Slow progress is progress nonetheless. I have made the sensible decision not to stress out and try to get this engine swap in for oldschool nats (our version of the retrorides gathering- but waaaaaaaaaaay more 'tightknit') That was a big carrot to aim for but its not realistic now. There are far too many other jobs going on with our landscaping etc plus several family members are coming to stay over the next couple of months and we both want to enjoy some holiday time.
I think the main reason though is that I know how stressy its can be trying to rush a project and suddenly the fun has gone and corners start to get cut. If I take my time and work on it when I really want to then it'll be better for it.
All that aside- I have still been plugging away on it and today it rained all day so I had no excuse but to stay inside and finish off a long tedious, but satisfying, part of the conversion. The exhaust headers.
But before I delve into that part there's some other bits that have happened.
I blew the dust off my bank card and bought an spendy shiny part of the project.
Yay. I got it while they were still on sale and it can now sit in the store room to collect some dust.
Another thing that I had to spend some money on, as mentioned in the last update, was to get this lot balanced..
I made some inquiries about and found an outfit very well recommended by many down in Christchurch. The owner Evan was very helpful and managed to fit the job in to suit my brothers trip south - saving plenty on postage!
I whipped up some sturdy wooden boxes to suit and away they went.
A couple of weeks later my brother returned them to me with a properly balanced assembly.
They'll stay stashed away safe until I can assemble the crankcase- which really is just waiting on me to give the pistons a clean and make some custom ring compressors similar to the honda items for assembly of the two halves. More on that later.
Back to that exhaust thing. I looked at various options for how to go about making some headers with compact enough bends to suit. Kept coming back to getting some bends and piecing them together bit by bit. I decided that with the tighter bends I knew I'd end up with that I would go up one size, 28mm, on the header tube diameter to help keep the flow nice.
The maths works in my head so I'll go with it. Really all I need to do is get the hot stuff out of the heads and out the back.
Priced up various bends within all the NZ suppliers I could find. Horrendous prices. Did an order through Ali express for a load of stainless bends of which arrived 10 days later - a nice surprise.
They'll do fine.
Plasma cut some flanges to suit a jig I was going to make - exactly like I did on my Viva V6.
Machined a little sleeve so my holesaw would take a tiny drill bit.
Then I made lots of holes.
The bits that the holes gave up (wooden marshmellows) were pushed onto equal lengths of tig rod which had been welded to the centre of each exhaust outlet area on the flanges. I was then able to bend them to suit and mock up my exhaust header runs. From what I have read it was not strictly needed to try and match the primary lengths on a flat six as there is nothing really to be gained. But it cant hurt to keep them matched so that's what I did. I wanted them tucked up away with no chance they can get smacked on anything and made sure I could get to the oil filter easily.
Now I knew what I was going to build I had to copy them with this lot..
I cut the remaining stubs off the old header flanges and tacked in some short bits of stainless tube..
I started to tig them in but the steel on the flanges was really odd and did not tig weld at all nicely. The arc was all over the place. Maybe magnetic? What ever it was it had me stumped. I ended up mig welding them - heaps of weld which I then ground down with a flap disc.
Now onto building the runners up. This is the first time I have made any headers from stainless steel and I wasn't going to take any chances with oxygen affecting the back of the welds ('sugaring') so leading to potential weakness or cracking. So I would have to purge the inside of the tubes with argon. I didn't have a suitable purging setup and buying the bits was a bit too spendy for my liking. Instead I rummaged through my box of old brass fittings...
dug out an old argon regulator and removed one gauge. Bought some vinyl tube ($7 ...big spender) and cobbled together something..
I needed something to plug the tube ends quickly and easily. I'd seen many people using tinfoil but it looked awkward and leak prone. I made a mold using a bit of tube the next size up, a bit of wood, a bit of copper tube and some grease.
Filled it with budget bathroom silicone sealant. out popped some plugs which I shaped to a taper in the lathe with a flap disc. Hey presto- heat resistant tube plugs...
Tee'd a line off the main feed to the welder. It worked a treat. I'd set the main regulator on the bottle to flow a bit more and then set the extra reg to flow just enough. I would then set the actual flow rate through the tube using the little brass tap so I could just hear the gas flow through the tube..
I was very happy with the way the welds on the inside of the tubes stayed so smooth and clean. No yucky porous flaky crystalised welds.
But there was nothing I could do about the appearance of my welds on the outside. I really can't make any excuses - I'm just not not experienced enough at welding stainless tube. So my welds here I shall call functional. I'm not even going to bother trying to clean them up. All I wanted was decent penetration and strength.
My welding did improve over the duration of building these. There were glimmers of neatness...
I had to use a foot pedal again- something I had stopped using years ago because its a hassle when building awkward furniture, kitchen framework jobs etc - which is the most common thing I use the DC for. I got used to the pedal again and started spotting where I was going wrong. Mainly my speed and feed technique required was too slow- (the tube I'd bought was 1.2mm - a bit thin perhaps but all I could find in this diameter). I bought a bigger shroud for my gas lens which helped too.
So yeah - I'm afraid there will be no welding porn with these headers. I will cunningly take my photos from a distance
I got tired early on of trying to hold bits of tube awkwardly in the vise to weld them so I built this little tool..
and bits of wood turned down to locate tubes to bends for mocking purposes..
plus a jig on each side to build towards and make sure the ends align with where I wanted them to head..
things took shape and I enjoyed the process...
Finally today I finished the last bits. I will now have to make up a couple of reducers/collectors to suit. They will feed into a V band flange, then a flexy joint on each side, then straight back to a large silencer assembly mounted across the back, pretty much like an early 911 has.
For now though I'm just very happy to have some headers built that from a metre away look quite fancy
...
They sit nicely on the engine. I'm not sure if I'll use any heat wrap as I have always done in the past - I'm a big fan of it (opens up a pub debate..) I'll have to see how they go.
Next thing to look at is finishing the water pipes. I'd also bought some smaller stainless bends for that but now realise I'd not bought enough. Ho hum.
Maybe I'll find some under the xmas tree (red and white striped)
