New motor running hot
Hey Gents, I finally fired up my new motor (1967 390). The builder said to start it and run it at 2000 RPM for 20 minutes. I got to about 10 minutes and it reached 230 degree and was very hot, so, I shut it down.
My father-in law said the fan clutch was shot and that it wasn't spinning no where near fast enough. Is that enough to make it get so hot so fast?
Also, I think understand the coolant flow in the engine, however what does the short nozzle between the intake manifold and the pump do?
One more, what is the purpose of running the engine so high for 20 minutes? I thought it was so the hydraulic lifters and rest of the engine get good oil flow. I was told once that if you don't do that you can ruin your cam.
I let it cool down for an hour, drained the water, then added a gallon of anti freeze and ran it again. This time it got up to 220 degrees in 5 minutes so I shut it down again. I wanted to get some anti freeze in the block. It's supposed to get in the low 30's tonight and I didn't want to risk a freeze.
thx, Dave J
Was the cooling system pressurized?
Yes, a declutched fan will make it run hot BUT, the purpose of the clutch is to slow the fan down as rpms go up. High rpms should mean that the car is running down the road.
2,000 rpm should run your car about 40 mph (or more). That is not fast for an engine. At 40, there should be enough wind going through your radiator to cool it without a fan (on these cool days). Sitting stagnant and running the engine in the driveway, I would run a garden hose with light/medium flow over the rad just to pull some of the heat away. That's another reason why I like electric fans; they only run when the coolant gets hot.
BTW, what's your oil pressure at idle, and above 1,500 rpm? I hope you have a small mechanical oil pressure gauge screwed in. - Dave
Yes, the system was under pressure, as a matter of fact the overflow tank developed a small "hiss" leak when it got really hot.
I'm embarrassed to say that I don't have an oil pressure gauge hooked up. I do have a new sensor and the idiot light though. Before starting the motor I turned the oil pump counter clockwise with a drill and 1/4 inch socket through the dizzy hole. After about 5 seconds I could definitely feel it develop pressure and bog down the drill a little as it pumped oil.
I never had overheat problems with the fan (in the summer) on the old engine. However I never ran the engine at 2000 rpm just sitting still before either.
I guess I can start it in the morning when it's 35 degrees outside and just let it idle to see the temp???
Do you think it's OK to just idle it now? Do you think it had enough time and heat for the break in?
Check your timing - too far retarded and its 'Chernobyll City' under the hood, trust me...
That's good to know Tom, thx!
I was told to get it running for 20 minutes and then let it idle and do the tuning, timing, etc.
Both times when it was over heating I turned it off it sputtered and popped twice out the exhaust, most likely too rich. I'm going to fire it up in the morning and set the timing. Then adjust the idle, let it warm up and do it again step by step. Hopefully it will help.
Time for bed here, (11:00pm) you should go have a pint and some lunch.
regards, Dave J
Dave, you need to know proper start-up and break-in procedures. Check out how Hastings Piston Ring company says to do it:
At Ford, we use Hastings (and have for many decades). Notice they want you to load the engine. They didn't say to run your engine fast but you do need to put a load on the engine to properly break-in rings.
They use the start-up procedure to tune the engine, so you can run the car. This is important. Start-up will tell if the engine has any immediate faults that need attention (like oil leaks, funny noises, etc.). We call this, "Hot Testing" the engine. Every single engine at Ford is loaded and tuned in the engine plant, and they all better be good before going to assembly.
At home, we don't have that luxury so you need to run the car.
After your initial break-in, simply run the car like any new car owner would. I would not let it sit running for 20 minutes. The engine needs a variety of speeds to let it settle-in.
Let me repeat, "The object is to apply a load to the engine for short periods of time and in rapid succession soon after engine warm up. This action thrusts the piston rings against the cylinder wall with increased pressure and results in accelerated ring seating."
This procedure will affect your engine for a very long time. Done right, your new overhaul should last at least ten years of hard service. - Dave
That's exactly what I had read on several sites. Run it for 20 minutes at 1800-2000. Then take it out and drive it up to 30mph and let off the gas to slow down. Then repeat. Some said to do that for a while and then move up to 50 mph and let it slow down, then back up.
The engine builder is Doug Anderson in Albuquerque. He's a very well respected and established builder in NM. He said I could do it that way too, or I could just run it for 20 minutes as I did and then just drive as normal, just don't go hot rodding it for the first 300 to 500 miles. He said that would be the best way to break in the clutch too. He said that molly rings seat themselves pretty well and it should be fine.
I'm just concerned with how hot it got. I'm going to do as I said and tune it etc and then see if it gets very hot. Then take it for a spin staying close to the house in case it overheats again.
If you remember my other posts it is a bit of a performance build. 390 with a bored 30 over with a 428 crank. A Lunati Cobra jet cam (the builder said he didn't want to go any wilder than that because of our high altitude and my need for vacuum for the power disc brakes). Cobra jet exhaust valves and comp springs in the c4ae-6090g heads. Edelbrock rpm performer intake and 750 carb. FPA headers.
thx a ton, hopefully it's the timing thing that scumdog spoke of.
Hmm, I can only get it to idle if I go about 20 degrees on my timing, and the idle is still around 800 which is too high. I also have to floor it to start it otherwise it just cranks and doesn't fire. When it shuts down it spurts out the carb and backfires.
Could I be a tooth off on the dizzy? Or will a motor even start like that? Once again my lack of car knowledge is letting me down.
While trying all this I ran it for a total of maybe 5 -6 minutes, and it shot up 230 degrees. Is there anyway to tell for sure that your thermostat is opening?
When I first started it yesterday I did so with the radiator cap off. It started gurgling and spitting water out, and then it just flowed out the cap. I thought this was due to air trapped in the motor, and as the air got hotter and boiled it pushed the water back out. But I really don't know.
Any ideas would be greatly appreciated, I'm starting to worry about ruining this new motor.
thx again, Dave J
OK, the latest. I read on the HAMB that if you use the ported vacuum line on the carb it can mess up idling and cause a retard that can cause overheating at idle.
Edelbrock says to use the ported one so that's where I was. As soon as I switched to the full vacuum port it the car started and idles fine. However, I was at about 20 degrees still, sooo I put the timing to 10 or 11 and it almost stalled. Soooo, I turned up the carb idle and it stays running nicely. However, it still gets really hot so I had to shut it down again.
As soon as it cools to 150 again I'll try adjusting the carb idle screws.
Started it up with the rad cap open and it gets up to 220 degrees. Tried adjusting the timing but to get it to stay running at 12 degrees before TBC I have to set the idle screw to run at about 1000 rpm.
Took it for a spin and it would cool down to about 210while cruising about 40 mph. So. at least the cooling is working, it's just running hot and I can't get the thing to idle at 700 rpm without stalling.
Scratching my head, time start over.
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