SOGI members have confirmed this, along w/ a few personal MKIII PacNW members, who went back to the stock 7M crank pulley...
 

·
Registered
Joined
·
4,871 Posts
Yes, Good point, Chris!! The harmonic balancer, also sometimes referred to as a harmonic or torsional dampener, helps to counteract or dampen the torsional forces (twist) placed on the crankshaft. The timing belt helps dampen some of the torsional twist but not near enough to be fully effective by itself. Removing the harmonic balancer can cause undue stress on the crankshaft and also raise cane with the crank and rod bearings. The crankshaft on an inline-6 engine is fairly long and more susceptible to twisting from torsional force than say a 4-cylinder Honda engine. :roll:
 

·
Registered
Joined
·
1,186 Posts
I would never install an underdrive crank pulley on an inline 6 for the reasons outlined above. There are other ways to make power (turbo) that are safer.
 

·
Registered
Joined
·
1,661 Posts
Underdrive pulleys are one of those things you install when you're chasing the last fraction of a hp, AFTER you've explored every other avenue of increasing your engine's power. Seriously, on anything less than a full-house race engine, you're not going to notice the difference. Don't waste your time!
 

·
Registered
Joined
·
406 Posts
Ive been trying to tell this to the Honda boys in town for years... thank god Ive found other people who believe it too!

If Steve Dinan wont use them for those reasons, then thats good enuf for me.

Aaron
 

·
Registered
Joined
·
15,035 Posts
also, by running a lightweight crank pulley and flywheel, you hurt the tq curve.
 
1 - 10 of 10 Posts
Top