| Author | Topic |
|---|
Location:
Lost in the K hole
Registered:
May 2002
|
|
making custom valves...
|
Tue, 24 December 2002 08:13
|
 |
just had a whacky idea::
ive got a TON of spare 7m valves lying around (32mm in, 28mm ex) and was considering a cheap way of bumping up the exhaust valve diameter 1mm...
can i machine (lathe) 12 spare intake valves (32mm) down to 29mm and use them as +1mm OS exhaust valves?? of course ill have to get the valve faces cut (was going to have to get the stock ones done anyway) and make sure the transition from the rear of the valve into the seat face is smooth... but is there anything amazingly stupid that im overlooking here? (yes the stem lengths are identical)
the existing valve seat inserts in the head are 29mm wide, and being cut presently for 28mm valves, theres plenty of spare material. is it ok to have the valve seat 45 cut made right to the edge of the seat insert (i would have thought so).
shrouding doesnt seem to be an issue, as the 29mm vlaves dont occupy much space...
anyone see anything qrong with this picture??
cheers
ed
|
|
|
Location:
Wollongong
Registered:
May 2002
|
|
Re: making custom valves...
|
Tue, 24 December 2002 08:51
|
|
Some valves are hollow or sodium filled. Machining them down would make them weaker and more prone to failure. However, I have no idea if 7M valves are hollow or solid.
Bear in mind, I know bugger all about valves, so I could be totally wrong.
|
|
|
Location:
Newcastle
Registered:
September 2002
|
 Re: making custom valves...
|
Tue, 24 December 2002 13:15
|
|
|
If you have a heap of them spare then get one machined down and check if it is hollow or not, or you could just cut one in half to check.
|
|
|
Location:
Lost in the K hole
Registered:
May 2002
|
|
Re: making custom valves...
|
Tue, 24 December 2002 14:11
|
|
it seems that the intake valves are two piece construction, non stainless steel, whereas the stock ex valves are exactly that. im getting a funny feeling that non SS 2 piece constructed valves wouldnt last too long in an exhaust port...
ed
|
|
|
Location:
North Sydney
Registered:
May 2002
|
|
Re: making custom valves...
|
Wed, 25 December 2002 01:01
|
|
|
Putting intake valves in your exhaust side usually burns them out extremely quickly. Different grade and manufactured material.
|
|
|
Location:
Hornsby, Sydney
Registered:
October 2002
|
|
Re: making custom valves...
|
Wed, 25 December 2002 03:12
|
|
|
after machining you would probably have to get them re case hardenned other wise they will wear out within no time. id imagen it would be cheaper to buy oversized valves depending on the engine and parts availability.
|
|
|
