GSL-SE Diagnostic Help: Running Lean or Bad Water Seals?
08-12-14, 10:31 AM
#1
GSL-SE Diagnostic Help: Running Lean or Bad Water Seals?
OK I am about to write a very long post to try and give the most complete picture of what the symptoms are.
Background:
- This is a lemons/chumpcar so this motor is run full tilt, shifting at 7k for about 14-18 hours at any given race and we have completed about 12 races with this motor.
-Motor is bone stock except for the following:
Removed air pump.
Removed A/C.
3rd Gen alternator.
Removed 5-6 port actuators and blocked off intake hole with block off plate.
Did the best I could to plug all vacuum lines associated with port acuator/air pump
Stock exhaust manifold going back to generic 2.5" staight through mineke exhaust.
Installed a large fuel filter in engine bay with second fuel pump between filter and fuel rail.
Mechanical fan removed: Electric fan in.
- We run ~6-8oz of premix per 5 gallons of 87 octane fuel. so between 80/1 and 100/1 and the OMP is still functioning.
For awhile now we have had some minor cooling issues. The temp guage (stock guage) would creep up to about 1/3 maybe more like 2/5 sometimes but it would always stay below half. We would often run with our fan on and that seemed to help a bit but not much. But the car never actually overheated.
Aside from that the motor has pulled well except occasionally (normally toward the end of a session or weekend) We would get some sputtering at high RPM under load. The power drops off and the motor sputters. Please keep in mind this has not been consistent or predictable. We have been trying to troubleshoot it for awhile.
-We replaced all the fuel pumps and the fuel filter.
-We checked the pressure at the fuel rail, where the soft line goes into the hard line under the intake. It was over 70 lbs. So no issue there.
*** Here is the big issue though. This past weekend the car started massively overheating. Basically the heat guage went straight to half way, then crept up to 3/4 where it would stay unless we backed way off and shifted at like 4k, then we could mostly manage to keep it around half to a little over half.
AND the oil pressure started to drop. It would fluctuate between 60 and 30lbs. It was at about 60 when water temp was at half and would go down to 30-40 when the temp was up at 3/4.
Prior to the overheat we were still feeling the occassional sputter although not bad.
A new development before the massive overheat problem. The car would not idle anymore. It always had a bit of trouble when cold but once it heated up it has always idled, albeit a bit lopey.
We replaced the water pump with no effect.
We also had to keep putting water in the radiator. We would come in every hour when the car would get hot and let it cool down and top off the radiator, which was low.
Assumption: The falling oil pressure is due to the engine overheating and not vise versa. When the motor is fully cooled the pressure guage stays at 70lbs even when reved to 7k.
WE CURRENTLY HAVE TWO RUNNING THEORIES
1. Water seals in the motor are going.
We are basing this on the fact the problem looks a lot like a head gasket issue on a piston engine.
a couple questions: Would water seals make the car overheat prior to the coolant actually getting low?
also: there doesn't appear to be water in the oil at all. Would this necessarily have to be in order for there to be water seal problems or could I still have bad seals and no water in the oil?
Would the lack of idle be caused by bad water seals?
2. The engine is running lean.
If the motor was running lean, this would cause overheating correct?
This might explain the stumbling at high rpm high load and the lack of idle.
And then the loss of water would be because of overheating.
ALSO: I have felt that we get better tan most track use rotary MPG. We use about 8-9 gallons per 2 hours.
Sorry for the long post but I wanted to get all the info in. Any help would be appreciated greatly.
Specifically, are there any good ways to test both these hypothesis independently?
Please remember it is track only car so can't drive it around the streets to diagnose problems.
We have access to general professional mechanic tools. So we can pressure test / pressurize systems.
Thanks again!
Background:
- This is a lemons/chumpcar so this motor is run full tilt, shifting at 7k for about 14-18 hours at any given race and we have completed about 12 races with this motor.
-Motor is bone stock except for the following:
Removed air pump.
Removed A/C.
3rd Gen alternator.
Removed 5-6 port actuators and blocked off intake hole with block off plate.
Did the best I could to plug all vacuum lines associated with port acuator/air pump
Stock exhaust manifold going back to generic 2.5" staight through mineke exhaust.
Installed a large fuel filter in engine bay with second fuel pump between filter and fuel rail.
Mechanical fan removed: Electric fan in.
- We run ~6-8oz of premix per 5 gallons of 87 octane fuel. so between 80/1 and 100/1 and the OMP is still functioning.
For awhile now we have had some minor cooling issues. The temp guage (stock guage) would creep up to about 1/3 maybe more like 2/5 sometimes but it would always stay below half. We would often run with our fan on and that seemed to help a bit but not much. But the car never actually overheated.
Aside from that the motor has pulled well except occasionally (normally toward the end of a session or weekend) We would get some sputtering at high RPM under load. The power drops off and the motor sputters. Please keep in mind this has not been consistent or predictable. We have been trying to troubleshoot it for awhile.
-We replaced all the fuel pumps and the fuel filter.
-We checked the pressure at the fuel rail, where the soft line goes into the hard line under the intake. It was over 70 lbs. So no issue there.
*** Here is the big issue though. This past weekend the car started massively overheating. Basically the heat guage went straight to half way, then crept up to 3/4 where it would stay unless we backed way off and shifted at like 4k, then we could mostly manage to keep it around half to a little over half.
AND the oil pressure started to drop. It would fluctuate between 60 and 30lbs. It was at about 60 when water temp was at half and would go down to 30-40 when the temp was up at 3/4.
Prior to the overheat we were still feeling the occassional sputter although not bad.
A new development before the massive overheat problem. The car would not idle anymore. It always had a bit of trouble when cold but once it heated up it has always idled, albeit a bit lopey.
We replaced the water pump with no effect.
We also had to keep putting water in the radiator. We would come in every hour when the car would get hot and let it cool down and top off the radiator, which was low.
Assumption: The falling oil pressure is due to the engine overheating and not vise versa. When the motor is fully cooled the pressure guage stays at 70lbs even when reved to 7k.
WE CURRENTLY HAVE TWO RUNNING THEORIES
1. Water seals in the motor are going.
We are basing this on the fact the problem looks a lot like a head gasket issue on a piston engine.
a couple questions: Would water seals make the car overheat prior to the coolant actually getting low?
also: there doesn't appear to be water in the oil at all. Would this necessarily have to be in order for there to be water seal problems or could I still have bad seals and no water in the oil?
Would the lack of idle be caused by bad water seals?
2. The engine is running lean.
If the motor was running lean, this would cause overheating correct?
This might explain the stumbling at high rpm high load and the lack of idle.
And then the loss of water would be because of overheating.
ALSO: I have felt that we get better tan most track use rotary MPG. We use about 8-9 gallons per 2 hours.
Sorry for the long post but I wanted to get all the info in. Any help would be appreciated greatly.
Specifically, are there any good ways to test both these hypothesis independently?
Please remember it is track only car so can't drive it around the streets to diagnose problems.
We have access to general professional mechanic tools. So we can pressure test / pressurize systems.
Thanks again!
08-12-14, 12:24 PM
#2
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i think #1. water seals can give symptoms like a head gasket, which can vary a bit. usually what happens is that the engine is old, and when you turn it off the ~15psi in the cooling system pushes water into the combustion chamber. however if you're racing the the 150psi in the combustion chamber pushes exhaust into the cooling system, and you'll see coolant loss and over heating etc etc.
easy to diagnose, put your cooling system pressure tester on it, set it to 20-25psi, and see if it holds overnight.
for the missing problem it could be a number of things. first thing to check is the plug wire resistance, if its too high, it'll misfire. second is the cap and rotor. 3rd is the distributor shaft play, this doesn't wear on the street, but it does on a race car.
easy to diagnose, put your cooling system pressure tester on it, set it to 20-25psi, and see if it holds overnight.
for the missing problem it could be a number of things. first thing to check is the plug wire resistance, if its too high, it'll misfire. second is the cap and rotor. 3rd is the distributor shaft play, this doesn't wear on the street, but it does on a race car.
08-12-14, 03:19 PM
#3
Waffles - hmmm good
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Most of the cooling in a rotary is done via the oil cooler. Make sure the coolant system works
well as j9fd3s says but then make sure the oil cooling is working as well too.
Make sure your oil cooler lines are good. If they collapse or otherwise get restricted it will cause
major overheating. If they are original, replace them now. It could help a lot.
well as j9fd3s says but then make sure the oil cooling is working as well too.
Make sure your oil cooler lines are good. If they collapse or otherwise get restricted it will cause
major overheating. If they are original, replace them now. It could help a lot.
08-12-14, 03:46 PM
#4
i think #1. water seals can give symptoms like a head gasket, which can vary a bit. usually what happens is that the engine is old, and when you turn it off the ~15psi in the cooling system pushes water into the combustion chamber. however if you're racing the the 150psi in the combustion chamber pushes exhaust into the cooling system, and you'll see coolant loss and over heating etc etc.
easy to diagnose, put your cooling system pressure tester on it, set it to 20-25psi, and see if it holds overnight.
for the missing problem it could be a number of things. first thing to check is the plug wire resistance, if its too high, it'll misfire. second is the cap and rotor. 3rd is the distributor shaft play, this doesn't wear on the street, but it does on a race car.
easy to diagnose, put your cooling system pressure tester on it, set it to 20-25psi, and see if it holds overnight.
for the missing problem it could be a number of things. first thing to check is the plug wire resistance, if its too high, it'll misfire. second is the cap and rotor. 3rd is the distributor shaft play, this doesn't wear on the street, but it does on a race car.
So a friend of mine also mentioned (for a piston anyway) You can presurize the combuston chamber and look for air bubbles coming out the radiator.
Is there any reason this wouldn't work for a rotary?
08-12-14, 04:29 PM
#5
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the oil cooler does do about 20% of the cooling, and there IS a 30 year old thermostat in there...
i have an old bulletin book that had you check for bad cooling seals just the way you describe, the engine needs to be on TDC, and then you put air into the spark plug hole and see where the bubbles come out.
you may want to try it cold and hot, or just hot.
i have an old bulletin book that had you check for bad cooling seals just the way you describe, the engine needs to be on TDC, and then you put air into the spark plug hole and see where the bubbles come out.
you may want to try it cold and hot, or just hot.
08-12-14, 06:29 PM
#6
Yes, we first thought the issue was overheating from poor oil circulation but as I mentioned, the oil pressure stays at correct levels except for when the car starts to overheat...
Although I realize this is a bit of the old chicken vs. the egg situation.
Its a mechanical oil pump though so I just can't imagine it would go bad. And if pressure is at 70lbs then the regulator must be working, correct?
I suppose the oil cooler could be clogged? I just don't know how to test this... I just know if I try to take those lines off they are going to break.
Probably should have mentioned this but the thermostat is operating correctly... but we took it out anyway so currently running with no thermostat.
Thanks for suggestions. I am trying to be diligent in my testing as I don't want to keep throwing parts at the car if it has a fatal issue, you know.
Doing some testing tonight
Although I realize this is a bit of the old chicken vs. the egg situation.
Its a mechanical oil pump though so I just can't imagine it would go bad. And if pressure is at 70lbs then the regulator must be working, correct?
I suppose the oil cooler could be clogged? I just don't know how to test this... I just know if I try to take those lines off they are going to break.
Probably should have mentioned this but the thermostat is operating correctly... but we took it out anyway so currently running with no thermostat.
Thanks for suggestions. I am trying to be diligent in my testing as I don't want to keep throwing parts at the car if it has a fatal issue, you know.
Doing some testing tonight
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