Upgrading a drive shaft
Thread Starter
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Upgrading a drive shaft
My stock 75 drive shaft is only 2.25 inches diameter and 27 inches long. I cut an old 3 inch and put it in just to see how it looked for clearance and it seemed to fit without any problems. I also have a 3 inch aluminum shaft. I am thinking of going to the larger 3 inch. Does the existing 2 1/4 inch shaft cause problems? Have any of you replace it with a 3 inch shaft? Is alumimun shafts ok or is it a problem welding the ends on? I have upgraded to a tremec TKO and while I am at it want to do something with my drive shaft. Why are driveshaft tubing so expensive? I had a shaft made up last year and it was $2.00 per inch for the tubing. Is it special? It certainly is not seamless.
Any opinion would be appreciated.
Thanks
Norval
Any opinion would be appreciated.
Thanks
Norval
Racer
Joined: Mar 2001
Posts: 372
Likes: 1
From: Ellicott City MD
Re: Upgrading a drive shaft (norvalwilhelm)
Hi norvalwilhelm - the 3" shaft will fit fine, and the aluminum is even better. I had to remove a little tunnel insulation, but no big deal. I replaced mine for 2 reasons, one a slight vibration in the driveline, and two, to lessen the stress on my driveline when I drop the clutch. The new shaft totally eliminated my vibration. The aluminum twists a lot more (19deg vs 5deg) than the steel, which helps to minimize wear on the drivetrain. I bought mine from http://www.driveshaftshop.com in NY. Approx $250 for the assembled alum shaft, alum end yokes, & Spicer U-joints. I also needed a new trans yoke (due to wear) which they charged me $95 for.
[Modified by fireball, 9:00 AM 10/9/2001]
[Modified by fireball, 9:00 AM 10/9/2001]
Le Mans Master
Joined: Feb 1999
Posts: 5,877
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From: Park Ridge IL
Re: Upgrading a drive shaft (norvalwilhelm)
I also upgraded my driveshaft when I installed my Tremec TKO. I went with a 3" diameter aluminum "Nitrous Ready" shaft with 1350 ujoints from Denny's Driveshafts. I'm pretty sure the tranny would break before the shaft or the big 1350 ujoints would. I also had them supply me with a new chrome moly pinion yoke to fit the bigger ujoints.
They also offer upgraded halfshafts as well, which I'm ordering next month.
They also offer upgraded halfshafts as well, which I'm ordering next month.
Le Mans Master
Joined: Feb 1999
Posts: 5,877
Likes: 1
From: Park Ridge IL
Re: Upgrading a drive shaft (Red73)
I'm thinking of going with aluminum, but Denny's offers them in both chrome moly steel and aluminum. While weight is certainly a consideration, strength is a priority. By next year I should have my bugs worked out ( a Centerforce Dual Friction that can't hold the torque) and am adding 17" tires, so I anticipate that the driveline will be taking a larger shock and load than what it was designed for. If I can get it to hook, I should be able to run high 9's or low 10's with the power I have. The engine was built for NO2, and I may eventually install a 200-250hp shot. I'm also thinking that next winter I may convert it to a twin turbo system, so I want to to be able to handle that as well.
Le Mans Master
Joined: Feb 1999
Posts: 5,877
Likes: 1
From: Park Ridge IL
Re: Upgrading a drive shaft (jimduchek)
Jim,
My experience was a little different than what most of the other guys who have done the C3 Tremec swap encountered. My '82 was originally equiped with a 700R4 and a removable, bolt in crossmember. Most of the other guys who have done the Tremec swap started with a manual equiped car, and usually a welded in tranny crossmember. It seems most of them removed the welded in crossmember, and rewelded it in the appropriate loaction.
I used a standard Lakewood SBC bellhousing and it bolted right in, along with the Tremec. Actually, my driveshaft would have worked except for the fact that the yoke that came with the Tremec is sized for 1350 ujoints, and the original driveshaft uses the smaller 1310 ujoints. I could have just used a conversion ujoint, but I wanted the stronger strength of the larger 1350 ujoint. In my situation, the Tremec's rear mount was about 4" forward of where the crossmembers mount was. I made an adapter plate out of 3/8" aluminum to joint the two. It was just a plate of aluminum with the appropriate holes drilled in it.
As mentioned before, the only real challenging part is the shifter location, but it's just a matter of spacing the shifter stem over about 2".
My experience was a little different than what most of the other guys who have done the C3 Tremec swap encountered. My '82 was originally equiped with a 700R4 and a removable, bolt in crossmember. Most of the other guys who have done the Tremec swap started with a manual equiped car, and usually a welded in tranny crossmember. It seems most of them removed the welded in crossmember, and rewelded it in the appropriate loaction.
I used a standard Lakewood SBC bellhousing and it bolted right in, along with the Tremec. Actually, my driveshaft would have worked except for the fact that the yoke that came with the Tremec is sized for 1350 ujoints, and the original driveshaft uses the smaller 1310 ujoints. I could have just used a conversion ujoint, but I wanted the stronger strength of the larger 1350 ujoint. In my situation, the Tremec's rear mount was about 4" forward of where the crossmembers mount was. I made an adapter plate out of 3/8" aluminum to joint the two. It was just a plate of aluminum with the appropriate holes drilled in it.
As mentioned before, the only real challenging part is the shifter location, but it's just a matter of spacing the shifter stem over about 2".
Thread Starter
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Re: Upgrading a drive shaft (Monty)
Thanks for the replies guys. Monty. When you swapped in the tremec I assume you went for the chevy conversion. The tremec is only built for fords and someone converts them to chevy . I went with the ford and quickly adapted it to fit a chev but the slip yoke is for a C6. It is not a easy service yoke so I am having a problem getting the driveshaft in and out. I can machine my own joint that comes apart but I would rather use a easy service C6 yoke. I assume you are using the stock 400 slip yoke. My driveshaft company can not work with aluminum so I will probably use a steel shaft. I thought the weight on the bottom of the tail stock of the tremec would hit the cross member but once the transmission was in place it cleared the stock cross member by at least 1/2 inch.
Thanks again for the replys.
Thanks again for the replys.
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Le Mans Master
Joined: Feb 1999
Posts: 5,877
Likes: 1
From: Park Ridge IL
Re: Upgrading a drive shaft (norvalwilhelm)
Yes, I used the converted Tremec TKO from Forte's. I also bought their slip yoke, which as you mentioned is a C6 spline.
You bring up a good point, I had to cut off that extended section of aluminum off the tailhousing to clear my crossmember. Only took about 5 minutes with a Sawzall, but I forgot to mention it. It may be a unigue situation for me though, since my crossmember is further back.
You bring up a good point, I had to cut off that extended section of aluminum off the tailhousing to clear my crossmember. Only took about 5 minutes with a Sawzall, but I forgot to mention it. It may be a unigue situation for me though, since my crossmember is further back.
Safety Car
Joined: Mar 2001
Posts: 4,847
Likes: 0
From: Tampa FL
Re: Upgrading a drive shaft (norvalwilhelm)
I concur with using Denny's. We ended up going with a shop locally because we wanted it custom made. It's either 3.25" or 3.5", I can't remember. Norval, I'm not sure I can recommend aluminum for your system. I know Denny says that his aluminum shafts can't be twisted, but I have told by many people that for super duty applications steel is best. The weight savings isn't that much of a consideration for me anyway...
Thread Starter
Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
Re: Upgrading a drive shaft (Merlin522)
Merlin I'm not sure about the aluminum either. The welded yokes are weaker being made of aluminum and welding softens the aluminum in the heat affected zone. I probably will go to steel.
Monty Was your 6 slip yoke the type that has the 2 caps for easy removal of the u joint. The one sent with the transmission is not so it makes removal of the joint a pressing engagement.
Monty Was your 6 slip yoke the type that has the 2 caps for easy removal of the u joint. The one sent with the transmission is not so it makes removal of the joint a pressing engagement.
Drifting
Joined: May 2001
Posts: 1,329
Likes: 12
Re: Upgrading a drive shaft (norvalwilhelm)
I dunno the price for it but did you guys ever consider a carbon fiber drive shaft? If ya never heard of it, I saw it in a mag. and could dig up the add if you want. Seemed sweet to me. 
Le Mans Master
Joined: Feb 1999
Posts: 5,877
Likes: 1
From: Park Ridge IL
Re: Upgrading a drive shaft (norvalwilhelm)
Norval,
No the one I have does not have removable caps. It's a solid chrome moly steel yoke.
I was a little apprehensive about an aluminum driveshaft too. But I was talking with the guys that do my amchine work at Fast Times. They race in NMCA/NSCA/NMRA and they use aluminum driveshafts as well. If figure if their 1800hp cars can run in the 1/4 in the high 6's at over 200mph, my 650hp high9/low 10 street car is just fine. By the way, the yokes aren't aluminum, only the tube, the yokes are chrome moly steel.
I am leaning towards staying with chrome moly steel halfshafts though - they incur more torque than the driveshaft, and they have additional loading since they are a stressed member of the rear suspension. Since they are so short, the weight savings off aluminum isn't as significant. Plus, if something were to break, I'd rather it be a driveshaft than a halfshaft. I've got driveshaft loops so it would be contained, but having a half shaft break would not only cause alot of collateral damage, but could result in the car going out of control.
[Modified by Monty, 3:28 PM 10/9/2001]
No the one I have does not have removable caps. It's a solid chrome moly steel yoke.
I was a little apprehensive about an aluminum driveshaft too. But I was talking with the guys that do my amchine work at Fast Times. They race in NMCA/NSCA/NMRA and they use aluminum driveshafts as well. If figure if their 1800hp cars can run in the 1/4 in the high 6's at over 200mph, my 650hp high9/low 10 street car is just fine. By the way, the yokes aren't aluminum, only the tube, the yokes are chrome moly steel.
I am leaning towards staying with chrome moly steel halfshafts though - they incur more torque than the driveshaft, and they have additional loading since they are a stressed member of the rear suspension. Since they are so short, the weight savings off aluminum isn't as significant. Plus, if something were to break, I'd rather it be a driveshaft than a halfshaft. I've got driveshaft loops so it would be contained, but having a half shaft break would not only cause alot of collateral damage, but could result in the car going out of control.
[Modified by Monty, 3:28 PM 10/9/2001]
Thread Starter
Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
Re: Upgrading a drive shaft (Monty)
Monty. If you have a solid slip yoke how do you install the drive shaft? Is there room to slid the shaft back to install the yoke in the back of the transmission or do you have to intall the universal under the car? That could be a real pain.
I cut up an aluminum shaft last night and removed both yokes. Mine were made of aluminum but for the 1310 universals so I dismissed that idea of making my own shaft and heliarc welding the shaft together.
I looked into a easy service slip joint yesterday and they wanted $250CDN just for the yoke. Too expensive but it does make removing the shaft easy.
Thanks Monty
I cut up an aluminum shaft last night and removed both yokes. Mine were made of aluminum but for the 1310 universals so I dismissed that idea of making my own shaft and heliarc welding the shaft together.
I looked into a easy service slip joint yesterday and they wanted $250CDN just for the yoke. Too expensive but it does make removing the shaft easy.
Thanks Monty
Melting Slicks
Joined: Feb 2000
Posts: 3,050
Likes: 9
From: Fairport NY
Re: Upgrading a drive shaft (norvalwilhelm)
Monty, When I spoke with Denny's last winter, he told me he would not make aluminum halfshafts for a vette that had more than stock HP. He had concerns about reliability and he would not be responsible for the half shafts breaking. Rod
Burning Brakes
Joined: Jul 1999
Posts: 922
Likes: 164
From: Hudson NH
Re: Upgrading a drive shaft (norvalwilhelm)
I have a Denny’s 3” steel driveshaft in my 67. I also upgraded to solid 1350 U-joints and Mark Williams 4340 slip yoke and companion flange. The slip yoke has bolt on caps which greatly facilitates removal. I do have occasional chatter from the large input yoke and companion flange/tunnel interference when cornering with a passenger.
I also have Denny’s 3” steel half shafts.
Take care,
Mark
I also have Denny’s 3” steel half shafts.
Take care,
Mark
Le Mans Master
Joined: Feb 1999
Posts: 5,877
Likes: 1
From: Park Ridge IL
Re: Upgrading a drive shaft (norvalwilhelm)
I'm sorry, I guess I didn't describe the yoke accurately, it doesn't have removable ujoint straps, it is a two piece yoke. The slip tube portion has a flat flange welded to it, and then there is another flat flange with the ujoint staps cast in place. The two halves bolt together with 4 1/2" bolts. The part with the ujoint straps is actually a Ford item, it has the Ford logo cast into it. This is what Forte's sent me.
