Jump to content
SAU Community

V35 2003 CVT GEARBOX CONVERSION TO 6MT


Recommended Posts

Hello guys,

I picked up a nice little 2003 350GT-8 with a buggered CVT gearbox, I fitted a secondhand CVT gearbox but was unable to rectify the faults.

After about 1 year of spending time trying to find the faults, I decided I would make the leap and convert the sedan to a 6MT from a 350Z.

Please try and refrain from writing things like "WHY DIDNT YOU JUST BUY A MANUAL TO START WITH" etc etc. I don't care.

The car cost me $1500 licensed and all, and 2k for the conversion. Still cheaper than buying a 350 6MT. 

This post will contain as many photos as possible as I progress through the build. This will be continually updated as I complete the stages. 

I have never been able to find out about mounting the handbrake lever, or the legalities on cutting the transmission tunnel out to fit the gearbox. I hope to provide some light on these matters for the next person to take on the conversion project.

Removed CVT and threw it in the skip bin. Best feeling of my life. GOOD RIDDANCE.

28946758_10160182400365290_737791601_o.thumb.jpg.dfeea4cddd84274f7cdb120468966d15.jpg

Removed the following;

  • Carpet (needed a clean anyway)
  • Front and rear seats
  • Center console
  • HVAC and anything in my way
  • Witing harness
  • Airbag module, Gyro & Traction control module. (NOTE ANYTHING WITH YELLOW PLUGS IS SRS AIRBAGS, MAKE SURE BATTERY UNPLUGGED ALSO DO NOT FLIP OVER THE SRS MODULE FROM UNDER THE CONSOLE, IF YOUR BATTERY IS CONNECTED OR IT HAS CHARGE IT WILL SET OFF YOUR AIRBAGS. IVE SEEN IT DONE. VERY DANGEROUS.)
  • Brackets and really anything you see is going to slow you down. 

Mock fitted the console and handbrake assembly to see the alignment. Measured gearbox to the tunnel. 

28946135_10160182399710290_1480898246_o.thumb.jpg.d8fd46ca556908320e9c6509911c6276.jpg28946230_10160182400570290_317575194_o.thumb.jpg.685a99bae5946eb8e7e919a1f8fbe9c7.jpg29405555_10160182401155290_125359531_o.thumb.jpg.5094aaf255bd4284efc131e1ebdd7a43.jpg

 

 Pictures of the handbrake assembly and how it DOES NOT match anything on the original tunnel, I guess you could make up a few brackets and cut some holes but that is dodgy and I want this thing to be as good as factory when I am done. 

 

29391771_10160182399620290_949657498_o.thumb.jpg.7440bb1454ecf962e5845a2274da4871.jpg

I have a manual tunnel from a 350Z, I have decided to remove the inner skin that has the moulding for the manual trans and the handbrake that I require. Once done will be as simple as bolting it all onto the new inner skin as per factory.

I was able to drill out the spot welds with a Spot weld cutter available for $20 its like a little hole saw. I have a qualified boilermaker / engineer on hand to weld the skin into the cars existing tunnel. 

5ab1cd8adaf8a_29243076_10160182399300290_2060332899_o(1).thumb.jpg.99590caeee0c25b6b85bc9ad79210b23.jpg28946697_10160182398620290_1930923885_o.thumb.jpg.128d0322c8e2c1455f0abdcf3e725276.jpg

There are A LOT of little spot welds not marked with arrows, the arrows are just pointing out a few of the ones I started to cut out. 

More photos and info to come! Thanks 

 

 

 

 

 

 

 

Edited by RiZZa_AU
  • Like 1
Link to comment
Share on other sites

Rizza well done on hand brake assembly. Are you going to opt for factory clutch line or and what I did is had custom made clutch line. Single complete length from clutch Reservoir to slave cylinder. Also air con ducting to rear seats can be rerouted to centre console storage to be used as fridge/ cold box

Link to comment
Share on other sites

Rizza well done on hand brake assembly. Are you going to opt for factory clutch line or and what I did is had custom made clutch line. Single complete length from clutch Reservoir to slave cylinder. Also air con ducting to rear seats can be rerouted to centre console storage to be used as fridge/ cold box
Cheers for feedback, if i can get away with the standard/factory lines I will. Was there any particular reason you opted for custom?

P.s im keen on the ducting for drinks idea too cheers.
Link to comment
Share on other sites

Awesome work man!! I struggle to take photos and document my process.. I had no idea about the difference in tranny tunnels for handbrake relocation until you mentioned it.. I'm going to have to make up some brackets I think. I don't have the means to modify the tunnel to level above unfortunately.

Keen to see how this pans out. Looking forward to the updates.

Cheers

  • Like 2
Link to comment
Share on other sites

  • 3 weeks later...

UPDATE 16/04/18

Clutch pedal and slave cylinder install. 


WOW! Anyone who said "Just line it up and drill a couple of holes" on all the forums 
ive read is an absolute wally.

So, start by removing brake pedal assy, Whilst doing this remove the brake booster also and get it all out the way. Trust me, do it first!

20180416_094634.thumb.jpg.be1f348c0b7bba33f778e2a26affa675.jpg

  • Removed the E-brake assembly and put it to the side (you'll need this for a bracket)20180416_084449.thumb.jpg.1b8bc3725becee4218c9f882a68ed524.jpg
  • Drilled out the E-brake bracket firewall spot welds with a spot weld hole saw (ez pz) You can throw this bracket in the bin you wont need it. 

20180416_084926.thumb.jpg.525541a540f4856a1392b9a4cf755cd8.jpg

  • Mock install the manual brake pedal assy for alignment
  • Line up your clutch pedal to your brake pedal and mark a hole or spot on the firewall.

20180416_103529.thumb.jpg.3fc9271041927f792a08a30360d9a4dc.jpg

  • Used my template to line up opposing hole, mark it and drill the mount holes. (if you want a copy there will be a link posted somewhere below soon)
  • (drill out the mount holes but NOT the main slave cylinder hole until last in case you stuff it)
  • Mock install clutch pedal and tighten with some bolts to see where it lines up and you're happy with it

Now, I found at this stage it was very very flimsy on the firewall and over a couple of hard drifts and shifts, it would most definitely crack somewhere. So my recommendation is make up a bracket for the top! This is how I did mine using the factory parts.

 

  • Drill out the spot welds from the top mounting plate on the old E-brake assy.
  • smash it out flat on a vice so we can modify it to fit onto the clutch assy
  • 20180416_104923.thumb.jpg.f16d5d737be30d3835657d643fc71e83.jpg
  • use a piece of cardboard to get roughly the right shape you need and bend that piece accordingly.
  • with the clutch mock installed, put the piece you've made up and keep bending and adjusting the piece until you think it fits, then mark it on the clutch assy where it needs to sit. Make sure the holes line up with the holes up top ;)
  • remove clutch pedal assy
  • weld it to the clutch pedal assy
  • refit and check (rinse and repeat until your happy with it)

20180416_113016.thumb.jpg.9699c91871972f86ab4e63a5aa267b90.jpg20180416_113024.thumb.jpg.aa5d9b88a5f99b76a426d55ebb3d4f8d.jpg

 

Once this is all done, everything is lined up you need a 32mm Sheetmetal hole saw and drill out the center hole.

20180416_124355.thumb.jpg.6431782c8222496d2bf95d56d60c1ba5.jpg

Fit it all up and bolt it all on. Clutch pedal install complete. Here are the finished photos of it mounted.

20180416_130522.thumb.jpg.99b211abb0599b4f81c75d311bc1a110.jpg

20180416_130504.thumb.jpg.766567dde0365617f47fffd7d07ba052.jpg20180416_130548.thumb.jpg.c7da0c2e9eae24563b3f0a96b46e912d.jpg

More updates soon!

Edited by RiZZa_AU
missed a bit
  • Like 2
Link to comment
Share on other sites

  • 3 weeks later...

UPDATE 03-05-18

Tunnel final prep completed and TIG welded into vehicle .

20180430_160134.thumb.jpg.6a96c5c6521dbe7e7baf8ad37977f46d.jpgTIG welding20180502_130619.thumb.jpg.f3c0926205b616c2e829f1fd84acb175.jpg20180430_180746.thumb.jpg.cfd0d4ca9c57e5e33858d607fcb544b7.jpg

Seam sealer applied for that OEM seal and look , Also primed and ready for reinstall of interior.

20180502_124831.thumb.jpg.89db59066c2bc06dbf3359998a22229e.jpg

20180502_162228.thumb.jpg.05c9a66a7d8b109f9506a25ad246da0b.jpg

20180503_121614.thumb.jpg.80e9618bb350ed2fa55f0083a0bff9d1.jpg

External shields refitted after under body prepped and primed. 

20180502_131118.thumb.jpg.2103c2f8b9f01fe67f44fa1e1841af49.jpg20180502_132621.thumb.jpg.4ce50b3be0b2e746cfe9662018500ca4.jpg

20180502_132743.thumb.jpg.a6c846960184a7d519e3b0fd75f5f3fc.jpg

Started install of flywheel / found 350Z pilot bushing would not fit into the crankshaft, so put it on my custom lathe :4_joy: (drill) and sanded it down for a nice fit. 

20180502_155223.thumb.jpg.10bc646375b9fd6e4b5fcebc07d4bc52.jpg

Installing clutch and gearbox today / Will post more photos and an update when its done.  :1_grinning:

Here is a photo of the brake booster and clutch reservoir & lines fitted using all the OEM mounting points this was super simple.

20180502_161034.thumb.jpg.309e2bb46b7aaa6e67310c227bdd2bff.jpg

20180502_161057.thumb.jpg.46bb95840a6caf41589060bd68bae009.jpg

 

Tunnel Build notes: 

  • My mate and I both agreed after completing the tunnel job, cutting the lip to fit the gearbox would have been a lot easier.
  • Ill be a lot happier knowing the handbrake mount is correct ( I've heard some horror stories :P you know who you are)
  • This job will probably turn you into a heavy drinker. 
  • CVT tail shafts are not compatible with the 6MT 350Z driveline couplings. I ended up having to order a 6MT Diff too.$$$

MORE UPDATES SOON!

Edited by RiZZa_AU
Link to comment
Share on other sites

UPDATE 03-05-18
Tunnel final prep completed and TIG welded into vehicle .
20180430_160134.thumb.jpg.6a96c5c6521dbe7e7baf8ad37977f46d.jpgTIG welding20180502_130619.thumb.jpg.f3c0926205b616c2e829f1fd84acb175.jpg20180430_180746.thumb.jpg.cfd0d4ca9c57e5e33858d607fcb544b7.jpg
Seam sealer applied for that OEM seal and look , Also primed and ready for reinstall of interior.
20180502_124831.thumb.jpg.89db59066c2bc06dbf3359998a22229e.jpg
20180502_162228.thumb.jpg.05c9a66a7d8b109f9506a25ad246da0b.jpg
20180503_121614.thumb.jpg.80e9618bb350ed2fa55f0083a0bff9d1.jpg
External shields refitted after under body prepped and primed. 
20180502_131118.thumb.jpg.2103c2f8b9f01fe67f44fa1e1841af49.jpg20180502_132621.thumb.jpg.4ce50b3be0b2e746cfe9662018500ca4.jpg
20180502_132743.thumb.jpg.a6c846960184a7d519e3b0fd75f5f3fc.jpg
Started install of flywheel / found 350Z pilot bushing would not fit into the crankshaft, so put it on my custom lathe :4_joy: (drill) and sanded it down for a nice fit. 
20180502_155223.thumb.jpg.10bc646375b9fd6e4b5fcebc07d4bc52.jpg
Installing clutch and gearbox today / Will post more photos and an update when its done.  :1_grinning:
Here is a photo of the brake booster and clutch reservoir & lines fitted using all the OEM mounting points this was super simple.
20180502_161034.thumb.jpg.309e2bb46b7aaa6e67310c227bdd2bff.jpg
20180502_161057.thumb.jpg.46bb95840a6caf41589060bd68bae009.jpg
 
Tunnel Build notes: 
  • My mate and I both agreed after completing the tunnel job, cutting the lip to fit the gearbox would have been a lot easier.
  • Ill be a lot happier knowing the handbrake mount is correct ( I've heard some horror stories [emoji14] you know who you are)
  • This job will probably turn you into a heavy drinker. 
  • CVT tail shafts are not compatible with the 6MT 350Z driveline couplings. I ended up having to order a 6MT Diff too.$$$
MORE UPDATES SOON!
Nice work Man...Once gear selector shaft has been unbolted (10mm sockethead)under square rubber grommet. Nothing should restrict the gearboxes installation. Did you manage to get 6mt crossmember support with gearbox or are you going to tap &dye new thread on current crossbar?

Link to comment
Share on other sites

UPDATE 03-05-18
Tunnel final prep completed and TIG welded into vehicle .
20180430_160134.thumb.jpg.6a96c5c6521dbe7e7baf8ad37977f46d.jpgTIG welding20180502_130619.thumb.jpg.f3c0926205b616c2e829f1fd84acb175.jpg20180430_180746.thumb.jpg.cfd0d4ca9c57e5e33858d607fcb544b7.jpg
Seam sealer applied for that OEM seal and look , Also primed and ready for reinstall of interior.
20180502_124831.thumb.jpg.89db59066c2bc06dbf3359998a22229e.jpg
20180502_162228.thumb.jpg.05c9a66a7d8b109f9506a25ad246da0b.jpg
20180503_121614.thumb.jpg.80e9618bb350ed2fa55f0083a0bff9d1.jpg
External shields refitted after under body prepped and primed. 
20180502_131118.thumb.jpg.2103c2f8b9f01fe67f44fa1e1841af49.jpg20180502_132621.thumb.jpg.4ce50b3be0b2e746cfe9662018500ca4.jpg
20180502_132743.thumb.jpg.a6c846960184a7d519e3b0fd75f5f3fc.jpg
Started install of flywheel / found 350Z pilot bushing would not fit into the crankshaft, so put it on my custom lathe :4_joy: (drill) and sanded it down for a nice fit. 
20180502_155223.thumb.jpg.10bc646375b9fd6e4b5fcebc07d4bc52.jpg
Installing clutch and gearbox today / Will post more photos and an update when its done.  :1_grinning:
Here is a photo of the brake booster and clutch reservoir & lines fitted using all the OEM mounting points this was super simple.
20180502_161034.thumb.jpg.309e2bb46b7aaa6e67310c227bdd2bff.jpg
20180502_161057.thumb.jpg.46bb95840a6caf41589060bd68bae009.jpg
 
Tunnel Build notes: 
  • My mate and I both agreed after completing the tunnel job, cutting the lip to fit the gearbox would have been a lot easier.
  • Ill be a lot happier knowing the handbrake mount is correct ( I've heard some horror stories [emoji14] you know who you are)
  • This job will probably turn you into a heavy drinker. 
  • CVT tail shafts are not compatible with the 6MT 350Z driveline couplings. I ended up having to order a 6MT Diff too.$$$
MORE UPDATES SOON!
Changing of the different is well worth it for diff\gear ratios.
Link to comment
Share on other sites

Update 07-05-18

Installed:

  • Clutch
  • 6MT gearbox (woooooooooooooo)
  • I had the 6mt 350z crossmember to fit (installed)
  • short shifter assy
  • rewired harness (sorta)
  • driveshafts (350z) bolted straight in no problems with 6mt diff
  • 6MT LSD differential (replaced the CVT one to due different coupling at pinion flange at rear) 

Nothing needed modifying and all was easy fit as part of the conversion. EZ PZ

Interior reinstalled:

  • Carpet, trims, seats, consoles, shifter trims etc.

Nothing needed modifying and all was easy fit as part of the conversion. EZ PZ

CVT-8 Startup Woes!

Ok so I bypassed the relay to switched ignition (PIN 43 or 53) Grey with Red Stripe. It was then able to crank but didn't fire. This is needed to be done for the clutch safety switch / starter relay.. its well documented elsewhere.  

I figured out it wanted to be in neutral for engine start. In doing this I have found an easy fix for reverse lights including the OEM beeps. I have a couple of the CVT's lying around so I used a damaged plug so I didn't have to hurt my good CVT so I can sell it. 

we will now refer to it as "RIZZAS CVT PLUG MOD" .

Remove old CVT shifter selection switch on side of the old gearbox. EZ

Chop that off as close to the unit as you can for maximum length... oh yeh :4_joy: ...

Green is for reverse - wire it up to your reverse switch and coming out with switch run it to the other black wire

Blue is for "N" neutral - solder it to the other black wire permanently.

Plug that bad boy in and wire up your reverse switch, and have a beer. Hells yeah nearly done. 

You will now have "N" on the dash selector, you can proceed to tell people it stands for "Nissan" or something :P:P:P

I do have the 6mt cluster / harness / ECU but im kinda over it all now and its running the way I have it so time to fill up the oils, service her and test drive. 

20180506_180317.thumb.jpg.4a2b739525e1b0d65f77d84beebce559.jpg

20180506_180327.thumb.jpg.6fb70c5e94a7460047bd5698bd8fd1d8.jpg

 

Having problems bleeding up my clutch but it was getting late and ran out of fluid, Ill do a final post for you all with anything else Ive missed. Thanks for reading I hope that I have helped as many people as I can who are looking to do this conversion. Hit me up if you have any questions. :D Cheers to Addski & Padlock , Thanks for letting me sound ideas of you and your advice and input.

Ill see any perthies on a JDM meet somewhere come say gday

Edited by RiZZa_AU
  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share



×
×
  • Create New...