Nice work and thanks for chasing up what the primer was.

Out of curiosity, how much extra would it cost to get new valve guides and a valve grind as well as the face cut? i.e. how much extra to have the head reconditioned so it's like new?

Re photos, you have to make sure they're under 200K otherwise they don't upload. No warning or anything it just doesn't work. Generally you need to resize them with something like IrfanView.

And here's a copy of the drawing for the mandrel. The material I used was a 2inch OD 24inch long Aluminium bar. 2 inch gave me a little bit to skim off to make sure it was straight.

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It does have an alloy plate. My vague memory is the guy I got it off thought it came out a corona. Depends what reference you believe, w58 is likely for an early 80s corona but I don't know for sure.

More pictures.

I'll say that there was quite a bit more weld distortion than I expected, maybe I should have done shorter passes, maybe I shouldn't have done the great big fillets in the acute angle areas, instead patching some plate over the top and create a hollow section. You live and learn. It should still work.

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So, over the last few months I have finally made a start to a project that's been sitting on the shed floor for years. Spurred on by the recent purchase of a 200amp AC/DC Inverter TIG. Loving melting metal together.

Anyhow, I started with what I think is a W58 gear box off a 21R engine (21R is stamped on the bell housing), measured, then measured again, then measured a different way and figured out I wanted a bell housing that was 151.1mm long to avoid a spigot spacer and limited spline engagement with the clutch plate. That ruled out any adapter plates as the auto bell housing and the 21R bell housing was too long for this. So I decided a cut and shut was the best way to proceed.

I had some 12mm plate, the 21R bell housing and a seemingly good condition A series box (standard 4 speed). So after more measuring, thinking, measuring etc. I figured I'd add 0.5mm machining allowance, take 59.6mm of the 21R bell housing (gearbox side of course), 12mm of plate, and 80mm of the A series bell housing. Each of the bell housing pieces were roughly hacked off and then taken to the Mill to get a nice parallel face cut at the desired height. (Turns out I needed to machine 1.6mm off and lost another 0.5mm somewhere (distortion is my guess), pretty sure I've got an A series spacer plate or 2 somewhere.)

To hold all of this in alignment I needed a nice solid mandrel. I found that I could get a 600mm 2 inch solid aluminium bar that with a small face cut would be a snug fit in standard big end bearings. I was aiming for 49.994mm but in reality we checked the fit with a main bearing in cap. That held it in the 5 main bearings, the other end we made a tight-ish sliding fit on the input nose of the gearbox since this locates off the main input bearing and is also a pretty snug fit. 34.9mm was the caliper measurement but we snuck up on it until the input nose (removed from the gearbox) was a nice snug sliding fit. (Don't forget the input shaft clearance hole!)

The other trick is the clutch which I haven't done yet and don't have in my note book. I've just got an SR20 pulsar pressure plate and a Hilux friction plate, there will be some flywheel machining and some thinking about throw out mechanisms, I'm think an Hydraulic throw out bearing at this stage.

More pictures to come, the child is awake....

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Is that copper paint on the panels prior to plug welding? What are you using to rust proof the inner panels? (Sorry if you've already said, this threads moving a bit fast for me to keep up with. had a small amount of time in the shed myself.)

Good work, I'm enjoying this build!

Leave it as is. I'll be adding longer runners before the plenum as well.

Nice work! That's some decent W/kg. This thread encouraged me to buy a weber manifold when I saw one come up second hand. Just finished boring it to weld in the injector bungs. Thanks for the inspiration!