Solid trans mounts, really a problem??

Eric P · 04-03-2006, 08:47 AM

I need new trans mounts for my '71. It seems I have 3 options:
1) Wevo job on my beam ~$275 said and done
2) Stromski 100% solid inserts ~$100
3) Factory replacement over $700

This is a racecar. Cockpit sound isn't an issue. I kinda want to do the solid inserts basically because it is cheap. BUT, I don't if it means I'm going to see a cracked transmission or something.

I've searched but no real data. Everyone talks about vibration issues but no one shared any actual experiences.

Note, I have poly bushings for the engine and I have MFI so there shouldn't be fuel issues related to vibration (like there apparently is with carbs).

I'll spend the $275 on the Wevo deal if I need to but I want to figure out if I need to first.

Any experiences with the SOLID mounts?

cstreit · cstreit's Garage

I think the vibration problems come more from the solid engine mounts. Personally I like the solid-trans/sport engine mount setup.

Eric P · 04-03-2006, 08:53 AM

That is what I thought. I wanted to hear from someone that uses that setup. How long have you used it?

ErVikingo · 04-03-2006, 10:22 AM

Can't write right now, on my way to the dentist to have my fillings fixed....

Shifting improves a lot but vibrations are significant. I have a solid trans mount with sport engine as indicated by Chris.

gestalt1 · 04-03-2006, 12:59 PM

i've heard many put solid mounts on the engine and sports or wevos on the trans. the engine crossbar isolates a lot of the vibrations from the engine. the trans mount has much less of a flexible arm to the actual mounts. More vibration gets into the chassis because of this. my car is not done yet so i don't know for certain however.

mm86911 · mm86911's Garage

Solid mounts both transmission and engine - no problems here

DByers · 04-03-2006, 04:38 PM

If you are running carbs and I think even MFI you will have a problem with solid mounts. See the PMO website for more info. Even though not a race car I replaced both engine and trans mounts with the WEVOS and it is one of the best improvents to date. Better throttle response, more precise and postive shifting, and no more vibration/noise transmission then the stock ones I replaced. Interior is stripped of all sound deadning and I only have an RS carpet kit in place.
I was/am on a budget but the WEVO just made sense in the long run.

Eric P · 04-03-2006, 07:06 PM

I don't really see how vibration would cause the highly pressurized MFI system problems. I'm open to explanations though.

Again, I'd like to hear if anyone has actually had problems, particularly structural, with solid trans mounts (I have poly engine mounts and thus some give). Lots of threads speculate on problems but I have not heard one person say a solid mount actually caused problems (at the trans).

Except maybe Juan whose mounts may have loosened his fillings

RaceProEngineer · 04-03-2006, 08:11 PM

Eric,

It's a racecar - it's supposed to vibrate! We worry because our SC doesn't seem to vibrate enough. Maybe a nice set of sub-woofers for balast??

Seriously (but only for a moment), we use solids for trans and motor. Everything feels like it "connects up" better with no free play. Naturally, we check mounting points and fasteners regularly. Absolutely no problems to date.

Ed

RSupdate · RSupdate's Garage

Stomski solid Trans & Engine....no problems...love it!!

JoeMag · 04-04-2006, 02:18 PM

930 race car -- Have solid motor and stomski racing 930 inserts. Had them on there for two years, no issues. I do check for cracks. There is definately more noise in cabin -- it's from trans gears. First time out, sounded like trans was going to blow up. ...now it sounds really cool down a long back stretch (like MidO) with the high pitch gear whining sound.

jacko241 · 04-04-2006, 04:47 PM

I run solid engine & trans mounts with carbs on my race car, and it runs smooth and strong. I think the vibration issue with carbs has been overstated. I have run solid mounts on all my racecars, including 550 hp asphalt oval track late models with carbs, and no problems.

Tyson Schmidt · 04-04-2006, 06:20 PM

If you use solid mounts front and rear, then the engine and trans become structural members of the chassis. This is both good and bad.

The good is that it will improve the torsional stiffness of the chassis, and improve handling and shifting.

The bad is that the trans and engine cases are now seeing torsional loads from chassis flex. I think if you are running aluminum trans and engine cases, and a rollcage it is probably fine.
But Mag case motors twist all on their own just from the torque of the motor, so I would advise against them with mag engine and trans cases. With these, I would only run solid mounts at one end.

jpnovak · 04-04-2006, 08:00 PM

What about the poly inserts for the early tranny mount? These might not be as bad as the solid mounts by stiffer than worn out rubber. I am just about done refreshing my 911/01 and really need new mounts. I have been looking at these or the WEVO setup but one is out of the budget right now.