Once again in the spirit of doing things right the first time, I have fabricated some solid motor mounts. Basically I replaced the rubber part of the OE mounts with 2 1/2 inch square tubing and kept the OEM design. I had alot of second thoughts though when bolting them up to the tranny. It is high quality steel and professionally welded. My concerns are :

-where will the torque go to ?
-will there be severe vibration ?
-is it really better than rubber mounts ?

Any input is appreciated.

Archie solid mounts a lot of his swaps. I think the Stinger uses all solid mounts. I am using solid in mine, also. I don't think there will be any problems.

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I'd say for a race type car, go for the steel, but I'd also be worried about the viberation so personally, I'd fab up some quality poly mounts to help that..

Remember, however, your putting a v8 in a fiero, things are going to break due to the torque, so as long as you have your wheels on the pavement, dont worry about the rest till it happens..

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02' 3800SC Poly, Koni, Enkei

Vibration? Thats what seat cushions are for.

Since your car is not an 88, your cradle is'nt solid mounted(unless you have alum. bushings) The rubber or Poly cradle bushings should be enough vibration damper for most. Althought, I would go with the poly. IMO, a v8 runs smoother than the 4cylinder anyday. So its going to be an improvement over that regardless.

That's exactly what I was hoping. My lil' brother works at a hotrod shop and they were like "you're gonna do WHAT ??" when I showed them the mounts. Figured it would be worth a second opinion.

I'm assuming this is for a street driven Fiero and not a race car? My V8 Fiero has solid motor mounts and poly cradle bushings... I love it. Like was said in a previous post, as long as you use poly or rubber cradle bushings, you'll have no problem. I recommend poly cradle bushings if this is a hipo engine and/or if you are going to drive in a "spirited" manner. Rubber cradle bushings and V8 torque don't seem to be very compatible.

Mine is a solid-cradle '88 with a solid-mount engine and trans, and I would not have done it any other way. Mine does use the stock harmonic balancer, which seems to maximize the engineered-in smoothness of this all-roller engine - of which truly there is quite a lot. What little vibration is there is nothing more than a reminder of how much engine is behind the seat. One misconception I'd like to clear up though, is polyurethane: in fact it does almost nothing to isolate vibration. Do not use it thinking that it's a halfway between rubber and solid - it's about 95% of a solid mount.

The key is consistency. Don't mix and match mount types, or you will tempt the fate of cracking your cradle or transaxle bellhousing from allowing twist in one part of the driveline and prohibiting it in another.

Dave

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- Electron Blue '88 GT 5-speed (1 of 1): Before After ZZ430 Ram-Port FI--Wanna Race? Follow it here on the Forum!
- Silver '88 GT 5-speed (1 of 139) w/cammed 3.4
- '98 6-speed Corvette Coupe, '87 Coupe SOLD!

quote The key is consistency. Don't mix and match mount types, or you will tempt the fate of cracking your cradle or transaxle bellhousing from allowing twist in one part of the driveline and prohibiting it in another.

I found a three inch crack on the bellhousing on my Getrag. Tranny was rubber mounted. TIG Welded the tranny and made some solid mounts. Works great now! Solid mount it!

Jim
87 GT T-TOP V8
87 GT
95 Talon TSi AWD

That is what I always have heard. If you go solid on the engine you should go solid on the trans. And the same for rubber, or poly. I think it has to do with two things. 1. If one mount is solid and one is rubber the solid one is going to take up all the stress. 2. If one is rubber and the other is solid. the solid one is going to have to bend if the rubber one moves at all. Over time this flexing could crack the solid mount. I know allot have people have done this with no problem, but it goes against everything I ever heard.

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LS1 v8 T-Top 87 GT

http://ls1swap.tripod.com/

So if someone were to use all solid mounts in an 88 with Archie's harmonic balancer pulley and no real damper wouldn't all that vibration break lots of things?
Nathan

quote Originally posted by 80's BOY: -where will the torque go to ? -will there be severe vibration ? -is it really better than rubber mounts ?

I smell a flame war in the making. This is, of course, a matter of pure opinion and experience. Here's mine:

I owned a V-8 Formula with solid mounts. Put 2000 miles on it and decided to part it out. I still have the engine conversion kit in the garage.

"where will the torque go?"
RIGHT UP YOUR A**. Loose parts are the order of the day. And twisted metal and tweaked frames are a fact of life. I had to GIVE away my Formula frame after it was tweaked out of square from corner-to-corner by 1 inch in 2000 miles!!!!

"will there be severe vibration?"
Some people say the vibration is not that bad, I disagree. I had to have the fillings in my teeth redone after driving it. Don't even dare to take a girl on a date in one!

Like I said, this is just one guy's experience. Others may be different. But I will never go with solid mounts ever again.

If you run solid engine mount, and rubber trans mounts, the tranny will move, and the engine will try to stay in place. Just like said above. Now if the trans is shifting, then the entire assembly will have to move Because the engine and trans are bolted together. Now you have movement from the trans to the solid motor mount, if your lucky, the Engine mount will be what gives. Or, Like in Jimmy's case, Something else will give. Just like his trans. That's why he had a crack in it. Now if you have rubber engine and trans, then the whole assembly moves together, and the rubber is what gives. Hopefully, with all that torque, they dont just rip right out.

V-8 Archie Input PLEASE!!!! Thanks Gary

quote Originally posted by GKDINC: V-8 Archie Input PLEASE!!!! Thanks Gary

ME!?!?......Heck I go both ways.

Okay, howabout solid mounts with rubber bushings ? That should confuse some people, huh ?

quote Originally posted by KissMySSFiero: If you run solid engine mount, and rubber trans mounts, the tranny will move, and the engine will try to stay in place. Just like said above. Now if the trans is shifting, then the entire assembly will have to move Because the engine and trans are bolted together. Now you have movement from the trans to the solid motor mount, if your lucky, the Engine mount will be what gives. Or, Like in Jimmy's case, Something else will give. Just like his trans. That's why he had a crack in it. Now if you have rubber engine and trans, then the whole assembly moves together, and the rubber is what gives. Hopefully, with all that torque, they dont just rip right out.

I also had the front engine mount cracking the he!! out of my cradle. I have since welded all the cracks on the cradle under the front solid mount, added a little extra reinforcement, and added metal "butresses" to better distribute the torque placed on my front engine mount. I have had ZERO problems since I went solid and I only wish I did it sooner.

Here is a little background about my car and what its been through. Over 14,000 hard miles on the Archie V8 swap(I dare say I have driven my V8 Fiero harder than any other on this forum), 13,000 of which was on a CF DF clutch. I'll make it simple, I BEAT on my car. Clutch dumps, races, drag strip appearances with traction compound, I let other people drive my car, and I let one of Archie's mechanics thuroughly thrash my car at the Dells last year! I built this car to have some fun, and though it is not my daily driver I somehow racked up 8,000 miles in 6 months last year! I take good care of my vehicle maintenance wise, I do most if not all my own labor, I built it to break it, and I enjoy every minute of it! I will continue to let others have a chance behind the wheel of my car as it is part of the fun for me in owning a V8 Fiero.

Jim

[This message has been edited by Jimmy (edited 04-10-2003).]

"So if someone were to use all solid mounts in an 88 with Archie's harmonic balancer pulley and no real damper wouldn't all that vibration break lots of things?
Nathan"
Archies crank pulley is a dampener... And the function of it is not really to absorb the vibrations of the engine but rather the flexing of the crank.

"Okay, howabout solid mounts with rubber bushings ? That should confuse some people, huh ?"
That would essentially be rubber mounts

Toddster, thank you for your post. I hope people read and heed what you said.

quote Originally posted by crazyd: polyurethane: in fact it does almost nothing to isolate vibration. Do not use it thinking that it's a halfway between rubber and solid - it's about 95% of a solid mount.

Not sure I completely agree with this thinking. Poly bushings do flex a little. Certainly much less than rubber bushings and certainly more than solid steel.

Like I said earlier, I have solid motor mounts and poly cradle bushings which works good for me. If I had it to do over again, for ultimate handling and performance, I'd go with solid cradle bushings (or 88 cradle conversion) and poly engine/tranny mounts.

[This message has been edited by batboy (edited 04-10-2003).]

quote Originally posted by Toddster: I owned a V-8 Formula with solid mounts. Put 2000 miles on it and decided to part it out. I still have the engine conversion kit in the garage. "where will the torque go?" RIGHT UP YOUR A**. Loose parts are the order of the day. And twisted metal and tweaked frames are a fact of life. I had to GIVE away my Formula frame after it was tweaked out of square from corner-to-corner by 1 inch in 2000 miles!!!! "will there be severe vibration?" Some people say the vibration is not that bad, I disagree. I had to have the fillings in my teeth redone after driving it. Don't even dare to take a girl on a date in one!

My swap was not done the traditional way, Archie went out of his way to keep the huge original SBC balancer, and very few if any other running V8 swaps are this way. Tina is the only forum member who has driven my car besides Archie, perhaps she can comment on it relative to a typical swap. Denise and Twiggy from the Yahoo-Fiero list rode in it at the Gilberts' Tech Day last year, but I don't think they're on the Forum.

Dave

I would tend to think that the milder you cam, the less vibes you would have. My 4.9 is solid mounted, and the vibes are minimal.

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88 GT, 4.9 Caddy v8, Getrag 5 speed, and a whole lot more.

It's all a matter of well thought out execution and design when doing a solid mount conversion. Mines been solid mounted (engine and trans) since 1993 with no issues, only benefits. The cradle was also recently checked for any minor stress cracks while having some other work done, nothing found. Nobody would guess it's solid mounted as the minimal vibration is no more noticable than any other really high performance car with rubber mounts.

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