S15 gearbox conversion to Z33 6 speed

[STF515]

Just thought after seeing the couple of threads on the z33 gearbox conversion, that I might put up some info, and a how too. I am still waiting for my new box to arrive, but everything else bar the tail shaft has been modded to suit.
So far I have bought the adapter kit from here - http://zilvia.net/f/drivetrain/370705-z33-sr20-adapters-back-limited-quantities.html
I managed to find an unused second hand kit here in Aus, Aud $850 delivered . This came with the adapter, rear gearbox mount frame to suit the 350z rear mount, and modified shifter housing assy and all bolts.
Next, I bought a generic short shifter off ebay, just cause it was there he he, and bolted that up.

After that was the hardest part - turning my ORC 559 twin plate clutch into a non duel mass flywheel setup. To do this, I grabbed a friends old rusty standard s13 flywheel, and sent it to a machinist I know, who just copied the ORC flywheel face onto the standard s13 flywheel, and drilled all the mounting holes for the basket fingers. The job he did is awesome, he even skimmed as much metal off the outside just to lighten it up, weighs the same as the original ORC flywheel!

I have mounted the adapter plate onto the motor, it required a small amount of grinding around the top LH corner where it was touching on a coolant pipe, other than that, a perfect fit. I did have to remove my dump pipe, and it will require some small rerouting mods, but a standard exh should be fine (I have a high mount setup)

Thats all the info for now, I will put up some pics later today, need to get them off my phone. If you have any questions, ask away
2 weeks and it should live again
:rotfl:

Steph
Merry gearbox, and hugs to all

 

[meddler]

sounds good. Did you have to modify the transmission tunnel at all. It seems that all gearbox conversion require beating the tunnel with a hammer.

 

[STF515]

I am still waiting for my new gearbox to arrive. And even when it does, I will need to get the bellhousing machined. So give me 2-3 weeks, and I will have definate answers for all your questions

 

[meddler]

Cool. no probs. If you can, take plenty of pictures (I am sure you will)

 

[Larsz]

Awesome! Cant wait for the write up / pictures. Thinking of doing this myself and any info at all is welcome

 

[STF515]

Ok, so here are some pics, just of my parts stockpile, as I said previously, I am still waiting on the actual gearbox.

First off, my freshly modified standard S13 flywheel. I had to get the machine shop to make a step down around the outside, drill and mount the clutch disc finger post. It came out pretty well. I am guessing that it will be possible with an OS Giken or Nismo twinplate as well, if your just doing a 5 speed conversion. The machinist also took as much weight from the outside edge off as well, the original pressure plate mount was about 15mm outside of the ring gear! It weighs the same as the dual mass replacement flywheel, so it should still hopefully rev up ok.

Next is the modified shifter housing, with a cheap short shifter kit I picked up. The housing is shortened about 100mm, when I get the new box I will take a comparison picture. (excuse the bad nail polish )

This pic shows how much bigger the bell housing flange is, and why I will need to reroute the exhaust, and maybe the waste gate/plumb back pipe. But this will allow me to add a flex, and plumb the screamer pipe in neatly with good flow (it did enter at 90 degrees to exhaust flow).

And here is a pic of why I am doing the conversion. I stripped 4th gear 2 months after purchasing, and as it was then my daily, found a gearbox rebuilding company that would supply me with a reco S15 6speed, and they also did the circlip mod, at my request, but said there would be no warranty. I didn't think this would be a problem, until I couldn't select 3rd leaving home on the way to work. I stripped the gearbox, and found that they had used a previously failed counter shaft, welded the cirlclip washer as requested, then welded the washer to the shaft to control end float. I contacted the business, and was told that that is how the circlip mod is done, and even after showing them pictures (different states) they refused to even offer a small refund. So anyone in Australia - DO NOT USE STATUS GEARBOX RECONDITIONERS!!!!!!!!!!!!!

 

[Larsz]

Iew, that circlip mod looks awefull :| But I was under the impression that you could keep the original S15 clutch and flywheel setup? Atleast thats what i read somewhere. But you say that you need to modify the exhaust path to?

 

[lvaleiron]

*tagged as favorite* definitively going to follow this thread as i opened a similar one a few weeks or months ago (can't seem to remember ) but 6 speed z33 is the way to go imho! let us know how it goes!

 

[STF515]

Larsz, the actual weld mod that was done was really good, its the fact that they used a second hand, already failed shaft and welded the washer to it to control end float that was the problem. With the flywheel/clutch, you can use the S15 clutch, but need the S13/14 flywheel, the dual mass moves everything too far into the bell housing. I already had the ORC twin, on a dual mass replacement, and didnt really want to loose it (amazing clutch - drives like a normal heavy duty!). ORC dont supply the s13/14 flywheel separate, so I just got the S13 one machined up.

I have jut bolted the flywheel/clutch up, using the input shaft out of my grenaded box, and am waiting impatiently for the gearbox to turn up early next week, so I can strip the bellhousing off and get the mounting face decked by 1/2 inch - the thickness of the adapter plate. While I have it apart I will also be checking all the syncro clearances, just to be on the safe side.

When I do strip the box, I will take pics of how to do it, and as soon as I get it back, a picfest on the install.

Peace N Hugs
Steph

 

[STF515]

OK, So update time with some more pics :nod:

I got my gearbox delivered to work today :rotfl: As soon as I finished my 10 hr day, I stripped the bell housing off, to get the mounting face machined down 12mm to account for the 12mm thick adapter plate.

To do this, firstly drain the oil if it hasn't been done, then lift onto a bench, preferably with a drip tray underneath, you WILL make a mess otherwise. Next you need to remove the throwout bearing carrier and fork, and remove the 12mm headed bolts holding the front bearing coverthat is in the bell housing. After doing this, you will see a circlip on the mainshaft bearing (the big one), remove this without damaging it, you need to rotate it to clear the counter shaft bearing. Also, while there, undo the 10mm headed nut at the bottom, this holds the gear train oil plate (circled in yellow), and the bellhousing wont come off. (Dont ask how I know )

The next thing you need to do, is stand the box on its nose (bellhoushing down). Remove the black cover near the shift link (7X 10mm head bolts, and remove it carefully - there is a detent spring held down by the cover. Once that is out of the way, remove the one 12mm headed bolt as pointed too, and then remove all the other 12mm headed bolts that hold the bellhousing to the carrier plate. Once this is done, you can pry the bellhousing away gently, and lift out the gearset, leaving you with an empty bellhousing ready for machining!

Tomorrow I will take the old stuffed S15 6 speed counter shaft in and get some pics, to show you the size difference, the syncros are MASSIVE in comparison. Hopefully I will get the bellhousing back in a few days, as soon as it is, it will be in the car for a test fitting, and exhaust rerouting. Then tailshaft modification. Then to test it:wack:

 

[Fruitbooter]

Good work! Looking forward to results :nod:

Have you changed / modified the starter motor at all?

 

[LuPix_S15]

Awesome progress thread :thumbs:

 

[STF515]

Good work! Looking forward to results :nod:

Have you changed / modified the starter motor at all?

Hi, I am still using the original starter, there is a mount on the adapter plate. This is perhaps the only thing I dont really like about this adapter - to remove the starter, the gearbox must be removed. You can see it mounted next to the crank in this pic, and also how much bigger the bolt pattern is on the Z33 gearbox.

Peace and hugs
Steph

 

[STF515]

Well I can safely say - IT FITS!!!! woop woop. No pics yet, I had to do some slight massaging of the tunnel, only at the front, for 2 bolt points, and this was mainly due the the thickness of my twinplate - with a standard h/d clutch it should be fine. around the transmission mount is TIGHT, but does fit ok, only needing a washer on each bolt to space it down to clear ok. The shifter sits back about 50mm, and will require some metal cutting, but other than that, it all seems pretty good

I will try and get some pics next week, I have to pull it back out to change the throwout carrier - its too short atm.

 

[meddler]

so could you fit this without bashing the tunnel? Also could the shoifter be modifed to go through the standard hole? As you may have gathered, I am not too keen on cutting holes in the car.

 

[STF515]

Hi Meddler, I reckon it will fit without massaging the tunnel with a standard heavy duty clutch. I only had to move a small part of the tunnel about 10mm, not noticeable in the car at all, this was only to get it to go in, once it is bolted up there is heaps of room. As for the cutting of the tunnel hole for the shifter to come thru, I dont think you would be able to, without moving the engine forward (this wouldn't be too hard).

I should see some more bits tomorrow, so might try and get it looking a bit more complete tomorrow night after work.
Any more questions, just let me know

Steph

 

[meddler]

cool... Will be interested to see more pics.

Actually, it would be good if you could get a pic of how the shifter is connected to the box. It seems there is a linkage involved. Just trying to get my head around the complete install.

Thanks for the info.

 

[SamB87]

Nice going Steph. I pretty much joined up here because someone linked me to this thread since I just scored a Z33 6-speed for $1k. Can't wait to attack mine like you have yours, although I'm going down the cut and shut bell housing route rather than the adapter plate.

Just can't get my head around what you've done with the flywheel. I'll be getting a Nismo twin plate clutch brand new, so should I just go S13/14 or get the 15 model and get another flywheel to mod?

 

[STF515]

You will need an S13/14 clutch/flywheel setup, the S15 dual mass replacement sits into the bellhousing too far, and would stop the box from sitting against the bellhousing. The reason I did the custom flywheel was the fact that you cant buy an ORC flywheel on its own, and my twinplate is only 10k km old.

As well as the bellhousing cut/shut, you will need to shorten the shifter bracket and rod, I will take some pictures when I pull it back out tonight. As well as the actual box/shifter assy, you will need the z33 throwout carrier - its longer, and the tailshaft slip yoke, I have been unable to find one aftermarket, and genuine you need to buy a complete tailshaft.

I hope that helps, there will be a heap of fitment pics taken tonight, I will upload them on the weekend. I am glad this thread is helping people

Steph

 

[haz's S15R]

Did you manage to get any pics of the install after Steph, this thread is making me want to do the same conversion!!!