Group head purchase? Ebay
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,266
Likes: 0
From: Allen, TX, USA
Group head purchase? Ebay
http://cgi.ebay.com/ebaymotors/ws/eB...ndexURL=0&rd=1
How can you tell if a valve seat has receeded? I hear this is one problem
to watch out for. But how far do they really receed? If it's receeded
you can put a larger valve, correct?
Safety Car
Joined: Jan 2000
Posts: 4,143
Likes: 0
Re: Group head purchase? Ebay (adam)
Hmmm... not sure on this one but I'll give it a try.
To my knowledge if (2) or more are badly receeded then you need to 'mill' the surface instead of using larger valves....(larger valves will cause clearance problems btwn. intake & exhaust valves plus the webbing in btwn will be prone to cracking - less than a dimes thickness is a 'bad' thing !)
However, be aware that these are 64cc and you can't mill them too much or else you'll wind up with 60cc and the valve clearance will be crucial. I once had a set that barely cleared the pistons with a 'stock' cam 'cause some idiot over-milled them.....not to mention that less than 64cc is gonna give you a very high compression like 11.5 to 1 or 12 to 1 depending on your setup. :yesnod:
To my knowledge if (2) or more are badly receeded then you need to 'mill' the surface instead of using larger valves....(larger valves will cause clearance problems btwn. intake & exhaust valves plus the webbing in btwn will be prone to cracking - less than a dimes thickness is a 'bad' thing !)
However, be aware that these are 64cc and you can't mill them too much or else you'll wind up with 60cc and the valve clearance will be crucial. I once had a set that barely cleared the pistons with a 'stock' cam 'cause some idiot over-milled them.....not to mention that less than 64cc is gonna give you a very high compression like 11.5 to 1 or 12 to 1 depending on your setup. :yesnod:
