skycar

Valve guides and removal on Big 6

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Hello to all here,

My '25 EPK Coupe has a Big 6 engine which I have removed the head, due to a stuck exhaust valve which gave the impression that it was a chaff cutter warming up.

I soon discovered that someone has been in there before me and used their improvised methods to keep the old timer running.

 

Firstly there is 2 (exhaust) valves that have collets as the retention method, as apposed to the hardened pin style on all the other valves.

There is also 3 short valve guides fitted instead of the longer original type in some of these locations, which do not give full support for the travel / lift of the valves.

The stuck valve has had a savage undercut to accommodate the newer valve/seat in the block and needs to be machined out and a new seat installed, to bring it back to the original height....... Approax .300" below original position and excessive corrosion/ pitting evident.

One of the attached pics shows visible valve guide lengths and the adjacent position has a barely noticeable valve guide protrusion,

(where the brutally attacked exhaust port seat is). It's approax 1 inch shorter than the original guides installed.

 

Does anyone have experience with removing the valve guides, what precautions or which method to extract these with (slide hammer after tapping etc) and what is the material used to make new ones, Brass / cast iron ?

Or can I still buy replacement guides?

All 12 guides are suffering 90 years of wear and tear. So a replacement would go well at this point and a lap of the seats etc.

 

Many thanks in advance for any thoughts, suggestions or helpful hints you can offer.

Regards Roger McDonnell 

Brisbane Australia

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