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I decided that the only logical thing to do with my spare $500 e38 is to drop a big block chevy in it. Some dude told me that I was a peasant by doing this swap, so this has been dubbed the Peasant Powered BMW. I’ve been wanting to build a big block for quite some time, and I think the e38 will make a great modern day muscle car. It doesn’t have quite the same appeal as a 60’s era muscle car, but it is a fraction of the price and still has plenty of its own merit.
I really want to keep as much of the functionality of the e38 as I can. I don’t want to build some clapped out beater BMW. I want fuel injection, overdrive, cruise control, AC, stock gauges, car phone, etc. The only thing I’m really willing to compromise on is fuel economy.
To start out with, I got myself a Gen VI big block and 4l80e out of a late 90’s 3500 chevy. It’s just a bone stock L29. Probably makes less power than an M62tu. Unlike the M62 though, there are catalogs filled with speed parts for big blocks. With heads, cam, and a good tune a big block should make over 500hp pretty easily. With a full build, it’ll probably be a lot more than I’ll ever need.
First things first, get the engine out of the car and figure out what logistical battles I’ll have to face to make everything fit well.
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The big block pan is rear sump and the m62 is front sump. I didn’t really want to have to build a custom oil pan and pickup so I looked for other solutions. 6 cylinder cars are favored for LS swaps on e39s because they accommodate a rear sump pan. I6 e39 subframes bolt into v8 e39’s, and v8 e39 subframes are the same as e38 front subframes, thus by the transient property the i6 e39 front subframe must bolt into the e38. I wasn’t positive it would fit, but they did also make a 6 cyl e38 in europe, so I didn't see many reason why it would not fit. Even so I was sort of determined to make it work no matter what so I bought the entire from suspension from a 530i, but I think all I6 e39 front subframes are the same.
The e39 I6 front subframes are all aluminum, accommodate a rear sump oil pan, and to top it off have rack and pinion steering. Nearly all the components on the front suspension are aluminum, even the struts have aluminum housings. I haven’t put it on a scale yet, but it is noticeably lighter than the e38 front subframe and suspension. So all in all there are other benefits besides just not having to build a custom pan and oil system.
It was worth the gamble, the I6 subframe almost bolts in with no modifications. The bolt patterns are the same, the only thing I’ll need is the correct length hardware and to make a couple of spacers. The subframe had a couple of spacers in the front most bolts that were too tall. Once remove, too short. No big deal, I'll just turn them down to fit. Also the strut tower bolt patterns are the same. I don't think that's news though, seems to me there have been a few guys that made e39 coilover kits work on e38s.
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That's all for this post. Next up is to get the engine/trans mocked up and get the thing back on 4 wheels so I can get it to my buddies shop so he can build the headers, engine/trans mount, and maybe a couple other things.
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Oh boy, this is gonna be great!
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Keep it up, I love threads that open up with progress
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Exciting
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wow!
1997 740iL; 5/96 build. Purchased 12/04.Off the road build project 2013 - 2021. back on road 3/2021. Became daily driver (only vehicle) 6/12/2021. Still not completed. Stay tuned as the adventure continues.
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I love it! You may have a sway bar issue with the flexplate/torque converter. You will need a fair amount of clearancing for the trans tunnel. Headers will be a witch. Good luck, I'm looking forward to seeing the completed pictures.
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Now this will be a great endeavor! Good luck!
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Yeah, the sway bar for sure looks in the way. Not sure what I'm going to do about that yet. I'm hoping I don't have to beat up the trans tunnel too much. The 5hp24 looks physically larger than the 4l80e going in. So as long as the new trans isn't much higher in location than the old trans, I think it should fit just fine. As far as headers are concerned, there is a decent amount of room, so i don't think that I'll have to compromise too much on header design. I'm going to try an off the shelf solution, if that doesn't work I'll just build a set, or rather, have someone build a set for me.Originally Posted by htrdbmr
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I spent the majority of my car time this week working on sorting out the front suspension and brakes. The e38 calipers would not bolt onto the e39 knuckles, but the e38 rotors fit fine on the e39 hubs. I bought some 540i calipers and they worked perfect with the e38 rotors on the 6cyl hubs. My brand new 740i pads also worked in the 540i caliper. As many of you may be aware, the e39 hub bore size is 74.1mm and e38 is 72.56mm. Although I have read that e60 hubs bolt into the e39 knuckles and have a 72.56mm hub dia, I decided that I would just turn down my e39 hubs to 72.56. It was a little bit of a challenge to hold onto in the little lathe that I have access to, so I built a little fixture from an old rotor to hold on the hubs. Chucked them up and skimmed off a couple of mm’s.
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The next order of business was to deal with the strut situation. When I bought the front suspension, struts were included, but the car I bought them from suffered an engine fire. Needless to say one of the casualties of the fire was one strut mount. I figure the 6 cyl stuff will be much to soggy with the big block up front anyway, so I decided to make the e38 stuff work in the e39 knuckles. There is about .100in difference in dia between the e38 strut housing and the e39 housing. My solution was to just turn up a little collar to make up the difference between the two housings. I started off with a couple of pieces of 2.5in x .375in wall DOM tube. It took forever to turn them down, but it’s what I had around.
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After all that and getting the front struts fitted to the knuckles and back in the car, I was finally able to set it down on its wheels only to find out that I had built an e38 lift kit. As it turns out the e38 struts are a few inches taller than the e39 struts. I feel a little silly for not looking into that before I started. In either case, I’m going to leave it for now, it will probably make it more convenient to work on the car with it sitting so tall. I’ll order up some coil overs when I’m closer to having the thing driving.
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On a more exciting note, I set the engine in to start getting an idea of how everything is going to fit. Not many surprises here, the 454 is much taller than the m62 and a little bit more narrow. There is more room for headers than I thought there was going to be. The most challenging part will be making everything fit under the stock hood. The factory 454 oil pan will not suffice, I’m going to have a get something that gives me a little more clearance around the rack and doesn’t hang so low. If I have to, I'll build a custom pan, but I would really like to avoid that.
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Next up on the chopping block is to order a new oil pan, new bolts/spacers for the subframe, and build a couple parts for the motor mounts. If I can keep myself from farting around too much, this thing may actually make it to my fabricators soon.
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Are those heater hose connections on the firewall going to play nice with the distributor, or do you have other plans for ignition?
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I doubt they will play nice, as i do plan on using the disrtibutor. Even the coil near plug system i want to use requires it for a cam signal. The heater valve stuff appears to be in the way also. Im going to have to get creative so that the engine doesnt end up to far forward.
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Try using the 750 heater valve.
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Whats the story on the 750 valves? Smaller or in a different location or something?
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Correct, mounted on the driver's side shock tower. (credit to blackknight530i for showing it like this)
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Oh nice, im going to have to look into that. Looks like itll buy me room in the back, but may affect the header story.
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Do we have any updates? I’m about to start this swap myself. Please make more mistakes so I don’t have to! 😬
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Do we have any updates? I’m about to start this swap myself. Please make more mistakes so I don’t have to! 😬
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I have been making a little progress on this, but my 740il daily has needed a decent amount if maintenance recently and has been chewing into car time lot. I have made a few parts for it over the last couple months. I built subframe spacers and have started working on the engine mounts. Ill post up some more pics and info soon.
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It’s been several months since I have updated this thread, but Dasbimr inspired me to share the little bit of progress I have made.
There are two big issues that I have been concerned about in terms of this swap. The oil pan and the height of the engine, and I think I have them both sorted. I really want this to be a very clean looking swap with minimal amount of cutting and welding, I also want everything to fit under a stock hood.
As it turns out, there are a lot of oil pan choices for big block chevrolets and a lot of information about their size. It made it really easy to find a pan that would fit. I ended up with a Canton 15-320T. The canton website has pretty good info on the size and shape of the pans they offer. I can’t remember the exact details but I think it gives me over an inch of ground clearance over the stock pan. It also lets set the motor forward enough for things to fit in the bay. Im not thrilled about where the engine has to sit, but I need it forward so I can take the distributor in and out. When I lose the distributor in the future, I may consider trying to move the engine farther back in the engine bay.
The issue of the fitting everything under the stock hood was a little bit more of a challenge and some compromises had to be made.
In the pic below, the engine is as low as it can go with the oil pan basically resting on the steering rack.
The compromise comes with me have to put spacers between the chassis and the subframe. This is not ideal because it changes the geometry of the front suspension and lowers the roll center in the front. Not exactly ideal. It is basically giving me all the downsides of lowering a car without any of the plus sides. I considered trying to find a different intake or building an intake, but i'm not prepared to make that commitment yet. I decided that 1 inch ought to do me and went off to make some spacers. With a little massaging everything should fit under the stock hood now.
The resulting circles
The engine is in the same relative location to the subframe as it was in the above pic, but with the 1.00in spacers installed.
With the engine location determined I can start building the mounts. I'm using the stock motor plates with some tubular mounts. Subject to change as these are not complete yet. The bushings are delrin right now, which I think will be too rigid for what I want this car to be. I'll problem find some poly bushings to use instead. I briefly investigated using OEM BMW mounts, but their location relative to the mounts on the big block are not good. So if anyone is interested I have some brand new URO 6 cyl mounts for sale, Ill give you a deal on them.
Once I finish up these mounts I can start on the headers. I'm taking some time off over the holidays and hoping to fit in some quality car time. I'm hoping to put this new toy to good use
Over and out
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I never thought of using a 3D printer to build headers, what a great idea!
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This is a most excellent endevor! I approve of any project where a person has a dream and the guts to actually go and pull it off. Interesting engine swaps and strange mods are cool.
I did a similarly ambitious project on an e36 by building a custom rotary valve engine head.
https://www.bimmerforums.com/forum/s...engine-project
Current fleet:
1999 BMW e36 M3
1999 BMW e36 328is with rotary valve engine head
1999 Oldsmobile Eighty Eight
1990 Jeep Comanche Eliminator
1962 Austin Healey Sprite
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Thanks, but by comparison to your rotary head project, im just a redneck with a sawzall.
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