How much would it cost to put a newer engine into an older car?

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Let's say you've found either a shell or a complete (but broken) classic car, and you fancied modernising it with a more powerful engine. For example, putting an E36 S50 engine into an E24 6 series?

Assuming there were no fitment issues, and ignoring suspension work, retromod work etc. so we're just talking engine, drive train, exhaust, and then syncing (or fitting new) instrument cluster etc.

How much would you estimate the swap to cost? £20k? I've no clue at all, I don't know much mechanically.



And then all in do you think it would exceed £100k?

Thanks :)
 
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A few grand at most, 100k would give you an entirely restomodded car.

I wouldn't be putting an S50 in to an E24 though, if you're going to go to all that trouble then make it worthwhile, stick a V12 in it from an 8 series or something, there's certainly enough space under that bonnet.
 
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It’ll depend on fabrication cost. Something like a bmw i6 going into another bmw i6 shell or even i4 has probably been done before so bar engine mounts, box adaptors/tunnel work it won’t be that hard. Fitting something like a rotary inside an mx5 shell requires a lot of fabrication and will cost a lot. An s50 in e24 is probably easy swap for any bmw specialist and you’ll probably have change from £5k not including engine/ecu(might not even need that, na engine to na is easier)
 
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grudas said:
It’ll depend on fabrication cost. Something like a bmw i6 going into another bmw i6 shell or even i4 has probably been done before so bar engine mounts, box adaptors/tunnel work it won’t be that hard. Fitting something like a rotary inside an mx5 shell requires a lot of fabrication and will cost a lot. An s50 in e24 is probably easy swap for any bmw specialist and you’ll probably have change from £5k not including engine/ecu(might not even need that, na engine to na is easier)
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Thanks for that, much less than I was thinking.

Diddums said:
A few grand at most, 100k would give you an entirely restomodded car.

I wouldn't be putting an S50 in to an E24 though, if you're going to go to all that trouble then make it worthwhile, stick a V12 in it from an 8 series or something, there's certainly enough space under that bonnet.
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I understand your point, but when taking the size and weight up to that amount I think the S85 (V10) would be the better choice :) However, nothing is decided as I'm just ball parking costs etc. atm. I think something like the S54 is a more likely candidate, it will all depend on the initial shell but I'd like a nice n/a straight 6 to enjoy.
 
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Modern CAN-BUS wiring looms and clusters and control units are far from trivial to tinker with, so the wiring aspect can get very expensive. Modern cars have a LOT of electronics in them.

A Supra TT engine and manual gearbox in an M3 shell was a tidy conversion I saw documented some years ago, and it made for a very quickly and torquey car. Used Getrag manual boxes in good order are very hard to find now though, and are no longer available new.

I find that costs quickly snowball and there are a lot of unfinished projects around as a result ...
 
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It depends if it's a path well trodden or not. Some cars have popular engine swaps so there'll be lots of off the shelf parts and knowledge to tap into, for example putting a modern Honda vtec engine into a classic mini has been done loads of times, you can buy subframes all ready to go. Same with a Honda K20 into a lotus Elise.

but if it's more unique then the it massively depends, i knew a guy who put a SR20 into an RX8 and it was a huge amount of work but as he was doing it all himself i don't know how you'd put a cost on it. Parts probably weren't a huge amount but if you wanted someone else to do it all for you it'd be into the hundreds of hours of labour.

Also after a certain age it's usually not worth it as engines got so complex with multiple ECU's and CANBUS etc so for most stuff you don't want to go much newer engine wise than the mid 2000's as a rough rule.

If you're not doing the work yourself you might be better off finding a specialist restorer or retromodder as they'll know what's more cost effective than just turning upto a garage with car A and engine B and asking them to make it work.
 
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Deep pockets could be needed and a very good specialist is a must if you are not doing the work yourself, I was quoted 20k to put a 2015 RS3 engine into a 1982 mk1 golf excluding the engine, ECU, clocks, keys & looms which I'd already bought but I just couldn't justify it after the money I'd wasted on the current engine so sold the RS setup.
 
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I think £20k should be more than enough to cover an engine conversion in an older BMW like that. I'd imagine at worst it would involve custom engine mounts, custom pipes/hoses to be bought or made up, wiring would need to be modified, custom exhaust etc.

It does depend entirely on the car and engine combo though, like the Saab engine into my Astra was done with 90% original parts to bold it all in because the Saab was also GM based. The wiring loom entered the bulkhead in the same location, the engine mounts are all original and lined up, drive shafts original, all the coolant pipes fit with a couple being cut down. The only real custom work done is a custom exhaust, intercooler and oil cooler, although the latter two originals can be made to fit with the stock turbo easily enough.
 
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Not wanting to de-rail the thread but with the above where would you even begin in terms of insurance.

Are there boxes for all of this? Or are specialists required!
 
Bit of a how long is a piece of string thing - I know someone who recently paid ~2.5K for the engine and ~2.8K for the swap, properly done with all the electronics properly working, etc. I've seen projects where they've put like a GTR engine into a Nissan Navara which has cost a full 20K, etc.
 
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Gilbert89 said:
Not wanting to de-rail the thread but with the above where would you even begin in terms of insurance.

Are there boxes for all of this? Or are specialists required!
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there is a company who are well known for covering highly modified cars, sports cars, exotic vehicles, vans converted into motorhomes

i forget their name but there are people who cover them
 
dave28 said:
there is a company who are well known for covering highly modified cars, sports cars, exotic vehicles, vans converted into motorhomes

i forget their name but there are people who cover them
Click to expand...

You're probably thinking of adrian flux, there's also sky insurance, greenlight among a few others that specialise in imports or modified cars. They can be surprisingly cheap to insure using a specialist but it is more of a faff than just going to gocompare and be done and dusted in 10 minutes as you have to have a long conversation and sometimes send pictures and other docs.
 
Thanks all :)

Chris Wilson said:
Modern CAN-BUS wiring looms and clusters and control units are far from trivial to tinker with, so the wiring aspect can get very expensive. Modern cars have a LOT of electronics in them.

A Supra TT engine and manual gearbox in an M3 shell was a tidy conversion I saw documented some years ago, and it made for a very quickly and torquey car. Used Getrag manual boxes in good order are very hard to find now though, and are no longer available new.

I find that costs quickly snowball and there are a lot of unfinished projects around as a result ...
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sovietspybob said:
It depends if it's a path well trodden or not. Some cars have popular engine swaps so there'll be lots of off the shelf parts and knowledge to tap into, for example putting a modern Honda vtec engine into a classic mini has been done loads of times, you can buy subframes all ready to go. Same with a Honda K20 into a lotus Elise.

but if it's more unique then the it massively depends, i knew a guy who put a SR20 into an RX8 and it was a huge amount of work but as he was doing it all himself i don't know how you'd put a cost on it. Parts probably weren't a huge amount but if you wanted someone else to do it all for you it'd be into the hundreds of hours of labour.

Also after a certain age it's usually not worth it as engines got so complex with multiple ECU's and CANBUS etc so for most stuff you don't want to go much newer engine wise than the mid 2000's as a rough rule.

If you're not doing the work yourself you might be better off finding a specialist restorer or retromodder as they'll know what's more cost effective than just turning upto a garage with car A and engine B and asking them to make it work.
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Cheers guys, yeh I am aware of this aspect which is why I'm looking at older engines around the year 2000 and sticking with BMW.

It will definitely be done by a specialist, I have one in mind local to me I'm going to liaise with before I choose an engine but I think I am set on an E24 shell as I've dreamed of one since a young kid.

In terms of drivetrain, would this need to be custom or could you bastardise a matching one to fit? I guess you can bastardise anything, but I mean without weakening the unit.
 
NVP said:
Thanks all :)




Cheers guys, yeh I am aware of this aspect which is why I'm looking at older engines around the year 2000 and sticking with BMW.

It will definitely be done by a specialist, I have one in mind local to me I'm going to liaise with before I choose an engine but I think I am set on an E24 shell as I've dreamed of one since a young kid.

In terms of drivetrain, would this need to be custom or could you bastardise a matching one to fit? I guess you can bastardise anything, but I mean without weakening the unit.
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Drivetrain can be anything again, sometimes you just need an adapter plate to mount to the original gearbox if that's what you want and will be strong enough to take the new power, sometimes you'll bring the gearbox over with the new engine and then just get a custom driveshaft made to mate up to the original rear end (assuming RWD). Sometimes you'll need to bring over the rear diff, half shafts and hubs as well so you're running new engine, gearbox, rear end to cope with the new power, It really depends on the specifics of it all. You'll want to keep a standard gearbox from either new or old car if you can as you don't want to go down the road of custom transmissions as they're silly money.

If you're staying within the same marque it can be easier, some cars are really like lego and you can plug swap and change from on to another with fairly little drama (Subaru is good for this) but others are harder and i've no idea about BMW stuff myself.
 
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Outrageous houses are owned by builders. Outrageous cars are owned by car builders. The only thing that changes the rule is very deep pockets.
 
son used to do this with nissan engines into virtually anything and more than one lexus lump conversion into nissans. infact at one time he had the whole front of a nissan from the bulkhead forwards in my garage , just so he could make custom mounts to fit the engines , i remember having to do conversions on wiring and make new looms just to get them to fit. he made a fair amount out of it , i got thanks :)))

then he started doing bmw 3 litre diesels into other vehicles , now i think he has a setup to do that at his new home :)
 
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If you have a compatible engine (connections, mount, etcetc) then it shouldn't cost a fortune.

I remember we had a bad headgasket somewhere in the early 2000's, just paying a scrappy 400 euros and they swapped the engine, so labour wise if it fits it's not a fortune.

Not comparable to a one in a mill classic car of course, with probably its own rust problems and stuff, but I'm saying the labour shouldn't be in the 100.000's... Or 20k's... 20k is like 300 ish hours of labour...
 
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