Views on a big valve cylinder head.

swooshdave wrote;

Considering that it's on the intake side and not likely to pass air, is that really a problem?

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At the moment it isn't a problem, but as far as I know, it wasn't evident when I had the head refurbished three years ago by Pete Lovell through Norvil. Assuming the crack is developing, I would think that it will eventually reach the valve seat at some time in the future.

Steve Maney seems to think that this is probably a late head, possibly the original RH4 for my bike as it is a 75 MK3. He said that near the end of production, the quality of the heads was no as good as in earlier production, and that the casting on this head is going to be like "swiss cheese" inside and very difficult to repair.

If I didn't have the other head, I would run it and see how long it lasted, but now, I'm not sure what to do. It cost me more than £500 for a FULL refurbishment three years ago (ouch :x ) If I sell it on ebay, being an honest chap I would have to disclose the defect. I would never sell this without being totally honest, but my worry is that some less scrupulous person who would have bought it for a song, may then re list it as in good nick, which the rest of it is, and pass it on to some poor unsuspecting person for a cheating profit.

]Considering that it's on the intake side and not likely to pass air, is that really a problem?[/quote] swoosh,a head like this will pass air,like a leaking manifold gasket, it could cause a weak mixture on that cylinder,i would have it tig welded on the outside and see how it goes,fill the port with parrafin to check for leaks, reggie,i have had dealings with pete lovell a few times and i think he,s great guy and an excelent engineer,but dont go through norvil,contact him direct,probably 200 of your 500 went to norvil

I agree that it would pass air. At idle and on the overrun the vacuum is very high. It would suck a golf ball thru a 50' garden hose as we used to say.

Russ

chris plant wrote;

reggie,i have had dealings with pete lovell a few times and i think he,s great guy and an excelent engineer,but dont go through norvil,contact him direct,probably 200 of your 500 went to norvil

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Steve Maney didn't think they were weldable without a lot of trouble, but I'll probably email the pictures to Pete in the near future for an opinion about their viability and cost. I have dealt with Pete in my earlier Norton days, and I would agree that he's a good bloke to deal with and knows his Nortons. Three years ago when I was chasing my cylinder head up and speaking to Pete, I gathered in a round about way that it would probably have been cheaper to go directly to Pete.

Thanks for the prompt, it's worth a try.