Need Help Determining a Noise

[DSM_23]

About a year ago I had raced my car right when I just started driving it, and after the race I noticed this slight sound almost like a knock but not loud like rod knock, but it happens whenever I ease the throttle around the 2800-3800rpm mark. If i mash it i dont tend to hear it, but especially if I free rev it to around thoughs rpms in neutral I hear it clearly, I haven't really looked into the noise very much because I didn't think much of it, but lately I've gotten curious and would like to figure out what it is, it seems to be coming from around the timing belt area, so that makes me think its my T-belt tensioner possibly.....i cant really think of what else it could be, what other possiblities are there? Any advice on what to do would be appreciated.

justin

 

[hose101772]

My 91 did that,upon tear down I noticed the rear balance shaft bearing surface had been ground away,flat spotted on the heavy side.It didn't shake or do anything strange,just a light knock at mid rpms when unloaded.

 

[DSM_23]

so do you have any suggestions on what i should do to stop this noise?

 

[BUCK]

Install a Balance Shaft Eliminator Kit.

http://www.vfaq.com/mods/balance-shafts.html

 

[DSM_23]

ok, so why would the balance shaft be making this sound around that rpm in the first place? I dont want something unexpected to go wrong, or is it really that big of a deal?

 

[BUCK]

Read the link! Especially the part about Balance Shaft Bearings seizing & potential wrecking your entire Motor - Experienced people are taking the time to give you the benefit of their experience - It would be courteous of you to take the time to READ what we've provided rather than ask a question which was already answered in our previous replies.

 

[DSM_23]

I did read the link, but i was basically just wandering is this the only possiblity of what the noise could be? Removing the balance shaft seems like a hell of a job also or is it not that bad?

 

[BUCK]

DSM_23 wrote on 02-29-2004 06:35 PM:
Hey reffering To your post on my topic about the strange noise, what is actually making the slight knocking sound coming from the BS? And i know there is the BS eliminator kit, but could you tell me whats the difference if say, I cut the BS belt only? It sounds like that makes sense to me. But im just wondering out of curiousity.... Thanks for your advice also in my posts.justin

Your symptoms as described are CLASSIC B/S problem - going into denial won't save your motor.

I did mine with engine in car so I just took the belt off the front Balance Shaft & removed the Rear B/S & replaced with Stub Shaft - If your car has the original Oil Seals in the Front Case you need to change them out anyway so it's not that much extra to do what I did. You'll be glad you did - there are SCORES of guys who didn't & regret it.

It's knocking like a bad rod bearing - You'd have to SEE a Balance Shaft to believe it - They are DAMN long & DAMN heavy - With a BIG counterweight on ONE side, so THEY THEMSELVES ARE NOT BALANCED (gee - I wonder why they eat bearings) - They are UNBALANCED shafts that spin at TWICE the rpm the Crank is spinning at - The Rear B/S is oil fed DIRECTLY off the Oil Pump - Oil flow that COULD be pumped elsewhere (& IS when you install the stub shaft from the Mirage) - The Front B/S is Oil fed DIRECTLY off the Main Oil Galley that feeds your Main Bearings & Squirters - Once again when you disable the Front Shaft more Oil flow can feed your bearings & rods like it should be doing.

If you cut the belt you only disable the FRONT B/S - & your Engine will shake like a SUMBITCH because you still have the Rear Counterweight / Balance Shaft spinning with no sister Counterweight spinning.