Date: 16 May 1994 17:29:58 U
From: "Dave Lapham" <Dave_Lapham@oakqm3.sps.mot.com>
Subject: Re: The Jensen Lives!!
RE> The Jensen Lives!!
> Sometime ago I started asking for help on a JH engine rebuild.
> I got some general pointers and learned that the engine was
> Lotus built and that I would get more info from the Lotus list.
> Actually they were pretty much in the same boat, no-one admitted
> to rebuilding the 907 series engine......
> Well, after weekends and (short) vacations, between school, work
> and a limited social life, the 907 Lotus engine roared to life May 10th.
I've only subscribed to my first internet mailing lists in the last month or
so, so I'm new to these waters and obviously missed your requests for
information about the 907 engine. I had a '73 JH in college which I gave to my
brother who, like many of us, is restoring it between addressing the
responsibilities of life. My car was very, very rusty and the PO had it
patched up very badly. I have a couple of spare 907s and know some things
about the engine.
I won't get into what little I know about it's biography, but I would like to
sing its praises a bit. It's a truly wonderful, racing-type lump to have under
the bonnet. It's extremely compact and light weight, tremendously strong
(except for the earliest ones), relatively simple, and phenomenally efficient.
The one I built I had precision balanced, connecting rods squared (they needed
it, too), I swapped the Strombergs for the Del'Orto DHLA45s, and added higher
performance cams from Dave Bean Engineering. On the dyno break-in the engine
was outputting somewhere near 200hp at just around 8000 rpm. No other special
things were done to the engine. Cams went right in without piston to valve
clearance problems (we certainly checked to confirm this). The Lotus TC Big
Valve and normally aspirated 90Xs I feel are efficient enough to run about
100hp/liter while still being civil enough for road use. And you don't have to
make major alterations from stock to attain this.
The 907 at this kind of hp/liter is entirely different in its dynamics than the
TC engine. The power/torque curve is much flatter with the 907, making it very
easy to drive in all conditions. It revs very smoothly and freely. I think
that the 907 would make a very nice motor for a Seven as a less expensive
alternative to the various Cosworths, or be a nice engine swap for a TVR.
There are lots of 907 information sources. I bugged Dave Bean Engineering and
Delta Motorsports quite a bit. The JH shop manual available through the Jensen
club or the version available through Delta Motorsports I found useful. Also,
shop manuals for the Lotus Elites and Eclats have lots of information on the
907. Like clubs tend to be, the Jensen club is a very good source of cars,
parts, and technical information. And the Lotus club has loads of folks ready
to donate high-quality technical advice for free.
The chassis and robust drive train handled it pretty well. Though the poorly
pieced together bodywork was a bit limp, the chassis was certainly capable of
managing the extra hp, especially with the addition of front and rear anti-roll
bars (the stock car doesn't use sways, but the suspension bits do have the tabs
for installing them), Spax shocks, and slightly higher-rate springs. Long-term
I don't know how everything would weather because the car didn't turn many
miles before I bought an Elan and gave the car to my brother for a much needed
sheetmetal restoration.
> A point for the JH as "The Wonderful Car", If you look for the two
> last models, the JH5 and the GT, I think they both have the
> 'overdrive' in their 5-speed trannies. Our Jensen is a 5-speed
> (it's a 74 1/2) and 5th is overdrive. It looks great and is
> reported to out handle the Porsche 911 of the day, skidpad #s
> I believe. Almost reasonably priced, usually less than $3k,
> although I've been told that "the Jensen-Healey is a three
> thousand dollar car with a two thousand dollar engine".
A JH as "The Wonderful Car?" While folks have made many, many great
suggestions, I agree with the comments made about the JH in this string and say
it could qualify. For $5k or less, it's clearly the one of the quickest, best
handling things around (yes, performance is my bias, but I understand that
there are many other charms that make cars entertaining as well). Though there
are TVRs around this price that are clearly more capable platforms, and they
are much rarer. And for just a bit more there are Lotuses like the hardtop
Elans, Europas, and Plus 2s which are more capable still. I certainly do like
the way the JH looks. I've read lots of reviews from it's day and most
reviewers had issues with its looks. It's not flowingly well proportioned the
way the E-Type or Elan is, or as classically shaped as an a AH 100 or 3000, and
it's not charming like an MGB or Spridget (I apologize for all the other
great-looking LBCs I've left out). But I certainly think it's a handsome car.
At the BMW Vintage Festival last fall I saw a very well kept one in the paddock
and thought it was very striking. It make me remember that it's been a very
long time since I last drove mine.
- Steven Jackson
Steven_Jackson.LOTUS@CRD.Lotus.com
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