Driveshaft Misalignment

[Skip Pipes]

I’m building a Fuel/Gas Roadster and laying out the drive train. I’m a big guy and need all the room I can get, and will sit low and alongside the driveshaft. Therefore, I’m looking to shift the rear axle over 4” ala Wilson & Waters #369 roadster. I’m also thinking of moving the engine (Big Block) over 2” and this gives me about 4 degrees of misalignment. I know the joints need to be in-phase and the angles corresponding to cancel vibration; however in researching the subject the Mark Williams site claims 2 degrees max for racing. With that as a caution the question is; with the limited miles the car will travel can I get away with 4 degrees without setting up a dangerous or damaging vibration?

Thanks All - Skip

[SPARKY]

how about rolling the eng over to pick up the off set?  very easy to do with dry sump and FI or EFI

[Milwaukee Midget]

By "shifting the axle over", are you saying the whole axle, or just using an offset pumpkin?

[Skip Pipes]

Hi Sparky,
Well, everybody says I’m a little bit off-kilter, so rolling over a few more degrees, that’ll be an improvement!  Seriously though, that’s a brilliant idea, however the 8-71 & Enderle will look a bit odd. Hmm, I’m gonna to mock it up. Maybe start a fad!

Hi MM
Yea, I see the statement “shifting the axle” as incomplete information. What I meant to say is I’ll shift the differential over, while keeping the axle centered to the chassis. 

Thanks - Skip

[SPARKY]

Skip,  That may be the first time anyone said one of my LSR ideas was briliant  --especially since I just posted it instead of using it first---lol 

[Stan Back]

Seems to me that rolling the engine over would put the blower more into the driver's sight line -- could also lower it, which wouldn't be a bad thing.

[John Burk]

If a 200# driver is 14" to the left and the 800# engine and drive line is 3 1/2" to the right that's balanced . I like Sparky's engine tilt suggestion . I got the idea to lower the top of my streamliner's motor by tilting it 30 deg from the Indy "lay down" Offys from the late'50's and early '60's .

[JimL]

Hi Skip....Dan and I ran almost 2" offset between trans and pinion without a problem (couldn't push the engine right because of the goofy intake).  I never spun the driveshaft over 9200 RPM, however.  That driveshaft was pretty long, so the angle was small.

If you tilt the engine, make sure you don't have to clock the trans back to level to keep the lube working.  We clocked the Prius hybrid transaxle 28 degrees and were almost out of the pickup for the final drive oil pump.  Your trans may have some splash tubes or channels that need to be level...?  (haven't a clue...hopefully someone on here will jump in with a suggestion)

Do you still need a couple hoops bent?  We've been bending on Terry Geers Prius, so everything is still set up.... swing by the shop sometime (gotta work the Grand Prix pit this weekend, however).

Regards, JimL

[Bob Drury]

  Skip, why not leave the engine where its supposed to go, and build a offset drive off the back of the trans...................you could move the pinion as far as you want............Bob

[SPARKY]

parasitic loss?

[jl222]

  Skip, why not leave the engine where its supposed to go, and build a offset drive off the back of the trans...................you could move the pinion as far as you want............Bob

  He's trying to move everything over to make more room for the driver.

  Skip-put a big procharger on and you could see better if you tilt the motor

     JL222

[SPARKY]

ProCharger, I guess, since it is possible to drive it off the front crank.

[Skip Pipes]

Hi All,
Thanks for the great suggestions. I think John Burk is on to something, if only I was 200#. I'm tall, just not tall enough for my weight.

Mocked everything up with a narrower seat and can live with the engine on centerline and the differential 2” offset ala JimL.

Hi Jim,
Yep, still need the hoops bent and was waiting to set the firewall and center horizontal tube, relative to engine shift. Will build hoop patterns this weekend and drop by next week.

JL222,
I'm a big fan of prochargers (and your Camero), however I just went the lower cost route and took delivery of a nice old school 8-71 from Bob Drury.   

Thanks - Skip

[mkilger]

Skip,  are you using a 29-38 body? make sure that the (floorbord) is in the stock place for the body and year of the body used 29= on top of frame.  "step pans are allowed, but belly pans or any other horizontal paneling not fitting the definition of (floorbord) is specifically forbidden"    "floorbords shall be mounted above the frame or in the stock location for the body style and year of vehicle" hope this helps a little good luck with your bulid, hows it coming along? got a rule book?

[Skip Pipes]

Hi Mike,
First off, I really like your roadster project, first class construction of an enviable race car.
Mine, it's a primitive low buck deal for a rookie driver (me). And I'm using a Poly-Form 29 body, which is mocked up on the basic frame rails. Got successive rule books to 2008 and will pick up a 09 at the El Mirage opener. I also plan on running “step pans” with secondary flooring in the cockpit. Will use floorboards aft and mounted above the frame, covering the suspension, as per JD’s suggestion.


Re: Step Pans/Secondary Flooring
« Reply #10 on: August 03, 2008, 04:30:58 PM »

All you guys have made this way to complicated. It's all in the book and I won't put numbers on them you can read them for yourselves. First and foremost READ the DEFINITIONS.

Gas/Fuel roadsters, Gas/Fuel Altered coupes.: You may install a flat panel from the aft most portion of the firewall to 9" (correction 10", JD) infront of the midline of the rear axle and side to side under the frame. If you are so choosing to remove the stock floorboard from your vehicle and use a "step pan" you must then add secondary flooring. Secondary flooring also has a definition and is needed in the advent of the step pan being torn away in an accident. It is to protect your legs from leaving the confines of the body. Secondary
flooring is used in every class that allows you ro remove the original floorboards and for vehecles like lakesters, streamliners, which have no original manufactured body and modified roadsters, and comp coupes .
 
If you have a coupe and have left the stock floor boards in the car and added a step pan you need not do anything for secondary flooring.  It cannot be attached to the step pan for obvious reasons.

Also in the above altered and roadsters every panel that does not meet the definition of a step pan must meet the floorboard rule. So after you have reached that area 9" infront of the centerline of the rear axle ALL paneling must then meet the definition of a floorboard; and I'll remind you again "Above the frame rails OVER the driveline components."

When you see me look under the rear of a roadster or altered  I'm not only looking at the drive shaft loop and traction bar restraints I'm looking at a lot of things and I'd better see a complete rear end, spring, and shocks. If you have decided to end your frame at the rear end I better see a whole lot of open space and no panel attached to the body.

You can bet my roadster panels have all been checked and are legal. I just put my transmisson back in today and the left secondary flooring which fits in after the linkage........Good Luck JD


Thanks - Skip