The Craftmans Shop > New from Old
Resurrection of a CFEI 100 KVA Induction Furnace
awemawson:
As I have no model number for this pump, just Dorman’s part number, finding spares is not easy. I’ve measured the body of the pump it's about 58 mm but 'rebuild kits' on the web show a smaller diameter body.
I laser cut a pair of 0.4 mm fuel and oil resisting paper gaskets, but wasn't convinced that they'd have sufficient give. Also rather oddly the central pillar on the pump into which the cover retaining screw fixes protrudes a few thou higher than the out sealing rim - maybe the cover has been over tightened? Anyway I rejected the 0.4 mm paper in favour of some 2 mm nitrile bonded cork gasket that I had that claims to be fuel and oil resistant. Now I know from previous attempts this stuff doesn't cut on the laser - it just burns - so it was a scalpel job. But after all it's a dead simple shape.
Anyway I've fitted it, bled down the diesel again and run the engine for a few minutes, and so far no weeps - but I've been here before so I'll withhold judgement for a day or two!
vtsteam:
I've had poor luck with my own made rubber/cork gaskets they seem to deteriorate fairly quickly. I don't know why. May be the quality of the material I've bought locally.
Andrew are you sure that's not meant to be more than just a gasket, ie a flexible diaphragm?
awemawson:
Steve I’d had the same thought before I pulled it apart, but the working diaphragm is in the next layer down and sound as far as I can tell. On the far side of that diaphragm are in inlet and outlet valves, this upper chamber being an inlet reserve.
If you look at the exploded diaphragm above it’s all explained I think. Part #10 is the working diaphragm.
I went out just now to check, and it’s dry as a bone I’m glad to say. It’s pretty good quality gasket material with cork bonded together with nitrile. You can’t pull it apart by hand. It’s the same material that I used on the housing for the water jacket thermostats and that’s holding OK.
I’ll run the engine for a more prolonged period tomorrow. I’ve a feeling that I have a large Lorry piston tucked away that can be turned into ingots !
vtsteam:
I'm thinking though not the pump diaphragm, it might be a damper diaphragm.
RussellT:
I assume we're talking about part number 4 on the exploded diagram.
If it's just a seal why would the cover need to be that funny shape with an air space under it. Could this be a diaphragm to maintain pressure while the working diaphragm is being pulled back?
Russell
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