Legality of Engine Swaps?

aji yra · June 20, 2021

I'm trying to purchase a BMW e36 3 Series with a 6 cylinder engine but I'm finding most on the market aren't originally 6 cylinders but 4 cylinder cars which have been engine swapped to 6 cylinder engines. With quality of work aside, is this legal? None of the cars I've seen have updated books reflecting the new engines. How hard would it be to get the book updated if I was to buy one of these vehicles. From the research I've done and the people I've spoken to it seems to be a legal grey area. Is this true? I've also heard that changes in displacement of less than 500cc is allowed. Any help on this matter would be appreciated.

matroska · June 26, 2021

On 6/20/2021 at 4:55 PM, aji yra said:

I'm trying to purchase a BMW e36 3 Series with a 6 cylinder engine but I'm finding most on the market aren't originally 6 cylinders but 4 cylinder cars which have been engine swapped to 6 cylinder engines. With quality of work aside, is this legal? None of the cars I've seen have updated books reflecting the new engines. How hard would it be to get the book updated if I was to buy one of these vehicles. From the research I've done and the people I've spoken to it seems to be a legal grey area. Is this true? I've also heard that changes in displacement of less than 500cc is allowed. Any help on this matter would be appreciated.

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While I know jacks#it about BMW's- generally speaking engine swaps are quite common - and was quite common in the past where petrol engines were converted to diesel etc. As far as I know currently there are the following regulations : of course others will add if there are more - You can swap an engine from the same brand (example: replace a GA15 with an SR20) as long as they are of the same fuel type (diesel-petrol conversions are no longer allowed) and the difference in engine size is less than 500 cc. Once done, the vehicle in stock form (no fancy alloys or stuff) needs to be taken to RMV and weighed and inspected and the book will be updated. I don't think there is any regulation regarding the number of cylinders in the engine.

Now comes the common scenario: most swapped engines are not updated in the CR. While a pug running a Toyota engine will definitely look odd and raise alarm bells at least when doing the eco test (eco testers will reject if they sense something foul) usually same-brand engine swaps go undetected. You'd see a lot of Subaru Legacies with EJ20 (2000 cc)engines with the CR actually mentioning the engine as EJ18(1800). These are hardly detected. Even more so are the Starlet GT conversions where the regular 4EFE is replaced with recon 4EFTE's (both are 1.3 L but the 4efte is turbo charged), and then the Imprezza conversions...the list goes on. Of course if there is going to be a lease/finance the company will not allow the lease if the engine no does not tally with the CR. So yeah It's not legal - its just that they don't get detected.

aji yra · June 26, 2021

Deleted

Edited June 26, 2021 by aji yra
Trying to delete this reply. Can u do that?

aji yra · June 26, 2021

On 6/26/2021 at 3:09 PM, matroska said:

While I know jacks#it about BMW's- generally speaking engine swaps are quite common - and was quite common in the past where petrol engines were converted to diesel etc. As far as I know currently there are the following regulations : of course others will add if there are more - You can swap an engine from the same brand (example: replace a GA15 with an SR20) as long as they are of the same fuel type (diesel-petrol conversions are no longer allowed) and the difference in engine size is less than 500 cc. Once done, the vehicle in stock form (no fancy alloys or stuff) needs to be taken to RMV and weighed and inspected and the book will be updated. I don't think there is any regulation regarding the number of cylinders in the engine.

Now comes the common scenario: most swapped engines are not updated in the CR. While a pug running a Toyota engine will definitely look odd and raise alarm bells at least when doing the eco test (eco testers will reject if they sense something foul) usually same-brand engine swaps go undetected. You'd see a lot of Subaru Legacies with EJ20 (2000 cc)engines with the CR actually mentioning the engine as EJ18(1800). These are hardly detected. Even more so are the Starlet GT conversions where the regular 4EFE is replaced with recon 4EFTE's (both are 1.3 L but the 4efte is turbo charged), and then the Imprezza conversions...the list goes on. Of course if there is going to be a lease/finance the company will not allow the lease if the engine no does not tally with the CR. So yeah It's not legal - its just that they don't get detected.

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Thanks this was so helpful and by far the most comprehensive explanation I've found online. Of course if anyone else has anything to add please do so.

charithtg · July 4, 2021

I think before actually carrying out the swap, you have to inform the Commissioner of MT about it with reasonable reasons for doing it and get a preliminary approval. then all the other stuff follows as @matroska has stated. this I remember reading somewhere in the DMT website longtime back.

iRage · July 5, 2021

On 7/4/2021 at 1:04 PM, charithtg said:

I think before actually carrying out the swap, you have to inform the Commissioner of MT about it with reasonable reasons for doing it and get a preliminary approval. then all the other stuff follows as @matroska has stated. this I remember reading somewhere in the DMT website longtime back.

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Yes this is true....you do need to get prior approval, not just for engine swaps but for all mods. However, if for some reason you do do the engine swap without prior approval you can still get the book updated. It is just that they make you jump through extra hoops and make your life miserable (it would help if you still have the old engine lying around and be willing to take it over to the inspection place if the officers are complete and utter a$$-h@t$ and you just want to shove it up their ***###@@@)