Interesting readings - degas bottle pressure
#1
11-13-2011, 04:11 PM
Interesting readings - degas bottle pressure
I finally got around to hooking up my pressure gauge on the degas bottle again (AFTER the installation of my head studs).
The readings I am getting are around 4-5 psig after I get the coolant temps to 190 degrees F - steady-state conditions. This is no doubt due to the fluid expansion from the heat-up cycle. When I stomp on it, I can MAYBE get it up to 8 or 9 psig now.
As far as I recall (pretty sure of it), this is 3-4 psig less than what I had before the head studs were installed. I am looking for the old data (I know it is somewhere, but recovering my hard drive after the crash is a pain!!).
I had .002 shaved off of the heads when I had the work done. I am wondering if the TTY bolts stretch just enough under max boost (or cylinder pressure) to allow just a little combustion gas into the coolant each time?
The readings I am getting are around 4-5 psig after I get the coolant temps to 190 degrees F - steady-state conditions. This is no doubt due to the fluid expansion from the heat-up cycle. When I stomp on it, I can MAYBE get it up to 8 or 9 psig now.
As far as I recall (pretty sure of it), this is 3-4 psig less than what I had before the head studs were installed. I am looking for the old data (I know it is somewhere, but recovering my hard drive after the crash is a pain!!).
I had .002 shaved off of the heads when I had the work done. I am wondering if the TTY bolts stretch just enough under max boost (or cylinder pressure) to allow just a little combustion gas into the coolant each time?
#3
11-13-2011, 04:25 PM
#4
11-13-2011, 05:57 PM
Did you get a chance to look at the head gaskets that came off your truck? On a gasser, once cylinder pressure makes it's way past the the metal part of the gasket around the cylinder, the path it took gets larger quick. In just a couple hundred miles a pin hole will often erode to the size of of a pencil lead or larger. I would imagine with the higher cylinder pressures of a diesel that process would happen even quicker. I'm sure you would have caught it on tear down if it had been leaking, even just a little. Did they do a flush or put fresh coolant in it? Maybe the cooling system is just working better now? Was the tuner on both times you checked pressure? Was it the same gauge? It's interesting it would act that way.
#5
11-13-2011, 06:20 PM
No tuner before the studs.
No flush, just replaced the coolant that was drained out.
I did not see the gaskets that came out (didn't see the heads or the block deck either). I was told that they looked to be in good shape. The work was done for me by Trucks Unlimited while I took a vacation in the Smokies!
It might be something in the coolant system, but the ECT's are 190 (maybe a few degrees cooler than before)/ I did install the BPD water pump w/ the billet aluminum impellor.
Edit (as an FYI):
I have a Quadzilla Recon XZT gauge system (it actually will measure 4 inputs: EGT's, Boost, fuel pressure and a second temperature). I use it to measure EGT's and fuel pressure. They don't sell it anymore, but I love it. I bought an extra pressure transducer (sending unit) and tee-ed it into the degas bottle tubing. I can then just disconnect the electrical connector and switch between the degas bottle pressure and fuel pressure and read it from the cab.
No flush, just replaced the coolant that was drained out.
I did not see the gaskets that came out (didn't see the heads or the block deck either). I was told that they looked to be in good shape. The work was done for me by Trucks Unlimited while I took a vacation in the Smokies!
It might be something in the coolant system, but the ECT's are 190 (maybe a few degrees cooler than before)/ I did install the BPD water pump w/ the billet aluminum impellor.
Edit (as an FYI):
I have a Quadzilla Recon XZT gauge system (it actually will measure 4 inputs: EGT's, Boost, fuel pressure and a second temperature). I use it to measure EGT's and fuel pressure. They don't sell it anymore, but I love it. I bought an extra pressure transducer (sending unit) and tee-ed it into the degas bottle tubing. I can then just disconnect the electrical connector and switch between the degas bottle pressure and fuel pressure and read it from the cab.
#7
11-13-2011, 08:28 PM
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#8
11-13-2011, 09:03 PM
Here is my post / the past pressure data:
https://www.ford-trucks.com/forums/1...ml#post9856694
https://www.ford-trucks.com/forums/1...ml#post9856694
I finally switched my fuel pressure gauge to the coolant reservoir (degas bottle). The objective is to see what typical pressure is in the reservoir and what effect, if any, a series of WOT events has on the pressure.
Here is my data:
Since the system was opened for the installation, the pressure after installing the gauge was 0 psig (calibration check).
Began drivingwith ambient temps around 34*F. Coolant temperature rose to 120*F before I saw 1 psig on the gauge.
As the temperature rose to 190*F, the pressure steadily increased to 6 psig.
After oil temps stabilized, the pressure stayed at 7 psig.
First WOT run - the pressure rose to 9 psig.
Within 10-15 seconds after the WOT run, the pressure dropped back to 7 psig.
I did a series of 4 back-to-back WOT runs and each time the pressure rose to 9 psig except for the last one and it "flickered" like it was almost at 10 psig.
Just as before, the pressure dropped quickly back to 7 psig every time.
The initial pressure rise was "as expected" as the coolant heated up and expended. The extra pressure during the WOT events was slight and also not un-expeced. It seems to me that there was no generation of any appreciable non-condensible gas since the pressure readily returned to the base state of 7 psig.
It was cold enough that my ECT's were stable at 185-187 before the WOT's. Maybe hit 190 during the WOT runs and then dropped back down the 3-4 degrees.
After a week of operating w/ the degas bottle pressure gauge, I am moving it back to the fuel pressure service.
The data in the last week has been essentially identical every day of driving. I will say that my baseline measurements did shift up by one psig (the only change I saw). The initial 7-8 psig at operating temps shifted to 8-9 psig. I assume because my degas bottle is not dropping back completely to zero when it cools. The way it behaved on every WOT was identical to what was previously described (except shifted up 1 psig). I verified that the system is holding pressure by watching the pressure reading every 15 minutes or so while it sat cooling off. The pressure profile looked the same (in reverse) during the cool-down as it did in the heat-up. The pressure dropped only in response to the temperature change.
Here is my data:
Since the system was opened for the installation, the pressure after installing the gauge was 0 psig (calibration check).
Began drivingwith ambient temps around 34*F. Coolant temperature rose to 120*F before I saw 1 psig on the gauge.
As the temperature rose to 190*F, the pressure steadily increased to 6 psig.
After oil temps stabilized, the pressure stayed at 7 psig.
First WOT run - the pressure rose to 9 psig.
Within 10-15 seconds after the WOT run, the pressure dropped back to 7 psig.
I did a series of 4 back-to-back WOT runs and each time the pressure rose to 9 psig except for the last one and it "flickered" like it was almost at 10 psig.
Just as before, the pressure dropped quickly back to 7 psig every time.
The initial pressure rise was "as expected" as the coolant heated up and expended. The extra pressure during the WOT events was slight and also not un-expeced. It seems to me that there was no generation of any appreciable non-condensible gas since the pressure readily returned to the base state of 7 psig.
It was cold enough that my ECT's were stable at 185-187 before the WOT's. Maybe hit 190 during the WOT runs and then dropped back down the 3-4 degrees.
After a week of operating w/ the degas bottle pressure gauge, I am moving it back to the fuel pressure service.
The data in the last week has been essentially identical every day of driving. I will say that my baseline measurements did shift up by one psig (the only change I saw). The initial 7-8 psig at operating temps shifted to 8-9 psig. I assume because my degas bottle is not dropping back completely to zero when it cools. The way it behaved on every WOT was identical to what was previously described (except shifted up 1 psig). I verified that the system is holding pressure by watching the pressure reading every 15 minutes or so while it sat cooling off. The pressure profile looked the same (in reverse) during the cool-down as it did in the heat-up. The pressure dropped only in response to the temperature change.
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