Motor break-in runs hot ??? Help

[geneo4116]

Installed rebuilt 350 chevy motor.ran motor 20 minutes at 2000rpm,during cam break-in motor running hot apprx 220 degrees,could my timing be retarded to much would that make it run hot, also what is the correct way to find where the distibutor should drop in,car turns over great started with out even making a full revolution, help help help,checked thermostat no problems,

 

[TiredIronGRB]

What type fuel system? Could it be running too lean, a new rebuild will run hot for a while especially if the ring gaps are set a little tight.

 

[Sam_Fear]

Break-in or not, if your running hot, IMO your t-stat is to high a range or your radiator is too small. ...or you have bad circulation. ...or your gauge is wrong. Assuming you have good oil pressure, etc. The cooling system should be able to handle off timing.

Again, my opinion.

220 doesn't seem that hot too me.

 

[geneo4116]

Well the other 350 i had never ran hot,but was a very old worn out motor,pulled thermostat out still runnin the same, but this was sitting still for 20 minutes at 2000 rpm, oil pressure good around 60 psi,runnin a edelbrock 650 mechanical fuel pump, we had a thermal reader for temp,guage was off by 20 degrees,cooling system was always good for the other motor, havent drove mew motor yet,just broke cam in,could timimg be retarted way to much ?

 

[The Rattler]

How hot is it outside and are you running the same radiator as the last 350?

Rattler

 

[TiredIronGRB]

I always break mine in on the road under a load, sitting still running 20 minutes a 2k rpm is a little rough on a new engine.

 

[geneo4116]

Same radiator apprx 90 degrees lots of humidity

 

[Willowbilly3]

Slow timing can cause overheating.
I haven't built or installed a new engine for a few years but did a lot of them when I was in the business. First off, I would never put a new engine with any of the old cooling system components. Usually a new radiator in a Chevy because 10 years is about the life of one. But at the least I would send them out to a radiator shop to get cleaned, rodded, pressure checked. Also new water pump, hoses ect. Removing the T-stat isn't something I'd do. It seldom helps, may make it worse and besides the system was designed to have one. But rarely is the T-stat the issue when there is an overheating problem. I also agree that 220 isn't anything to get alarmed about, many new engines run in that range, or hotter. The electric fans in GM cars used to come on at 232.
If the coolant stays in the system, it isn't too hot IMHO. Others may disagree.

 

[fuzz]

Sitting still in the garage is probably why it got hot, not enough air circulation. Take it out on the road and drive it around to see if it runs cool like the old motor.

 

[geneo4116]

Radiator is apprx 2 yrs old at most,water pump maybe 2 yrs old,thermostat was a 160,car never ran hot before drove it 200 miles never put fan on,but it was 90 and humdity was high very muggy ran 20 mniutes at 2000rpm sitting still to break cam in .what happened was the overflow hose off the radiator blew off { old hose just pushed on no clamp, so actually dont know if it over heated but was runnin 220 degrees, and you guys are saying thats not over heating, we thought it might blow a head gasket.

 

[geneo4116]

I hope your right,i will do that later today,will change oil and drive about 100 miles if possible,will get back this evening,thanks for all the replys

 

[Willowbilly3]

If you capped it with air trapped in the system it might cause it to run hotter, and to blow off the overflow (hose) I'd say do like you plan, take it on a run but maybe a short one of just a couple mile loop back to the shop and recheck everything before the 100 miler. Don't forget to burp it, run it up until the coolant circulates before putting the radiator cap on.

 

[2muchtorque]

If you capped it with air trapped in the system it might cause it to run hotter, and to blow off the overflow (hose) I'd say do like you plan, take it on a run but maybe a short one of just a couple mile loop back to the shop and recheck everything before the 100 miler. Don't forget to burp it, run it up until the coolant circulates before putting the radiator cap on.

WB3, people think I'm nuts when I mention " burping ", glad to hear you know about it too. This old time racer taught me years ago, drove his race car up car ramps to get the rad up to be the highest point in his cooling system to help burp his sytem. I never forgot that. Like everything, there is a right way and a wrong way.

 

[geneo4116]

Well so far so good took it on a 150 mile trip from 20 to 80mph,no problems never got over 160,has awesome thumper comp cam,but afraid my cheap edelbrock carb isnt gonna let it idle to good at low rpms,proably will switch to proform holley, thanks alot for reply to thread.

 

[Willowbilly3]

A crappy carb can ruin a new engine, don't wait to get it off there if you think it's dumping fuel, you don't want to wash down those new cylinders.
If it was mine, I'd switch to a hotter stat, 160 is a little on the cool side.

 

[tcat55371]

hey

Make sure your waterpump isnt running backwards. I went thru all this with mine and thats what my problem was. If the water pump came off a car with a serpintine belt and your not running one it is most likely running backwards.

I had a water pump off a mid 80's chev truck 350 on my older 350 and it was going backwards. I ran 210/220 all the time and now I run 180.

 

[geneo4116]

Well car runs awsome,had to install 600cfm holley pro form carb, made all the difference in the world,with the thumper cam,the edelbrock was okay from 30mph on,but would not idle kept dying with the bigger cam,holley feels like it added 30 hp,very streetable now,no over heating,never thought carb could make such a difference.