Fragged U-joint: How Dangerous?

[Jerry Clayton]

Lowell

If you build a drive shaft with Spicer spl 1350 joints you will gain tremendous increase in strengh
First they have no grease fittings--the greasable u joints are not as strong as the non greasable ones
Second they are much bigger and stonger


Third--the SPF cars I have seen (including the ones pictured in these driveshaft threads) have an excessive drive shaft angle that is unnecessary --with the irs this is a constant misalignment whereas with an live axle the rear would fluatate. So you have an shaft that is always seeing an eccessive amount of wear and tear leading to possible premature failure--your drive line angle can be corrected dramatilly by shimming the tailshaft of your trans by 1/2 to 3/4 inch higher which probably will only change the engine level front to rear by less than ONE degree!!!

Correct the drive shaft angle and the failure possiblity goes down--change to higher strengh/quality components and you will virtually eliminate it.

Note--with a ONE FOOT long driveshaft the force at the end of a flailing about shaft will equal your torque/rpm numbers on your dyno sheet--of course the rpm will be reduced if you are in one of the lower gears/increased if your in an overdrive gear.

There are 4130 and carbon fibre parts available from drag racing or sprint car racing that can be adapted to your car.

Next time your at the train station stop in

Jerry

[767Jockey]

This isn't an urban legend. I actually happened to a guy who lived a few doors down from me growing up. It happened in the late 70's in a fairly new at the time Pontiac Trans Am. He had put quite a bit of work done on the car, and was street racing at fairly high speed. Accident investigation proved that the chain of events was that while at speed his front u joint failed. The front of the driveshaft fell to the ground and stuck into a joint in the concrete highway. Apparently it stuck just long enough and with just enough force to unload the rear end and put the tail of the car out of control. He hit a phone pole at high speed and died at the age of 19. Every high performance car I have owned since that day had had a driveshaft safety loop. His name was John Schellie (sp?), and it happened on Montauk Highway in Bay Shore, NY. Perhaps there's a report out there somewhere that some of you more internet savvy guys can find. I know that his family sued Pontiac. I don't know what the final disposition of the case was, as the family moved shortly after.

[Ant]

Come to think of it I had a C Clip come out once at 100mph, this destroyed the Universal joint, ie the needle rollers turned into paste with the grease, there was a horrible vibration and the alloy bellhousing fractured badly, all this was after the engineering shop modified the shaft, and I failed to check it when I installed it.........!

I havent read any articles on driveshaft failure, but I wouldn't think there is any need to cover the U/Js, as normally when they are worn or break the needles and cross get all munched up, and I assume if the cross comes out all together its the actual D/S that causes any problems, but I could emagine a huge whip and boom if under a drag racing situation!

The old cars with the enclosed D/S were very safe, and when modern D/S's came out I guess there was skepticism on the safety of them! Run a hoop and fit a cover of 14- 16 gauge metal close over the top half of the shaft!

[1985 CCX]

For the low cost of $24.95 Summit Racing offers a loop that passes requirements of both the NHRA & IHRA authorities. The loop is in four parts and appears to be very versitile for mounting to just about everything auto.

It is part #SUM-G7900......................

Cheap and easy installed insurance!
Jeff