Underdrive crank screwup

Dirk SC

Dirk SC

Registered User
I managed to install my crank pulley from an underdrive set on but I noticed it went on funny and wobbles when i turned the car on. DONT WORRY I WONT TURN IT ON AGAIN TILL FIXED.

After the fact I did a search on the forum and read that the bolts are not symmetrical and there is a certain way to put it on.:( The underdrive pulley is on and my question now is how screwed am I and how do I fix my mistake.

Edit* I know i can take it off again but i am worried about damage to the threads.
 
Either way the threads are probably damaged. They arent going to get stripped coming out, only going in wrong. I had a heck of a time putting mine on. I turned the crank so one bolt was at the top. I put it in half way and tried the rest. When one started to go in wrong, I removed them and turned the pulley clockwise and did the same thing until they went right in. The pulley was a tight fit on the HB so I had to tap it on each time to make sure it was flush first.

The only problem is I think you are suppose to use loc-tite and I didnt. Hope this helps. Just pull them out, look at the threads and start over.
 
Dirk SC said:
I managed to install my crank pulley from an underdrive set on but I noticed it went on funny and wobbles when i turned the car on. DONT WORRY I WONT TURN IT ON AGAIN TILL FIXED.

After the fact I did a search on the forum and read that the bolts are not symmetrical and there is a certain way to put it on.:( The underdrive pulley is on and my question now is how screwed am I and how do I fix my mistake.

Edit* I know i can take it off again but i am worried about damage to the threads.
Click to expand...

It's probably okay...might just need a new set of bolts.

David
 
So what is the best way to install it then. Just turn it until all the holes line up nicely, or is there a trick to it? Thanks for the replies.
 
If you can't eyeball it, you'll just have to turn it till the holes line up and try the bolts till they go in easily. I think the holes are made that way so people wouldn't put the pulley on wrong, thus getting the motor out of balance.

With the crank pulley up against the balancer flush, if you can't get more than two of the bolts started, then it needs to be rotated a 1/4 turn and try again till they line up.
 
The shop installed my crank pulley incorrectly as well. I just retapped the holes and it has held so far. I have a BHJ though, not sure if that makes a diff.
 
Nope. Took it off and tried new bolts. Two went in fine and the other two wont.I have never retapped anything and im tired of messing with it so into the shop it goes tomorrow. Hope its not too bad. Thanks for the help guys.

BTW what is the advantage of a BHJ balancer? Mine still works fine as far as I can tell.
 
How much wobble?? very noticable right away?? I installed a BHJ and March pulleys and I have a "little" wobble. Or was yours shakin all over the place?
 
Dirk SC said:
Nope. Took it off and tried new bolts. Two went in fine and the other two wont.I have never retapped anything and im tired of messing with it so into the shop it goes tomorrow. Hope its not too bad. Thanks for the help guys.

BTW what is the advantage of a BHJ balancer? Mine still works fine as far as I can tell.
Click to expand...

Listen.....two bolts will go in fine if you don't have all four holes aligned. This is what gets most people. Keep trying to get all four holes to align and when they do you'll know it is right on. I just kept rotating the pulley until all holes were aligned. Have you tried this?
 
pablon2 said:
Listen.....two bolts will go in fine if you don't have all four holes aligned. This is what gets most people. Keep trying to get all four holes to align and when they do you'll know it is right on. I just kept rotating the pulley until all holes were aligned. Have you tried this?
Click to expand...

Thats exactly what I said in the first place. Turn the crank so there is a bolt hole at TDC. Tap the pulley on. Start the top screw and put the others in. If one goes in cocked. Turn the pulley one hole clockwise and try again. Keep doing it until all four go in straight. The hardest part is bending over the core support.
 
pablon2 said:
Listen.....two bolts will go in fine if you don't have all four holes aligned. This is what gets most people. Keep trying to get all four holes to align and when they do you'll know it is right on. I just kept rotating the pulley until all holes were aligned. Have you tried this?
Click to expand...

Two bolts will not go in fine with nothing on it. I tried the bolts without the puley on just to see if they would thread fine or not. No dice.
 
Isn't it highly recommended to use a BHJ dampner when using any aftermarket (zero balanced) crank pulley? Since the stock pulley and "balancer" are balanced to each other (not the engine) they need to stick together. When you swap an aftermarket pulley on, you risk ruining your balancer, since the new pulley isn't balanced to your old balancer.

...lots of balance in that paragraph...
 
DrFishbone said:
Isn't it highly recommended to use a BHJ dampner when using any aftermarket (zero balanced) crank pulley? Since the stock pulley and "balancer" are balanced to each other (not the engine) they need to stick together. When you swap an aftermarket pulley on, you risk ruining your balancer, since the new pulley isn't balanced to your old balancer.

...lots of balance in that paragraph...
Click to expand...

Is this true?
 
Payton said:
All aftermarket pulleys have to be 0 balanced, shouldn't they?
Click to expand...

I'm not sure but I got them from Ryan and I have heard nothing but great stuff about his product. This is the first time I have ever heard of underdrives putting the balancer out of balance.

I find out if I need a new one tomorrow or not. Luckily I have a parts car in case.
 
Dirk,
A retap is easy. You find the correct size tap and gently spin it in while keeping it strait. After a few threads, it should pull itself in. Just make sure you start it straight and your set.
 
You must log in or register to reply here.
Back
Top