MONZTER Posted February 1, 2008 Share Posted February 1, 2008 Hey All, I just finished up making my new transmission mount for the 71c swap. I'm pretty pleased with the results, so I thought I would share some pictures. It looks like It is going to be plenty strong, and the new design for the urethane bushing should keep the trans pretty tight. Another benefit is the improved exhaust clearance. I will be running 3.5 inch tubing from the turbo back, not the pipe tucks way up above the floor, which is pretty tough to do on a 240 with its narrow tunnel. So here are the specs: 71c trans Engine moved back 3/4 of an inch just so the valve cover fits past the hood catch -(the 71c mounts sit about 1 inch further back and the engine is now 3/4 back so a total of 1.75 setback on the mount) You can see the bowed shape of the cross member to allow mounting in the factory screw holes. 6061 T-6 CNC machined cross member 4140 Chrome-moly steel CNC machined trans mount bracket Urethane bushings from 73 up cross member 1/2-20 grade 8 hardware. I think I will anodize the cross member black and powder coat the trans bracket black as well (nothing too flashy on my car) Here are some pics of the CAD models as well as the finished parts. Click on the pics for a larger view from my picture gallery. Thanks Jeff I like the way it tucks up behind the tranny case Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted February 1, 2008 Share Posted February 1, 2008 Wow thats some nice work right there, great job. Quote Link to comment Share on other sites More sharing options...
DRTY260Z Posted February 1, 2008 Share Posted February 1, 2008 Sweeeet Quote Link to comment Share on other sites More sharing options...
olie05 Posted February 1, 2008 Share Posted February 1, 2008 please educate, what is a 71c gearbox, and do I need one on my car? edit... aha "fs5w71c" Right? Quote Link to comment Share on other sites More sharing options...
MONZTER Posted February 1, 2008 Author Share Posted February 1, 2008 please educate, what is a 71c gearbox, and do I need one on my car? edit... aha "fs5w71c" Right? Yep, aka 240sx 5 speed conversion Quote Link to comment Share on other sites More sharing options...
S31-RB26 Posted February 1, 2008 Share Posted February 1, 2008 WOW~!! Your work never seizes to amaze me. Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted February 2, 2008 Share Posted February 2, 2008 Wait you CNC'd the 4130 brace? Why not just have a sheet metal place bend it up for you? Justin Quote Link to comment Share on other sites More sharing options...
MONZTER Posted February 2, 2008 Author Share Posted February 2, 2008 Wait you CNC'd the 4130 brace? Why not just have a sheet metal place bend it up for you? Justin Good Question - To bend up the bracket accurately (I'm a freak about that sort of stuff) I would have had to either laser cut or CNC the blank out of 4130 plate. Well a lot charge at the Laser Company is $175.00. And I only planned on making 1. Now the time to set up the bending, and screw a few up getting the spring back just right as well as the compensation of bend = lots of time and money, again for 1 pc. Now after bending it would have to be fixture and drilled for the cross bolt that pass through the bushings = more time. CNC is easy to set up, and can run unattended unlike a bender or all the driving around to the different shops. So long story short more material cost, but less overall labor time. Again for 1 pc. Now production I agree 100% with you, hence why the part looks like it does, because it was designed for production bending. Oh ya, and my friend own the CNC shop :-P:-P Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted February 2, 2008 Share Posted February 2, 2008 Mmm, how thick is the plate? I figured you could punch all the features in the flat and bend it up. Anyway, If I had a friend with a CNC I could use for cheap I would have done the same as you. Justin Quote Link to comment Share on other sites More sharing options...
MONZTER Posted February 2, 2008 Author Share Posted February 2, 2008 Mmm, how thick is the plate? I figured you could punch all the features in the flat and bend it up. Anyway, If I had a friend with a CNC I could use for cheap I would have done the same as you. Justin Hi Justin, The plate is .250. Punching 4130 that thick will work but the coined edges are not so pretty. For high volume production that would be the ticket. So what do you guys think about the urethane bushings? are they going to hold up, and do you think the set-up will be too stiff and noisy? I have a urethane filled stock mount now, and the gearbox rattles around pretty good at idle with cam I use. I could always put some rubber ones in there for the street? Quote Link to comment Share on other sites More sharing options...
Nostalgic_hero Posted February 3, 2008 Share Posted February 3, 2008 looks good, for a personal project, very nice! for manufacturing... kinda radius intensive. ooh, and it would prolly be nicer to have the holes THROUGH rather than blind (the pockets you made for the steel plate to trans hardware clearance) this makes servicing the unit just a tad more pleasant. (take a look at OE S13 trans crossmember and you'll see what i mean) as for the urethane... it should hold up.. PEAK makes mounts for SR motors that seem to do just fine... but their solid urethane dogbones tend to deflect and crap out after a year or so (poor design). Im sure you'll end up playing with different durometers anyways.. p.s. very european looking. Cheers! Quote Link to comment Share on other sites More sharing options...
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