26 tourer, hasn't had prolonged running for 60 years. Cleaned out radiator and block, ( head off),pistons feel OK not much play and no discernible ridge in top of cylinders, faced head, re-seated and lapped in valves, re-kitted carby, new commutator and loom, new plugs, disassembled muffler and ran wire up exhaust pipe to make sure no restrictions, starts and runs on coils and magneto, got it jacked up on axle stands, but after 5 minutes or so can see the exhaust and end of manifold starting to get red glow and that worries me... any ideas?
The spark is likely too far retarded.
Ron the Coilman
That is what I had happen the first time I ran mine, I did not advance the spark and it got red hot real fast.
If advancing the timing doesn't cure the problem (but it really should), try enriching the fuel mixture.
Check for any leaks around the intake manifold. Intake leads will lean out the mixture and cause the engine to run hot.
By the way, ridges does not form in Model T cylinders with original pistons. The cast iron pistons has wide rings that goes all the way up to the deck plane at TDC so there's no chance for ridges to form. I was surprised many years ago when I found std alu pistons at a swap meet and tried in my engine I thought was fairly unworn since it didn't have any ridges - well, lots of play & I still haven't found use for those pistons.
Tony, just checked your profile. Get a hold of Frank Van Ekeren... you can search him on the forum, or PM me and I will put you in touch.
Thanks all for the replies.. had to adjust the rod length to the commutator and gave it a run. seems to have made a difference. Interesting comment re the ridges Roger... another bit of knowledge to store ..