Britbike forum
Posted By: 68triton Oversize Inlet valve (DBD) - 04/28/20 1:23 pm
Hi Guys, I have acquired a cylinder head with a bent inlet valve due to spring failure, the valve is 100 thou oversize (1.950") and the valve seat was just recut to suit this valve. The valve is also slightly longer in the stem, but same diameter.
In the UK I have tried the usual Goldie suppliers and a few racers , but none available. Is there a supply in the states?

There was a batch made by G and S Valves some years back and they have a drawing, the firm are in my neighbourhood, but it will cost me £300 for a 1 off.


Posted By: slow learner Re: Oversize Inlet valve (DBD) - 04/28/20 5:15 pm
Local to me famous Gold Star guy Jim Hunter always used cut down Chevy valves for inlets. Also, would not use a head diameter bigger than standard as they were apt to tangle with the exhaust.
Posted By: 68triton Re: Oversize Inlet valve (DBD) - 04/29/20 11:33 am
Yes, it's all getting very close. The racing boys over here have used a modifield Velo Thruxton inlet, but that almost certain requires different cam set-up.


Posted By: DMadigan Re: Oversize Inlet valve (DBD) - 04/29/20 1:52 pm
The IHC 8.7L 12 valve diesel tractor intake valves are 1.970" diameter, 0.3124' stem, 5.789" long, 60degree seat.
IHC Navistar/heavy duty 7.6L turbo diesel uses the same.
If you can use a slightly smaller valve
Chrysler 8.0L 20 valve VIN W "truck" 1994-2003 has 1.920" head, 0.3115" stem, 5.728" long, 46 seat.
Chrysler 5.9L 16 valve VIN 5, Z 1989-2003 has 1.920" head, 0.3115" stem, 4.906" long, 44 seat.
5.2L VIN Y 1988-2003 and 3.9L VIN X 1988-2003 uses same.
More at 1.91" and 1.89" head.
Posted By: hunter h Re: Oversize Inlet valve (DBD) - 04/29/20 4:33 pm
cheers to all just putting my 2cents in but why not just have a stock size seat put in . which would need a oversize O D . then you will be able to use sock valves. just give Phil a call and let him make it right. h
Posted By: 68triton Re: Oversize Inlet valve (DBD) - 04/30/20 3:34 pm
Thanks, I have spoken to PP and other Gurus but no stock (as per my original post). There is cost involved with new seat and I think that is the way it s going, however the big valve with touring cams pulled really nicely, I do not have the exepertise to move away from the main specification to much and it seems that an oversize valve can cause problems.

Posted By: 68triton Re: Oversize Inlet valve (DBD) - 04/30/20 3:38 pm
Thanks, There is a few valves there! I have another set of engine cases and parts to build another engine might experiment later. Keep up a the good work on the triple parts I have 2 MK1s.

Posted By: DMadigan Re: Oversize Inlet valve (DBD) - 05/02/20 1:12 am
Manley lists some 1.900" and 1.920" intake valves with 0.311" stem, also 2.000", 2.020", 2.050" with 3.125" stem
© Britbike forum