Karsten - Seagrave

Seagrave 16000 ccm speedster

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Nice update, Did you build a complete new driven sprocket of machine of the teeth and weld on a new sprocket gear?


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The bigger sprocket is a new part  manufactured and hardened on the older ones basis. No weldings as it is a security part that transmits the brake power from the drums installed on the same drive shaft.



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Starting  to do maintenence on the F6 engine I discovered that some valve guides are burned. One valve has a 3 mm long fracture on the shaft. Does somebody have information about the valve guide material and if the fracture is to be considered to become a valve failure, breaking appart?




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I am not familiar with Seagrave motors... however, my assumption is the valve guides are either screw-in or pressed in.

I would replace them given the condition and the fact that they are all probably well worn from years of use.


If they are pressed they can easily be pressed out. If they are threaded than I would suggest boring them out

until the remaining shell is thin enough to break-up and remove.


For material - that's a no-brainer - good old grey cast iron.


While your at it I would look into either doing a complete re-build of the original valves (grind stems etc. and

ream the new guides to compensate) or find or fabricate new valves.


I went through this whole process a few years ago with a big 18 liter Wisconsin T-head. I had to replace all the valve guides

and fabricate new valves.


The valve guides we machined out of grey cast iron. Since I could not find replacement valves I ended-up using a wonderful

set of blanks intended for EMD diesel locomotives. These were stainless bi-alloy (one alloy for the stem, another

for the head). After turning the head to the proper 2-5/8" diameter, cutting the seat, keeper slots and to length they came out great!

However, the original stems were .500" dia and the new stems were .577" dia. That wasn't a problem because we simply

reamed the new valve guides to fit.


I believe on the valve guides I held .002" clearance on the intake side and .003" on the exhaust.



New valve guides




Valve blank a received from Carl M. Cummings Manufacturing



Turning to size and cutting the seats - we also used a tool post grinder on the seats as well.



12 new valves, 12 new valve guides all installed









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