General Forums => The O' Club => Topic started by: SFRT - Frenchy on November 06, 2016, 01:11:54 AM
Title: Any1 knows anything about driveshafts?
Post by: SFRT - Frenchy on November 06, 2016, 01:11:54 AM
Building this M37 I don't have much room between the trans and the TC. What would u recommend to connect the two. Would the angle between the trans and TC be stressing the output shaft or TC input yoke too much? :uhoh
Title: Re: Any1 knows anything about driveshafts?
Post by: Skuzzy on November 06, 2016, 06:35:11 AM
You want some angle in the driveshaft. It should not be inline with the transmission output shaft and the pinion yoke.
BUT, and this is a big one. The output shaft and the pinion yoke MUST be parallel to each other. You will end up tearing up a transimission and/or rear end if those two are not in parallel to each other.
You want a little angle in the driveshaft so the u-joints actually work. If there is no angle, the u-joints will seize after running for a bit. Not a good thing.
My Cobra driveshaft is 11" long. The shaft itself. I am going with an aluminum shaft.
Title: Re: Any1 knows anything about driveshafts?
Post by: DaveBB on November 06, 2016, 08:14:59 AM
Why aluminum Skuzzy? It is a far weaker metal and far more prone to cracking than steel.
Title: Re: Any1 knows anything about driveshafts?
Post by: SFRT - Frenchy on November 06, 2016, 09:27:20 AM
Not if it's designed properly. They even have carbon fiber DS on race cars. It's like a light wheel, light flywheel ... less rotating mass the quicker stuffs spools up :lol
Title: Re: Any1 knows anything about driveshafts?
Post by: SFRT - Frenchy on November 06, 2016, 10:40:45 AM
Skuzz, what do u mean by parallel. What would u fix?
Title: Re: Any1 knows anything about driveshafts?
Post by: Hajo on November 06, 2016, 10:44:33 AM
Nice job Frenchy! Looking at the alignment it would put me in a quandary also. I'd have lots of questions also. I'd need some professional advice also. Good luck! It's a great looking project!
Title: Re: Any1 knows anything about driveshafts?
Post by: SIK1 on November 06, 2016, 12:14:24 PM
There is a pretty good article here: http://www.4crawler.com/4x4/CheapTricks/Driveline-101.shtml
It's hard to see in the pictures without an angle finder, but the angles look to exceed the two, or three degrees difference from parallel. (Your output shaft points at the ground while your T-case input looks to be parallel to the ground.) You'll notice in the article I linked that operating angle and shaft RPM have a direct correlation The side to side offset would also be a concern for me because of how short the shaft is, and the resulting severe angle placed on the u-joint. Another thing it looks like you have a fixed output yoke, so what kind of slip setup were you going to use?
If you don't get it right a poorly setup drive shaft will be nothing but a headache, They eat u-joints, destroy bearings, seals and can even ruin the transmission, or t-case/differential. Do it right and it will give you years of trouble free service.
:salute Sik
Title: Re: Any1 knows anything about driveshafts?
Post by: JOACH1M on November 06, 2016, 01:26:19 PM
https://youtu.be/gmV4qwLfOMY
Good 2 minute video about drivelines
Title: Re: Any1 knows anything about driveshafts?
Post by: SFRT - Frenchy on November 06, 2016, 01:43:48 PM
It is a great article Sik1. Thank you.
The angle Vs RPM is interesting. The engine will see 3000 max as it's an International. At highway speed with the overdrive of .75 I should be 3750 DS RPM. What trips me is the factory TS to front differential angle is pretty extreme.
Why aluminum Skuzzy? It is a far weaker metal and far more prone to cracking than steel.
My car weighs about 2250 pounds, wet. The driveshaft is not going to be stressed as much as a car weighing in at 4,000 pounds. The shaft, itself, is only 11" long. The shorter shaft is less likely to twist/flex as much as a longer shaft.
You also get less snap with an aluminum shaft. Steel does flex more and that flex can cause stability issues when you are on and off the gas a lot. It acts like a spring winding and unwinding all the time. You are right. Aluminum will crack when steel will flex, but it is a low risk in such a light car.
Frenchy, I assume you got the answers you needed from the various links. That pinion yoke angle seems really extreme.
Title: Re: Any1 knows anything about driveshafts?
Post by: Shuffler on November 07, 2016, 11:35:25 AM
3000 series aluminum is very flexible. 6ooo series has minimal flesh but is more brittle.
For aluminum boxes we use 5052, bends well and is strong. For sub panels we use 6062 as it is stout for mounting things. 3000 series is seen on grass farms and such on the big wheel sprayers. The pipe flexes all over and does not break.
Title: Re: Any1 knows anything about driveshafts?
Post by: Skuzzy on November 07, 2016, 01:18:56 PM
Virtually all the autmotive drive shafts are 6061 with 1/8 wall thickness.
I would really like to go with a carbon fiber drive shaft, as it is lighter than aluminum and also exceeds harmonic vibration absorption better than steel. Best of all worlds.
And if the carbon fiber shaft breaks, it simply disintegrates, whereas steel and aluminum can do some serious damage to the car.
Title: Re: Any1 knows anything about driveshafts?
Post by: Shuffler on November 07, 2016, 02:14:57 PM
I used to twist driveshafts in half on my 75 4WD Vega estate station wagon. If those 38.5 monster mudders did not break loose. I had to make a new 33 1/2" shaft every time. The end on the transfer case would destroy both exhaust. I finally went with a jeep drive shaft. It was smaller diameter than the GMC shafts but thicker wall. Then I started center punching flywheels. LOL those were the days.
Yup I'm redneck.
Title: Re: Any1 knows anything about driveshafts?
Post by: SFRT - Frenchy on November 07, 2016, 02:15:19 PM
Thank you folks, I learned a lot. The engine trany pivots on the trans monts located on the bell housing virtually in the middle of the engine/trany.
- If I lower the front I raise the back to be parallel to the TC but I hit the bottom of the cab (meaning I have to cut/bulge the floor .. aka .. work. - If I lower the whole engine/trans and make it level the pumpkin will hit the oil pan at high flex. (Not by much but still ... again weld/cut/paint refab).
... maybe a double cardan short sliding driveshaft is my cheapest answer, CV joint my most expensive one. :old:
Title: Re: Any1 knows anything about driveshafts?
Post by: GScholz on November 07, 2016, 03:50:14 PM
Thompson joint. It's like a double-cardan, but in one unit. It's been around for like ten years now.
Title: Re: Any1 knows anything about driveshafts?
Post by: morfiend on November 07, 2016, 04:13:13 PM
Virtually all the autmotive drive shafts are 6061 with 1/8 wall thickness.
I would really like to go with a carbon fiber drive shaft, as it is lighter than aluminum and also exceeds harmonic vibration absorption better than steel. Best of all worlds.
And if the carbon fiber shaft breaks, it simply disintegrates, whereas steel and aluminum can do some serious damage to the car.
Once saw a front yoke blow and the Maverick grabber flipped on it's roof! It kinda did a pole vault as the shaft dung in and lifted the rearend up and over.
I notice you have a shaft hoop in the cobra... :aok
:salute
Title: Re: Any1 knows anything about driveshafts?
Post by: Hajo on November 07, 2016, 05:32:09 PM
Once saw a front yoke blow and the Maverick grabber flipped on it's roof! It kinda did a pole vault as the shaft dung in and lifted the rearend up and over.
I notice you have a shaft hoop in the cobra... :aok
:salute
drive shaft loops are required here to run the car at the strip. Unless it is a 6 cylinder Maverick.
Title: Re: Any1 knows anything about driveshafts?
Post by: morfiend on November 07, 2016, 05:41:53 PM
:rofl :rofl :rofl
It was no 6 maverick,grabber with a 302 that had"some" work done. The "strip" was an unused piece of road in the country!
There were a couple cars "parked" a few miles either side of the "strip" and they had CB radios so the heads up could be given! Even had a Xmas tree set of lights when it got serious!
We had a service station so I always knew when the runs would happen and would be there as often as I could!
:salute
Title: Re: Any1 knows anything about driveshafts?
Post by: icepac on November 07, 2016, 08:28:40 PM
I've had amazing luck just eyeing it out and getting as close as possible with what I have to work with.
I don't recommend it but had to mention it.
I also always use new engine, transmission and differential mounts in every project.
Title: Re: Any1 knows anything about driveshafts?
Post by: Skuzzy on November 08, 2016, 06:26:32 AM
I made a couple of jigs with laser levels and targets attached. When the lasers hit the dots on the targets then they are parallel with a predetermined amount of offset.
I'll post a pic of the setup when I get ready to line mine up.