TR2/3/3A Decarbonizing a head

[sp53]

Decarbonizing a head, I see there is something in the factory service manual about decarbonizing the head, but it would be a first for me. I guess I need one of those valve spring compressors and a way to organize and keep separate the valves and those 2 little keepers. It looks straight forward, but I am not sure how aggressive I should be. I have seen pictures about lapping the valves with some kind of compound, but this head was rebuilt at a machine shop (which has moved) and only has a few hours on it. I must say I think there is a lot of carbon in there for the short time the engine ran. Any suggestions would be helpful.

Steve.

 

[bobhustead]

Your head looks good to me as is. When needed, I use mounted wire brushes (flat and cup) in a drill. With low time on the system, no need to lap or regrind valves unless you actually see a problem. Of course, don't brush the seats or the valve heads unless you are going to do a regrind.
Bob

 

[CJD]

It is the combustion chamber that gets the carbon. For the amount of time you have run the engine, a wire brush would be plenty good to remove any carbon. I would not worry about pulling the valves until you have a few thousand miles on the engine.

 

[sp53]

Thanks guys, the actual valve stem inside the head feels very sticky with a kinda heavy film, but I guess the force of the engine would clean or scape the sticky old fuel away. Should I spray some oil like WD40 inside the chamber to cut sticky stuff? Then on valves faces, how should I clean those? Perhaps scotch bright and soapy water?

steve

 

[bobhustead]

Wire brush is fine on the valve faces you see in the combustion chambers. These things are not delicate. They routinely run at 900 to 1300 degrees and get slammed down on the valve seats 1500 times a minute at 3000rpm. I would not worry about sticky stuff on the valve stems.
Bob

 

[poolboy]

Since you may not have a way to vacuum or pressure test the results of your 'valve job' when you have the valve job completed, put spark plugs back and turn the head upside down, but supported a couple inches or more off the bench top and fill the combustion chamber with rubbing alcohol...If any alcohol drips down a valve stem onto the bench top, that valve isn't sealing.

 

[CJD]

Use carb or brake cleaner to remove that sticky fuel residue. Be sure to re-oil the valve stems afterwards so they are not dry at your next start up.