I built a mild Vortec head, hydraulic flat tappet cam 385 stroker motor over the winter. Last night was the first time we ran it. My good friend just happened to drive by my parents when my son (8) and I were getting ready to start it.

Started right up. We set the idle at about 2300 RPM. The coolant temperature went up to about 200° after a few minutes. Then it shot right up to about 230°. We shut it off. It only ran for about 6 or 7 minutes. We checked everything and let it cool down and started it back up. It did the same thing. We only ran it for a total of about 15 minutes last night.

I called Lunati this morning and talked to one of their tech guys. He said shutting it off was fine as long as when we ran it, it ran over 2000 RPM's. Which it did. I asked him if I should start it up this morning and treat it like it still needed to be broke in. He said to vary the engine speed between 2000 and 2500 RPM's for another 10 minutes or so. Then set the idle speed and timing. Then vary the engine speed as I run it and drive it the first few times.

I have no idea why it's getting so hot. It took a lot longer to get that hot today, but it still did. It has a 180° T-Stat that I tested a few times before I put it in, a new water pump, the larger size 3 row radiator for a '78 Camaro. It was 90° out last night and about 85° this morning when I ran it. It was probably over 100° in the garage. The car is nose 1st in the garage with the rear of the car towards the overhead door.

I used Summit's straight 30W non-synthetic oil which has 1800 PPM zinc (ZDDP) with the flat tappet cam oil additive. At idle and 200° coolant temp. it has 40 PSI oil pressure. My oil pump is a Melling High Performance Series that has a 10% volume increase over the stock volume output.

Do you think if I changed my oil to a 5W-30 oil that would help lower my temp.? I've been told and have read that to much oil pressure creates excessive heat. If so, who makes a non-synthetic 5W-30 oil with at least 1200 PPM zinc (ZDDP) in it. Or is it ok to run regular oil and add zinc (ZDDP) to it. I'm going to run full synthetic oil with 1400 PPM zinc (ZDDP) in it once it's broke in.

Thanks, NYH1!

 

That's not too much oil pressure. Mine runs 40 lbs. at idle hot, and higher cold. You should carefully check your timing and valve settings to ensure the timing is correct and the valves are fully closing. Better a little excess lash when breaking a new engine in, than to have them too tight and end up allowing hot combustion gases to cut the valve seats and burn them.
Nothing wrong with straight 30 either. I've never run anything else since I first built my engine, and it works fine.
Have you got a fan shroud on the radiator? If not you need one. Without a shroud you will not direct the air flow evenly across the core and cool properly. If you fire it again you might turn the car around and get the frontend out to allow for more cool air into the engine. It's going to run hotter with it sitting still than it will moving, so expect higher temps there in the garage.
I'd continue the breakin and keep shutting it down if it ghets hot, and once it's done you can better address the cooling issues. But do check the valve lash and timing before continuing any more breakin.

 

The right (and best) way to break in an engine is while driving the car so that the load puts appropriate pressure against the rings to seat them properly against the cylinder walls. I wouldn't do any more in the garage free-loading if it was my engine, especially with it getting too hot like it is.

 

Thanks guys!