I have an 84 Fiero that I put a 350 Horse Chev into using a V8 Archies kit. I had Jim at J.P.T. Inc. in Michigan supply the torque and transmission. My problem is that last year I made 7 runs in our street legal drags and blew the R/H CV joint. These were original so I assumed they may have been weak. I installed new ones I bought from NAPA and last night got 8 runs and blew the same side. Can I get something stronger to use as this will not be a useful car the way it is. Please advise if you can.
Thanks in advance, Don Collison

U-joints are stronger than CV joints. You don't need CV joints in the rear because the rear wheels don't turn. Have a driveshaft shop make custom u-joint axles for you. I have about 450hp in the back of my Fiero and still have the original axles with billet steel shafts and have not broken a joint yet. Broken CV joints are a common problem for cars with high torque. I just launch it easier then get on it after I'm moving. Your other option is to preload the axles when racing. The shock of the drivetrain could be causing your breakage. Preload the axles and take out the slack so it's not like a hammer hitting your cv joints.
Dave

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1999 Mercedes ML430, 450hp 1987 Fiero GT, 1986 Fiero SE-soon to be 3800, certified master technician
www.njautobahn.com

Have you called Archie? Bet he knows.

I've read in this forum that aftermarket shafts aren't as strong as OEM.

You might get in touch w/ Capt. Fiero (he's in BC, too.) He's into V8's too.

[This message has been edited by Brian Lamberts (edited 07-01-2007).]

Do you have any pictures to post and are the failures simular across the failures? I'm curious as to whether or not your suspension might not have something to do with it if the same side keeps failing where both sides share the same part except for the length of the axle shaft. Do you have a high stall torque converter, or maybe there's more traction on the right rear since the engine is off center to the right side. From the way the internal bearing guide hub is designed, it is thickest in the center and tapers toward both edges where the bearing load is located when the joint angle moves away from the perpendicular to shaft plain, during a tail end squat on acceleration. Just a guess, sounds like something unusual is happening to cause that kind of frequency.

It sounds like you need to call Mark Williams or Strange and have them make a drag race CV axle for you. A guy in my club snapped an axel w a V8 and I believe that he just replaced it with a new GM unit and he's still on the road. You are putting a lot of torque on your axle and CV joints. I would avoid aftermarket cv axles as much of the time they are made of thinner axle stock and softer steel, some are imported Chinese crap and not even heat treated correctly. Also are you using street tires, drag radials or slicks? If you are running slicks the force that which they lock up will require special high strength axle units.

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87GT 3.4 Turbo- 0-60 5.2 seconds
2006 3800SC Series III swap in progress
Engine Controls, PCM goodies,
re-programming & odd electronics stuff
" I'M ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by bmwguru: U-joints are stronger than CV joints. Have a driveshaft shop make custom u-joint axles for you. I have about 450hp in the back of my Fiero and still have the original axles with billet steel shafts and have not broken a joint yet. Broken CV joints are a common problem for cars with high torque. I just launch it easier then get on it after I'm moving. Your other option is to preload the axles when racing. The shock of the drivetrain could be causing your breakage. Preload the axles and take out the slack so it's not like a hammer hitting your cv joints. Dave

Interesting. Do you have any pics or specs on these axels? I have a LT1 and have yet to dump the clutch at a stand still for fear of breaking a joint or the tranny.

Bonzo

My axles are from the Zumalt kit made many years ago. They are 2" longer and 2" shorter to balance the engine in the middle of the engine bay better. Any performance shop should be able to make you custom axles. Personally, you don't need billet steel axles because it is never the shaft that breaks, it is the cv joint. I would seriouly look into u-joint axles because they can take a beating harder than a cv joint...or as Dennis said, get custom racing cv joints.
I still think it may be the way you are launching the car. the only time I've ever broken a cv joint (not on my Fiero) was using slicks and not preloading the suspension/axles. The bang broke the cv joint. Get a line lock and you won't need to spend the money on new axles.
Also an afterthought...is your drivetrain in proper alignment. You just can't put the engine in and hope it is straight. If the axle is at a slight angle, it will bind and prematurely wear out.
Dave

[This message has been edited by bmwguru (edited 07-01-2007).]

If the cup is shattering perhaps a thick wide welded bead around the outside perimeter of the cup will solve the problem. It may detemper it some but I doubt it would compromise the overall strength in the manner that welding two pieces of tempered/hardened steel together would since in order to break it you would have to bust through a much thicker area of metal.

quote Originally posted by bmwguru: My axles are from the Zumalt kit made many years ago. They are 2" longer and 2" shorter to balance the engine in the middle of the engine bay better. Any performance shop should be able to make you custom axles. Personally, you don't need billet steel axles because it is never the shaft that breaks, it is the cv joint. I would seriouly look into u-joint axles because they can take a beating harder than a cv joint...or as Dennis said, get custom racing cv joints. I still think it may be the way you are launching the car. the only time I've ever broken a cv joint (not on my Fiero) was using slicks and not preloading the suspension/axles. The bang broke the cv joint. Get a line lock and you won't need to spend the money on new axles. Also an afterthought...is your drivetrain in proper alignment. You just can't put the engine in and hope it is straight. If the axle is at a slight angle, it will bind and prematurely wear out. Dave

When Gary Zumalt was making V8 conversion kits he used Mark Williams CV racing axles. Dave has some good advise here on preloading before launching but I would shy away from racing slicks as they can greatly add quite a bit of stress to the driveline. I believe that the jury is out on using slicks with a high torque engine in a Fiero. However, I would not chance using them as it's tire slip that saves the drivetrain.

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87GT 3.4 Turbo- 0-60 5.2 seconds
2006 3800SC Series III swap in progress
Engine Controls, PCM goodies,
re-programming & odd electronics stuff
" I'M ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Brian Lamberts: Have you called Archie? Bet he knows.

Actually he EMailed me before he started this thread. I emailed him back about 4 hours before I spotted this thread.

So here's a copy of what I emailed him at the time.

A customer of mine, Pat Ciarcia, Used to drag race his car & he used to have a problem with the outside C/J joint. He ran low 11's with his car. With the load it was putting on the outboard C/V's, the Spyder cage on the inside was expanding and breaking up. His solution in that case was to use steel banding like you see used in strapping boxes together in shipping. His car was used for racing only & before a weekend of racing he'd grease up the joints good then he'd use the banding instead of a boot & he'd band up the C/V joint all the way out to the axle.

At this point, without seeing any pictures I'd say one of 2 things is going wrong.

#1 A lot of C/V joints that are coming from places like AutoZone & the others are are being made overseas with little if any heat treating.

#2 I suspect that when you put your car together that maybe you moved the engine 1/2" too far to the left in the car. Or maybe you have an AutoZone, Advance Auto (or other) axle assembly. It has been found many times here on PFF that some of these axles assemblies that are put together in sweat shops are actually assembled with the incorrect shaft lengths (see paragraph below) & thus you would have a short axle which would give the same effect as moving the engine to far to the right during assembly. You see the Inboard Tri-pots "Bell-out" a little bit towards the Boot. If the axle doesn't have the correct depth into the Tri-pot then there is more rotational slop in the axles assembly.

This is the paragraph below.......

The Right side Fiero axle assembly is supposed to have a shaft that is 17.938" long. GM has made 21 axle shafts that have the same shaft diameter & splines as the Fiero Automatic uses. Of those 21 lengths 2 of them are less than 1" shorter than the correct Fiero axle length. (& 2 of them are just over 1" longer) I don't know if you've ever been in a axle rebuilding operation but nothing there is measured real close & it would be real easy to grab an axles to assemble that is just a little short.

I hope this helps

Archie

i drive the sh*t out of my v8 fiero (chirp the tires into third with easy), im always running threw the gears, i have yet to run into any drivetrain/drive line probems. i still have the oem axles and the unknow conditoin of my used 4 speed trans. maybe its my 215 tires that give me the cushion. when i go to the track (same tires) i just let the clutch out real fast, not popping the cluthc, jsut fast enough not to burn it up, then i give it holy hell. my sixty foot times are crap though 1.8, 1.9

I haven't broken an axle in over 4 yrs, but putting Micket Thompson ET Streets didn't help me. I broke the shorter side shaft. Twisted right in half, not even in the ring grooves, which is very strange. There was some twisting on both ends in that ring groove area though. Haven't had any problems with the original joints. However I must find another "Zumalt" type short shaft. If anyone has some info to point me in the right direction, that'd be great.
Thanks,
Jurell