View single post by Ron Earp
 Posted: 10-08-2006 05:29 pm
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Ron Earp

Joined: 03-12-2005
Location: Cary, North Carolina USA
Posts: 339

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 here:

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.  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 (but we're keeping the Super Secret Racer ModTM) 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:

Video will work in QuickTime.



Last edited on 10-08-2006 06:11 pm by Ron Earp