Fan belt too tight...caused damage ?

Trueoo7 · #1 (**permalink**) 07-02-2007, 09:22 PM

Not my car but my brothers, after about 500 miles on a ford crate engine
(302) EFI. Started making a rattling noise, removed the fan belt which was very, very tight and the noise goes away. Decided to replace the water pump which it turns out he had the wrong one on anyway, alternator was fine. Put the fan belt back on and he still has the noise. Adjusted the fan belt ever so slightly and noise goes away somewhat. Changed out the fan belt to a slightly longer one for more adjustment and the noise, while not totally gone is there on deceleration only and only for a brief second or two, if you don't listen carefully you'll miss it. Decided to check the oil and filter. Oil looks very clean and cut the filter open and found no babbit material whatsoever.

We're thinking that due to the extra tension put on the front main bearing from the belt being so tight that this may be the start of a problem down the road. Has anyone else run into this problem? We've been told that the snouts on 302 are not all that beefy and this could have caused undue wear. Planned on pulling the engine this winter for a better look, if it makes it that long.

vettestr · #2 (**permalink**) 07-02-2007, 10:56 PM

You are fine and have not hurt the main bearings with a tight v-belt. We run roots blowers that are belt driven and no bearing harm is caused by the belt and I am talking about several hundred horse to turn the blower at full boost/RPM.
You would pull the v-belts apart before any damage would be done so do not worry about bending the crank or taking out the main bearings.Extra bearing wear on an alt. or water pump bearing would happen way before main bearing damage.

lineslinger · #3 (**permalink**) 07-02-2007, 11:08 PM

Quote:

Originally Posted by vettestr

You are fine and have not hurt the main bearings with a tight v-belt. We run roots blowers that are belt driven and no bearing harm is caused by the belt and I am talking about several hundred horse to turn the blower at full boost/RPM.
You would pull the v-belts apart before any damage would be done so do not worry about bending the crank or taking out the main bearings.Extra bearing wear on an alt. or water pump bearing would happen way before main bearing damage.

But you may have cooked the bearings in the water pump, keep listening.

vettestr · #4 (**permalink**) 07-03-2007, 12:19 AM

Hey Lineslinger,
He mentioned the original engine and pump only had 500 miles on his Toy when problem noise appeared. They just replaced the water pump but noise still remains but a little better. With the newer engines using the serpentine belts also use reverse rotation pumps. I have chased 1 weird noises to find the pump is caveatting do to being driven the wrong direction, but it was not overheating to my surprise. I think advise to keep listening is good advise.

Trueoo7 · #5 (**permalink**) 07-03-2007, 07:37 AM

Vettestr
You are correct, to our surprise we did replace the water pump and found the first one was the wrong rotation, funny thing was it never overheated, stayed at 180-190deg.. Put the new one on and no difference, still 180-190deg. Will keep listening though. Good point about the blowers, you would think the belt would come apart first !!

vettestr · #6 (**permalink**) 07-03-2007, 09:25 AM

True,
We do now run a front bearing plate or brakets that help remove pull from blower belt but this is to reduce broken crank snouts more than bearing wear. it takes from something like 200 to over 600 horse power just to turn the blower with the bigger displacement blowers at RPM. The fuel boys make and consume crazy numbers compaired to an alky car like we run. Here is a fun facts page for the fuel guys. http://www.motortrend.com/features/c...ers/index.html

trularin · #7 (**permalink**) 07-03-2007, 11:37 AM

try Silicone on the belt.

Jac Mac · #8 (**permalink**) 07-03-2007, 02:51 PM

I know it sounds simple ,but have you checked the Bolt holding the damper on to the crank along with the 4 bolts of the crankshaft pulley. I have seen cases where the shank of the pulley bolts bottom out just as the bolt starts to clamp the pulley due to different material thickness etc, and gives the impression that all is well, but the pulley can move slightly under load.

Jac Mac

Trueoo7 · #9 (**permalink**) 07-08-2007, 08:40 PM

Jac Mac
I will pass that along to him. He drove it around this weekend and no apparent noise or damage with the longer belt. We'll see what happens....
Thanks

CHANMADD · #10 (**permalink**) 07-08-2007, 10:36 PM

With that tight a belt you may have cracked a pulley,either crank or water pump.