Injecting, the remedy

Well, it worked, sort of, well not really but.....



OK let's go through it - O rings in the inlet manifolds. 

This didn't go well, the O rings, despite being heat and fuel resistant Viton material, deformed. The machining came close to the edge of the manifold and we lost a bit, it sort of blew out. It was a bit think before but now, it's gone.


We were aware of how close the groove had been machined initially and were almost expecting this. The O ring failure however was unexpected. I've researched other materials and I did find some that would work but at over £100 per O ring I just didn't feel we should go on. 

All in all, a bit of an expensive fail but I hope we've come out the other side with a decent result.

So, plan B - return the manifolds to flush fitting with some suitable epoxy metal and use a conventional gasket, maybe with some high temp RTV to ensure a full and durable seal.


The reason that we took the inlets off was not to examine these O rings, they were doing OK. No, it was to drop the exhaust manifold in order to weld in a boss for a lambda probe. The idea being that we'll add an AFR gauge. If we also add in a vacuum gauge then together with the existing fuel pressure gauge we have enough data to effectively tune the PI on the road. This car is being built to go up mountains - more on that in later blogs :-)



Because the exhaust is mild steel and been on there for 25+ years, it's pretty well stuck on there. I decided that it was not worth the risk of damage to pull it completely off. James said he could weld the boss by dropping the exhaust but not fully removing it. So that's what's been done - it was still too tight to get a welding mask on whilst doing the welding! He did a decent job despite some difficult conditions.

I now need to try and find a suitable AFR gauge, a vacuum gauge and a place to put them. The current pair of SPA digital gauges are really nice but there's no real space there to slip another one in without some major surgery. 


Might have to go into the dash 😮


So, does it all run OK now? Dunno yet! 


 

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