240Z gearbox upgrade to S13 | The Z Club of Great Britain
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240Z gearbox upgrade to S13

Discussion in '240Z / 260Z / 280Z' started by Seniorsideways, Sep 20, 2016.

  1. Seniorsideways

    Seniorsideways Forum User

    Hi, new to the forum. I wonder if anyone in the UK (preferably in the midlands area) can recommend a reputable garage to supply and fit a S13 gearbox for my 240Z
    The car is running a 2.9 litre engine with 222BHP and therefore a stronger gearbox would be a good upgrade?

    Thanks in advance for any help / recommendations
  2. richiep

    Z Club Member

    Hi there. I'm not sure any particular garage offers this service (maybe Fourways down $$$outh could do it). The installation is the simple bit though; the parts are where the work is needed. It requires various custom alterations - swap of S13/14 bellhousing to a Z one, Z bellhousing altering in very specific ways so that it bolts up, gearbox crossmember modifying, propshaft shortening etc. You'll probably need to source a suitable box yourself.

    I would recommend talking to Pete MacDonald (pmac on this forum) as he and Steve Kiddell (who lives near you) have performed this swap and built kits to do it on quite a few occasions. They aren't regularly making the kits anymore but are setup to supply the critical modified components. I'm sure he won't mind giving you some advice on the specifics.

    His email (take the spaces out) is pmaczc @ madasafish.com

    He might see this, but just mention I suggested you contact him for advice.
  3. Seniorsideways

    Seniorsideways Forum User


    I have spoken to Peter but he told me that he and Steve have retired from this type of work. I will see if he has the bespoke parts and thanks for the heads up.
  4. pmac

    pmac Well-Known Forum User

    I have just sold the last bellhousings I had and I am not doing any more.

    Thank you for the kind words Richie but as I said to "Seniorsideways" earlier Steve and myself have terminated our involvement with these conversions and getting parts machined etc.
    Its been good and we have had a few beers out of it but we have our own cars to work on and a couple of engines for family and friends to build which will occupy us for the forseeable future, so now is the time to bow out .
  5. jonbills

    ZClub Administrator
    Staff Member Moderator

    Will be a shame to lose access to the tooling and experienced engineering shop you used for this Pete - could this be passed on to someone to keep it going? (I'm not volunteering!)
  6. richiep

    Z Club Member

    Okay. As I alluded to, Pete and Steve have backed away from providing kits and doing all the hard work to concentrate on their own projects. EDIT - see Pete's comment!!

    Others on the forum elsewhere in the country may chip in with suggestions too. Generally, the task is a DIY one, based on sourcing the required parts and having them modified to suit. In my case, I bought an S14a box off eBay for £150 (I was very lucky price-wise, especially as it is in good condition), had a prop shortened by a specialist local to me in Cheshire for £60, and was able to get a pre-modified bellhousing from Pete a while back when they were still doing them (trading a stock Z one as a core), along with him modding a crossmember for me. I need a couple more bits and will finally get around to an install soon down at a friend's garage nearby.

    I guess it all depends on how much effort you are willing to devote to the exercise as opposed to trying to hand it off to a single third party. Good luck anyway! :)

    The details of the bellhousing conversion are out there on the web - it's finding somewhere competent to do it correctly so that it fits.
  7. Huw

    Z Club Member
    Staff Member

  8. Mr.G

    Z Club Member

    S13/S14 is a nice upgrade and will allow you to run more power through it, but I think you'll be ok with a stock 280ZX box with the power you are running so not essential.
  9. twigster

    twigster New Forum User

    Try MZR Roadsports Bradford
    They have a Facebook page or mzr-roadsports.com
  10. richiep

    Z Club Member

    That is a good suggestion. I keep forgetting about Rahail/MZR. Some of the restomods MZR have sold have been 71C gearbox equipped. EDIT: MZR list a full kit under their 'upgrades' action of the website. http://www.mzr-roadsports.com/index.php/en/upgrade

    Mr. G did also make a good point though. Your engine power isn't radical enough to make a gearbox upgrade necessary really. The 71C boxes do give a nicer, more modern experience though and are a bit more future proof in terms of parts availability.
    Last edited by a moderator: Sep 20, 2016
  11. SacCyclone

    Z Club Member

    I have a 240sx (s13-s14) box in my car and it is a very good box.

    My mechanic has installed about 10 of these boxes in the last few years and we found that modification of the box is not necessary, just swap the front shaft bearing and change bell housing. I will get some more info on this today and pass it on.

    I have two s13 boxes and one 5 speed roadster box that has the correct bell housing and driveshaft for a zed. Currently buying a used box for $300-500 and then cost of rebuild. More and more chaps making the conversion here so the supply has been short.

    Following this thread and will pass on more info as I get it.
  12. status

    Z Club Member

    Your280zx box is ample for the BHP you are pushing out,my 260 is pushing a lot more than that and my 280late box is ample,it is now sitting on my garage floor as I have just had the s14a conversion done but can't drive it yet as due to a bit of wriggling about getting new box in ,the fuel union that goes into the throttle bodies broke and Jenny being bloody useless didn't get the new rails out for next day so I am totally pissed off with em and UPS,I'll report back when it's bin driven,it's a simple swop once you have all the bits so a decent garage shouldn't charge more the £100 if they are proper mechanics
  13. Getnjgywitit

    Getnjgywitit Forum User

    The 1-2 shift rod hole still needs to be drilled out from 14mm to 16mm on the bell housing. The front cluster bearing should be from the older transmission and then the bell housing will be just fine. Here is a pic of the older front cluster bearing. Maybe you guys can find the bearing with these numbers. [​IMG]

    Hope that helps!
  14. jonbills

    ZClub Administrator
    Staff Member Moderator

    As I recall, the larger front bearing is one of the benefits of the upgrade, the smaller one on the earlier boxes being a weak point. Maybe not a big deal if you're not putting too much power through it though.
  15. richiep

    Z Club Member

    The larger S13/14 bearing can (should?) be retained as Jon notes. The zhome tutorial linked above covers that - the hole for it in the Z bellhousing needs enlarging from 56mm to 62mm.
  16. Getnjgywitit

    Getnjgywitit Forum User

    Yeah, I heard the same, but I would imagine if you are running stock to a medium built motor, you will be fine.
  17. SacCyclone

    Z Club Member

    Thanks Mike, that is what Gary and I discussed today at lunch.

    We have been tracking our Zeds for the last few years with the small bearing and I have not had any problems with wear. We are not running more than 225 RWHP so that may have something to do with the lack of wear.
  18. johnymd

    Z Club Member

    The other mod that often gets missing is the reverse gear indicator switch. This is offset by an inch or so. You have 3 options on fixing this:
    1. Re-drill and tap the hole in the new location and fit a blank to the old hole.
    2. Machine/grind a new slot on the shaft.
    3. Live with no reversing lights.
  19. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

    John, I can't recall having any issue with mine.

    The bearing debate - I seem to remember the bellhousing had to be machined for clearance of a gear too. So even if you retain the smaller bearing you can't get away with just enlarging the selector rod hole. It's a long time since I did mine though so I need to look at some pics.

    Edit. Pic added. Notice the wider gear which could foul the bearing 'boss'. Also John my reverse notch was more or less in the same place - perhaps there are different situations so yes something to check.

    Attached Files:

    Last edited by a moderator: Sep 21, 2016
  20. richiep

    Z Club Member

    It's all covered under the aforementioned zhome link:


    1-2 shift rod hole enlarged from 14-16mm. Counter shaft bearing hole enlarged from 56-62mm if using the larger 71C bearing. Inner case surface around countershaft bearing hole relieved to provide clearance for the countershaft gear regardless of which bearing is being used.

    The reverse switch position is only an issue if using 4-speed bellhousings according to the write-up.

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