Taking on an engine swap project can be daunting. Think about it: You're throwing away the complex, thorough engineering work done by an actual automaker, and attempting to replace it with a cobbled-together collection of parts that you think will do a better job. The quick answer is to buy a finished project from someone else, ideally after they've figured out all the problems involved in the swap. Or, you can find an experienced builder and hit them up for advice, tips, tricks—basically, a how-to guide for completing your own engine swap.
This V8-swapped E30 M3 can do both of those things.
Welcome to You Must Buy, our daily look at the cars you really should be buying instead of that boring commuter sedan.
Before you even read , you can tell this is a very well-done swap. The body is straight and clean; the LS1 engine looks completely at home in that BMW engine bay.
But it's the seller's description that sets this thing apart. You could build an excellent V8-swapped E30 M3 of your own just based on what the seller explains on eBay. Here, we'll break it down for you, using slightly-edited excerpts from the eBay listing.
Determining the fit:
The first step was to obtain, in this case rent, one of those foam replicas of a small-block Chevy engine and a tranny and make a trip to the local junkyard that contained a few E30 chassis. Imagine the looks you’d get walking through a junkyard on a Saturday afternoon with an engine under one arm and a transmission under the other. Anyway, it became obvious that there was plenty of room in an E30 engine bay for a small-block Chevy so I knew the LS1/6 would also fit.
Positioning the engine:
The motor mounts are stock Camaro units cut, modified, boxed and welded using ¼” plate to mate up to the mounting points on the BMW cross member. The rubber and steel transmission mount is also a stock Camaro unit and it is attached to the frame and transmission with some custom fabricated pieces of angle iron. It seems to be very strong. When I raised that engine and tranny up into the chassis I had to pinch myself it fit so well. The shifter actually fit exactly in the center of the hole in the tunnel where the original BMW shifter was. I did end up moving the entire unit ¾” back to improve the overall configuration. In order to move it back and get the engine as low as I wanted to in the chassis, I had to modify a front sump GM Holden Australian oil pan. It looks like this engine and tranny were made for this car.
Setting up the brakes:
The weight of the engine and tranny is very little more than an iron-block, BMW, 3.2, M3, 6 cylinder engine and tranny, which is a popular swap, so brake and suspension modifications are not necessary although I did install E36 M Roadster/Coupe front and rear suspension with larger brakes, larger bearings and strengthened rear control arms. The swap is almost bolt-on. Since the M Roadster/Coupes weigh around 3100 lbs, this car at about 300 lbs less has much more than adequate brakes.
Getting the gearing right:
A T-56, 6-speed, aluminum Camaro/Firebird tranny bolts-up to the LS1/6, measurements indicated it would fit well, was light weight and the gear ratios were perfect, i.e. 60 mph at 1700 rpm in 6th. The 212 mph at 6000 rpm won’t be of much use for me. [...] The gear ratios (2.66, 1.78, 1.30, 1.00, .74, .50) are perfect for the stock 4.10 limited slip diff [...] The differential is the stock M3, 4.10, limited-slip unit and, along with the E36, M Roadster half-shafts the rear end of the drive train seems to be more than strong enough [...] At 60 mph in 6th gear the engine is at about 1700 rpm if my math and the tach are correct. It is a very comfortable freeway cruiser!
Tuning for a responsive engine with great midrange:
I completely disassembled the new engine to check everything out and to blueprint it. I installed Katech rod bolts, ported the oil-pump, installed ARP head-studs and main bearing studs, up-graded the timing gears (Cloyes) and chain (HME-G68VC-60) from Katech, Comp Cams chrome moly pushrods, modified a GM Holden front sump oil pan so it would clear the front cross member and steering rack, installed a carefully selected cam, (569 intake and exhaust lift, 222/226 duration @ .050”). The cam is considerably more radical than a stock LS6 cam but I took Chris’ (from Katech) advice and it turned out perfectly.
How to keep it running cool:
The engine has no tendency to overheat unless I sit at a stoplight or behind a school bus for too long and then I just flip the electric fan switch and it cools right down. I’m using a Meziere remote electric water pump (part no. WP 316 S, 55 gpm) mounted in front of the windshield washer fluid container behind the right headlights, a Summit Racing aluminum radiator (part no. 380425), and the stock BMW electric fan wired to a switch on the dash. I fabricated aluminum adapters from ½” aluminum plate to fit the water inlet and outlet holes in the block (Meziere now makes them) and welded Earls 90 degree aluminum, ¾” hose barb fittings into them for my water lines. I used a Meziere “Y” fitting to collect the hot coolant from the heads in ¾” heater hoses and then to the radiator through 1 ¾” radiator hose. Since the 1 ¾” Meziere hose barb and the radiator inlet butted up next to each other inside the hose I filed a little material out of the inside of the hose barb so a Prestone 357-180 thermostat would slip into it and then ground the outside edge of the thermostat down until it was about 1 ¾” in diameter. When I installed the 1 ¾” radiator hose between the hose barb and the radiator the thermostat was captured and held tightly. I then tightened a stainless steel hose clamp in the middle of the hose so coolant wouldn’t escape around the thermostat. The heater hoses have to be attached to the correct BMW inlet and outlet heater core tubes if you want your heater to produce heat. The heater works flawlessly.
There's plenty more great advice in the eBay listing, should you desire an even deeper look at what it takes to build a functional, reliable V8-swapped E30 M3. Or you could —though with a current bid of over $40,000 and five days left in the auction, that might turn out to be an expensive idea.