Jensen Healey Race Shakedown.....and Failure

[Ron Earp]

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.

First session out we were having some mixture problems with the Strombergs. The car was reluctant to take throttle and pull like it should, but I think we eventually got most of that sorted out. In the second session the car was running pretty well and would pull to our intended shift point for the test day, about 5500 to 6000 RPM.

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. If you turned in too sharply the tail would readily step out and it was definitely a step out that was out of proportion to tire grip; that is to say, it wasn’t tire related. The rear end would also break away under increasing g cornering too, in a manner that was predictable but that happened far too early to be racable. I think the rear was far too “hard” and had trouble getting hooked up. The front was better than the rear, but I didn’t have a good chance to push the front as the rear was limiting me. 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, a sharp right hander, and started down the 4000’ straight. There were no other cars around for about half a mile or so. At about 70mph and just a little ways down the straight, 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, it was still rolling a bit as I jumped from the cage (open top cars quick to get out of, a good thing!!!!). The car was leaking fluids out of three places and I could hear a heavy flow of liquid splashing on the ground that turned out to be fuel from the broken pump and line system. 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. 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 sheared off the exhaust system while turning itself into a 3” diameter metal facsimile of a snake.

The engine was spinning at about 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. Electrical switch was broken, and my MSD timing control was reduced in size by about a third. 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. 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’m sure 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. Safe to say you won’t see the Jensen on track in the very near future though, unfortunately.

[Gregg]

Sounds like a very frightening experience. Thankfully you are o.k. which is the most important part.

[Big-Foot]

Thankfully you appear to have escaped unscathed.
Many others have not been so fortunate.
You didn't mention any driveshaft safety loops. I'm sure they will be on the list of upgrades / repairs.
I had a U-joint failure that was not near as bad as yours in regard to damage done but it took out the mainshaft of the transmission and tailshaft housing. The other odd thing was that the rear end had a problem as well - Turned out that the shock from the failure had broken both of the differential pinion (spider) gears. This was in a 9" Ford no less.
Curious what could have precipitated the failure.

[Ron Earp]

While it didn't have a drive shaft loop, it did have "anti pole valut plate", a stout quarter inch metal plate connecting the tunnel and would hold up the shaft. It was bolted in place with 5/16" bolts with 3/4" washers - clearly not enough. That was ripped out of the chassis and I don't know where it went. Gone, so it didn't serve the purpose it was supposed to. Yep, if we rebuild this thing it'll have a proper loop as well as some "armor" around those rotating bits. I'm happy to be typing this now at home in my red chair with my cat, instead of being in a hospital somewhere, or worse.

[Steve Briscoe]

What an ordeal! Those pictures of the drive drive train tunnel look like a grenade went off underneath the car. I'm working on a '70 Mach I project with my son and I'll alter the list to include a new balanced drive shaft. Don't want to take a chance with the old one after seeing what a broken one can do.

Fortunately, you flipped the kill switch before the energy found its way into the motor. Long ago, I had a '67 Corvette with a 427 and I got it stopped right when I first heard noise. Saved the numbers matching motor but wound up with two sleeved cylinders. If you're quick enough, there's always some good news that comes out of the bad.

[Bill D]

Glad you're OK Ron. That was quite an accident. Any idea of what caused the failure?

[Joey Dean]

Ron,

Already posted on the JH site, but just want to say again I am glad you body is in good shape even if your head still is spooked. That welded spider come lose you think?

[Ron Earp]

I think the motor is fine in this case. As far as the diff, no, that didn't cause this issue I don't think. I know guys that run those on track with much more powerful cars (just read Mark Donahue and crew were running welded diff Hewlands in some of their cars back in the day) and say they are dead reliable, and this one was done by a fellow that has done many, many, many welded diffs. There is something funny up with the transmission/driveshaft I think in this case. More inspection will reveal the answer I think, but for now that joker is staying on the trailer. I don't know if I want to rebuild the car or not. Sort of down about it right now, but that might pass.

Part of the "problem" I have in not getting excited about it was performance. This car has to compete with some serious machines in ITS - second gen RX7s (and if you don't know what Mazda has been up to for the last 20 years, as I didn't, you'll find their "average" sports cars are fantastic racers), BMW 325s, Z cars, etc. - and I'm not sure it can. The motor build is a serious build and is IT max legal, but she's about 25 to 40 rear wheel hp shy, at least, from being in the hunt on power to weight with the class winners. And handling was "okay" out of the box, I know it'll get better with development, but I don't know if it'll get to the levels it needs to be. Have to think on it.

[Neal]

Ouch! Glad to see you are OK.

[Malcolm]

Hey, no fire! Now thats an improvement Ron!

Glad you are ok!

[I LOVE GT40- Paolo]

Mamma mia what a damage.

Glad u are ok Ron...seems the little Jensen feels a little tired to fight with other SCCA cars (all the ones u listed are really newer than her)

why not repair and sell her and make Fran's T70 a real race car?

Paolo

[Ron Earp]

Originally Posted by kenshiro8

why not repair and sell her and make Fran's T70 a real race car?

Paolo

Oh, the T70 is going to be a real SCCA car in SPO but with a bent on winning the 13 hour Enduro at VIR. Just waiting on a cage slot for time, and some parts from our favorite buddies at Kennedy.

I'll be thinking of what to do with the JH. I really would like my main class SCCA car to be modern, plentiful, and have fuel injection. I spend too much time working on these cars and not nearly enough time driving them, no where near close enough. And that is not good.

Ron

[Ross Nicol]

Wow! That hole in the tunnel is way too close to where your family jewels were strapped.Glad you were'nt hurt.I always am concerned about flywheels and their proximity to the legs and body too. Of course this situation is mostly removed with mid engine layout so you will feel more comfortable in the T70. Do you think that car is jinxed?
Ross

[Ron Earp]

Originally Posted by ross nicol

Do you think that car is jinxed?
Ross

You are quite perceptive. For me there is such thing as bad karma. And I wonder if this car is it in physical form. Still thinking and planning on what to do for the racing future.....

I mean, we can build and prep cars - lots of our cars run fine, race well, and can win. This one isn't prepped any differently. Sure, there are some things on this car I'd do differently now if starting today instead of two years ago, but for the most part it is mechanically done well. But it still refuses to race. I think it needs a field, and a tree to lie under, so that it can do what it wants to do - give in to entropy and rust away.....

R

[Ross Nicol]

Ron
If the motor is good sell it to a Lotus Esprit owner where it was used as well. Part the rest out and you might come out even maybe.Move on, that one's no good.I was impressed by an Escort owner in the next garage to me who stripped 3rd gear, got the box out returned across Melbourne to workshop fixed it and got back to the track only missing one race.Of course they were lucky we had a tea break for an hour during that time. I doubt I could do that with the ZF.
Ross
Ross

[Lynn]

Ron,

After all of the time & effort, you should at least pull the motor and sell it on eBay or something :-)

(can laugh now, a bit, knowing you escaped the shrapnel, but you'll have to get a new helmet - you didn't mention the gouge in it)

Lynn

[Ron Earp]

Might be time to move on with it, but I need to think some more. A big decision. The helmet has a chip in the gelcoat from something hitting it and going off, but it isn't a hole or anything like that. Definite metal impact though, no doubt. I discovered it while waiting on the tow truck and pondering my luck, lucky indeed.

R