break-in overheating, Help

[Sammys70]

just searched some old threads but wondering if you guys could come up with other ideas or point me in right direction
heres what i have:
new basic gm crate 350
comp262 cam with 981 springs
duel electric fans
180 themostat that I drilled two small hole in and bench tested !
I manually am turning on fans before I start up!

now trying to break in cam but as I get to 5min or so it overheats
seems like i'm getting flow in radiator
radiator tanks are hot, but I get hold my hand on front of radiator
lower hose is hot but I can touch
top hose is hotter than hell and very firm

I'm leaning towards air trapped in system but feel like I should have got it out by now

gonna try running without thermo tomorrow

any other advice would be nice, I can't wait to drive it!!!

[hotroddin]

Air in the system. Take your thermostat out and fill from there, leave the radiator cap off as well.

[FirstOwner69]

Overheats as in the gauge says it's really hot or does it boil over? Just a reminder that the stock radiators without an overflow tank are to be filled only to about 3" below where the cap seals.

[Sammys70]

Definitely overheating, only had light go off once and that's when I pushed it trying to get the air out that I still think I have.
Just finished taking thermostat out and will leave level down a bit
Gonna try tomorrow

[FirstOwner69]

Old school heads or Vortec? A/C? Where's the temperature sensor? Is it your original? Sounds like you don't have a gauge dash, and you are basing the overheat condition based on a warning light Correct?

[sduckworth13]

Just curious how long did you run it for after it exceeded 180? As soon as mine hit about 210 we shut it down and just tried to purge the air by squeezing the radiator hoses, fired it back up and it went to roughly 215 a few nervous seconds and then shot back down to a steady 180.

[Sammys70]

No a/c, old school heads, temp light only, with new sensor. Saw light once and was shutting it down as I saw it so not long. It's an overheat and not a sensor, I have lots of steam and scorching hot radiator fluid.

[46stude]

Got initial timing set w/ a light?

[Sammys70]

Yeh. Set at +11
Plugs at .045
Starts and runs great

[Acorn]

Double check timing and air in system. Do you have your heater hoses hooked up? It would be really good if you could get a test gauge so you can see exactly what the temp is and if your t stat is opening.
Really dumb question but, are the fans blowing the correct way? (I ask because I've put one on backward once!) do they have a shroud? Do they feel like they are blowing good?
Be extra careful to not overheat a new eng. you could collapse your rings....

[68350]

For my camaro I just went to O'Reillys and grabbed a 3 guage pod. Alt, temp, and oil pressure. 50 bucks or so and its a breeze to put in. Guages are autometer. A brand new fresh motor will probably run a lil warmer than normal just because all the tolerances are tight. Once it breaks in should run normal temp. What degree thermostat did you put in?

[GASoline71]

11 degrees advance is not a lot of advance timing. Even for a stock engine. With the 262 cam even 14 degrees advance will be good. Is it the old original balancer? Is the timing mark on the balancer correct? If you have timing too far retarded it will run hot. It can run so hot it will make the exhaust manifolds glow orange.

Gary

[geezer#99]

X2!!
I run 14 initial with a stock 305.
Have run 22 with an 11 to 1 aluminum headed motor.
Running well below optimum timing is like pouring one gallon of gas on the ground when you put 10 in the tank.

[Sammys70]

Well I'm definitely not an expert on timing. Had my friend who has lots of experience set it and I trust him. Although we will check again. It's was a new balancer which was put on by machine shop that installed cam. Will know more once I get temp gauge hooked up.

[GASoline71]

Timing with a timing light? Or winging it?

Gary

[Grumpy old man]

are you using a good break in oil to start ?

[Sammys70]

With a light

Used brad penn break in green oil

[Sammys70]

Just wanted to update this in case anyone else has a problem in the future.
Turns out it was the radiator.
My "old" one looked good, inside and out, but I suspected some flow issues and I finally caved in and bought a cheap a369 from autozone, now it's right at 180*.
Thanks again for all the suggestions

[Sklptrljay]

Glad you finally got it going. I hate when crap like that happens.

You wonder if you spent all that money and time for nothing. Really creates some serious pucker factor in your BVDs.

[VWNate1]

Before tossing the old radiator , give it a citric acid flush , that cleans better than anything else I've ever used .