new motor blues
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 38
From: EXTREME southwest CT
Did you install the head gaskets correctly?
Seen it before where a friend rebuilt his 351 and screwed up, blocking the water to one head.
One faces forward and one to the rear but they should both be marked "up".
Just a thought.
Seen it before where a friend rebuilt his 351 and screwed up, blocking the water to one head.
One faces forward and one to the rear but they should both be marked "up".
Just a thought.
Postmaster
Joined: Feb 2008
Posts: 2,658
Likes: 5
From: Out of here
If you are not running a thermostat, you should put one of those restrictor washers in the housing.
The coolant needs to stay in the block for some amount of time to pull the heat out. I'm not saying it's your problem, but not having anything to restrict the flow somewhat is not a good idea.
Check your ignition timing. Too far advanced will make it run hot.
Did you put the correct rotation water pump in? Serpentine pumps turn the opposite way and I have seen this before. Later model pumps use the same casting but they have reverse rotation impellors pressed on the shaft and will not circulate the coolant.
Same goes for an older pump on a newer motor. I always check the impellor rotation when installing a new pump.
The pump gaskets are different too and you have to make sure none of the passages on the motor gets blocked off.
We had this same problem running a race motor on the dyno one day only to find out they gave us the wrong pump.
The coolant needs to stay in the block for some amount of time to pull the heat out. I'm not saying it's your problem, but not having anything to restrict the flow somewhat is not a good idea.
Check your ignition timing. Too far advanced will make it run hot.
Did you put the correct rotation water pump in? Serpentine pumps turn the opposite way and I have seen this before. Later model pumps use the same casting but they have reverse rotation impellors pressed on the shaft and will not circulate the coolant.
Same goes for an older pump on a newer motor. I always check the impellor rotation when installing a new pump.
The pump gaskets are different too and you have to make sure none of the passages on the motor gets blocked off.
We had this same problem running a race motor on the dyno one day only to find out they gave us the wrong pump.
Fleet Mechanic
Joined: Apr 2007
Posts: 1,429
Likes: 4
From: patricia ab canada
with out a thermostat the coolant flows to quickly not allowing the coolant to transafer the heat properly.i don't understand why people seem to think removing the thermostat will cure their overheating issues.i have replaced more head gaskets and engines due to this misconception.these are not race cars that run at full throttle and can get away with
those restrictor plates .these engines run their best at a proper operating temp.put a thermostat in, they are cheap.if still over heats then check your water pump.don't trust some of those parts guys,very easily have given you one of the reverse rotation pumps.when you first fired the engine up did you run with the rad cap off,to purge the system of air.air or steam pockets can cause flow restrictions as well.let us know how it turns out
those restrictor plates .these engines run their best at a proper operating temp.put a thermostat in, they are cheap.if still over heats then check your water pump.don't trust some of those parts guys,very easily have given you one of the reverse rotation pumps.when you first fired the engine up did you run with the rad cap off,to purge the system of air.air or steam pockets can cause flow restrictions as well.let us know how it turns out
Postmaster
Joined: Feb 2008
Posts: 2,658
Likes: 5
From: Out of here
That's what I meant about the restriction washer in place of thermostat. I'm not sure exactly what they call them.
It's just a big washer that comes with several different size small openings that will slow down the coolant leaving the motor if you don't have any thermostat in.
It's just a big washer that comes with several different size small openings that will slow down the coolant leaving the motor if you don't have any thermostat in.
Junior User
Joined: Apr 2009
Posts: 55
Likes: 0
From: Waycross, GA
How hot is hot? Boiling and steaming?
When does it get hot? Idling at intersections or going down teh road?
If when it is sitting still and idling do you have a fan shroud on it?
If going down the road, shceck timing, and then maybe you are running it to lean. We have had racecar engines run hot that we cured bby increasing the jet size by one.
When does it get hot? Idling at intersections or going down teh road?
If when it is sitting still and idling do you have a fan shroud on it?
If going down the road, shceck timing, and then maybe you are running it to lean. We have had racecar engines run hot that we cured bby increasing the jet size by one.
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Methanoholic
Joined: Mar 2009
Posts: 6,442
Likes: 8
From: Maine (NorCal Native)
They are called Water Restrictors, they are for motors that run a consistent RPM and would not be good for the street.
It needs a proper thermostat.
-Enjoy
fh : )_~
It needs a proper thermostat.
-Enjoy
fh : )_~
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Thread Starter
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New User
Joined: Apr 2009
Posts: 13
Likes: 0
forgot to mention this engine is a 351 modified ...can hear water boiling in block, I checked rotation of water pump its the right pump.this is the second new water pump Ive put on.left the thermostat out to make sure water was flowing.some one mentioned the head gaskets.I checked and made sure all holes were lined up,before putting on heads .I dont remember seeing any markings on gasket for installing.if I leave the radiator cap off it starts pushing all the water back out. i getting so frustrated ive built 4 other motors and never had this problem before. this is the only transportation I have and having trouble getting back and forth to work.All help and suggestion are greatly apperaciated
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New User
Joined: Apr 2009
Posts: 13
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also I pulled both heater hoses off (on the core side)with the motor running to check pressure.If I held the hoses higher than the intake no water comes out shouldn't it be blowing a good stream of water???
Last edited by zman7928; Apr 23, 2009 at 07:09 PM. Reason: left out info
Postmaster
Joined: Feb 2008
Posts: 2,658
Likes: 5
From: Out of here
It may be pushing the water out cause there are air bubbles in the block. I'd let it run out for a while and see if you can burp it.
351M's are a whole other animal and I don't think there is more than one style of water pump for it. I doubt it was ever offered with a serpentine setup.
I'll bet you still have air in the system.
351M's are a whole other animal and I don't think there is more than one style of water pump for it. I doubt it was ever offered with a serpentine setup.
I'll bet you still have air in the system.
Post Fiend
Joined: Nov 2005
Posts: 7,437
Likes: 4
From: Charles Town, W bygod Va
With no thermostat it might not push through the heater hoses. To check for the right water pump, disconnect the upper hose from the rad and start it up )you might want to get a big drain pan) it should pull from the bottom of the rad and push water out of the upper hose
Thread Starter
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New User
Joined: Apr 2009
Posts: 13
Likes: 0
How hot is hot? Boiling and steaming?
When does it get hot? Idling at intersections or going down teh road?
If when it is sitting still and idling do you have a fan shroud on it?
If going down the road, shceck timing, and then maybe you are running it to lean. We have had racecar engines run hot that we cured bby increasing the jet size by one.
When does it get hot? Idling at intersections or going down teh road?
If when it is sitting still and idling do you have a fan shroud on it?
If going down the road, shceck timing, and then maybe you are running it to lean. We have had racecar engines run hot that we cured bby increasing the jet size by one.
Fleet Mechanic
Joined: Apr 2007
Posts: 1,429
Likes: 4
From: patricia ab canada
i think the reason it's not flowing through your heater lines is there is not restriction in the flow.water is lazy,it will take the path of least resistance.with no stat the pump is just pulling water out the rad quickly through the motor and in to the rad.also are you using anti freeze. if you use strait water it will have a lower boiling temp.anti freeze will raise the boiling temp and lube your water pump.i would put a stat in fill it with a 50/50 mix of coolant.start it with the rad cap off.it will take a bit of time but you will burp those air pockets out.when that coolant boils it creates steam ,and restricts the flow.