I bought this poly kit last winter but have since read on several occasions that they have, or cause, problems. In fact Willcox does not endorse them and recommends OEM-style rubber although they do sell them. It has not been clear to me what the problems with poly are. This is not a big-ticket item (my labour is) and I can get the rubber version if need be but what harm, if any, would be done if I install them? Just curious.

 

I'm awaiting delivery any day now the same parts. I'm interested in replys also

 

ive got full poly in my rear suspension, including that poly diff mounting set up. not a single problem with it so far, and no squeaks from anything either.

 

do ypu experience any wheel hop??....just wondering if that is the problem.......

 

I would question the sources of where you read of these issues. If they're only saying that they had problems without expanding on the problem, then take it with a grain of salt.

 

I used an aluminum one from Guldstrand in mine. Afterwards, I had a problem that on a good launch, the u-joint would rub the tunnel (a '64).

I added two fender washers above the mount and this provided the needed clearance and solved the problem. With the car on the lift, it wasn't difficult to remove the bolt and using a big screwdriver, pry the pumpkin away enough to slip in the two washers and reinsert the bolt.

 

First thing I'd do is to trash the poly bushings where the diff nose snubber bracket attaches to the frame and replace them with the correct OEM rubber bushings that have the molded-in tubular spacer and bonded washers; the poly bushings for that application are junk - they're too thin, and don't have the spacer tube or washers.

This is a typical comment that I don't understand. All the parts are there.



Just as a diversion, I had the chance yesterday to drive with new front shocks and poly swaybar bushings. The front end felt very firm and solid compared with the old shocks and deformed rubber bushings. I am rather pleased.

 

I have had VBP poly mounts on that snubber for some 15 years, and over the last few months have noticed some clunks in the back end under my butt.....dunno the source yet, but I typically have to hit the gas in order to induce the sound....

busy with other things so not remembering to get under there and check it....did ONCE and tightened hell outta that main bolt...but no change....

 

Haven't had any issues, but only put about 400 miles on my set up.

 

I'm beginning to think that this is a non-issue but I respect the Willcox folks and they do not seem to recommend poly. Perhaps Norm or Ernie are out there and can comment. They do sell the product (via Corvette America) and I bought it.

 

Some of the poly throw off the alignment on the diff because the dimensioning is off, just like the ES poly trans bushings. Some are ok but some are crap. Never had a problem using the rubber bushings Bairs sells, I would consider it a non issue. Have seen imported ones sold by other vendors without the steel sleeve as well. Your car,your choice but I sure would never use them on a st car.

 

The issue might affect the C2 cars more than ours; the poly cushions are much thicker and and are not as compliant as the OEM rubber. This has lead to drive train vibration issue and in some cases the rear u-joint striking the underbody.

Like many of the poly bushings they are a perfect solution to a non-problems, every marketing man's dream come true. Sham-wow forever!

 

Gary,
What is an "st car"?

 

Mike,
I saw that thread over in the C2 area. And the quote comes from JohnZ whom we all respect as a wealth of knowledge. I really don't have problems in that area at the moment. I'm going through my 1974 bit-by-bit for 35-year-old maintenance. Perhaps if Willcox will give me a tit-for-tat I can just exchange for rubber. But you know the shipping etc. to Canada is more than the product cost....

 

I have been running one for 2 years and had no problems. Didnt notice any gains by fitting it (good condition rubber one removed).

Lester

 

i have not, but i havnt done any nice smokey burnouts with it either. punched it hard from a rolling start more then once and didnt have any problems.

 

With an L-48, 195hp I don't anticipate many burnourts .

 

Ok! I’ll probably fire the whole lot of you up with this one! I’m putting on my bullet shield right now, strapping in and oh. .. I’m painting a target on my back too!

I’ll start with Norm: Way back when Lassie was a pup, we installed poly on Norm’s car! Countless times of putting grease on the poly sway bar bushings did not stop the squeaks. Finally we just replace the entire poly for the standard parts and no squeaks, no grease!

On my own personal car years ago I installed Poly! Same issues and one A-Arm shot! Yes I was hard on this car too so I’m sure this added to the problems.

It has always been my “Personal Belief” (and you have to realize that Poly has been around a long long time.) that poly should only be run on cars that are going to be raced around pylons, road raced and or for someone wanting to just run the car hard on a back hills road. Every where poly is installed in a car tightens up the car and I agree that this is a good thing if handling is what you want. If I were racing a car there is no way I would use anything else.

However, it is also my thought that everywhere you replace a part that was designed to have give and movement you also sacrifice ride! A good example of this is the front A arm bushings! The bushing was designed to have movement and not be hard and fixed; something has to suffer from changing them out.

If I remember correctly on some vendor sites there are notes about the poly bushings being used for the snubber cushion? I have seen the rear end on a performance car actually damage the frame bracket from having a poly busing installed in the car. (on a stock car I doubt you could damage this bracket with poly). If this bushing was designed to be solid I would thing GM would have just bolted the rear end front bracket straight to the frame.

You also have to remember that I was raised in a Chevy dealership! I’m not GM brainwashed, but sometimes I think making a better mouse trap can be a down fall. Most of us are driving the cars to enjoy them and lets face it the cars do ride hard enough on their own. Maybe I’ve brainwashed myself and my employee’s and maybe I’m the nut here. . . But I would rather tell you what I think over just keeping my mouth shut.

I could keep going on, but to me and PLEASE remember, this is my belief and I’m sure there are plenty of people that will think I’m crazy. . . But it is just an opinion. Ok, let the guns sling!

Willcox

 

Street car?

 

I have a poly installed on mine but I will be changing it out before the body goes back on. It was one that didn't have the sleeve or washers with it and it just doesn't look or fit right on the mount.