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Rebuilding Lotus 907 - Parts acquired, Advice?

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I've reviewed the Jensen-Healey Preservations Society's site and what people there have done and suggested in rebuilding their engines and I'd be interested in knowing other people's views are on the bits and pieces I've accumulated to rebuild mine as a fast road car. I've acquired:

1) a cross-drilled 2.2 crank and bearings.
2) a set of 10.9:1 Mahle pistons.
3) a later, high compression head.
4) a steel flywheel (~13 lbs)
5) I'll use a later Elite 907 block instead of my early one.
6) 107 cams for both Intake and Exhaust.

to be acquired/done:

7) twin Dellorto 45s- spec 9?- have manifold already.
8) SS intake and exhaust valves
9) HTD cam belt system
10) Balancing during the rebuild.
11) Ignition- either Petronix or Electronic, haven't really made my mind up.
12) Water pump- replace/rebuild for higher output.
13) The piston rings, gaskets, oil seals, etc.

I'm basically rebuilding the engine to a Lotus 912S spec except for using 2x107 cams instead of the 104/107 combo.

Advice Please:

The narrowness of the Jensen-Healey's sub-frame doesn't allow me to use a later, stronger block and I'm limited to the narrower early one. Will it be advisable to use a steel girdle/strengthening plate to reinforce the lower block? I've seen comments suggesting it go between the block and bearing carrier, or between the carrier and the sump. Is there a supplier for these? Materials? Thickness? Any advice/comments about the design or fabrication of one?

I'm still unsure about the 104/107 or 107/107 cam choice. Its not going to be raced, but.... I'll very probably install a full set of competition valve springs so a cam-swap wouldn't mean having to pull the head to change springs then.

Head porting. Where to start? Where to stop? Port matching?

Hardware: Head Studs/Bearing Caps/Con Rods- I think I should get these new in any case, but are better ones needed for a non-race application?

My pistons seem an odd set, three are marked "A" and one "B"- can they be mixed? I understand these designations were used to denote slightly different sizes- is this likely to cause problems (balance) or with fit?

Other: I've acquired a Lotus/Toyota W58 transmission with bellhousing and will be installing it too when the engine is done. I've a spare sub-frame for the front that will be rebuilt and the whole front suspension/engine/transmission done at the same time.

I'm still acquiring parts, and intend on seriously starting the rebuild in January.

Thanks.

James.
 
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Deleted member 3577

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The 907 sounds like an interesting engine...

It was used in more cars than I thought.

* 1972-1974 Jensen-Healey
* 1975-1976 Jensen-Healey GT
* 1974-1980 Lotus Elite S1
* 1975-1985 Lotus Eclat S1
* 1975-1978 Lotus Esprit S1
* 1978-1981 Lotus Esprit S2
 

DrEntropy

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They are kinda neat. Angled holes keeps the depth in line with low profile engine bays, the thing can be built out to produce gobs of power, manifolds were cast for Webers...
Sir Colin's approach to 'turbocharging' was kinda neat too.
 
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One of my favorite pictures.

kdkworth.jpg

(Duckworth, Hill, Chapman & ?)

From what I read the 907 was the first Lotus "home made" engine.

A guy by the name of Ron Burr got snagged from Coventry to design the head.

Chapman liked to "hijack" talent from other designers.
 

DrEntropy

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He was bloody GOOD at it! That ain't no 907... /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

DFV's made sweet music. Looks like Lucas "slider" injection there.

Yup, 907 was the first "in-house" effort. Darned good job, too.
 
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