510 Auto to 5 speed hole cutting

[beev]

Hello,

 

I posted this in the 510 realm but wasn't able to find a solution, they suggested I try here. I tried looking here but the search function doesn't seem to be working. I am sure this is covered somewhere. I have a 510 automatic on the tree and am going to convert it to a 280 5 speed transmission. However given that the auto is on the tree there is no reference for where to cut the hole in the tunnel. Does anyone have the measurements for location and pattern for the hole I need to cut? The best information I can find says don't cut the brake lines. Seems like sage advice but brakes only slow you down.

 

I was given this as guidance already but it doesn't have a starting location and is a way bigger hole than I need.

 

http://www.datsport.com/Transmission_cu ... rsion.html

 

Thanks for the hours saved if someone has these details! It is difficult to measure 3 times and cut once without measurements.

[datzenmike]

beev, yes we discussed this on The Realm. I'm sure someone has put a 71B 5 speed in a pre '71 automatic but I don't recall any.

 

About all I can tell you is that from the front top of the transmission where it bolts to the engine, it's 79.7 cm or maybe easier to measure exactly 29 inches back to the center of the shifter. That's to the center of the holes for the pin that holds the shifter.

 

 

I just went out and measured this on my spare zx 5 speed. If your engine is in place, and level, measure back from the block surface where the transmission mounts to it and mark the underside of the tunnel. Drill and open up a hole, say the size of a tennis ball. Mount the transmission and now that you can see exactly where the shifter will be, expand the hole to suit. I can't think of a place to measure from on the body inside or out and be this accurate.  

[beev]

Thank you. Only other constraint is to not cut too big I can't find a boot to cover the hole!

[datzenmike]

Yes. You do have to have a minimum size so that you can hit all the gears. Doesn't have to be a Datsun boot so look around the wrecking yards for something you like.

[Three B's Racing]

Like is said on the realm,

 

Install the trans and with a long screw driver or punch line it up with the shifter and hit it with a hammer creating a dimple you'll see from the top side. There you now know exactly where to cut your hole. Becareful with you brake line.

[Stoffregen Motorsports]

A boot from a mid to late 70's MGB looks appropriate in a Datsun, and the heavy gauge chrome ring (black on later models) makes it easy to mount and keep in good condition.  The early ones had a round ring, while the later ones were oblong.

 

https://www.google.com/search?q=MGB+shifter+boot+and+ring&client=firefox-b-1&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiU_JqFl6HbAhXdGTQIHfayA-wQ_AUICygC&biw=1680&bih=908

[BambooU]

I didn't cut my tunnel but the previous owner did. I'd line it up on the group or risen on a jack with the transmission that you have (if you have the motor mounted). From there, draw a point where the center of your new hole with be (should be directly up from the center of the shifter in Neutral). From there, cut a square or circular hole with that center in mind. 

 

Worst case scenario, cut a small (like 3 inch around) hole and make your way larger from there until you have full range of shifter motion. 

 

At least that's what I'd do without prior guidance on measurements pertaining to your exact transmission motor setup. 

[thisismatt]

Why don't you just measure from your block to the shifter location?  I honestly don't understand how this is a cross-forum brain teaser...?

[Charlie69]

Quit being timid and cut the damn hole!

[Dolomite]

280zx boot covers perfectly and looks 80’s cool.