Jensen Racing - I hate Chevys!

The first race outing for the Jensen Healey ended up badly, unfortunately. Jeff and I decided to head down to the Memorial Monster event at Carolina Motorsports Park for a lot of racing - two sprints, one mini enduro, and the Carolina Cup. Friday, the day before, was an open testing day so we signed up for that to shake the car down.

We'd previously had the Jensen out at Roebling Road and learned it had cooling issues, as well as oiling issues. Since then I'd spent a lot of time putting in a new NASCAR radiator, adding an Accusump, larger oil cooler, and dual remote oil filters. I was pretty sure we'd handled the cooling and oiling problems, that was we'd be allowed to concentrate on figuring out other problems with car.

Well, out we go on the first practice session and on lap two, on the front straight, the remote oil filter adapter blows off the block and within about 5-7 seconds pumps the oil out of the sump, Accusump, and runs the engine dry. And, naturally, the car oiled the track down and closed it for about 20 minutes for clean up. I felt horrible about that.

Anyway, after a flat tow back in the paddock we were able to check it out. The adapter was not the correct adapter for the motor. The adapter that blew off was for a Chevy with 3/4" threads, while I needed the Ford one with 13/16" threads. You can put a Chevy adapter on a Ford nipple, and it will tighten up. And, most kits just come with Chevy adapters since they think everyone wants a Chevy motor. The adapter won't stay on and when you have thread tape on the nipple it is extremely difficult to tell that the adapter is in fact the wrong size. I've always not liked Chevys. It's my fault, yes I know.

A 120 mile parts hunt Friday turned up the correct part. After cleaning everything, carefully, and putting it back together the moment of truth arrived. We fired up the motor and she had pressure, great! But, after about 15 minutes of running a ticking noise slowly became louder and eventually became an identifiable rod knock.

I am hoping we only wiped a rod bearing and that the bearing is damaged while everything else is okay. That could be repaired relatively easily since the bearings for the motor are not expensive. Bearings are there to protect machined surfaces, right? Maybe I'll get lucky on this one.

Extremely disappointing day, but we'll be back. At least there was one glimmer of hope - Jeff's TR8 that I wrench on placed 4th on Saturday and led the IT racing on Sunday for about four laps. One day in the not too distant future some Brit cars will bring home some IT trophies!

Ron

Sorry to hear of your bad day. We had one too at Donnington a while back. After ten minutes on track bedding in new brake pads, a disc (rotor) cracked up. Day over and 6 weeks later I am still waiting for delivery of my replacement discs! But it did lead to a positive action in that whilst the car is inactive, it is stripped down for re painting the front clip.

Say Hi to Jeff and Mark. Say how did Mark do in MAX5 over here? I never heard.

Hate to hear your sourcing troubles. You ought to fit that thing with some common brakes, like NASCAR rotors and calipers, and you'll be on easy street for not much cash.

Mark did pretty well in Max5. Max5 has far fewer modifications than our Spec Miata Series, and, the racing is somewhat tighter since folks cannot diddle with stuff. Bad thing is street compounds are used so lots of slipping and sliding and tire use. He ended up being about 1.5s off the pole, around top eight or so. I think he did pretty well for himself considering he'd never driven Donnington before nor a Max5 car. All in all Max5 sounds pretty cool and you should get one and start doing some wheel to wheel there!

Sometimes I think I have the WRX sorted, and then I laugh at myself and wait.
Motor racing is a mugs game, but it's hell fun!
Better luck next time Ron.

Tim.

Yeah I know I should get one Ron, in fact I was musing on it only yesterday. But I doubt my testicles could take another car purchase right now, the Prosport was allowed but another would be pushing it. Maybe once the kitchen remodelling is started AND finished..... Wendy also did say that I could only have as many race cars as we have kids. Thank goodness the Lotus is hers!

Hello Malcolm -- thanks for the "hello" to Mark and I. Things are going well here, except for the issues with JH which we will sort. Mark had a blast at Donnington -- said the MAX5 series was a lot more fun than our SMs.

Hope to see you guys in the fall. Tell Julian I said hello.

Jeff

Hi Jeff

How can 30 minutes compare to 13 hours? Glad Mark enjoyed it though, next visit I hope to make it along. However since last post I am seeing someone on Sunday at Thruxton for BTCC with a view of getting a team togetehr for MAX5. Unlikely to come off but you got to give it a go!

LOL...well, at least when I run 30 minutes, I can keep my lunch down.

Actually, in many ways, a 30 minute race is more intense than 13 hours. EVERY corner, every braking point, every turn of the wheel is critical to finishing well. The start is mayhem because it is so important and then you drive flat out, no holding back, for 30 minutes.

Part of my problem at the enduros is I sprint race them from the start and set a pace I can't maintain. Need to relax a bit, back off a few seconds, and just get in that 1.5 hour rythmn.

P.S. My new Exige just showed up. Great car.

Yep, you need to hold back in the enduro so we don't look bad in lap time comparisons! Jeff, you must bear in mind a sprint race to those guys in the UK is a SCCA Solo thing to us.

SCCA Solo is you against the watch, no wheel to wheel racing. And that seems to be akin to the Hill Climbs and Sprint races in the UK. An SCCA sprint race is just that, a wheel to wheel race for 10 laps or so, that is balls out use it all up - which Jeff does pretty well since his TR8 needed brake rebuilds, calipers and rotors, both races this weekend! Over 500 F caliper temps burned up the seals, pads, and ruined one rotor on one side.

To be honest when Malcolm and Jools were talking about having done a lot of sprint races, hill climbs, etc. I thought they were speaking of having done a lotof wheel to wheel stuff. So, I didn't think anything of it when they were headed over here to race. At least, I didn't until they arrived and we started talking about who is starting the enduro with a 70 cars field, who will qualify etc. and it dawned on me - oh! their sprint races are like out solo stuff, so I better start since these chaps hadn't ever had the experience of starting a race like that! And hadn't done the wheel to wheel thing either!

My worries were unfounded though because they both did beautifully and had no problems at all with traffic. Good drivers, both of them, and this time back they can pull a start off and deal with that mayhem!

The Exige is a fantastic car Malcolm! Jeff gave me the opportunity to drive a couple miles in it and it is the lightest steering thing I've ever driven and incredibly nimble. I think you'd like! Only thing I've expereienced in that league is the Atom, but I'm hoping that Fran's Lola can reach that level of nimbleness and add in a lot of power/torque to the driving experience. The Exige/Elise pair is long overdue in the US and it is nice to see them finally here, really cool cars!!!!!

Ron

You kept that quiet Ron!!!!

Traffic? If you live in the south east of the UK you know all about traffic! I believe there is a US state that is bigger than the UK and has 600,000 inhabitants. We have 66 million!

I am up for a start this year....I think!

Your sprint races are what I would call our regular races here in UK, as Mark experienced recently. The fact is you get 2 of these plus a mini enduro of 1.5 hours in a weekend. Plus practice/qualifying. That is about 4 hours of seat time, for what, $400? We are envious!

I see the Exige at a lot of track days. I think they look fab and they do just what it says on the tin, goes like stink! I can see you US Eurocar fans enjoying these cars. They are what Lotus is all about. At some of our racing car shows you occaisionally see full on V8 race versions that have been commisioned and they are really cool. Someone should have a race series for them, it would be very popular I think.

But the difference between an Exige and how I would expect your Lola to be is quite different. You will be carrying a sodding great V8 in the back and to change direction nimbly will be harder than when you have a tiny aluminium engine weighing peanuts. What will be your kerb weight of the Lola? Hopefully under 1000KG? I would recommend, if budget, allows that you have a dry sumped engine to lower your CoG. That will help nimbleness as well as some extra grunt. The difference I have recently experienced between a higher CoG car (GTD) to a lower CoG lighter car (Prosport) is amazing. Don't make it a point and squirt car but one where you keep momentum and speed up in corners. You can get away with less power (= more reliabilty for racing) but still have great lap times.

I saw the pictures of your Lola in production. Nice!

400 hp Exige...

Hey Ron! Lotus have even developed a one-off "Sport" Exige for a Far Eastern customer (it could easily be repeated they reckon).

Perhaps you could identify the original powerplant? It seems like it may come from your side of the pond maybe or perhaps it's what we know in Europe as the "Omega" V6.

"A narrow angle V6, 2,998 cc Swindon Racing Engines tuned GM racing engine is mounted longitudinally in the Lotus Sport Exige. The naturally aspirated 32-valve engine produces 400 hp (296 kW or 405 PS) at 7,750 rpm and 294 lb.ft (398 Nm or 40.6 kgm) of torque at 6,500 rpm and has a maximum engine speed of 8,250 rpm. When the light weight of the Lotus Sport Exige is taken into consideration, the power to weight ratio is a phenomenal 470 hp / tonne (0.351 kW/kg or 476 PS/tonne). The engine itself weighs 157 kg.

The power is transferred from the engine to the rear wheels via a single mass stepped flywheel, AP Racing twin-disc cerametallic race clutch and Hewland NLT sequential six-speed dog type transmission (with in-line shift mechanism). The gearbox itself is cooled through an oil-water heat exchanger. A limited slip differential (separate power and brake ramp angles) completes the powertrain package.

The dry-sump engine, with a bore of 89.0 mm and stroke of 93.7 mm is water cooled and also uses an oil-water heat exchanger to efficiently cool the oil. The whole engine is controlled by a Motec M600 electronic engine management system fitted inside the cockpit."

I'll bet that flies....

Bang!

Well (all good stories start like that), we got the motor out and the pan off. Lo and behold, lots of metal bits in the pickup screen and in the oil pan. Lots of little blue/black ribbons of metal that used to be a bearing shell. Now, which one? Didn't take long to figure out. Judson suggested go for number three since it fails quickly. Nada, nice and clean bearings. Number two? Nope, not behind door number two. Use a little light and viola - look, number four is oozing metal out around the con rod! Pop the cap and all was revealed. Number four spun and coughed bits in the pan. Bearing was still all there though and the crank is not heinously scored. It has some roughness compared to #1 and #3 which are smooth, but not so much to catch a fingernail or measure. I think it might polish up with cloth, or at least we'll try. Some pictures below, looks like fun times ahead!

Eeeeeeeeek!

Machining, hardware or torque problem Ron? Isn't it a little unusual to spin a rod bearing?

No, not when the oil pressure goes to zero at 6500 RPM. I turned it off quick, but it probably ran for 4-8 seconds, there abouts. All the rod bearings little or no wear, but the 907 is known for being touchy with respect to rod bearing oiling. Interuptions in oil supply are not tolerated on the little motor.

R

Well, got everything apart now.

The motor spun the bearing but there is no damage to the rod big end, and, the material on the crank basically polished off with 1500 grit paper (thanks for sending that down Al H., fantastic!!!!). Specs on the big end and the crank are exactly where they were when the thing was put together. All the other bearings look perfect, and I do mean perfect, just little normal wear. I'm replacing them though, but I'm not pulling the motor down as some have suggested - if I did it'd cost a lot more than I can afford now and it'd not be back together for months. Sure, if it blows up I lose the $75 in new bearings and labor, but we don't have a lot of labor in it on R&R (about 5 hours so far) and I can afford the $75.

I don't think it spun the bearing when I lost oil pressure. I think it spun the bearing when we tried to crank it in the paddock after getting the oiling system back together. When I hit the starter for just a second it made a strange "clunk" noise and didn't start. Jeff heard it too. Then, we hit the starter again and it fired up and ran at idle. I could hear a ticking though, and it got louder. We only ran it for maybe a minute before we decided that was definitely rod knock and we were done. RPM was never over 2000 or so during this period.

Before it goes out to a track event, and oils down another venue, plus costing me a lot of time in towing and gas, we're going to take it to a local asphalt roundy round track and run it for a few hours. They rent out for about $150-$200 for four hours, all you and only you, so it'll be worth it to run the car in.

Racing is frustrating, or at least it has been for me over the last five months with a lot of grunt work and little seat time. But, when you run it is so much fun it makes it worthwhile!

R

So Ron,
Are you having fun yet?

Is there ANYTHING more frustrating than racing?

Rick

Hi Ron,
I dont think you will get away without further problems, particularly with #4 rod given the amount of heat discolouration on it. Have you refitted /torqued the #4 rod cap and measured the tunnel size, and again with brg fitted to check for out of round?

Jac Mac

Still have that to do. It might not make it, but, we shall see. I'll check clearance, we'll do round too, and see where it is. So far it looks good. Sometimes it works, sometimes it doesn't. I've had good luck in the past doing it when everything was in spec and looked good, has have others, but we still have some checking to do.

As I said, it doesn't cost much to do this but if I pull it down it'll be some months and a whole lot of $$$ to redo everything.

Ron

PS-Added 10/06 - Jac Mac, you were right. When I tried to put the new bearings on and torque the caps it was too tight. Basically, the plastigauge showed 0 clearance, if it can do that - turned into a flat film way wider than the card and was hard to locate. Crank would not turn either, so, I was unlucky. Some folks have replaced spun bearings and run for years, but, as you rightly pointed out, that joker was far to hot to make it.

Jeff and I made the journey to Atlanta to pick up the Jensen with new motor from Judson Manning, our Lotus 907 engine guru. Judson rebuilt the motor after I did bad things to it outlined eariler

Judson put this motor together and fixed a few of the issues with oiling, adapters, lines, etc. that caused the last failure. I think we'll be in business this time around, at least as far as the motor is concerned.

We were able to use Judson's GA tag from his road going Jensen to have a few spins around the block in the race car. In fact, I have some rather crude video of Jeff driving as well as some pictures I'll download off the camera and post.

Anyhow, with a street muffler setup the car drove very well! Motor was smooth, as smooth as a 907 is going to be - like a box of rocks. Power is good I think. Pulls decently to about 4k, and then pulls really strongly from about 4.5k to around 6.5k-7k, at least strong for a 4V 2L.

We were able to run it back to back against Judson's 2.2L car with Delortos and Supra 5 speed (which is an EXCELLENT modification) and it was really interesting. Judson's motor definitely has more poke in the 3k-4.5k range or so, but from about 4 to 4.5k on up to red line both cars behave identically, which is a very nice suprise considering all the press the 2.2L cars get.

Judson feels in this RPM range the head is limited and I agree with him, although our minor port work on the race motor might have allowed us to equal the larger displacement 2.2L. Anyhow, they both drove very nicely and I'd prefer a 2.2L except for those pesky rules....but a well assembled 2L with Strombergs can get the job done.

We've got more work to do though. We feel we'll pick up some more power on the race motor as we've not optimized timing and A/F on the dyno and we're running a street muffler. Carbs need to be gone through carefully with everything setup just so. We really don't know much about the dizzy advance curve and our initial timing is set at a conservative 10 degrees, so, there is some power there unless we're just lucky out of the box.

From our exhaust gas probes fitted on #1 and #3 we know that we're running a tad to rich, which also hurts power a little. Work on these a little bit and see what can be done here. All work for the coming months!

Judson has built a very good motor and I'm very encouraged by what we've seen so far. My race partner Jeff was really excited about the power as we're been concerned that the car might not hold its own in ITS given some of the other iron in the class. I think if we can eek out a little more juice from it we'll be good to go.-

Anyhow, it has been a long road on this car, very long indeed. Jeff Young has put in countless hours on this car and I really appreciate his time and effort, it is as much his car as it is mine and we hope to run The Jensen and the TR8 in ITS for 2007. A British Attack!! Judson has done a fantastic job on the motors (two motors) and we're looking forward to flogging his engine around on the track to see how it works out.

Here are some really bad camera phone photos and video:




http://www.gt40s.com/images/jh.3gp


Video will work in QuickTime.

Ron


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