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Discussion Topic:
Rebuilt engine breakin problems
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lightflyer1 |
08-26-2010 @ 1:03 PM
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New Member
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My friend has a 1936 Ford Coupe and recently had the engine block crack. A new engine was built and shipped and installed. Upon startup it starts and idles fine. The problem is overheating. Skips pumps installed but no the pressure valve. New radiator and clutch and pressure plate as well. After 15 minutes or so it starts overheating and chugging water out of the radiator. 225 degrees on the gauge. Shutdown to cool off. It is hot here in Texas now (Austin) and was 107 that day. I told him to try again the next day with an electric fan on the radiator and to follow some of the break in instructions I found here. Any suggestions on problems or issues we may have overlooked? I told him about possibly having an air pocket and to be sure to try and insure it is full. 50/50 water/antifreeze. Thanks for your help!
This message was edited by lightflyer1 on 8-26-10 @ 1:04 PM
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supereal |
08-26-2010 @ 2:08 PM
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Senior
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It sounds as if the engine may have been set up too tight. Many "rebuilders" use present day clearances with bearings and rings instead of the correct ones for flatheads. When the engine reaches operating temperature, the clearances diminish, causing the engine to overheat. This is particularly true if pistons were not properly fitted to the bores. The pattern you outline is typical of that problem, and usually shows up as an engine that is so tight the starter can't budge it when it is hot. High ambient temperatures don't help, but a properly set up engine will run with the temp well below boiling, even though it is hotter than usual. I suspect the engine will have to go back to the place where it was assembled.
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lightflyer1 |
08-26-2010 @ 2:40 PM
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It was built here: http://www.flatheadcity.com/home.html Any one have any experience with them?
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MG |
08-26-2010 @ 3:42 PM
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lightflyer1, I like your idea about an air-pocket as a possible cause of the over-heating. If the car is outside you might want to stick a garden hose in the radiator and run the engine with the petcocks open for awhile. This would probably clear the air-pocket and allow the engine to run longer without fear of overheating.
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37RAGTOPMAN |
08-26-2010 @ 4:14 PM
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what I would do it wait till night, place a house fan in front of the radiator.on a stand on some sort of stand and let it blow at high speed for a couple of hours,BREAK IT IN, see if this keep it from overheating, some engines just need a little runnning in, stay with it be sure to keep a eye on it, if you gets hot. shut it off and come back the next day and do it over.till it runs cooler. but when it is hot outside it will run hot, are you using a temp gauge ?, pouring out and over the top does not mean it is running to hot,coolant will expand and come out the neck, use a thermometer in the neck, WHAT TEMP is it? 180 would be normal even a little higher with a new engine,just do not let it get to STEAM.BOILING POINT, this would be bad, I installed SKIPS VALVE. and it seems to keep the coolant in were it belongs, I am assuming the raditor is in GOOD CONDITION,has it been cleaned ? LET'S HEAR HOW YOU MADE OUT. 37RAGTOPMAN and KEEP ON TRUCKIN,,,!!!!!!!!!!!
This message was edited by 37RAGTOPMAN on 8-30-10 @ 5:06 AM
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TomO |
08-27-2010 @ 7:39 AM
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Is the engine just idling when it overheats? If so, try driving it at varying speeds of 30-40 mph. If it is overheating when driving, I would first try changing to water with a rust inhibitor and water pump lubricant. I would as add Water Wetter or Purple Ice to reduce the surface tension of the water. Skip recommend driving without thermostats with his pumps.
Tom
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lightflyer1 |
08-27-2010 @ 7:57 AM
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Using a gauge for temp. Not the car gauge. No thermostats being used. At idle it seems fine. It is when driving it gets hot he said. Couldn't make it around the block. I am going over tomorrow and have a look at it. I will try and bleed the system to insure it is completely full and stays that way. I will let you know how it turns out.
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supereal |
08-27-2010 @ 8:23 AM
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It is unlikely that any "air pockets" exist after driving the car as much as said, if the radiator level was kept at least to the bottom of the filler neck. There are things that produce, or aid, overheating. Dragging brakes, too lean fuel mixture, incorrect timing, restricted exhaust, incorrect valve lash, and a slipping water pump belt all are possibilities. It is also possible that an incorrect or leaking head gasket is at fault. I'd bet the engine will have to come back out and be sent to the rebuilder, or someone who can find the cause.
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lightflyer1 |
08-27-2010 @ 9:28 AM
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Timing was set at 4 degrees BTDC (he said that is spec). He was wondering about messing with the timing. I told him to leave it for now, if that is spec. Have to start somewhere. I also mentioned a lean mixture as well to him. Would re jetting have to be done if this is the case? Brakes and exhaust appear to be okay and functional . Anything internal to the engine itself will have to be sent back to the builder. Supposedly the builder recommended flow restrictors (thermostats or washer with hole in the middle)in the water lines. This causes me to worry. There seem to be two trains of thought on this. Too much water flow through the engine /radiator and too little. I will check all fluids and belts before starting. I am suggesting to put a fan in front tomorrow morning when it is cool and let it idle for awhile while watching it and see what it does and for how long it can run before it gets hot. He is of course worried about having to pull it and return to the builder. Has anyone here had any experience with Flathead City? http://www.flatheadcity.com/home.html
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supereal |
08-27-2010 @ 11:18 AM
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That timing shouldn't figure in your problem. I would be concerned about anyone who still thinks the water goes thru the radiator "too fast". Cooling is a zero sum situation. The longer the water stays in the engine, the hotter it becomes. The radiator has a limited ability to transfer heat to air, so the faster the coolant moves, the more efficient the transfer. That is why the new turbine design pumps increase cooling. This belief that the coolant "needs to slow down" has existed for years, and is baloney.
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