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Transmission Mount for 260z RB26 300zx


garvice

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Hi guys,

 

I am putting a RB26 in my 260z with a 300zx transmission (RB26 bellhousing, 300zx transmission). I found very few photos of custom transmission mounts so wanted to share what I had done in the minor chance it might help someone else in the future. I included lots of photos as they tell the story far better then words. I have sat my engine completely vertical to allow more exhaust space, this is why my transmission is on an angle.

 

As most are away, the 300zx transmission is longer then the existing L series 5 speed and and the mount is further back.

My original transmission mount was the later style with two ears off either side of the tunnel and a crossmember between.

 

I started by cutting the ears off (spot welded on). This is the drivers side, don't have a photo of the passenger side.

260z_300zx_TM_1.jpg

 

I then folded some 2mm sheet to make the drivers side mount parallel to the existing mount (essentially taking the thought of extending the existing mount base). The existing mount is 2mm and is spot welded to the transmission tunnel (which is much thinner) so I felt this was an appropriate thickness. To get the mount to marry up to the tunnel I used a profile gauge (quick google search will bring up what it is). Worked a treat and got the profile spot on first time.

260z_300zx_TM_2.jpg

 

I plug welded it to the existing mount and then seam welded around the edges. I hope I never have to remove this as it will be a complete pain to remove.

260z_300zx_TM_3.jpg

260z_300zx_TM_4.jpg

 

The passenger side was a bit more difficult as the tunnel actually narrows rear of the existing mount rather then getting wider like the drivers side. So I just plated the tunnel with some 2mm sheet (it is not parallel to the existing mount like the drivers side is). To weld this on, I plug welded through the tunnel from the inside, then again seam welded around the mount.

260z_300zx_TM_5.jpg

260z_300zx_TM_9.jpg

260z_300zx_TM_10.jpg

 

The next couple of photos are of the existing crossmember and two different isolation mounts. The first is the L series isolation mount and the second is the GM mount (that I bought for the diff). I had to move the fixing hole in the existing crossmember over to allow for where the transmission sits in the tunnel. This created an issue with the crossmember hitting the transmission bolts. In the end I decided to go with the GM mount as it felt like it had a better construction. The white pipe is 90mm water pipe to simulate an exhaust and the blue tape is in line with the chassis rails.

260z_300zx_TM_7.jpg

260z_300zx_TM_8.jpg

 

I wasn't overly happy with how the crossmember sat on the GM mount in relation to the new tunnel mounts (sat a bit low at the mounting points).

260z_300zx_TM_11.jpg

 

So after a bit of deliberation I decided to make my own crossmember (also didn't want to have to burn out the isolation mount, burning rubber stinks). The original is a 2mm pressed mount (a top hat construction with a small bridge over the bottom), so I built mine out of 2mm sheet. The 2mm sheet is rather easy to bend over some pipe. Here is how I made it. Cut a 40mm strip of 2mm sheet, bent to the shape of the mount I wanted. Laid the shape on a sheet and drew a line offset 20mm from the top sheet. Bent a 60mm strip to match this line. Held them together with magnets to offset them 20mm and transfered the shape onto some 2mm sheet. Cutout the shape in two pieces and then had my four sides. Used some 30mm pipe for the isolation mounts. Ok here are the pictures that really explain it.

260z_300zx_TM_12.jpg

260z_300zx_TM_13.jpg

Reinforced the bolt hole section with more 2mm sheet

260z_300zx_TM_14.jpg

260z_300zx_TM_15.jpg

260z_300zx_TM_16.jpg

Measure twice cut once people, I drilled some holes in the bottom sheet and then realised I had drilled too far over, had to weld the hole back up.

260z_300zx_TM_17.jpg

260z_300zx_TM_18.jpg

Had to turn down the isolation mounts as my pipe is a bit smaller then the existing crossmember.

260z_300zx_TM_19.jpg

 

The new crossmember although larger is considerably lighter then the original (not quite as wide).

260z_300zx_TM_20.jpg

260z_300zx_TM_21.jpg

260z_300zx_TM_22.jpg

 

Cardboard templates for the mounting ears

260z_300zx_TM_23.jpg

Made the ears out of 4mm sheet (existing ears where a folded piece of 2mm sheet and then a second piece of 2mm sheet to reinforce), notched and seam welded from both sides.

260z_300zx_TM_24.jpg

260z_300zx_TM_25.jpg

260z_300zx_TM_26.jpg

260z_300zx_TM_27.jpg

260z_300zx_TM_28.jpg

260z_300zx_TM_29.jpg

260z_300zx_TM_30.jpg

260z_300zx_TM_31.jpg

 

Finished crossmember and mount

260z_300zx_TM_32.jpg

260z_300zx_TM_33.jpg

260z_300zx_TM_34.jpg

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  • 2 weeks later...

The shifter cages had a round bar welded between them. I cut the bar out and welded the cages together. I also used one of 240hoke's shifter relocators. This brought the remote shifter forward about 50mm and now it sits at the rear of the original hole. Haven't put the centre console back on to see if still fits.

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  • 2 months later...
  • 2 weeks later...

Forgot to put these photos up.

2011-04-27165910.jpg

2011-04-27165900.jpg

 

How did the shifter position end up doing it this way?

Secondly, how is the shifter action?

 

My original plan was to just mount the shifter directly to the first joint and then counter brace it half way up for in/out motion.

 

a quick google image search brings up exactly my thoughts...

 

http://photobucket.com/images/z32+shortened+shifter+for+rb+use/

 

I had read that shifter placement using stock linkage might be too far back, but haven't mocked up my engine yet to check.

 

Any thoughts would be appreciated.

 

Mark

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I didn't use the full linkage (cut out the rod between the two unijoints).

Below are pictures of how it sits in the car. The feel seems fine at the moment (need to get new bushes for the shifter). The z32 shifter is angled a bit too far forward for my current liking (I.E. Neutral is straight up down which feels a bit strange), might bend the shifter back a bit if I don't get use to it.

 

Gas_Forum_Build0026.jpg

 

Gas_Forum_Build0027.jpg

 

Gas_Forum_Build0028.jpg

 

Gas_Forum_Build0029.jpg

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That was my shifter setup i used for my swap

glad you could use the idea!

just an fyi for anyone who uses that setup though, make sure you reinforce the shifter plate that the hyme joint bolts to using sheetmetal and washers. use lots of loctite and lockwashers as its hard to get to if it rattles loose.

Edited by 240zdan
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240zdan,

 

Sorry haven't seen your setup? This is a 240hoke shifter mount that he made for his z32 swaps.

Also, what heim joint are you talking about? No heim joints in the mounts.

 

Brad

Edited by garvice
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  • 1 year later...

Sorry to bring this back up but for those that search for this I measured the lenght you need to have the shifter in the center of the Datsun's hole. From center of motor mounts on the crossmember. You have 47" inches to center if like me you use Mckinney mounts and a RB26 bellhousing on a Z32 tranny then the original lenght without shiter mods is 51 7/8 inches. So if you count that the hole is 7" more or less long you have a max lenght of around 50" but i dont think at 50" you will be able to shift smoothly it is just the max lenght for the shifter to poke through.

 

Wedge

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