Overheating Flathead

[FlatheadTed]

X2 ,on the Radiator
.try another Radiator shop for a 2nd opinion I would say its blocked /flow restricted .You could add a shroud that will pull the tempt down ,this may be considered a band aid though .
boiling noises. The radiator has been flow tested twice

 

[aussie merc]

just guessing but have you checked the opperation of the advance plate in the dissy you said its timed correctly but whats happening as the revs vary ive got caught big time thanks to mine going nuts sometimes it would work sometimes it wouldnt talk about chasing ghosts

 

[Ggmac]

Any reduction in performance just prior or during the overheat? I was thinking of checking the exhaust for blockage . A vacuum gauge would help eliminate a timing , blockage or valve problem . You should have a steady needle between 18-20" .

 

[AnthonyG]

I had similar issues w overheating and losing water every 2 or three times i took it out. I noticed vapor in the exhaust on the right side, have dual exhaust w no crossover. tightened / re torqued, head bolts improved for a while. Same thing started again, researched & found many were using aluminum powder or copper powder in radiator / engine indicating it would seal the leaks and hold up to pressure. Again worked ok for a while but started again. finally took the right head off, gasket looked fine but I could see evidence of steam moisture stained the #4 cylinder walls. could see a path of the stain and a bit of rust in one of the head bolt holes. builder must not have used enough thread sealant and gave water a path from that hole to valves so I believe most was leaving the engine as steam. Oil has water in it on each occasion after 'Wish Fixes'. Ran a chaser bolt thru all the head bolt thread holes, cleaned all on that side well. cleaned threads on head bolts, carefully used non hardening sealant on head bolts, snugged but under torque, let sit overnite, torqued, no prob's after.