300 auto conversion- stupidity??

[benzburner]

as the title suggests, i'm thinking about a 3l engine conversion and auto gearbox conversion for my '90 124. is this possible? if so, is this insanity? i've been making a few enquiries about engines and 'boxes online but no results yet. any idea what they would cost to buy?
i'm sure it's a bit of work but i (still) need a headgasket and rad which would leave me with a working 200k mile manual 200E. the body on the merc is particularly good and it really stands out as a good example. it has had a lot of non-engine work done as well. tbh, i really like the ****** thing and it really would be a shame to scrap it.
if it is deemed to be too expensive or too much trouble i'll probably just get on with the head gasket and sell it but i would rather find an excuse to keep it.

 

[Bolide]

If you can get a complete engine / ancilliaries / box / ECU / ignition system / instrument binnacle (for the Tacho) for a good price then why not?

You'll need things like engine mounts, radiator & etc and the exhaust will likely be different. But everything else should be OK. The rear axle ratio on a 200 may be a bit lower (numerically higher) so it'll go like a rocket...

Most of it will fit straight in but there will be a few things that will eat up lots of time. Like fitting the ECU and finding you don't have the right bits of loom for it

If the car currently has a manual box I wouldn't change it to an auto - I expect getting everything to fit the tunnel would be a nightmare

Nick Froome
www.w124.co.uk

 

[benzburner]

thanks for the reply nick
wouldn't it be inappropriate for a 3ltr 124 to have a manual 'box? would the ratios be correct?
are you saying the transmission tunnel on the manuals are different?

 

[Bolide]

thanks for the reply nick
wouldn't it be inappropriate for a 3ltr 124 to have a manual 'box?

Well if you found a 300-24 engine and a manual box it might be fun. I'm fairly sure a 300 engine will fit a 200 box but the box may have a hard time with the torque. An auto engine will probably have a different crank spigot bearing to a manual one and your chances of finding a donor 300 manual engine are probably zero

would the ratios be correct?

You'd need to dig out a W124 Owner's Manual to look at the in-gear speeds to work that out

are you saying the transmission tunnel on the manuals are different?

I suspect the tunnels are different but don't know for sure. There may be brake master cylinder differences between auto & manual cars as well because the pedal box is different

Personally I'd rather do an engine swop than a manual / auto swop. The easiest swops will always be those where you mix & match least so a complete engine & box will be easier to do and easier to fault-find, assuming you could test it before you put it in

The guys at Mercman should know how manual and auto cars differ and may have some ideas on donor engines

Nick Froome
www.w124.co.uk

 

[Ian B Walker]

As Nick says, stick with an auto box. The tunnels are the same but the engine will kill a manual box. You will need a new fly wheel too. Which leads on to bell housing length. I know of someone who changed a box as you intend only to have to take it out three times as the clutch proved to be a sod to sort out. There are two different types of flywheel.

 

[benzburner]

As Nick says, stick with an auto box...

guys, thanks for your help but i'm still a little confused. maybe i haven't been clear enough that i have a 2.0 manual car and i'd like to convert it to a 3.0 auto set up.

in fact, i'm more concerned about converting it to automatic than getting the power increase. if i had to carry on with a manual box, i probably wouldn't be inclined to go to the trouble of getting the bigger engine.

are you saying it's too much work to replace a manual gearbox with an auto box? or are you saying that i should get the 300-24 engine and auto box complete from a donor?

would it be vastly easier to stick with a four cylinder auto box or is it best just to leave the car as a 2.0 manual??

again thanks for the help and Happy New Year.

 

[Bolide]

Re-reading my post the last para was a bit confusing

If you swop to an auto box then that change will require quite a lot of work and will entail probably more hassle than the engine swop. If you're confident about installing an auto box then it doesn't really matter what engine & box you install - the amount of work will be pretty much the same

Putting in a known-good, working engine / box will be the best way to go. If you can find a good 300-24 that'd be fun. A later 280 or 320 would be good as well with the caveat that you might need to replace the engine wiring loom. I find the 300 a bit too uneconomical for day-to-day use but then maybe I've never driven a really good one

You would be well-advised to replace the front brakes as well. Late E320 brakes are excellent and you should be able to pick up a set of calipers pretty easily

Hopefully your car has ABS. I've been told it's a lot of work to retrofit it. If your car has aircon then try and get a donor car that has it too. If your donor car is an estate the power steering pump will be different as it includes a self-levelling pump

The easiest way to do this would be to locate a complete, crashed or rusty donor vehicle. That way you shouldn't need to buy any parts apart from hoses & etc

I would definitely fit new engine & gearbox mounts and front propshaft doughnut. I don't know if the prop is different on a manual car - it may be. But if you have a donor car that won't be a problem

I'd also MOT your car before starting to see if you need to replace brake pipes, subframe bushes or other common MOT fail items

Nick Froome
www.w124.co.uk

 

[benzburner]

they sound like words of wisdom indeed. the search for a decent donor will continue and i'll take it from there.....

thanks Nick. thanks Ian

 

[230K]

Hi

Find a wrecked 24 valve Diesel and change her to derv it is the only way to go...
There are guys who specialize in the swap over here in Ireland

230K

 

[Bolide]

Find a wrecked 24 valve Diesel and change her to derv it is the only way to go...

I'd go along with that 100%

Nick Froome
www.w124.co.uk

 

[benzburner]

a professional conversion. that sounds expensive

whereabouts are they 230? know anyone who's had it done?

 

[230K]

Hi

I will find out the name and number of one of the guys he used to do 2 a week at the peak apparently, i was at his place looking to buy an estate about 2 months ago i will dig out his number it is a mate who has it and i will PM it to ya tomorrow hopefully.
Putting a 300D in a petrol estate more than doubles their value.

230K

 

[benzburner]

http://cgi.ebay.co.uk/MERCEDES-3-li...ryZ10398QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

what do you think of this?
the seller got back to me today and he seems on the level. apparently it's from an '89 300e 12v with 87k on the clock and the price for the engine and box is pretty reasonable.

i have a feeling that my mechanic is going to have a strong opinion on the subject

 

[Bolide]

You'll need the throttle cable, kickdown cable & etc, engine loom, ECU, coil packs, HT leads & etc

As per my previous posts a 300 would be my least favourite for a conversion

Nick Froome
www.w124.co.uk

 

[benzburner]

i have been strongly thinking about the 300d option.

 

[230K]

Hi

Sent you the guys number by PM.

230k

 

[benzburner]

http://cgi.ebay.co.uk/Mercedes-3000...5QQihZ016QQcategoryZ10398QQrdZ1QQcmdZViewItem


what about this one? it's got 173k miles and the seller is raving about it. should it be suitable? is it someone on here?