Is my Crank Pulley/Harmonic Balancer bad?

[chris89]

Hi, a while a go i noticed something that sounded just like a rod knock... so i took it to a shop and it was the bolt that holds the pulley, it was missing... They put a new one on and the engine ran super smooth with no knock... Until my headgasket went bad then after everything was done and tightened the pulley bolt up, now i can see a pretty decent amount of wobble in the pulley... and it sounds like it's a light knock just like before. It's most audible at idle. I found a pulley for less than $100 Brand new, is that a good deal. Also the engine is fully rebuilt less than 10k ago... so it's not bad bearings.

 

[jdub]

The bolt has either loosened up again or the keyway is FUBAR. You'll have to pull the dampner (pulley) to be sure. $100 for a new dampner is good

 

[AJ'S 88NA]

Hope you are not driving it that way and you caught it in time, it can hammer your bearings.

 

[chris89]

I was thinking about getting an underdrive crank pulley made by OBX... should i do that or just go with a factory brand new balancer?

 

[Tanya]

brand new balancer is going to cost you about $400. Probably can find a decent used one that's not chipped, cracked or destroyed where the keyways go.

 

[IJ.]

OBX one isn't a damper it's just a pully and NOT a good idea for a 7M.

Pity about the distance I have a 4000 Km old one here I swapped out for an ATI when they started making them but postage would kill due to the weight.

 

[chris89]

well i wanna get a pulley that increase power and gas milage and make the engine smoother... what underdrive crank pulley would i wanna get? Specific brand, model, Website?

 

[IJ.]

No such thing for a 7M other than the ATI one, it's about half the weight of stock but doesn't underdrive anything (not the best idea anyway as the waterpump can barely keep up at idle/low rpm now)

 

[chris89]

ok well that clears it up. I'll just get a brand new factory crank pulley. I've heard lots of bad things about underdrive crank pulley's as they don't have a damper so it'll vibrate more? and cause engine problems? So why do ppl say they gain power and gas milage and the engine is alot smoother? that's exactly what i want... What about an unorthodox underdrive crank pulley? Does anyone have one and have anything to say about it?

 

[IJ.]

UO same same just a pully

 

[JesseH]

UO same same just a pully

wasn't there a whole thread about this awhile ago that gave some in depth diagrams that I believe Jdub posted?? oh and Ian, as I was looking for that thread I noitced that you were the last post on almost all the threads that were refering to a "light weight underdrive pully" ....i guess people just dont get it lol

 

[IJ.]

LOL I'm consistant

 

[chris89]

ok well i found out that the pulley i thought was brand new had less than 40k on it for $80... Should i risk it? or just get a brand spankin new one from the dealer or something? I think they are about $320!!!

 

[cuel]

Around 40k miles is okay. Mine have over 200k, and its still intact. What does the crank look like? The key way worn, or the key damaged?

 

[chris89]

I'll take some pics after i pull the pulley off to pull the new one on... What would it mean if the key way was worn? and if the key was damaged?

 

[cuel]

If the key way in the crank is worn(key fits loosely, or the notch is damaged), you'l need to have it repaired, or get a new crank. If the key is broken, or the edges are badly rounded, you need to get a new key. Either way, if you just slap a new pulley on, and the crank or key is messed up, it won't be long and you'll have the same problems.

 

[chris89]

When we were putting it in time, the crank had 5* of play in it before the cam gears would start turning... what's that all about?

 

[cuel]

Timing belt tension is incorrect, or you're turning it the wrong way.

 

[chris89]

turning it counter clockwise it would have 5 degrees of play but clockwise there was no play. Before there was no play in either direction...

 

[cuel]

Timing belt adjustment, or maybe a loose tensioner. The belt is rubber, and will eventually stretch. CW is the correct way to turn the motor. CCW is backwards.