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which gearbox to rebuild......


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#1 WogsRus

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Posted 15 July 2015 - 05:49 PM

Ok so after pulling apart my two spare gearbox i have the following

1) Early steel synchro type with the following gear ratios. 2.90625 1.902272727 1.308441558 1.001196172 0.863636364
The gearbox needs a full rebuild, sloppy bearings and mashed synchroes.

2) Later style gearbox from my spare 2+2 which has three sensors on the side, no idea what for, with the following ratios. 3.321428571 2.076555024 1.308441558 1.001196172 0.863636364
Gearbox is tight and runs brass type synchroes so it can be fully rebuilt.

The car runs a mildly hot L28, everything else drive-line wise is stock.

So which one do i go with?

#2 Lurch ™

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Posted 15 July 2015 - 06:39 PM

1.

#3 WogsRus

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Posted 15 July 2015 - 07:19 PM

Thanks lurch, but its a taller ratio, ie more speed in first and second.

However i cant buy the steel synchroes and i am not sure if you can use the number 1 gear set with number 2 synchroes.

#4 dat2kman

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Posted 15 July 2015 - 11:19 PM

Rebuild number 1
It'll be more fun to drive.
Less engine rpm drop on the gear upchanges.

Keep number 2as a spare, even consider using its bellhousing if you were to do an RB/SR conversion
Number 2 is a very common box, number 1 is getting hard to find.

#5 WogsRus

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Posted 16 July 2015 - 12:06 PM

Well ok so today i had a look at the gearbox still in the car and looks like that one is a 2.9 first as-well and the strange thing is it has a blue spedo drive, indicating a 3.7 diff?

WEIRD

#6 1600dave

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Posted 16 July 2015 - 12:55 PM

Well ok so today i had a look at the gearbox still in the car and looks like that one is a 2.9 first as-well and the strange thing is it has a blue spedo drive, indicating a 3.7 diff?

WEIRD


When it was traded in, my brother's 260Z had a 3.9 240K R180 diff instead of the original R200, and a C210 skyline box replacing the original auto. 

My old 1600 has a bluebird box that is fitted with a different speedo drive to suit the 4.11 diff.

These things are 40 years old, who knows what has been replaced and what it has been replaced with over the years.

#7 Howdy

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Posted 16 July 2015 - 09:42 PM

Definitely keep the 2.9 1st gear if your not running over about 300Hp. The boxes are getting rare now. I don't think you can get syncros (I brought the last genuine ones in OZ about 15 years ago) but you can press off the syncro hubs and press on the brass syncro hubs from the later boxes and it makes a sweet shifting box. 3.3 1st gears suck in a Z.

#8 WogsRus

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Posted 16 July 2015 - 09:59 PM

Thanks Howdy, yeah i now have three 2.9 gearboxes, so i could put one good one together with steel synchroes, the issues is all have a completely lunged third gear etc.

AND as you have said, i have just learned that the cones can be pressed in and out soooooo, i am going to rebuild the 2.9 gear-set with warne style synchronizes. Best of both worlds.

SOOOO now to take it all apart and pray for the best.


So the aim if for a 2.9 gearset with a 3.9 diff. YEEHHHAAAA.

#9 WogsRus

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Posted 17 July 2015 - 12:57 PM

Gearbox stip down has begun, parts on their way, full kit to rebuild the new box with old gear set was $114 form the us including synchreos. So essentially i will be converting the old gearset to run with new synchros.

Also for those who are looking into rebuilding an older servo synchro gerbox, have a look here

http://www.pelicanpa...01_synchros.htm

Parts are interchangeable at a fraction of the cost.






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