4 replies to this topic

[Covert]

Need new valves and guides on my 11 stud 12g940 head, its already had a load if porting work , but will still need proper refurbishment by a professional ie skim, cut valve seats etc etc


Is the valve guides something i can do with a workshop press ?
Any special tools needed?
I understand the new guides have to be set to the correct depth
Any guidance happily accepted !

Edited by Covert, 14 November 2015 - 08:19 PM.

[Cooperman]

The guides have to go in so that they sit at a set height above the head level. Best way to ensure this is set for all valves equally is to make up a steel tube of the correct length with an internal diameter just slightly bigger than the outside dia of the guides.

Then, using a bench press, press the valves in until the steel tube stops the valve guide from going further. That way all will be identical. I use a short bolt with a washer under the head to sit inside the guide and this prevents any possibility of distorting the top edge of the guide when installing it. Lightly grease the guide before installing to help with the pressing-in.

[Covert]

Thanks Cooperman , makes sense now , just found this video which makes me visualise what you mean .

[Cooperman]

Not seen that before, but it's exactly what I do except: I would never use a steel hammer to start the guide into the head, a copper or plastic faced mallet is what you should use and, secondly, I press them in rather than use an air tool.

You need to ream the guides at 9/32" after fitting if they are the iron guides. If phos-bronze or manganese bronze check that the valves will run freely.

Personally I use the iron guides because I've had the valves bind when using manganese-bronze as the engine heats up, even though they appeared to run freely when assembled at cold.

[Covert]

Is it true i cant use stainless valves if i use the iron ones ?
Thanks again for all your help