Blowerman

2 things to try. Make sure your upper rad hose goes uphill to your radiator from your thermostat.
Drill an 1/8 inch bleed hole in the outer part of your thermostat. If you have combustion entering your coolant, this will allow it to purge out from behind your thermostat and allow it to sense temperature from the coolant better. And yes it's a bandaid but it will tell you something.

Jason Hunt

Did this, the temp on the gauge has not changed. The system isnt building enough pressure to pop the radiator cap open. It was running at around 230 for 15 minutes today and didn't burp out an ounce of water

Blowerman

Consider purchasing a kit that will sample for combustion gasses. They're cheap.
Let us know.

pancherj

Since you have a temp gun, shoot the temperature of all of the header pipes (close to the cylinder head). I still think you have a timing/carb issue. You mentioned that advancing the timing at idle helped a little but it would ping at WOT. Do you have vacuum advance on that distributer? At idle/low speed it is going to want something over 40 degrees advance. My 355 with a similar cam and compression runs best at 52 degrees advance at idle and 34 degrees WOT. My mechanical advance is limited to 14 degrees.

Jason Hunt

Shot the headers with the gun, all are within about 20 degrees of eachother between 220-240 degrees at idle. Today I took the bowls/metering blocks off the carb and couldn't find any blockages. Upped my primary jet by 2 sizes with no change. Also reprogrammed my timing to 20 initial/36 total, not really much of a change. I did manage to get the idle vacuum up to about 10 psi by playing with the carb.

Jason Hunt

Going to rent the tester from Oreilly's tomorrow, I've just been putting it off because it seems odd that when running at 230* the radiator doesnt burp ANY water from the overflow hose. I drove it probably 100 miles today and didnt lose a drop of water from the radiator, temp was sometimes creeping up to the 230-area. I would think if it were getting combustion gases in it that I would see it in the compression, or excess pressure/coolant loss in the system.

Blowerman

It could be frothing up the coolant and won't necessarily push coolant out.

FU_I_AM_UltraZ

iTrader: (20)

not sure if it was said yet as i skimmed thru the replies...
have you checked the t-stat to make sure its not stuck?
be rad cap or cap for wrong psi? wrong pressure in the system would prevent the flow from what i was told. i had an issue once on my 98 t/a and replaced t-stat and rad cap and problem went away.
also, fans kicking on?

sowbelle

Also, have you checked your lower radiater hose for obstructions and separation.
I had one that separated inside and restricted flow through the engine. and is the hose reinforced? Meaning, it is not collapsing at any time.
I noticed that you say engine temp is 230 but radiater temp is 130. Where at in the radiater is it 130? Top? Bottom?

darren roar

iTrader: (1)

I'm having trouble with my 355. This will sound dumb I think. I put a later model serpentine belt system from a 90's truck on it and the same year water pump. Do I need an older water pump? It overheats almost immediately. I also have my temp sensor in the head, should I put it in the intake? Could it be my heater core because the heater hose is hot and the upper radiator hose is warm?

SLOW BOAT 71 :-{=

Like Jimmy blue said look at your head gaskets. You might want to drill the steam holes to 1/4 " hot aluminum heads will make steam quickly.

alex722607

iTrader: (4)

That's what I am doing. I gave up on my gen 1 sbc only because it always ran with 305 electronics, was a rebuild to start with -- 20 years old, and now am having starting issues. I decided it was pointless to continue pouring money into an old engine and upgrade.