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4.2 V8 ABZ conversion of Lotus Esprit

607K views 491 replies 130 participants last post by  GTRClive 
#1 ·
I have been acquiring parts for my project for a bit and thought it was time to start a project thread on it.

This is the plan........

Take one 1981 Lotus Esprit S3


Pull out the 2.2litre 4 pot Lotus engine/Citroen gearbox and chuck in an Audi 4.2 V8 and six speed transaxle in here.


I have finally got hold of an ABZ from Germany and have balanced a 6 speed 01X gearbox onto it for giggles.


Got the tape measure out an I reckon it should be a pretty good fit as the ABZ is a fair bit shorter than the Lotus 912 which is coming out.

Unfortunatly this is were it all starts to go pear shaped. The engine suffered a bit as the sump got bent during shipping. So I whipped it off to straighten it and in the process this is what found in the sump.


Arse !!!!!!!!!!!
Had a look inside the crankcase to find plenty of dents from flying metal.


So what are the lumps that fell out of the bottom of the engine ??????

Time for a game, spot the difference between these 2 pictures ...............



The observant among you will notice that the piston oil spray bars are missing in the second picture.
Laying the mashed bits of metal out it becomes evident that in fact 2 of them have come adrift.


So it is time to strip the engine down to investigate a bit further.
I find that piston number 8 has taken a hit from flying metal and has suffered a bit of weight reduction.


Unfortunately the cylinder wall hasn't come out scott free either.


So I now have a very large and heavy paper weight in my back garden.
On the bright side, the guy I bought the engine from is sending me another ABZ and doesn't want the old one back which means I have got a whole pile of spares :)

When the replacement turns up I can start cobbling the bits together ready to give the engine hoist some stick.

Andy
 
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#3 ·
Well I am glad to see that some people still stand behind their sales and service..That's awesome they are sending you another ABZ and you keep the old one to boot!
What obstacles do you have to overcome on the tranny/drivetrain side?
And did you get the harness/ecu for that setup?
 
#5 ·
Maybe you should tell him the tranny was fubar as well! I'de buy it :-D

But looks good as h e (double hockey sticks)!
Thanks
Ron
 
#7 ·
a4kquattro said:
good service from the seller! Might as well post the name because in my book they deserve credit.

Now, onto your project!

OMFG! That's awesome!
I got the engine from a geeza on eBay.de
I won't post his name for the time being as I haven't got the replacement yet.
All I can say it was a damn good job his English was good !!!

nuugen said:
What obstacles do you have to overcome on the tranny/drivetrain side?
And did you get the harness/ecu for that setup?
The 01X bolts up to the block OK (need to drill a couple of extra holes here and there) and the engine/transaxle will fit in the hole so I don't for see any major problems.
I will have to make up some drive-shaft extension as the 01X is a fair bit narrower than the old Citreon SM gearbox. Another complication is that the car currently had inboard rear brakes (ie the calipers are mounted on the transaxle) but that isn't too difficult to get round with the help of a mill.
The only other head scratching issue is the gear change linkage, but I have a plan for that and have already made up some parts which I'll post when I am a bit further down the road.

I did get the wiring loom with it, but no ECU, which was OK as I will be using either MegaSquirt or VEMS (need to speak to Jorgen about the VEMS).

Corey said:
You mean to say that you're not keeping it "quattro"?

Rolling Eyes some people just don't do things right slap
If anyone can come up with a plan to get the rear drive out of the back of the transaxle (which is where the exhaust boxes will be), turn 180 degrees, back past the engine, down the centre channel of the chassis which is currently full of coolant pips and gear-linkage and then fit a suitable axle for the front then I'll give it a bash :)

Andy
 
#9 ·
mid engine- rear drive

front engine -rear drive

the first is what this lotus is ;)
 
#12 ·
billzcat1 said:
Is it just me or does that rod look a little bent?
Hmmmmmmmm, it could be. If you look at the bottom of the piston you can see marks where it has been clobbered, but I would of thought that would straighten the rod instead of bend it.

When I strip it down to component parts I'll check it out.

Andy
 
#13 ·
Wizard-of-OD said:
billzcat1 said:
Is it just me or does that rod look a little bent?
well the piston did break the oil squirter so I would assume that the rod would have to be bent in order for the piston that far down.
When you turn the engine over all the piston come out of the cylinders that far. I thought it was a bit odd as well but I guess it is supposed to be like that :?

I still haven't worked out which bit broke first to cause the damage. The bolts that hold the oil squirters are still in the right places so they didn't just fall off. However the danage to the piston is from one of the oil squirter bits so that didn't let go first either.

My guess is that something else got in there (will never know as it probably got drained out with the oil) and that got picked up by the crank wizzing round and ripped off the oil squirters (there is sod all clearance) and then the piston got knocked out.

Anybody else seen an ABZ failure like this ??????

Andy
 
#15 ·
What probably happened is the rod got bent by liquid in the cylinders which made it shorter. Then on the down stroke, the piston hit the squirter, and possible the crank shaft. The liquid then evaporated from the left over heat of the engine running.
Be warned I have been unable to source crankshaft main bearings other than using RS6 units.

Did 4.2 engine come with front wheel drive only? As i recall in the states, the 3.7 engine came in fwd and the 4.2 was quattro.
 
#17 ·
8) ... and about a ton less weight than the donor car :woowoo:
 
#18 ·
WAUG0806 said:
8) ... and about a ton less weight than the donor car :woowoo:
Not quite a ton but a fair chunk less :)

The A8 which the ABZ is from comes in at about 1700KG (3750lb) where as the Lotus is 1100KG (2400lb) so it should be pretty quick, that is the plan any how. The later turbo Esprits had 276BHP and would hit 0-60MPH in 4.7 sec but I will be adding a bit of weight to that (the ABZ alone is 100lb heavier than the old lump) so if I get sub 5sec I will be happy.

I'll try and get the heads off the knackered engine today to measure the piston heights to see if any of the rods are in fact bent. I have got the damaged piston sitting on the desk beside my desktop PC and the rod on that one is OK :wtf:
 
#19 ·
Well I did a quick measurement of the piston heights and found that all the piston crowns protrude 1mm ( /- 0.1mm) out of the bores so if the rods are bent then it isn't by much. I'll have to strip the engine down to check the rods properly.

Hmmmmmmmm, the mystery continues .....................
 
#20 ·
It has been a while since I posted any progress on this project, the reason is that there hasn't been any :(

Until now that is........
I have finally got hold of another ABZ from a crashed A8.
Went to a field in Gloucestershire and spent 7 hours removing this thing (jeez were the bellhousing bolts hard to get at).


I am starting to get a bit of a collection of these things :)


Now that I have got some working bits to carry on with the conversion first thing to do was to remove the old Lotus engine.


With it out you can see the similar configuration to the Audi front wheel drive layout.


Getting this out took most of Sunday, but there was time to trial fit the ABZ and 01X into the engine bay. First impressions are that it is a pretty good fit, it even goes round the OEM engine covers.



It is not all rosy though, the ABZ has a much wider sump than the Lotus 912, things are made even worse as it is offset to one side. This unfortunatly means that the sump hits the chassis by the engine mount.


This is why the engine looks tilted to one side in the couple of pictures. I can't chop the chassis about to gain clearance as there would then be nowhere to put the engine mount.
So I am going to have to cut a section off the sump. Not ideal, but I have no choice. Other than that it is looking good at the moment.

Next on the list is to make sure there is clearance for the exhaust manifolds and then I'll chop a chunk off the sump, check it fits and then start fabbing up some engine and gearbox mounts.

Andy
 
#23 ·
So this weekend I threw on the exhaust manifolds to check that they cleared the chassis rails and would you belive it, they fit like they were designed to go it the Lotus engine bay, so that is one problem out of the way.

Now onto the sump, if I can't cut a chunk off of that then it is a show stopper :(
So I take the sump off the wrecked engine to see what is in the section that is hitting the frame.


The bit that is causing the problem is at the top in the picture.
Well there is nothing in there that can't be hacked off as the oil pump, pick-up and baffle are on the other side, so out comes the saw.


Now I will obviously have to weld a section back in to stop the oil peeing out, but for the time being I need to put it back on the wrecked engine to check that it will now fit and the project is still do-able.

Back on the engine with a section cut off the pan to match.


Put the gearbox back on then throw it back into the car.
Phew!!! it now fits, with plenty of clearance on both sides, result :)



Now it is time to get on with the new engine and gearbox mounts.
Centered up the engine and put it on wooden spacers to get it to the final height.
Knocked up some cardboard templates which I can then take measurements from and draw in CAD.

Engine passanger side (in the UK that is)


Engine drivers side


Gearbox passanger side


Gearbox drivers side


Now I would of liked to make the mounts out of alloy, I can't or don't have the equipment to weld that stuff so I would have to get someone else to make them.
If I do that, I have a nasty feeling they won't fit right when I get them back.

Which means I will have make them out of steel.
I'll cut out the required shapes and then tack them together in situ and then weld them properly off the car.
That way they will defo fit, just a bit heavier that I would like.

Off to the metal shop...........
 
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