RICHARDHUMBLE wrote:Shug wrote:
The head doesn't eat itself.
Hmm, are you thinking of my "Special" or the standard?
Special isn't far off, no sign of porosity yet and I have nearly finished! I'm not sure about one of the valve seats (1mm, got a bit heavy handed with the grinder...
) or the cut down valve guides. Might just have a go anyway. Pretty sure all that will happen is that the valve stems will wear a bit more than normal. Afterall it's only a HG and a few ancillaries to swop back over DIY.
Is this a sh*t idea?
TB is standard ATM but will follow the 52mm eventually (56mm?).
Rich
(I am not a mentalist)
I thought all this guff was for the 'special'.... The porosity might not show until it's had a few heat cycles - when Stu skimmed a few heads for me, you could make out wee dots in the mating faces, but I think Stu's kit for skimming is pretty accurate.... The one that was originally fitted was fine for about 30K (in standard form, it was the original head) and only went with the additional heat of the 160odd bhp it would have been running at the time it let go. The failure wasn't near any of the machining.
Not sure what running cut down valve guides will do, might be worth emailing Dave Andrews - he's really good at answering specific questions.
Like you say, it's not the end of the world if it goes and you'll have a complete standard head sitting there to get you running. Might be worth having a look at the state of my guides (bronze colisboros) in the old head, as I'm sure it's just the seals that are junk. I could let you have them for reasonable cheapness if you could get them out without killing the head (as I might yet resurrect it it some form...)
Load of hassle though, if the cut down originals will work.
BTW, I think I've got a 52mm TB kicking about (TBH, I'd have to measure it, as it might just be a 48mm ally one) if you fancy it to go with the manifold - one less constriction and the engine could probably make good use of it....
