This probably isn't an original idea but I've never seen it discussed so I'm going to bring it up...

First - I think that all would agree that a larger clutch/pressure plate (C/PP) would be more desirable and more reliable if your running a higher HP motor.

Second - Right now, the only alternative to slipage is expensive clutches and special pressure plate that are small enough to stil fit inside the Fiero trannys.

Third - Is my idea: Why not machine off the bellhousing of a Fiero tranny, weld a couple of ears on the case and bolt on a V8 bell housing? I realize you'd have to run a V8 adapter plate for al 60-degree engines but not for a SBC.

The larger bellhousing would allow a larger flywheel and readily availible and relitively inexpensive performance C/PPs

You'd have to find a way to move the starter outward to allow for the larger flywheel. You could use a hydrolic throwout bearing to engauge the clutch. The V8 adaptors and V8s will clear the axles now so clearance shouldn't be a problem.

Well, what do you guys think? Kind of a bass-ackwards approach to an age old problem.

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Roy

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*** UPDATED 1/24/03 ***

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Suncoast Fieros

Discussed the same idea with the repair shop that does some of the work on my car about 2 years ago. We concluded it could be done, but your talking a fair amount of money to have some one figure it out initially, proper alignment, and strength are critical issues.

I'm still waiting for someone to be 'first on the block' with this modification, and learn from their experience. Sounds like a excellent project for Archie!!!

[This message has been edited by California Kid (edited 06-12-2003).]

quote Originally posted by California Kid: Sounds like a excellent project for Archie!!! [This message has been edited by California Kid (edited 06-12-2003).]

wouldnt that be cutting his own throat?

You can get up to a 9 11/16 clutch in a stock fiero, archies kit fits a stock fiero clutch. The clutch I most likely will be running is this size. My buddy is going to test it in his 88 gt with a 400sbc. The clutch is 1/4" in diameter larger on the outside edge of the disk and PP. and also about 1/8 of an inch on the inside diamter of the Disk and PP. Doesnt sound like much compared to a standard 9 1/8" plate until you look at them side by side. We ordered it with the same friction material as the CF clutch. TIf you look at the CF and this clutch side by side, you would toss the CF as far as your arm would allow. Its TINY compared to this one. I'll have more info about it in the next few months. If all goes well, It will be available for sale.

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quote Originally posted by KissMySSFiero: wouldnt that be cutting his own throat?

Perhaps not. If he copyrights the design, he simply sells Getrag bellhousings instead of the adapter with his current kit. I'm sure it would raise the cost of the kit substantially, though - and require custom machining.

While it CAN be done, I'm not sure the benefit outweighs the cost.

quote Originally posted by KissMySSFiero: TIf you look at the CF and this clutch side by side, you would toss the CF as far as your arm would allow. Its TINY compared to this one. I'll have more info about it in the next few months. If all goes well, It will be available for sale.

Be sure to keep us in the loop on the progress, unfortunely it takes time to put mileage on the clutch to determine durability (mileage between changes).

I'm still patiently waiting more feedback from people running the 'Spec' clutch with their hi-hp V8's. Just because I want to know what options are out there. My Quarter Master setup is top-notch, but it isn't intended for street, and doesn't tolerate excessive stop and go traffic very well. It is a very tight tolerance unit that when subjected to a lot of heat, will warp either the face plate or floater ring (once you go over about .006" warp on these part, you're slipping).

While it's an excellent clutch with great grip, these 'race only' disks have short durability of about 10,000 miles. I'm going 'experimental' on my setup by modifying the Quarter Master clutch disks to be recovered with the latest NASCAR Hi-Tech Kevlar compound. It's supposed to be much better than the compound used by Quarter Master, but only time will tell for sure. The car should be out of the shop tomorrow or Sat.

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Click to Listen!

[This message has been edited by California Kid (edited 06-12-2003).]

Thanks for the input guys. I was talking to a buddy of mine who races a 69 Camaro in Vintage SCCA. He was telling me about his clutch. It's stock on one side and kevlar on the other. He said it grips really well but the stock side allows for soft shifts.

It would be nice to have a clutch that can hold 300+ HP and still be streetable. The only way I can see that happening is by using a larger surface area.

I would like to measure a Chevy bell housing to see how deep it is. If they are too deep then the shaft on the tranny wouldn't be able to engauge the pilot bushing. If anyone has one laying around and can get a quick measurement it may go a long way in settling this discussion.

Can anyone think of anything else that may prevent it from working?

Roy

quote Originally posted by mrfixit58: Can anyone think of anything else that may prevent it from working? Roy

It might not clear the CV joint. I don't know, but there's not a whole lot of room there.

I think if I were to try this I would cut the bell housing off the tranny and cut the rear off the new one then weld the new one to it with some extra bracing on the outside where you have clearance. If I had a tig welder I would give it a try. Why not?
If I could find an old chevy 4.3 deisle FWD I would use that tranny although they are all auto's.
Now where to mount the starter?

quote Originally posted by Earl: I think if I were to try this I would cut the bell housing off the tranny and cut the rear off the new one then weld the new one to it with some extra bracing on the outside where you have clearance.

Yea, that's kind of the idea. I've got an old TH400 tranny that's ready to be junked. The biggest problem would be getting cut square. I guess you could just drill a couple of holes in it to a line to a hydraulic throw-out bearing.

quote Originally posted by Earl: ... Now where to mount the starter?

If you use a SBC, the stock location would work. But you would still have to use a small high torque starter. For anything else, you may have to machine a spacer block to move the starter down or out.

Are there any machinists ion the forum that would give us an estimate on how much it would cost to fly cut the donor bell housing and Fiero tranny?

Good thoughts, let's keep it up. If we can answer all the questions, it may be worth trying.

Roy

Are you talking about using the SBC starter mounting position? The Fiero axle is going right through there. I'm still not sure you can get the larger bell housing to clear the CV joint. Here's a picture (thanks ls1swap) to give an idea of the position of the CV joint relative to the SBC bellhousing bolt pattern.

Cool idea... I'm just not sure you'll have the room.

DRH,

Good point. I was thinking that all the adaptors do are to allow the SBC to bolt to the Fiero tranny. So what your saying is it relocates the starter as well. How far is the relocated starter from the original location? I know that the starter on Pontiacs were on the opposite side as compaired to SBC. Do you think that a Pontiac bell housing be a better option?

Roy

I've been thinking about this and I think the real limiting factor is that the transaxle bell housing and the differential case share a common "wall". You can cut away most of the bellhousing, but the part where the axle is can't really be changed. Look at the picture I posted above. The distance from the input shaft to the part of the bellhousing next to the axle is fixed. This will limit the size of the clutch to essentially the current size regardless of what you do with the rest of the bellhousing.

Most traverse transaxles I've seen have basically the same design. What you really need is a transaxle with a greater distance from the input shaft to the axle.

quote Originally posted by DRH: What you really need is a transaxle with a greater distance from the input shaft to the axle.

maybe a getrag 284? but then again you have to be one crazy guy to tear one of those rare gems apart!!

The 153 tooth SBC flywheel WILL fit in there. I am using one in my "semi homemade" swap. It clears the output shaft and inner CV joint just fine. In fact, the outer diameter of the starter ring gear is almost the same as the outer edge of the stock bellhousing. If I had a SBC bellhousing on there, I could use a 10-1/2" clutch. That would GREATLY reduce the clutch cost as I could get a parts store replacement for a 1985 Camaro or any performance clutch for Chevy.

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I briefly thought about doing this before but you guys have better ideas than I did. I gave up on the thought because the tranny is too weak for my intended purpose. I can help you brainstorm though

If you remove the front of the case and carefully splice and integrate the Chevy bellhousing into the case you could then use it as a buck to sand or investment cast new front cases. That would greatly reduce the cost of replicating them. The more time spent blending the two together - the better the end result.

PIP won't work - was going to "point to" the case bolts I am referring to. It seems to split along the middle of the diff.

Last note: no patents, no copyrights (except maybe individual design features) because the whole concept was discussed openly, for all the world to see,this idea is public domain. Competition is good for everyone.

perk

I cant find it now and he may have removed it after the last drug debate but I think Cliff has all rights to anything posted on "his" forum.

quote Originally posted by perkidelic: Last note: no patents, no copyrights (except maybe individual design features) because the whole concept was discussed openly, for all the world to see,this idea is public domain. Competition is good for everyone. perk

PIP is working for me so I decided to add the pic that shows what I was talking about in my last post.

perk

The only easy way to do this is to find a tranny from a 1982-1985 chevy celebrity with a 4.3 diesel. It is a FWD transaxel with the SBC bolt patern. I have to wish anyone woh wants to find one GOOD LUCK!! I have been looking for about a year. With out any luck at all. I will keep looking untill I find one. No matter how long it takes. If any one has one they would sell please let me know.

Coming from a background in motorcycles, I wonder if there is room for dual clutch disks that are thinner with one driven steel plate between them? This way you could double the surface area of the current clutch setup and keep the same diameter. Being that this would be a dry clutch setup, it could rattle when the clutch is disengaged but really the only time the clutch is disingaged is at take off and during shifting so even if it did rattle it wouldn't be often nor for long durations.

Just a thought.

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1985 Fiero SE, 350 V8, NOS injected fun!

quote Originally posted by NOSV8SE: Coming from a background in motorcycles, I wonder if there is room for dual clutch disks that are thinner with one driven steel plate between them? This way you could double the surface area of the current clutch setup and keep the same diameter. Being that this would be a dry clutch setup, it could rattle when the clutch is disengaged but really the only time the clutch is disingaged is at take off and during shifting so even if it did rattle it wouldn't be often nor for long durations. Just a thought.

wcapman, California Kid and Tina here on the forum are using 2 disc Quarter Master 7.25" clutches with success.

A new case half would be an interesting idea. What are the costs of having it cast? I thought that most of the costs of a casting are in the pattern, which we would make by welding the Chevy housing to the Getrag case half. Machine work would also be involved, but that sounds workable. That market is VERY small, however, so volume would be low and costs high.

quote Originally posted by Earl: The only easy way to do this is to find a tranny from a 1982-1985 chevy celebrity with a 4.3 diesel. It is a FWD transaxel with the SBC bolt patern. I have to wish anyone woh wants to find one GOOD LUCK!! I have been looking for about a year. With out any luck at all. I will keep looking untill I find one. No matter how long it takes. If any one has one they would sell please let me know.

According to this guy, the 4.3 block came in 2 versions. One for the RWD with a SBC pattern and one for the FWD with a 60 degree V6 pattern. They might be hard to find because they don't exist...

http://members.tripod.com/~A350Diesel/v6bell.html

I did some searches on:
http://www.mypartshop.com/

The TH125 transaxle for the 4.3 diesel seems pretty common and cheap ($100 or so). Apparently the 84 and 85 models came with a TH440 option. I only found a couple of those (PA and WA) for an 84 and they didn't have a website so I don't know about price.

Well, maybe the My Part Shop link will give you some leads. (Use Find Parts, they list General Motors instead of Chevy, Pontiac, etc.) You might want to double check that it is a SBC pattern though... A SBC transaxle, even an Automatic one, would be GREAT!!! Let us know...

Ok after some research I have found that you are right. Their were 2 diferent 4.3 diesel engins produced the FWD has the same bolt patern as the 2.8 sory for this mistake on my part. However I am not afected by this because I wanted to use a 4.3 in the first place. I was missled when I was told the engine was the same and the tranny was diferent. This is good news for me because I wanted to use my tranny in the first place. Again I am sorry if I got you hopes up.

Now I have to find a FWD 4.3 diesel engine to convert to gas. I assume the block is at least as strong if not stronger than the ones used for gas engines. I hope I can find one. If anyone knows where I can find one please feel free to email or PM me with the details.

Thanks

Can anyone post some pics of the front case half from all different angles, especially interior views. We can use them to at least get an idea how complex the molds would be. I have done sand cast aluminum parts before, and plan to have a small foundry in my new shop when it's finally finished. I talked with a guy online who is experienced in investment casting aluminum parts - I'll see if I can find him when I have some pics to show him.

perk