Jensen Healey Shakedown at VIR.....

Ron Earp

Administrator
We (Jeff Y, Jeffery R, Robert M, and myself) took the Jensen went out for a track testing session at VIR yesterday for a 2007 shake down. This is the first track session that it has had in about nine months now and we had reasonably positive expectations. It has a new engine and a much better level of prep than it had when it went out on track last June, so we figured we could run around in the Touring Lights club class to learn about the car.

I was able to make a few laps and start to get a feel for the handling of the car at about a 65-75% race pace. I’d say the handling was okay, nothing spectacular. It had fantastic turn in though, I really liked that aspect of the car, but the cornering grip was difficult to feel out. The rear end would break away under increasing g cornering, in a manner that was predictable but that happened far too early to be racable. The front was better than the rear, but I didn’t have a good chance to push the front as the rear somewhat limiting. Anyhow, these are things that can be solved with development and part of the fun of running a car.

About the fifth or sixth lap around during the second session we had a fairly heinous failure. I came out of Oak Tree and there were no other cars around for about half a mile or so. At about 65-70mph and just a little ways down the straight, with no warning at all, I heard a tremendous BANG!!!!! There was dirt (what I thought was dirt at the time) and debris flying all around the car with a lot of vibrations coursing through the chassis. There were various noises clanking and clunking so I figured maybe it’d be a good time to pull off track.

I reached down to hit my cockpit electrical kill switch but it wasn’t there. A quick glance revealed that most of the drive tunnel that my kill switch and accusump were mounted to wasn’t there either, and my gear shift was poking out of the tunnel at a really strange angle. I managed to turn off all the switches on my electrical panel and get the car pointed left of track. As soon as the car rolled across the track curbing I was up and out and could see the track was littered with pieces of metal, driveshaft, and exhaust system. I was a bit shaken up, no doubt.

To make a long story short it appears that the driveshaft broke (far from a failure analysis, I'm sure there is more to it than that). When it broke the car was moving and it was securely bolted to the differential, so of course it had to rotate. It beat the hell out of the transmission tunnel, broke the cross bar loop, and knocked off the exhaust system while turning itself into a 3” diameter metal facsimile of a snake. The engine was spinning at about 4000 to 5000 RPM when this happened so of course the transmission was being turned until I could shut off the engine. The output yoke of the transmission is a heavy u joint affair and it just about cut the center console in half while taking scattering shards of metal all through the cockpit. The accusump got deformed and vented oil making a nice shower. The tunnel is trashed and the carnage goes all the way back to the rear deck.

Once we got to looking underneath the car we could see that the transmission is missing some casing and the differential isn’t being a differential any more. The transmission is pulled away from the bell housing about an eighth of an inch, so bad things are going on there too. The diff sounds like a box of rocks when turned and input flange wobbles around in a non-circular way. Shifter structure is mostly gone, as is the transmission output flange, and some other bits back there.

Good news though – due to my last “bad” on track experience I was very protective of the motor. I don’t remember much about the bang and what happened right after, but I distinctly remember seeing 75psi on the oil pressure gauge as I flipped the power to the MSD off – so I think the motor is okay.

I’ve learned a lot from this recent experience but need to think about what I’ve learned before I really know what my next move is going to be. I know I am very fortunate to have gotten out of this deal without a serious injury, very fortunate. Safe to say you won’t see the Jensen on track in the very near future though.

I wonder what the factory repair is for a tranny tunnel being cut in two?

This is when things were good:
ronthumbsup.JPG

jensenready2007.JPG


And this is when things were bad:
failure2.JPG

failure4.JPG
 
Dang, dude.

So the "dirt" was the rusty remains of the driveshaft?

"Heinous" is exactly the right word. Sorry to hear about the setback!

K
 
Not sure what the "dirt" is/was other than piece of metal debris and some chassis rust from the tunnel area. The drive shaft, the large part still attached to the car, is quite solid with no rust on the inside. But, that doesn't mean that the welds etc. that attached the splined end to the shaft weren't crap. Also don't know if the driveshaft broke first, or if the transmission locked up and helped break it. The transmission has been working fine though, had plenty oil cause it ended up all over the track and the bottom of the car, and never showed signs of a problem over the last couple years.

That pile of metal flakes in the passenger footwell is a lot of rusty metal debris. There are bolts and nuts all over the drivers side and passenger side that I don't know where the came from - they just appeared.

I don't know what we'll do with this thing now.

Ron
 
This spooked me bad. If whatever was banging around enough to cut the transmission tunnel had exited on the driver's side as opposed to the passenger side, Ron would have gotten hurt, bad. I've read that portion of the GCR saying that scattershields are recommended and now I know why.

We are totally perplexed by this failure. The other failures in the past we can attribute to some error on our part, and that gave us some hope about the car, but this right now is inexplicable and most likely a part failure of some sort. After just 5-6 laps.

I'm still behind the Jensen and after driving it a short bit feel it has ITS power. However, I think the plan -- although Ron makes the call on this -- is we put the Jensen away for a while and have him run the newly resurrected Z.

This is the first equipment failure I've seen that could have resuled in an injury. Something to think about.
 
Ron,

.... Wow, Man, I sure am glad you didn't get hurt.

.... Oak Tree turn at VIR is the most torque inducing turn I think I have run. A good example was when I saw the BMW transmission at the entrance to the South Course pit road. Twisted it right out of the car.

.... Don't blame the car though, I have had plenty of part failures, and most of the time it was something that happened to the part that caused the problem. It may go back to when you oiled down CMP. You may have locked up the motor and damaged the drive shaft.

.... I damaged a drive shaft at Charlotte last year during a downshift and had to replace it, the vibration was terrible. Thankfully, mine gave me plenty of warning. But it would have failed had I continued using it
 
Jeff and Ron.........get rid of the british cars. Time to build a Supra or something like that. I know guys enjoy the challange, but I have known you since you started racing, and you have spent far too much time and money on those projects for as little racing as you have gotten in. I don't mean to be a nay sayer and all that......but.

And seriously Ron, you are really lucky to have walked away from that without being hurt. I thank the racing gods that they were smiling on you that day.
 
Yep, I'm seriously thinking about what to do now. My goal is to race, improve my skills, and have a shot at running upfront someday. I need to consider many options, and make the logical choice that will allow that to happen. I don't anticipate doing anything with the Jensen in the sort term since this isn't something that can be fixed quickly. Focus grasshopper....
 
If you still have the SM, drive the crap out of it. Run it in SM and ITA. Double up on track time, learn to work traffic and how to keep momemtum up.

Then build an ITR car.
 
i agree, as a british car racer I can relate to the joy of running something different. However, at the end of the day it comes to track time. If you have a miata, I would run that thing all day long. You know they thing will always run, easy parts to get, and loads of fellow competitors.
I can also relate to the problem. I have twice had a driveshaft blow apart on me in a TR7. Not as much damage as you got, but did have to pull the tranny out because the bell housing was cracked up. No other damage, but I will never forget the sound when they blew. I was like someone on the side of the track shot a cannon at me.
 
Maybe it's not the (British) car's fault. I've seen driveshaft failures caused by the snap-ring that retains the U joint not having been properly seated. Had it happen on my old man's 54 Ford wagon on my way to high scool graduation at about 60mph. One second I was grooving along, then instantly, all Hell broke loose: the entire car shook like it was going to disintegrate! Snapped the rear of the 3spd MT in half. If the driveshaft would have become disconnected completely, I expect the results would have more resembled yours. The local gas station had just replaced the frt U joint the day before. Don't despair; this could even happen to a Vovo! phil
 
WOW...That's an explosion....You may have also damaged it on the chassis dyno if the operator locked the brake up, etc...Just a thought since ya'll just finished a tuning session not too far back! I'm glad that didn't happen at speed at the Rock coming up...Glad your ok, sorry about the car. Step away from it for a bit and run the piss out of the Z-car, that's what they're made for. Take care, Chris
 
Chris, it is actually worse in person. It deformed the transmission tunnel all the way back to the rear deck lid. Underneath the car, the rear end is destroyed, and the body pan to the right of the driveshaft is basically gone. The car is plain torn up.

I noticed a vibration on the dyno about 6k rpm. It certainly makes you wonder about what went on there.

It will take a long time to fix this, if it is even economically feasible to do so.
 
Jeff:

Glad to hear you are OK. The car can be replaced.

Did you have a loop specfically designed for capturing the driveshaft? I can't remember if it is needed in RWD cars in IT, but it would definitely be something to consider if you didn't.
 
Thanks -- actually Ron in the car but I was to go in next, so we are both glad to be in one piece.

Yes, it had a 1/4 steel driveshaft retainer. The driveshaft broke it - we couldn't even find pieces of it.

After this incident, I would strongly consider scattershields and driveshaft loops on all RWD cars.
 
the problem is I can not find where a driveshaft loop is legal in IT.

I am sorry about the car. It is a really cool project. set it aside and in time I think you will take another shot at it.
 
Why couldn't it be fixed quickly?
bend the tunnel back into shape, and patch with sheet metal and spot welds. paint
get new transmission
get new driveshaft, check it for phase and alignment.
bolt them back onto the car, GO.

*edit* oh should've read the whole thread before posting.

I guess though that a body man and a drive line man could have you back in business in fairly short order.
 
I saw you there Sat. we were breaking in a new engine in the 944S in touring lights as well. i was behind you some of the time i think or close by somwhere. sorry about he car man.

we were getting some data for VIPER, thats a VA teck program. had about 80k worth of sensors on the car. going to put it on the 8 point shaker rig soon at the VIR complex. i think it is the only 8 point in on the planet right now. looks like something out of star wars. We will post what ever finding we have if we can get someone to help with the size of the data.
may help a lot of IT drivers with set up. They have some grad students doing some of this sruff for us. FREE TOO can you say lucky!!! :D maybe i will have some pictures of some of this later this week.

again sorry about the car. i saw it and thought well how many of them can there be so its got to be the IT guy posting about it on the site. i had to take a bunch of the students for a ride and just ran out of time to find you and say hello. sounds like you would have had little time to chat anyway. maybe another time.

Lawrence
 
Why couldn't it be fixed quickly?
bend the tunnel back into shape, and patch with sheet metal and spot welds. paint
get new transmission
get new driveshaft, check it for phase and alignment.
bolt them back onto the car, GO.
[/b]

I understand your point, and if this were a Ford, Nissan, or even a TR8 it'd be no trouble. A bit more trouble with the Jensen.

In the end, these sorts of things are sometimes more emotional than "just parts". I can find the parts eventually. I'm just sort of run down on this project, I need to race, not work on cars. I can work on cars just fine, and know that is part of racing, but my ratio with this thing is really, really, really skewed to too much work, not enough racing.

Hey Lawrence, would have liked to have met you there. I'm a former VT grad too!


Ron
 
Back
Top