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Coventry Climax Engine?
D Beddows - 25/6/08 at 08:29 AM

Anyone had any experience with these? there are always 1 or 2 FW (ie pump) engines on ebay...... I take it converting them to FWA engines is more trouble/cost than it's worth? I've had a go on Google but can't seem to come up with much regarding converting them which I'm guessing means it's not worth doing..........?

Mr Whippy - 25/6/08 at 08:49 AM

So long as you can get the parts at a reasonable price don't see why not.

how long do you think it will take for someone to tell you to put a bike engine in? I give it 20 minutes at most

'You don't what to do that!, you want a bike engine not that bit of old iron!'






[Edited on 25/6/08 by Mr Whippy]

bilbo - 25/6/08 at 09:23 AM

Some info here:

http://www.imps4ever.info/tech/cov_clim.html

Looks like there is a big difference between the FW and FWA:

quote:
The block had been rebored, new pistons were fitted, as were a steel crankshaft and twin carbs, alterations to the valves and ports were made and the compression ratio was increased. Power output of the little fire-pump had been increased from 38 to 72bhp at 6100rpm.

D Beddows - 25/6/08 at 09:29 AM

quote:

You don't what to do that!, you want a bike engine not that bit of old iron!'


They're not iron though...........

britishtrident - 25/6/08 at 09:54 AM

Main things that would have to be changed are the flywheel, engine back plate, both manifolds, pulleys carbs, iginition, camshaft, compression ratio, water pump fitted quite a lot of work.

I suspect the only way to raise the compression ratio suffiently would be flat top pistons.

I can't see any Imp parts being suitable for the conversion except perhaps valves and valve springs and perhaps pistons and bearings.
An easier alternative might be to aquire a Chrysler Sunbeam 928 engine which mates straight to a light alloy Avenger gearbox.

http://www.hillmanimpspecialists.com/pricelist13.htm

nitram38 - 25/6/08 at 10:43 AM

Unless it is the 998 engine to start with, then don't even bother.
The 875cc one is pants and you can only get about 80bhp out of it. The 998 is about 120bhp when tuned.
I used to race imps in the classic saloon club.
The climax engine will need lots of work as said before.
If you must go for an imp engine, look out for someone called Reg Pattern.
He is an imp engine pro. He used to live in Wallington Surrey but I don't know where as the estate he lives on has been rebuilt.

britishtrident - 25/6/08 at 11:40 AM

quote:
Originally posted by nitram38
Unless it is the 998 engine to start with, then don't even bother.

snip
snip

Apart from very a few dry liner units built for the original factory homologation Rallye Imps -
No Imp engine ever started out as 998cc.

All post 1966 998cc and larger units were converted from a 875cc Imp or 928cc Chrysler Sunbeam block by boring away the original cast in dry liner and surounding block material and pushing in new wet liners which are largely held in by copious ammounts of green loctite.

These conversions are still be done to Imp and Chrysler/Talbot Sunbeam blocks.

The big disadvantage of not converting an Imp engine to 998 is that the smaller bore sizes cannot use a Wills ring head gasket which is required to keep a decent seal between block and head. The bigger bore of the 998 also allows the use of the 1.4" inlet valve which is of dubious advantage as it kills torque.

In the early 1970s a full house 850cc imp race engine (de-stroked for the old 850cc class) could chuck out about 95-100 bhp as opposed to 115bhp claimed for the race 998 from the same builder. By the end of the 70s 123bhp with a better spread of torque was the norm from a Greetham engine.


The main differences between the Climax engines and the Rootes/Chrysler engines are
(1) The Coventry Climax units used an conventional closed deck block casting a bit like an alloy version of an Xflo but with drop in liners, the prouction Imp engines were open deck similar to the Rover K.
(
2) Although the cylinder heads look superficially similar the order of the inlet and exhaust ports is different. ie

Imp is Inlet, exhaust, Inlet, Exhaust, Inlet, Exhaust, Inlet Exhaust.

Climax is: Exhaust, Inlet, Inlet, Exhaust, Exhaust, Inlet, Inlet exhaust.




[Edited on 25/6/08 by britishtrident]

Mr Whippy - 25/6/08 at 11:46 AM

that seems quite a lot of power for such a small engine

nitram38 - 25/6/08 at 11:57 AM

We were forced to change from 998 back to 875 by the classic saloon car club because of imp pole postions at small circuits like the Brands Indy circuit.
It seemed that the lotus cortina boys (namely an old ex-works driver called Les Nash) decided to make us only use Group 1 cars. This meant the original engine plus the rad in the normal position.
Not only were we down on power, it was difficult not to cane the engine temp.
Very often we would end the race with some sort of temp or oil warning light issues.
It is for that reason I gave up racing.
Big budget boys changing the rules to suit themselves.
We used to wills rings our 875 with no liner issues.

D Beddows - 25/6/08 at 12:13 PM

You've got to love this forum sometimes

Cheers guys, some interesting stuff (and links) there!

Not such a 'lump of old iron' after all eh Mr Whippy

paulf - 25/6/08 at 12:45 PM

They also made some generators fitted with them, a few years back there was a guy selling some ex mod ones at the Newark show for about £100 each.I was tempted as i always liked the imp engines but after looking into it they need to much work to make them fit in a car plus the power was to low.
Paul.

bob - 25/6/08 at 02:41 PM

There was big pile of them at the beaulieu auto jumble a few years back too, all ex MOD probs same seller. GOV must have been having a clearout, they seemed to be selling well across the weekend infact plenty moved on the traders day friday.

nitram38 - 25/6/08 at 06:40 PM

A lot of them are used as fire engine pumps, especially in asia

monkeyspanna - 27/6/08 at 07:24 PM

These engines were also used in the Albatross speed boats, built in Oulton Broad on the Norfolk /Suffolk border,during the 50's and 60's.
The works team and many independants raced e'm, and loads of them are still about so they must be tough as old boots.
Classic Motor Boat Association have a web site and forum, you might track one down, complete but marinised [ not a problem to convert back] or.... You might end up with yet another project

nitram38 - 28/6/08 at 03:29 AM

I also seem to remember (from the dark receases) that the engine was used in formula 4?
I think that the engine was turned around and the gearbox turned upside down to ensure the correct driveshaft rotation.
More useless info stored in the noggin!

britishtrident - 28/6/08 at 08:17 AM

quote:
Originally posted by monkeyspanna
These engines were also used in the Albatross speed boats, built in Oulton Broad on the Norfolk /Suffolk border,during the 50's and 60's.
The works team and many independants raced e'm, and loads of them are still about so they must be tough as old boots.
Classic Motor Boat Association have a web site and forum, you might track one down, complete but marinised [ not a problem to convert back] or.... You might end up with yet another project


Nearly Albatross speed boats had 1172cc 100E sidevalve Ford engines, towards the end of production the OHV Anglia pre-xflo engine was used.

mad-butcher - 28/6/08 at 03:14 PM

they were also used to great effect in the 70's in road racing sidecars, the pulley end was machined down to be splined to take a triplex chain which in turn ran through a norton commando gearbox and clutch, made a lovely low outfit with it's forward facing webbers
Tony

monkeyspanna - 28/6/08 at 09:36 PM

The Albatross did use the Ford sidevalve as its mainstream lump, but the climax was offered as an option. The old grey matter has thawed a bit and I recall seeing one of these boats recently with a tuned reliant engine, no idea of the output and it is a very light aluminium boat, but he was pulling a mono skier out no problem, and without the skier it went like stink. does anyone know of this unit being used in 750 racing or elswhere?