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Engine rebuild/replace?  Rating:  Rating
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 Posted: 12-16-2012 03:02 pm
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RSGill
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Recently my oil pressure dropped, engine's leaking out the rear seal like there's almost no seal, and my top end started sounding like a Singer sewing machine.
 I'm thinking that since the engine's a '73, I'd like to take the opportunity to replace it with one that's been professionally rebuilt. Something closer to 200 HP.
Any recommendations on who, how or where would be a good place to start?
Not intimidated changing engines, but would be overwhelmed rebuilding one.
Really appreciate any guidance.

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 Posted: 12-16-2012 08:37 pm
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Art DeKneef
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There are several threads on here detailing the pros and cons between the 907 and other engine swaps as to feasibility, cost, work involved, and on and on.... My opinion is it's your car do what you feel comfortable with.
 
Having said that I believe the car will be worth more in the long run if it has the 907 engine in it. Most of the engine swaps I have seen advertised and sold over the years seem to be less than those that still had the 907. The 907 is what helps make the car. Within the past year here in AZ I have seen 3 project JHs slated for a different engine swap that never got completed. One I rescued (soon to be on the road), another was bought by someone else for parts and the third unfortunately is going to the junk yard.
 
On to your questions. If your car is an early 73 then it has a rope seal and in order to replace it the engine best be out of the car to replace it. The top end could be valves need adjusting/replacing. Do you know what the pressure is across all 4 cylinders? Are they close in numbers to each other?
 
Getting the 907 to 200 HP isn't impossible, it just takes longer and costs more. Depending on how much work is needed and how much you do yourself I'm guessing the basic rebuild will be around $3,000.00. Getting to the 200 HP mark figure $8,000 to $10,000.00. Here you need new pistons and cams, a rebuilt 2.2 L crank, Dellorto carbs, rebuilt upgraded head, etc. Again several threads here about rebuilding the engine.
 
Going with a different engine means new engine mount location, concern for weight vs. balance, height of engine requiring modification to the hood, different trans and drive shaft, connecting to the rear end, clutch mechanism change from cable to hydraulic, etc.
 
You should be able to find someone in your area to do some of the rebuild for you. Hopefully others in your area here will be able to chime in with their recommendations.

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 Posted: 12-16-2012 09:10 pm
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RSGill
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Thanks Art,
Definitely want to stick with the 907.
I know if I rebuilt this engine, I'd want somebody that had some experience. Don't know anybody in the DC area that knows anything about 907s.
When I bought the car, the compression was a bit low in the #3, and I'm sure it hasn't gotten any better.

It does have a rope seal, and I know it needs a valve job, but it sure would be nice just to swap this engine for a fresh one.

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 Posted: 12-17-2012 12:20 am
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chrisl
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G'day

I have a 1973 JH Mk1 with exactly the same oil leak problems you described. I preferred to keep the engine that came with the car and replace the seals but as others have said, it's entirely up to you what you want to do. I was offered a rebuilt engine from someone in the UK which was sorely tempting but I decided to stick with the old lump.

You can readily buy the seals needed for the job from the Club Store/Warehouse or even Ebay. I bought mine via the JHPS, except that the rope seal supplied was the wrong one (have given some feedback to Greg - in fairness this part isn't used too often!). On that, rather than cut corners, get the genuine Lotus rope seal (part number A907E60112). I got mine from Ross Hockley Autos in Sydney (see http://www.jensencarco.com.au ) who is super helpful. The seal comes in a kit with some rather vague instructions, a metal plate and some goop labelled 'Ford' (!).

The job itself isn't too difficult, the engine needs to come out, bolted to an engine mount and, well, take it from there. A mechanic who might have worked on Lotus cars like the Espirit should be able to do the job, and might be easier to locate than you think. In my (albeit limited) experience if you can source and supply the parts they need, more are open to taking it on.

As an aside, my car whas now been off the road for over a year - the mechanic who originally took the engine out, took it to pieces but then went bust... Have found another who's taking it on but sheesh.  I think though that I was just unlucky - I don't have the time, space or expertise to do a job like this but have been let down on this occasion.

 

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 Posted: 12-17-2012 03:22 pm
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pbahr
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I'm a proponent of NOT using any engine in the JH other than the 907. My suggestions are thus:
  • If rebuilt well, the 907 is a great engine and it saves the character of the JH.
  • Don't bother with the rope-seal engine.
  • Richard Reyman West Coast Racing Cylinder Heads, http://www.proheads.com/ did mine several years ago and still does that work. 
YELODOG

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 Posted: 12-17-2012 04:31 pm
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Jensen Healey
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This shop is listed in the tech area:

Old English Auto
Rusty Owen
Severn, Maryland 410-863-0132
Provides full service & repair of Jensen automobiles as well as Jaguar and Land Rover.

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 Posted: 12-20-2012 03:17 pm
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roverman
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Is it possible to convert from rope rear seal to later one piece, by machining? I have done this conversion on many 215" V8's. I counterbore the rope seal area to accept the later one piece seal. Have you considered a turbo, for more power ? Good Luck, roverman.

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 Posted: 12-22-2012 10:17 am
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roland11a
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Hi There

I've just been through a similar exercise and to add to the comments on the rear rope seal, It can't be retro fitted with a later type of seal. The rear of the block is different with a bolt on seal housing. Also the seal runs in the flywheel flange which will need to be reground if using the original crank. The advise i received was to go for a later block and transfer all my internals over. The later blocks have the later type lip seal, holes cast in the crank case webs for better breathing, Different crank case breather, eliminating the need for the 'bean can oil trap/Filler, and improved oil pick up pipe/strainer.

This is all probably an over simplification and the choices seem endless. such as do you go for the 2.2 crank and high compression pistons.

I was lucky and dropped on a new set of standard Lotus pistons and liners for £100 ($150) and i got a Lotus (Esprit i think) short engine off e bay for £25 ($37)

Not up and running as yet as cars not ready.

Roland


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 Posted: 01-01-2013 10:41 pm
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RSGill
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Really appreciate all the advice. Guess I just needed a a little push in the right direction. Might as well bite the bullet and build the engine I'll be happy with.

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 Posted: 01-04-2013 05:15 pm
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Gary Martin JH 15371
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I would look for the later 907 engine (74 and on) with the later rear seal and rebuild that engine. I'm sure if you ask around you could fine one. I don't understand why people swap other engines in the JH. Who would not be happy with a Lotus powered car ? It is the whole reason I own one !

Gary

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 Posted: 01-07-2013 11:43 am
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RSGill
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Can't imagine a JH without the 907.
Saw a Danon Yogurt commercial yesterday while watching Top Gear, and it featured 2 young women in a red Jensen Healey. (Right hand drive). Gorgeous.
Really motivational for getting the car back on the road.

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