Dragged out of hiding, I wrote this a couple of years ago after converting my auto 260 to manual using a 280zx gearbox, and since then keep being unable to find it when someone asks how to do it and whats required. This list should have every part required for the conversion, and the steps should hold true for most conversions, although keep in mind my car was a late 260, there may be some differences to a 240.
Thanks to StevoGJ for the photos supplied, and confirmation of details with the late 260 conversion. Anyone who would like to contribute experience from an earlier car would be most welcome.
Thanks also to Lurch for the comprehensive list of donor gearboxes in the thread linked to shortly below.
- You'll need a gearbox. See this thread for possibilities and discussion thereof: what gearboxes fit?
- Remember to get the gearlever with it, or one to suit. The levers may differ between the possible donor gearboxes.
- Manual brake pedal and and clutch pedal (also one of the bolts at the top which retain the pedal, along with the plastic bushes and return spring (See second photo, Step 5, items B and C), you will remove another bolt and spring from your auto brake pedal). 280zx pedals are NOT suitable, 240 and 260 may interchange (unconfirmed)
- Flywheel (bolts to the crankshaft)
- Clutch friction and pressure plates + thrust bearing (usually all in one kit when bought new, I wouldn't bother getting secondhand personally, bolts to the flywheel),
- Spigot bush for the rear of the crankshaft, should be available from the same place as your clutch kit (Brake shops, Repco etc)
- Clutch fork and pivot (if not already in the bellhousing of gearbox)
- clutch master cylinder and the little pin (See second photo, Step 5, item C) that attaches the pushrod to the clutch pedal (NOTE: 280zx master cylinders have the bolt holes rotated about 45 degrees from a 260 one, so aren't suitable. 240 and 260 may be interchangeable - unconfirmed),
Cylinder on the left is a 280zx one, note that it has the mounting holes 45 degrees to the ground, while the 260z on the right has vertical mounting holes.
- Clutch slave cylinder (if it didn't come with the gearbox)
- flexible clutch hose (to go between hard line and slave cylinder, if you get a crappy one a brake place should be able to make a new hose from the sample)
- and either the metal clutch piping, or a metal rear brake line off a zed (can be reshaped to fit, as i did with mine).
Optional parts (Not required to have a drivable car, but recommended)
- Rear main seal for the engine (there will never be a better time to replace it, mostly as a preventative measure if not leaking, and they are relatively inexpensive)
- Rubber boots to seal transmission tunnel around gear lever against fumes, and a bracket to clamp it down. You can probably use a generic brand one from Bursons/Repco/Supercheap etc, or spring for the genuine article (which may not fit so well if you have to cut the tunnel for the gearlever, as noted in step 5)
- Pretty gearstick boot (leather, vinyl etc) to cover the rubber boot, or to cover the hole in the floor if you didn't fit a rubber boot!
STEP 1 - Remove tailshaft, then remove auto (DUH!) Don't forget to undo the torque convertor bolts...
STEP 2 - remove ring gear from back of motor, carefully install spigot bush, after priming with oil (fill centre with oil, squeeze your fingers in on either end until the oil oozes through the porous brass to the outside). If you chose to replace your rear main seal, do that now. Then bolt flywheel on - OBSERVE TORQUE SPECS. Probably wise to have the flywheel machined flat before installing to give a good surface (about $50?)
STEP 3 - Install clutch and pressure plate, making sure clutch plate is properly aligned. Use a universal clutch aligning tool, old input shaft or my favourite - broom handle with electrical tape around it. Also make sure that the friction plate goes in the correct way - most will have 'Engine (flywheel) side' or 'Gearbox side' printed on them. If it doesn't, look and see which way will not allow the friction surface to make contact with the flywheel - that is the wrong way. Generally the side of the plate where the centre protrudes more faces the gearbox.
STEP 4 - Remove speedo drive from the auto, fit to manual box (speedo drives are matched to the diff). Remove the crossmember from under the auto, and fit it to your gearbox. While you're at it, join the two wires together which prevent the car being started in anything other than park and neutral, otherwise the starter motor won't work when you are finished. Make sure you get the correct wires, there should be some for the reverse lights as well (which you don't bridge, simply refit to reverse light switch)
STEP 5 - Install gearbox. With the auto crossmember, it should line up fine. 2 notes here about 280zx boxes, if you use one: 1, The bellhousing bolts need to be longer (Ie: get manual 280zx bellhousing bolts). 2, The transmission tunnel hole needs to be trimmed between 10 and 50 mm at the front edge.
Install tailshaft. Should fit easily.
STEP 6 - Unbolt and remove the cover plate over the clutch master cylinder hole (on passengers side of brake booster). Bolt clutch master cylinder in place.
Master cylinder in position.
Remove the auto brake pedal (bolt (same as A) at top of pedal, and a pin with a clip (same as C) on the pushrod from the brake booster) YOU SHOULD NOT NEED TO REMOVE THE WHOLE PEDAL BOX, as the manual and auto use the same pedal box, just loaded with different pedals. Definitely the case in a late 260, and should hold true for early 260 and 240 (confirmation would be appreciated for the latter two). Install manual brake pedal (reverse procedure)
View of pedal box loaded with manual pedals with no dashboard covering it! A is the retaining bolt (pivot point), B is the return spring, C is the pin which connects to the clutch master cylinder pushrod.
Install the clutch pedal, using the other retaining bolt you got, along with spring and bushes. Fit the pin to connect the clutch master pushrod to the clutch pedal.
Install clutch slave cylinder if it wasn't already fitted to gearbox (Note, bleed nipple must be at the top, otherwise it'll never bleed up). Install hard clutch line (or shape and fit your rear brake line). See note 2 at this point. Fit flexible hose between clutch pipe and slave cylinder.
Image showing clutch master cylinder at top, with hard line running down to the flexible hose which is bolted into the slave cylinder at the bottom of the picture.
Fill with fluid, crack bleed nipple on slave cylinder and wait till fluid starts to run out (hopefully it should run after a couple of drips). Bleed with the help of someone else.
STEP 7 - Check everything is tight, check the clutch freeplay, then start car in neutral, push clutch pedal in and carefully attempt to engage gear.
And that is your manual conversion from start to finish. About a days work if you are mechanically minded and have all the bits when you start.
NOTES: (will update if and when necessary)
1. With the speedo drive gear swap, you may need to knock the pin out of the gears, and actually swap the cogs themselves over - as in fit the auto gear onto your manual speedo drive gear housing, and fit it into the gearbox.
2. If fluid fails to start running out of the slave cylinder bleed nipple, there are a couple of things to try. First, try to avoid having your metal clutch pipe running higher than the master cylinder bore at any point, and also avoid having it go up then down. When you follow the line from master to slave, it should always be getting closer and closer to the ground. Any higher point (especially higher than the master cylinder) can potentially trap air. Second, get a syringe with some tubing or a vacuum bleeding kit, and try sucking the fluid through from the nipple. I have managed to bleed some of the most troublesome clutch lines ever using an old syringe of about 100cc capacity, and heaving on the back end of it to suck the fluid through, and then only got an assistant to bleed with to double-check.
Edited by gav240z, 07 November 2015 - 03:20 PM.
Fix broken image references.