All Small Six Engine will die after higher RPMs.

[1964170ci]

Hello Everyone, I have a semi heavily built 1965 dated 200CI block. My modifications to the engine are as listed
Holley 2bbl 350 cfm carb
Clay smith H274 8 b cam
DUI elec ignition
Summit racing headers
And a 10:1 compression ratio.

After around 15 minutes of driving the car prior to reaching operating temperature in the higher RPM band the engine will cut and will not want to start for around 3 minutes after cutting out. I have theories of possible over heating , lack of fuel flow (still on mechanical fuel pump) or loss or oil pressure. I do not have a working engine temp or oil pressure guage installed however while idling and light pulls a handheld oil pressure guage reads around 45psi. Any guesses.

 

[B RON CO]

Hi, did you check for spark at the plugs and fuel in the carb? If you have spark see if the accelerator pump squirts or if the fuel pump will fill a coffee can with the fuel line removed from the carb. My guess is you are losing spark. If you have a tach I would remove the tach wire from the coil for now. Good luck

 

[1964170ci]

Hi, did you check for spark at the plugs and fuel in the carb? If you have spark see if the accelerator pump squirts or if the fuel pump will fill a coffee can with the fuel line removed from the carb. My guess is you are losing spark. If you have a tach I would remove the tach wire from the coil for now. Good luck

Thank you, I will try these and let you know.

 

[drag-200stang]

What I have learned after 50 years of hot roding 200's is, If you think that it is fuel related it is probably ignition, and if you think that it is ignition related , it is probably fuel.
It would not hurt to check the ignition switch. Good luck.

 

[wsa111]

If you have spark, & think it maybe fuel related, check the vent on the gas cap. When the engine dies out & remove the fuel cap, if you hear air rushing in that might be you problem.
X2 on all the above posts.

 

[1964170ci]

Thanks everyone I'll definitely look into the spark and open the gas cap. It'll probably be a week or so ill be on vacation. When I get back I'll probably take it to an abandoned municipal airport to look into it better

 

[mustang6]

One way to check for fuel starvation is to install one of those see-through (I prefer the glass bodied) fuel filters. They don‘t completely fill up in normal operation, but you can definitely tell the difference between where it normally runs and fuel starved. when it won’t run, just pop the hood and look.

 

[wsa111]

If you have fuel starvation, also the sock filter on the sending unit in the fuel tank could be clogging. Ethanol fuel is very harsh on old fuel systems.

 

[woodbutcher]

Have you tried a known good coil?The symptions sounds like the coil is about to go belly up.When a coil warms up the resistance goes up,and will eventually stop electrical flow.And please don`t ask me how I know.
Good luck.Have fun.Be safe.
Leo

 

[escaper]

I forgot about that little tidbit. Happened to me about 40 years ago.

 

[wsa111]

Heat the coil with a hair dryer with engine at idle & see if it fails???

 

[chad]

200 just back in?
What wuz the break-in like?