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HybridZ

RB25DET gearbox -> 260Z


drunkenmaster

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Has anyone fitted this box to their Z without cutting the car?

 

I have been having a tough time getting the box in as it seems to be too wide for the old gearbox mounting tabs/ears. I would prefer to get away without cutting them if possible but at this point I cant see how.

 

Thanks

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Great photos, that was what I was planning to do however the box doesnt appear to be fitting in between the ears.

 

The box used in those photos seems much narrower, is it an RB20DET box or definitely also an RB25DET box?

 

Here is a photo of mine I took, it is from the side so doesnt show the mounting issue but you get an idea of the sheer size of the thing:

 

box1.jpg

 

Thanks

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The left mount is the stock Z31 mount.

http://www.motorworx.com/images/S30%20Project%20022.jpg

 

The Right mount gets cut down and an angle change.

http://www.motorworx.com/images/S30%20RB26%20Engine%20Mount%2010.jpg

 

It makes the engine sit a lot lower in the car and with the proper slant. It's really easy, you just cut it at the angle of the mount on the cross member until the bottom of the oil pan is parallel with the cross member. I weld a flat piece of 4130 .125 to it and drill the mount hole and locater hole for the insulator where they need to be.

http://www.motorworx.com/images/S30%20Project%20037.jpg

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Matt,

 

I think i remember you telling me the blue S30 was getting or had a rb20 tranny in it right?

 

The r33 gtst tranny is too wide and will not fit inbetween the ears... atleast for the Late model 260s.

 

The 2 speed powerglide is another story also it dosnt fit without tunnel mods :x .

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Matt' date='

The r33 gtst tranny is too wide and will not fit inbetween the ears... atleast for the Late model 260s.

[/quote']

 

Well, that makes my day considerably worse.

 

In relocating the "ears" further back to suit, did you create new bracing around the new area of the tunnel to suit the new stresses of supporting the box?

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Well' date=' that makes my day considerably worse.

 

In relocating the "ears" further back to suit, did you create new bracing around the new area of the tunnel to suit the new stresses of supporting the box?[/quote']

 

 

Not sure how yours is but i dont think you will be able to go back far enough to have to brace anything. the plate the stock ears are welder to is pretty big and should accomadate moving the ears back an inch or so

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Well, looks like the engine and box are going back in again for some more investigation.

 

From the looks of it moving the ears back an inch wouldnt seem to help as the box still seems pretty thick, perhaps trimming the ears back may do the trick, but structurally I am unsure.

 

Nothing is ever easy.

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  • 2 weeks later...

The Right mount gets cut down and an angle change.

http://www.motorworx.com/images/S30%20RB26%20Engine%20Mount%2010.jpg

 

Matt, was this mount a Z31 mount? Or did you cut the stock mount which was then cut? I'm kind of confused. Also replying to Stony, did you use a RB20DET Tranny?

 

 

Okay, I notice that most of you guys have the tranny mount where the bolts slide in from the side. I have a 1970 Z, and tranny mount is totally different. It has the style where it bolts straight up into the car. What do you suggest I do for this?

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Matt' date=' was this mount a Z31 mount? Or did you cut the stock mount which was then cut? I'm kind of confused. Also replying to Stony, did you use a RB20DET Tranny?

 

 

Okay, I notice that most of you guys have the tranny mount where the bolts slide in from the side. I have a 1970 Z, and tranny mount is totally different. It has the style where it bolts straight up into the car. What do you suggest I do for this?[/quote']

 

Yes, those are Z31 mounts and that's an RB20 trans. If yours bolts straight up, clearance for the 33 trans in the tunnel shouldn't be a problem? Besides helping Stony, I've only done two other 26 swaps into old Z's and they both used the RB20 trans (not race cars). Putting them into newer, Nissan RWD cars is so much easier :)

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Yes, the ears have to be cut off, or trimmed way down for the motor/trans to go in together. At least it did with my early 260.

 

I remember finding that out the hard way..... I had to lower the tail shaft back down to the floor, so that I could cut the ears off. Then I just tied a wire around the trans, and up thru the shifter hole, I braced it up with a 12" piece of rebar.

 

Once James got to working on it, this is how it turned out.

 

trannymount1.jpg

 

trannymount2.jpg

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