OEM vs Poly Bushes

Why do you want going back OEM when you are happy with the drive? Honestly I equipped all my rides with polybushes and I am happy with it. Longer life than OEM and you can play a bit with the stiffness (not necessary using the strongest one) when you make the choice. Have 1500 mls on my Pantera speedo with the bushings and no complaints. 

I thought the downside of urethane was NVH - noise (squeaking), vibration, and harshness.

If you have none of the above, why switch back?

I guess the question isn't around being happy and going back, per se.

I should explained. I didn't fit the polybush, so I wouldn't know what make/model they were, but I am undertaking a total suspension, brakes, wheel and tyre refresh, so would replace the bushes anyway.

The team undertaking the work recommend I switch them out for  Metalastik bushes.

If I can keep sharp handling, and get less noise, more comfort, that has to be a good thing, no? I am afraid I am not super technical when it comes to suspension, so someone might have some interesting insights.

Thanks, Tom

The oem style rubber bushings have bonded center and outer so the rubber is stretched/springy in operation, whereas most of the poly bushes on offer don't have such as they are not fixed and rotate around the center tube which leads to the squeak.

Dennis Quella has a style that has a hex steel core so the bushes do not rotate on the center but are forced to act more like the oem rubber ones and as there is no poly on center rotation they don't squeak either!

If it ain't broke don't fix it! Poly bushings are easy as they don't require a press, personally I'd stick with oem rubber, there's nothing wrong with them other than they are 35 years old and need replacing.

Beautiful car Tom.  I love the color.  Do you know what the color and paint code are?

jimmym posted:

Beautiful car Tom.  I love the color.  Do you know what the color and paint code are?

Hi JimmyM,

Thank you, I absolutely adore the colour, real depth, and a nice tonal variance in different lights. Lots more photos and video on my Instagram (same hook as here).

I don't know the code, but it is Porsche Iris Blue Metallic.

It was on the 993 range of Porsche 911.

Thanks For the info Tom.  Again, very nice.

I am also about to start a suspension overhaul as I just pulled my gearbox to send to Lloyd at RBT for service. My second and third gear syncros we’re starting to make a slight grinding sound after seven years of use. 

My suspension squeaks a bit also and I figure now is a good time to overhaul it while waiting for the gearbox. Everything I have appears to be stock OEM with Koni 82-1702 and rubber A-arm bushings. My plan is to send the shocks to Koni for a rebuild, powder coat the A-arms, springs, sway bar etc gloss black. My goal is to retain the OEM look and ride, I plan on installing new rubber bushings rather than Poly. Should be complete in a couple of months (hopefully) as I already miss driving the car....

If you haven't done so already, consider adding more caster (offset bushings, cut down ball joint or modified a-arm), the wide body cars really benefit from it and are happiest at around 7 degrees of caster in my experience.

Thanks for the advice Joules. Haven’t measured caster yet, will probably verify settings in the next couple of days prior to tear down. Tire size is 345/35/15 in the rear and visually the caster setting looks like about a 3. I know when upgrading to larger diameter wheels, most people increase caster, but with my 15’s, the tires wear fairly even and handling is good. 

Jack

Stay with Poly. They are more predictable load wise and a snap to change out if necessary.

I see no advantage to the original rubber units at all. Plus, you need to press them in and out.

It is the poly that has the reputation of squeaking but in my case I think the rubber is worse and absolutely deforms.

The graphite impregnated are the quietest and Joules recommendation of the offset bushings is a very trick and good solution to front end caster.

Front caster is typically ~2.5 degrees stock, if you are running 285 tires up front the increased caster will reduce the tendency for tram lining, albeit make the steering wheel a little harder to turn at parking lot speeds.