New Zealand Datsun Club

Got the gearbox mandrel back from machining so started the welding procedure. Broke all the tacks from last time and shaved both pieces down a bit, retacked and had a measure.

This process actually takes ages.

I'm really hating welding this stuff. The tacks crack within seconds of cooling even with a preheat, you can actually see the material visibly spring back as it contracts and breaks the tack. The L16 block acting as a big heatsink means the cooling happens faster than
I'd like also.

Got this far before quitting for the night anyway.

Keep at it buddy. Going to be so good.
Can you stick the block in the oven while the misses is out?

So I decided it would be best to weld the inside fully first to try to control some of the horrific cracking on the outside welds for when I get to finishing those. This seemed to work, the whole thing stayed a lot more consistently warm and while I heard a few loud cracks start on the outside, everything on the inside seemed to hold up.

Of course I ran out of argon.

Anyway, I think if I can finish the last short run inside and then die grind out all the exterior cracks I should be ok to put a finishing run on the outside with the jig all set up.

I think I'll try to preheat the bellhousing in the oven first to try to prevent the cracking again.

Progress so far - you can see there's one big gap to bridge still, not sure how I want to tackle that section.

Nice work , do you maybe need to up the welding current to really get some penetration to try stop the cracking

2 doors wrote:Nice work , do you maybe need to up the welding current to really get some penetration to try stop the cracking

Maybe, I was worried that going too hot would be too much of a thermal shock for the casting. Reading online guys were saying not to heavily clamp/restrain the workpiece, but I kind of have to in order to keep it trued up. My hope is that with the inside run finished and lots of preheat I will be able to keep cracks under control for the last outside pass.

A bloke I know who is pretty good with a tig used to use his BBQ to preheat larger items prior to welding them.

Wow just read the build thread, what a thorough rebuild. She's going to be super sweet when finished !

slo_dat wrote:Wow just read the build thread, what a thorough rebuild. She's going to be super sweet when finished !

Cheers mate, I hope it ends up as tidy as yours!

If thoughts were actions this would be done by now. I’ve been poor and had a lot going on lately, but found some time to do the new brake and fuel tubing. I wanted the modern plastic coated tubing that new cars have but could only find it in 3/16” (from Wurth) so started with that and new nuts for the rear brake crossover pipe. Wasn’t sure what to do about the section from here forward to the engine bay - the factory line goes in the trans tunnel but Bart scared me into thinking I won’t be allowed it there for cert, and I’m pretty sure I’m going to have to cut the tunnel up to fit the gearbox also. On to the fuel feed and return pipes - I tried making a cheap bundy straightener but it didn’t really work so I’m just going to deal with having non-show quality bundy tubing. The Datsun metal flaps to hold it are crap though, so I rivnutted the floor to mount these BMW clamps with stainless button head bolts. Ended up with this I’m not a total spastic, the reason it looks all wonky is that one pipe can’t sit down properly due to the factory pipe clamps being in the way. Tried to undo them but they kept spinning and I can’t access the tops. So I tried to slice them with a cutoff wheel and I broke one of the pins on my grinder plug. After that I just had a tantrum and went inside for the night.

Looking good John!

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Lol tantrums are all part of classic car ownership.