kens 77z Posted June 7, 2011 Share Posted June 7, 2011 I am about 90% done swapping a 2.8L 96 BMW328i engine in my 77 280z. I decided on the straight six M52 engine after reading RTz's thread. I liked the idea of retaining the straight six. I loved the sound of my Z engine. I chose the M52 over the S52 (M series engine) as it is considerably cheaper. I figure swapping a M50 manifold with the easier to deal with EWS1 computer system onto the M52 engine would give me close to 220hp which is about 60-70 hp more than my Z engine was making. Plenty for me. That will get me in enough trouble on track days. I fabricated my engine mounts out of 1/4" plate and 2" square tubing. It worked out fine except my welding is extremely ugly. It got a little better when I switched to gas shielded solid wire instead of the flux core. I only show these as examples as a way to fab engine mounts. Ignore the welds if you can. and here is the transmission mount. I used the ears off of the Z mount. I left the front suspension crossmember in the original location instead of lowering it like RTz. I did not want to mess up the steering geometry any more after lowering the car with shorter springs. With the engine sitting on a piece of 1/2" plywood on the steering rack and raising the transmission until the shirt mechanism cleared the tunnel by about 1/4", I measured the angle of inclination of the transmission output and the angle of the diff input and it read the same on my cheap Harbor Freight angle finder. Of course I stupidly fabbed the engine mounts with the engine in that position and when the plywood block wsa removed the enginee sank about 1/4". You would think a structural engineer wuld have anticipated that. I solved that with a3'8" thick, 2" diameter aluminum washers between the top of the rubber and the metal mount. Quote Link to comment Share on other sites More sharing options...
kens 77z Posted June 7, 2011 Author Share Posted June 7, 2011 For the drive shaft I used the front part of the BMW drive shaft and the back part of the Z drive shaft. One slid inside of the other for a snug fit! When I sanded the paint off it was a little looser, but still fine. I attached the drive shaft in place and tack welded it and took it off and took it to a friend who can weld. Before welding after welding And here is my shifter extension, For the upper aluminum part I JB welded it using some threaded rod and some flat aluminum for splicing. For the lower part I welded a threaded rod in one end and a nut on the other. Now I can adjust the angle of my shift lever easily be removing a clip and turning the link in or out to change the length. More tomorrow. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted June 16, 2011 Administrators Share Posted June 16, 2011 Thanks for starting a build thread! I have a couple concerns about your driveshaft... 1) U-joints, when run at anything other than 0 degrees, accelerate and decelerate as they spin. Typically they are used in pairs and 'timed' to each other to cancel or balance each other out. If you use only one, it may prove tough to get control of vibrations. 2) When driveshaft parts are assembled, such as a trunnion for example, they are pressed in and welded. The press fit contributes GREATLY to the strength of the assembly. If you only 'slip' it together and rely on a simple weld, there's some likelihood of failure. 3) In every shaft I've ever encountered there has always been some method to allow the shaft to run at varying lengths. In other words, the motor and trans are normally allowed to move longitudinally under acceleration and braking, independently of the differential. It looks like your arrangement would bind them together. Not entirely certain of the consequences, but if you haven't given it some thought, you probably should Quote Link to comment Share on other sites More sharing options...
kens 77z Posted November 27, 2011 Author Share Posted November 27, 2011 I swapped in an engine and transmission from a 1996 325I with the wiring and EWS1 computer and intake manifold from a 1993 325I. I did not lower the front cross memeber. The oil pan clears the steering rack clamp by about 1/4". I was trying for 1/2", but did not adequately account for the compression of the engine mounts. Since the engine torques the oposite direction, that tight clearance has not been a problem. The drive shaft is made up of the front half of the BMW drive shaft and the back half of the Z shaft. One slipped into the other snuggly. It was a little loose after I took the paint off. It is fine since I had it balanced. I got the length correct by bolting everything up and tack welding the two pieces together under the car. I raised the tail of the transmission until it clears the top of the tunnel about 1/8". The shift lever was modified as shown itn one of the photos. The aluminum part was spliced with JB weld. The lower steel part was welded. Rear Wheel Hp – 197-202 (3 runs) Torque – 210+/- Car weight No driver – 2603 maybe 4 gals short of full LF 648 RF 651 LR 636 RR 668 No driver - 2755 LF 701 RF 653 LR 699 RR 704 Quote Link to comment Share on other sites More sharing options...
kens 77z Posted November 27, 2011 Author Share Posted November 27, 2011 Remaining items are getting the speedo to read correctly and getting a higher gearing to lower engine rpm at highway speeds plus raise the top speed. When I ran the car at Road Atlanta last weekend I was hitting about 110mph at about 5500 rpm (per a datalogger) before I was halfway down the straght. The car did not seem very stable at that speed so I never pushed it much past that. I have an electronic speedometer hooked up to the BMW sensor mounted on the left half shaft. Unfortunately it does not read steady long enough for me to do a proper calibration. I installed a shielded cable and shielded the sensor, but it still has problems. Here is a picture before I shielded the sensor. Another problem is the coolant temperature gauge. The BMW sensor for the 1996 engine is a dual sensor. the part that sends to the computer has resistance readings identical to the Z sensor, but the part going to the gaqge reads with a much higher resistance which to the gage means a cooler temperature. As a result, at normal operating temperature the gage needle never moves. I guess I will need to put a sensor somewhere else. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted November 27, 2011 Share Posted November 27, 2011 Pull up resistor for the temp sender unit aught to fix that, just like the tach fixes for most swaps. Quote Link to comment Share on other sites More sharing options...
alternativez2003 Posted March 28, 2012 Share Posted March 28, 2012 Really cool! I made a similar speedo pickup on my m42 in my '76 2002, and it works fine. Maybe line the sensor up a little straighter. Nice job. I'm still thinking of my '85 635 engine in the Z, just because I have everything to do it. Good luck! Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted March 29, 2012 Administrators Share Posted March 29, 2012 I merged your two build threads. Thanks for the update. Keep them coming! Quote Link to comment Share on other sites More sharing options...
JSM Posted March 29, 2012 Share Posted March 29, 2012 What is the process for the wiring harness and ECU swap? Is it fairly simple to incorporate? Quote Link to comment Share on other sites More sharing options...
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