overheat only over 3000 rpm
- Thread starter diehard polylover
- Start date
-
Next time it gets hot pull over and pull a plug . White ? Might be running lean at cruise ?
Ditch the electric fans and get a 7 blade with clutch … I run them in both my cars at 105degrees with no issues . 1 is a 408 with solid roller.
Apologies if this has been mentioned
Ditch the electric fans and get a 7 blade with clutch … I run them in both my cars at 105degrees with no issues . 1 is a 408 with solid roller.
Apologies if this has been mentioned
C J Pony parts or something has lower hose springs. Or you could try bending up a coat hanger. I have put springs in the lower hoses of all 3 of my cars. You just need the proper diameter.
Inertia
Well-Known Member
Stainless welding rod, or heavy piano wire. (We had a music store down the block.)
diehard polylover
Member
Hi
thanks for the reply.
No, it wasn't sucking shut.
A long time ago I hadn't the spare to put on and I adapted (on the road) a Ford Transit coolant hose, which has he same bends. Only a little longer.
AS it came out, when is new and helastic it holds the rear bend without problem. Then, after some time ( heating/cooling cycles) it collapses in that bend and reduces the flow.
At least, that's what happened to me....
Inertia
Well-Known Member
For me, it was an old funeral car, early 50s Cadillac Hearse.
It ran fine during the procession out to the Burial Park,the other cars could return on the hiway, but this one overheated at speed.
When brought to us, we rifled thru the glove box, found the newish looking rad was just a coupla years old by the receipts etc.
Test drive had the fan belt squealing like hell, it was loose, adjusted it, fat belts.
I was watching the generator pulley as it seemed bent at speed.
It was actually the lower hose sucking shut directly below the pulley that my eye was seeing, but my focus wasn't on the hose, whoda thunk hose.
After watching a while, I could hold the revs at about 2000, and after a few seconds, the hose would collapse, - then open as soon as the revs dropped.
Happened a few years later on a 6 cyl too.
Showed the crew .
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hotrod swinger
Well-Known Member
Here’s a hint. Check the timing with a light.
Wvbuzzmaster
Well-Known Member
I am not going to make any friends with this post, but I think it’s accurate for your situation, plus I just don’t care if you like this.
You want answers to why your car is overheating and have given some loose facts for what is going on and what you have tried so far. As you have been quizzed on specific details from members trying to help you narrow down the multitude of variables in your situation to find a cause you immediately go on the defensive as to why that isn’t relevant information to the problem you have. If you want a solution from the brain trust of knowledge at your fingertips you will have to get off your high horse and answer their questions with facts whether you think it is relevant or not.
Such as the actual timing curve you have with an actual timing light. No one is saying you have to change it, but right now it’s something that can’t be ruled out, no matter how much you argue it’s irrelevance… because it’s not rooted in a number, therefore it’s still a potential option. Pull a few plugs and check the color… that’s a question I saw you disregard too, because you ruled out your perfect carb tuning ability. Ok, great, you ruled it out, that doesn’t mean anyone else has. Same with just yanking out the thermostat for a test. If you have done these things great, share that information in a factual way so everyone else can rule it out and move to the next possible cause.
Now, what sticks out to me in this setup you have is that your go to solution was add a bunch of electric fans and because that has “improved” the situation you have grown very attached to these fans. One fact we all know is that from the factory this did not overheat with mechanical fan. So what everyone else has said that has been totally dismissed was that we can’t be sure it’s not restricted air flow on the highway where your RPM overheating issue is occurring. Your immediate response was “they are fine cause they can’t restrict air flow on the back of the radiator” yet that’s not true… a restriction on either side of that radiator is a restriction on that whole section of the radiator.
I have seen others ask about water pump condition. Have you installed a new water pump on it? I get you say you have limited options for high performance water pump, but what about a stock replacement water pump without 9 million miles on it?
Not trying to be mean here, but we are two pages in with a bunch of very experienced and helpful members that want to help you and you still have their attention. But keep dismissing theirs suggestions and questions and you will lose your audience and have to return to solving the overheating on your own… and none of us will feel bad about it.
You want answers to why your car is overheating and have given some loose facts for what is going on and what you have tried so far. As you have been quizzed on specific details from members trying to help you narrow down the multitude of variables in your situation to find a cause you immediately go on the defensive as to why that isn’t relevant information to the problem you have. If you want a solution from the brain trust of knowledge at your fingertips you will have to get off your high horse and answer their questions with facts whether you think it is relevant or not.
Such as the actual timing curve you have with an actual timing light. No one is saying you have to change it, but right now it’s something that can’t be ruled out, no matter how much you argue it’s irrelevance… because it’s not rooted in a number, therefore it’s still a potential option. Pull a few plugs and check the color… that’s a question I saw you disregard too, because you ruled out your perfect carb tuning ability. Ok, great, you ruled it out, that doesn’t mean anyone else has. Same with just yanking out the thermostat for a test. If you have done these things great, share that information in a factual way so everyone else can rule it out and move to the next possible cause.
Now, what sticks out to me in this setup you have is that your go to solution was add a bunch of electric fans and because that has “improved” the situation you have grown very attached to these fans. One fact we all know is that from the factory this did not overheat with mechanical fan. So what everyone else has said that has been totally dismissed was that we can’t be sure it’s not restricted air flow on the highway where your RPM overheating issue is occurring. Your immediate response was “they are fine cause they can’t restrict air flow on the back of the radiator” yet that’s not true… a restriction on either side of that radiator is a restriction on that whole section of the radiator.
I have seen others ask about water pump condition. Have you installed a new water pump on it? I get you say you have limited options for high performance water pump, but what about a stock replacement water pump without 9 million miles on it?
Not trying to be mean here, but we are two pages in with a bunch of very experienced and helpful members that want to help you and you still have their attention. But keep dismissing theirs suggestions and questions and you will lose your audience and have to return to solving the overheating on your own… and none of us will feel bad about it.
Excellent post.
Water pump impeller distance to the back of the timing cover can be off and cause flow issues and cavitation. Cant assume any parts now a days are good or assembled right. A pump with a round disc on the back of the impeller eliminates the problem.
Also you mention fans pushing in the right direction, and that they are mounted on the back side of the radiator. Mounted like that they should be pulling air not pushing it.
Also you mention fans pushing in the right direction, and that they are mounted on the back side of the radiator. Mounted like that they should be pulling air not pushing it.
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Most, perhaps all, of what needs to be said regarding your cooling system, has been said.
So I just want to touch on ignition timing.
Most of us here have been tuning cars for over 50 years.
IDK about the rest of the guys but as for me, tuning the idle-timing by ear, for highest idle, is IMHO, a bad idea; unless you mean,
setting the idle-timing to 13* and then twiddling the Mixture screws for highest idle @13*; which IMO is still wrong,
because;
Even then, at 13*, the throttles are very nearly closed, which means the Transfer slots are also nearly closed, which means you are gonna have to crank the mixture screws open, for it to get enough fuel to idle ok. But then, as soon as you open the throttles, and the transfers come back on line, the AFR goes rich because of the fat mixture screw setting..
But if you have tuned your idle by advancing the timing for highest idle-rpm, that is just wrong;
because;
If 13* is the factory idle timing,
and 35* was the factory power-timing, at say 3400;
that means there is 35 less 13 =22* in the factory distributor.
If you are timing by ear for highest idle rpm, don't be surprised to see 25 to 30 degrees by timing light. Adding 22*distributor, to say 27*Idle-timing, is 49* of power-timing
which is WELL INTO detonation under Power.
And your VA could be say 15*. adding the VA to the cruise timing at 3000, could put you as high as 49+15= 64, but more likely is ~54* , if the springs are still working.
IDK anything about the Poly chambers, so IDK if 54*@3000 is acceptable cruise-timing;
But Ima thinking that if you are cruising at 3000 rpm, you will want the cruise-timing to be at least 48*.
But one thing I do know is that 49* of Power-timing in an LA will kill it.
Now, I have to tell you a couple of things;
1) the first time your engine cares about Power-timing is at Stall-speed.
2) the Second time it cares about Power-Timing, is from about 3500 rpm and beyond. These two data points are used to build your Power-Timing curve.
3) Part Throttle Timing is the thing that you want to concentrate on AFTER the Power-Timing has been finalized. This is done by modifying the VA.
4) Idle-timing is a big ol' window from about 5 to 20 degrees, and where you are in it, is nearly meaningless.
5) my current cruise rpm is 65=2240 in overdrive. But this method, described below, also worked for me when it was 65=2870
6) cruise-timing on a CityCar, can be sacrificed.
7) if your vehicle does not have a PCV system on it, but the carb has a PCV port on it, then the carb will never meter fuel properly except at WOT; so put a PCV system on it.
8) if your vehicle does have a PCV on it, with a carb that was never set up for it, then it will never meter fuel correctly at all; so get a carb that will.
Here's how I set my car up for cruising;
1) I revved the engine up to cruising rpm, and blocked it there.
2) without regard to the actual numbers, I advanced the timing for highest rpm at that blocked throttle.
3) I reduced the idle speed back down to cruise rpm, and fine tuned the timing again. Thus the engine is set up for best cruise-timing, at a no-load setting.
4) with the engine still running at cruise rpm, I now set the Mixture screws for best LEAN AFR.
5) now I read the timing. From that, I subtract 3* for load compensation, and then build my timing curve to hit that mark.
6) I return the engine to idle, and let her cool off.
Jus trying to help
So I just want to touch on ignition timing.
Most of us here have been tuning cars for over 50 years.
IDK about the rest of the guys but as for me, tuning the idle-timing by ear, for highest idle, is IMHO, a bad idea; unless you mean,
setting the idle-timing to 13* and then twiddling the Mixture screws for highest idle @13*; which IMO is still wrong,
because;
Even then, at 13*, the throttles are very nearly closed, which means the Transfer slots are also nearly closed, which means you are gonna have to crank the mixture screws open, for it to get enough fuel to idle ok. But then, as soon as you open the throttles, and the transfers come back on line, the AFR goes rich because of the fat mixture screw setting..
But if you have tuned your idle by advancing the timing for highest idle-rpm, that is just wrong;
because;
If 13* is the factory idle timing,
and 35* was the factory power-timing, at say 3400;
that means there is 35 less 13 =22* in the factory distributor.
If you are timing by ear for highest idle rpm, don't be surprised to see 25 to 30 degrees by timing light. Adding 22*distributor, to say 27*Idle-timing, is 49* of power-timing
which is WELL INTO detonation under Power.
And your VA could be say 15*. adding the VA to the cruise timing at 3000, could put you as high as 49+15= 64, but more likely is ~54* , if the springs are still working.
IDK anything about the Poly chambers, so IDK if 54*@3000 is acceptable cruise-timing;
But Ima thinking that if you are cruising at 3000 rpm, you will want the cruise-timing to be at least 48*.
But one thing I do know is that 49* of Power-timing in an LA will kill it.
Now, I have to tell you a couple of things;
1) the first time your engine cares about Power-timing is at Stall-speed.
2) the Second time it cares about Power-Timing, is from about 3500 rpm and beyond. These two data points are used to build your Power-Timing curve.
3) Part Throttle Timing is the thing that you want to concentrate on AFTER the Power-Timing has been finalized. This is done by modifying the VA.
4) Idle-timing is a big ol' window from about 5 to 20 degrees, and where you are in it, is nearly meaningless.
5) my current cruise rpm is 65=2240 in overdrive. But this method, described below, also worked for me when it was 65=2870
6) cruise-timing on a CityCar, can be sacrificed.
7) if your vehicle does not have a PCV system on it, but the carb has a PCV port on it, then the carb will never meter fuel properly except at WOT; so put a PCV system on it.
8) if your vehicle does have a PCV on it, with a carb that was never set up for it, then it will never meter fuel correctly at all; so get a carb that will.
Here's how I set my car up for cruising;
1) I revved the engine up to cruising rpm, and blocked it there.
2) without regard to the actual numbers, I advanced the timing for highest rpm at that blocked throttle.
3) I reduced the idle speed back down to cruise rpm, and fine tuned the timing again. Thus the engine is set up for best cruise-timing, at a no-load setting.
4) with the engine still running at cruise rpm, I now set the Mixture screws for best LEAN AFR.
5) now I read the timing. From that, I subtract 3* for load compensation, and then build my timing curve to hit that mark.
6) I return the engine to idle, and let her cool off.
Jus trying to help
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This could also be an engine running lean. When engines get tired & old, worn rings etc, they lose power. Engine has become less efficient & the engine has to work harder to maintain the same road speed. Since the overheating is happening at cruise speed, it would be worth richening the cruise cct of the carb to see if it helps. Raising the fuel level in the carb by 0.100" will richen the mixture slightly, to see if that helps.
Another method to richen the mixture for a test drive is to close the choke, engine idling, is to close the choke until the engine sound changes. Wire the choke in this position & test drive.
Another method to richen the mixture for a test drive is to close the choke, engine idling, is to close the choke until the engine sound changes. Wire the choke in this position & test drive.
diehard polylover
Member
Hello Gang !
I'm back again.
The problem was finally solved !!!
I thank all of you for being so helpful with many hints and individual procedures for timing.
I agree with most of what you say,
Wonder what was the problem ?
I had modified the fixture that holds the radiator, putting 4 rubber antivibration supports, to avoid any future crack on the radiator body.
This simply pushed the radiator backwards 7/8".
Being the smart I am, I cut the top hose to macth the shorter distance but I forgot to do the same with the lower hose.
So the poor hose was pushed backwards and bent at a sharp angle..... and let it pass only a fraction of the coolant to the engine.
Obviously his quantity was enough to cool the engine at low rpm but insufficient at higher speeds.
I cut the excess of hose, restablishing the correct bend and everything now is running fine.
Now hitting the same stretch of highway where I had the problems the temperature stays at the right place all the time.
Problem solved ...
As for the timing, Of course I block the engine at 3000 rpm ( I have a tachometer) and there I turn the distributor to find the best point. Usually the rpm climbs to 3200 - 3300 when doing so.
Then as the member AJ FORMS also wrote in his post, I return to idle and I set the air screws at their best position. As you all know you have to play with idle screws and throttle screw up and down to find the correct mixture.
Then again, a little check at the distribtor position again to see if there is a change in rpm while turning it, and often I have to retard it a little little. THis often requires a little more adjusting at the three screws above.
Of course I have to be sure that the contact points are set correctly and everything in the distributor work as it should.
My final final check of the timing is is on the road. I have a vacuum meter on my cockpit and when you are on the highway at part trottle it shows immediately if the engine is running at its best or still need some adjusting of the timing.
Up to now I believe I have the best performance out my beloved 318 A Poly.
Cheers to everybody
I'm back again.
The problem was finally solved !!!
I thank all of you for being so helpful with many hints and individual procedures for timing.
I agree with most of what you say,
Wonder what was the problem ?
I had modified the fixture that holds the radiator, putting 4 rubber antivibration supports, to avoid any future crack on the radiator body.
This simply pushed the radiator backwards 7/8".
Being the smart I am, I cut the top hose to macth the shorter distance but I forgot to do the same with the lower hose.
So the poor hose was pushed backwards and bent at a sharp angle..... and let it pass only a fraction of the coolant to the engine.
Obviously his quantity was enough to cool the engine at low rpm but insufficient at higher speeds.
I cut the excess of hose, restablishing the correct bend and everything now is running fine.
Now hitting the same stretch of highway where I had the problems the temperature stays at the right place all the time.
Problem solved ...
As for the timing, Of course I block the engine at 3000 rpm ( I have a tachometer) and there I turn the distributor to find the best point. Usually the rpm climbs to 3200 - 3300 when doing so.
Then as the member AJ FORMS also wrote in his post, I return to idle and I set the air screws at their best position. As you all know you have to play with idle screws and throttle screw up and down to find the correct mixture.
Then again, a little check at the distribtor position again to see if there is a change in rpm while turning it, and often I have to retard it a little little. THis often requires a little more adjusting at the three screws above.
Of course I have to be sure that the contact points are set correctly and everything in the distributor work as it should.
My final final check of the timing is is on the road. I have a vacuum meter on my cockpit and when you are on the highway at part trottle it shows immediately if the engine is running at its best or still need some adjusting of the timing.
Up to now I believe I have the best performance out my beloved 318 A Poly.
Cheers to everybody
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