Noise Over Bumps

[patkeefe]

I just rebuilt all of my suspension, then retrofitted Chuck Moreland's Elephant PolyBronze in the front. I have developed a noise in the rear over bumps, mostly over small deflection bumps. It's more like a dull thud. I can't duplicate it by jumping on the car, jacking it, rocking it from side to side. All of the new suspension parts are tight, torqued up to specs. I though maybe it was the hood, but it's not, nor is it the shock cover, or undercar A/C condenser.

I had a similar noise when I first got the car, right side engine mount top washer was caving in. I put a couple of big steel washers in there, and it went away. I just put some new steel washers in the same one, as the old new fix was getting concave also.

What do mounts sound like when they go bad? The right side rubber in the mount is torn up on one side, kind of like a loaf of bread that you rip apart at a restaurant, and just a chunk was taken off. However, I can't duplicate the noise on hard acceleration, deceleraton, engine revving, and it does it when I coast down my street over the little bumps. I am officially baffled.

Pat

[Randy Blaylock]

Beer bottle under the seat?

[patkeefe]

No such luck

[patkeefe]

Well, I put the WEVO engine mounts in tonight. Now, it doesn't make that noise any longer going over bumps. It just transmits noise all of the time.

I have to change the trans mounts next, and continue searching for that beer bottle.

Pat

[patkeefe]

Ok, so now I put in the WEVO trans mounts. I have now gone from annoying intermittent noise, to full time noise, to now having a locomotive in the back of the car.

This beer bottle has taken on a life of its own.

Pat

[Randy Blaylock]

Must be a "40" :-)

[patkeefe]

Maybe a couple of Grolsch bottles, filled with buckshot. Those WEVO mounts sure do isolate...I have a nice high frequency vibration coming into the gearshift lever too. Maybe I'll reset the coupler.

[island911]

Originally posted by patkeefe
Maybe a couple of Grolsch bottles, filled with buckshot. Those WEVO mounts sure do isolate...I have a nice high frequency vibration coming into the gearshift lever too. Maybe I'll reset the coupler.

state of the art





loose CV ?

[patkeefe]

I think my CV's are crap, but I took them apart and relubricated them when I did the suspension. I considered this as part of the problem. They work, and I'll replace them over the winter during the Project X phase of rebuild.

I have the noise with the car running and not moving. The noise is present running on level floor, or having the rear up on jackstands. I find nothing unusual when poking around with my stethoscope. But the noise is really like a deep rumble. I could swear its like a exhaust or muffler noise, but I can't locate it. The noise magnifies when the car is in motion.

I used to be a good diagnostician, but I have, alas, become stupid, evidently. Maybe I can think this over some more as I power wash the deck.

[Hoffman912]

wevo engine mounts are stiffer and more geared towards racing. read they are not for comfort, but for durability. dont expect to be noise free and as comfortable as the car was new.

[patkeefe]

I did keep this in mind when I bought them. However, this problem is just being magnified by the mounts. it seems. A little noise is ok, but this is really bad.

[island911]

while stopped, does the prob go away with the clutch in?

(isolating the prob to the motor or tranny)

[Hoffman912]

when you replaced the spring plate bushings did you replace the bannana arm bushings as well? how are the rear shocks?

[patkeefe]

Harry/Doctor:
I took off the belt for the A/C compressor. I noticed a small gap where one of the top right engine studs passes through the carrier plate. Evidently there is supposed to be a nut on there? Huh? So. I'm looking for a nut, and see if that improves it.

Problem remains wih clutch engaged or disengaged...I even adjusted my clutch last night as part of "possible cause elimination" witch hunt. I have found that I need alternator bearings, and I have a myriad of oil leaks.

Every freaking bushing in the suspension is new, along with new Bilstein Sport shocks, wheel bearings. Practically everything from the point of ground contact to the point of mounting to the body is new.

I also appreciate the thought your are giving this on my behalf.

Thanks!
Pat

[patkeefe]

OK, I put the nut on, so that the engine is solidly mounted to the supporting structure carrier. The starter is on tight. Everything appears very solid.

I'm wondering about the alternator bearings now. However, the noise is not very high pitched, more like a low, loud rattle, and not dependant on engine speed. It is more prevalent at higher RPM.

It's not the main bearings, as it doesn't get noticeable when I go up a steep hill to put a big load on the engine. I think I should peek into the tunnel. Maybe adjust the valves also.

[patkeefe]

Ran the motor this morning, cold, with the altenator belt off for 20 seconds (don't try this at home kids). No noise...hmmmm. Changed to a new belt, played with the shims and tension for awhile. Much improved. Now I'm back to the original question/statement of just having the vibration over bumps.

Of course, every modification I have done to this car has been to firm up the ride, so I expect a bit of harshness, but this is out of the ordinary. I'll get it eventually.

BTW. I used the leaf blower for cooling after the brief run this AM; very effective.

Pat

[patkeefe]

Update on the noise problem...

I have suspected the right rear shock absorber, and with the three day old tires, and a few trips at Watkins Glen, the noise was really starting to annoy me. So, when I got home today, I disconnected the rear shocks and took the car for a ride on my street, in the sections where I always hear the noise. Holy crap, the noise went away!!

So, I called Bilstein. They're stumped also, but offered to examine them on their dyno. So, I'll send them in when the winter arrives.

But, it gets better! While reinstalling the lower shock bolts into the trailing arm, the left side bolt lost it's grip long before it reached the 92 ft-lb of torque. Damn threads stripped in the trailing arm. So, now I have to find a 14 x1.5 heli-coil kit to fix it. So, if anyone happens to have one lying around, let me know. Or, if anyone has another solution, I'd be obliged to hear it.
Pat