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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1535
Registered: 6-2009
Posted on Wednesday, 22 July, 2015 - 11:34 am:   Edit PostDelete PostView Post/Check IP

I am hoping that this thread might end up being the repository for this data for a number of SY cars produced over the life of the model, which I'm quite certain will vary to some degree.

This first set of data from me is from SRH33576 from a drive of approximately 36 miles on a day with ambient temperatures between 86 and 90 F (30 and 32.2C). The air conditioning was on the entire time and the auxiliary electric fan was not observed to be on at any time, including at the peak measured temperature.

When I looked back at my service records I realized that I have never installed the correct Stant thermostat in this car. The one I put in was a 13649 which was later determined to be unable to close the bypass when completely open; the disc is about 10mm above the bypass port when maximally open. That being said, the car does not overheat if one considers overheating either boiling the coolant or the needle going above the white zone. The behavior I've seen with this thermostat is entirely consistent with what was occurring with the original UE36600 before it was changed out (which is why I've never felt really pressed to rush out and install a correct Stant 13558/NAPA 136).

Measurement Data

15.9 mi/25.6 km traveled

Needle position: ~ 1/3 up the white band (normal resting place during cold months)

202.4F / 94.7C upon stopping
210.9F / 99.4C after running in place for about 30 seconds

Heat soak during the stop to fuel up pushed the needle up from about 1/3 of the way up the white band to a bit above 1/2 when restarting
__________________________________________________

33.9 mi/54.6 km traveled

Needle position: around 1/2 way up the white band and stable there during driving at speeds between 25 MPH and 70 MPH with most being around 55-60 MPH

218.3F / 103.5C upon stopping
224.7F / 107.1C after running in place for about 30 seconds
220.1F / 104.5C around 45 seconds

Heat soak while parked pushed the needle to just ever so slightly below the top of the white band upon restarting
__________________________________________________

36.1 mi/58.1 km traveled, 2.2 miles between last stop and home, stopped at several traffic lights and maximum speed was about 45 MPH, most travel around 30 MPH

Needle Position: During the drive home the needle went back down from its high point to between 1/2 and 2/3 way up the white band

214.7F / 101.5C immediately after stopping
220.1F / 104.5C about 30 to 40 seconds after having stopped
217.5F / 103.1C a few moments later


I presume I might get a bit better control with the Stant 13558/NAPA 136 since it can close the bypass, but I doubt the overall "contour" would change all that much. The "low normal" position of the needle about 1/3 way into the white band is clearly at least 12 F above opening temperature of 192 F [which I am guessing would have a needle position of the very bottom of the white band].

General Tools & Instruments IR Thermometer model number IRT207 used to take readings.

I wish I had taken a reading just before restarting the engine during my last stop before home since that would have given a fairly clear picture of what temperature is represented near to the very top of the white band (at least on SRH33576).

Brian
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Christian S. Hansen
Experienced User
Username: enquiring_mind

Post Number: 33
Registered: 4-2015
Posted on Wednesday, 22 July, 2015 - 02:04 pm:   Edit PostDelete PostView Post/Check IP

Brian...
Your attention to detail is impressive, but unless I misread, perhaps consider indicating the temp monitoring locations in order to provide a control standard. Back when I was stressing (what did you say? torturing?) myself over mine, I found that readings would be all over the place depending on where taken.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1537
Registered: 6-2009
Posted on Wednesday, 22 July, 2015 - 02:09 pm:   Edit PostDelete PostView Post/Check IP

Christian,

That was an accidental omission on my part. All temperature readings were taken on the top of the thermostat housing.

I also did a couple at the inlet to the radiator, but they varied just the slightest bit from the top of the thermostat housing. Those were neither recorded nor reported here.

I was hoping to get readings at the outlet to the lower radiator hose but that's tricky in practice when you're in a hurry.

I agree that the data is pretty useless unless the temperatures are being taken at the same location. I also kept the IR thermometer within 6-8 inches of the housing so that it would be very narrowly focused as far as its "reading spot" goes.

On a related note, way back in April when you chimed in with your first concerns about your car's operating temperature on a thread I'd started about the auxiliary fan, Paul Yorke mentioned that you should check to make sure your radiator (and, I'd think, AC condenser) were free of crud that would prevent air from flowing. Given a recent thread entitled, Car running hot, on rollsroyceforums.com, and the fact that this was a resolution to at least one person's major overheating at idle problem, it's worth pursuing that avenue.

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 861
Registered: 5-2012
Posted on Wednesday, 22 July, 2015 - 02:31 pm:   Edit PostDelete PostView Post/Check IP

Christian

I also read the thread Brian has just mentioned. What amused me was rather than hiring a pressure cleaner the owner just loosened the grill/rad cover so he could easily remove it and drove the car round to the local car (jet) wash and used their sprayer at a fraction of the cost. Best done out of sight of the owner/manager I would have thought.

Geoff
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1538
Registered: 6-2009
Posted on Wednesday, 22 July, 2015 - 11:50 pm:   Edit PostDelete PostView Post/Check IP

Geoff,

I doubt most car wash owners (at least where I live) would care. All of them have "Use is completely at your own risk" signage up and while spraying the radiator I guess could damage the car (but that's mighty unlikely) I can't see how it could damage the sprayer itself at all.

I've seen people pulling in to the local car washes with all sorts of things in pick-up truck beds and using the power sprayers to hose them down. No one blinks an eye. I am certain, however, that attitudes toward this practice vary by location.

Brian
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Chris Browne
Prolific User
Username: chrisb

Post Number: 224
Registered: 2-2010
Posted on Thursday, 23 July, 2015 - 05:56 pm:   Edit PostDelete PostView Post/Check IP

Hello Brian,

Thanks for posting this data. It makes for very interesting reading and it will be useful if a few message boarders can post relevant figures for their cars so we can all get some idea of what is "normal range". When I next take my Shadow 2 out (SRH37131 1979), I will compile the same list as yours and post it here. The only difference in my car is that I fitted a new OE thermostat recently.

Kind regards,

Chris
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1544
Registered: 6-2009
Posted on Thursday, 23 July, 2015 - 11:32 pm:   Edit PostDelete PostView Post/Check IP

Chris,

Additional data would be most useful to have. Your Shadow II and my Wraith II are only 21 chassis numbers apart. I have no sense regarding how many cars might have been "under construction" at Crewe at any moment in time, but if they weren't there together then mine "was born" only ever so slightly later than yours.

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 865
Registered: 5-2012
Posted on Friday, 24 July, 2015 - 01:27 am:   Edit PostDelete PostView Post/Check IP

Hi Brian

I doubt most car wash owners (at least where I live) would care.

I'm still in small country mode, where I still think rules and regulations apply to the whole country.

In Las Vegas most car wash owners are strict about not allowing the washing off of excessive amounts of oil and gunge in their facilities. Water is collected and recycled in Las Vegas car washes, reducing the amount of fresh water that needs to be used. You can understand their reluctance in having their expensive kit being too abused.

Useful information though. I doubt the State of Florida is too fussed. Anything goes here - lol.

I too will be putting up temperature data, just as soon as I have driven the car a reasonable distance.

Geoff
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 921
Registered: 5-2012
Posted on Thursday, 20 August, 2015 - 06:23 am:   Edit PostDelete PostView Post/Check IP

Hi Folks

I went for a 15 mile drive earlier today, which gave me an opportunity to check out my newly fitted temperature gauge. The car is a 74 SY1 (SRX18501). The results were quite interesting.

Previous measurements taken from the top of the thermostat housing with an IR thermometer gave figures of around 190F. This was consistent with temperatures reported by other SY1 owners. I was expecting the readings from my in car temperature gauge to be roughly the same.

On traveling about 3 miles, the temperature increased quite rapidly to 195F. From this point, the temperature rise was much slower, consistent with the thermostat opening, eventually plateauing at 205F. Far higher than I expected. This figure was achieved after 9-10 miles and then remained fairly constant, wandering up to 206-7F at traffic lights and then back down to 205F as the car proceeded.

On returning home I took a reading with the IR thermometer from the top of the thermostat housing which came out as 188F. Concerned that the new thermometer gauge was wildly inaccurate I took another reading with the IR thermometer. This time it was through the gap near the carbs and on the plate that now houses the temperature sender unit.

temp

The red arrow points to the position from which I took the IR reading. The brass fitting is the new sender plug.

From this new position I recorded a temperature of 201F. This is entirely consistent with the temperature displayed by the car's temperature gauge, being 205F. The 4F discrepancy either being due to the sender measuring the internal water temperature, or inaccuracies between the two instruments, albeit well within their stated tolerances.

It looks like my SY1 is achieving the same temperatures as Brian's SY2, after the shorter 15 mile drive.

I have yet to carry out a longer "heat soak" journey, the results of which will be interesting.

I have no idea why my top of thermostat reading, confirmed again today, should be so much lower than the actual crankcase water temperature. Maybe the paint on the housing is offering some insulation from the hot coolant passing within, or maybe the fan is offering more cooling effect than expected on the housing, which is in an exposed position.

Ambient temperature was 88F, cabin temp, 120F. Since I had just renewed the coolant I needed to make sure it was circulating the heater matrix properly and blowing hot air. Got quite warm in there.

Geoff
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1613
Registered: 6-2009
Posted on Friday, 21 August, 2015 - 01:24 am:   Edit PostDelete PostView Post/Check IP

Geoff,

I cannot recall at the moment, but where does the input to the heater core take off from the main cooling system and the output from the heater core get dumped back in?

If the water that's gone through the heater core is being reintroduced into the system not far upstream of the thermostat housing the cooling effect from the heater core (a secondary radiator, for all practical intents and purposes) could easily drop your temperature at the top of the thermostat housing.

Brian
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1614
Registered: 6-2009
Posted on Friday, 21 August, 2015 - 11:06 am:   Edit PostDelete PostView Post/Check IP

Geoff,

You inspired me to take another "sundown pleasure cruise" this evening after a day of doing coat two of cutting in on my living room walls. Of course, this involved temperature data collection as well.

Ambient temperature started out around 81 F before sunset and dropped only a couple of degrees to 79 F by the time I returned an hour later. I did not use the climate control system at all for the first 20 miles of travel.

Measurement Data

3.4 mi traveled shortly after temp gauge sprung to its 1/3 way up the white band

190.7 F on thermostat housing
192.0 F on "triangle plate"

15.8 mi traveled

194.5 F TH
196.1 F TP

24.0 mi traveled climate control turned on to full hot at 20 miles and allowed to run that way until this temperature check

201.2 F TH
197.8 F TP

which, based on the next measurement, suggests to me that the heater core acts as a pretty decent radiator. Even at full hot the air was only truly full hot for about 1 minute and then the system started mixing things with very warm air coming out in the foot wells and air that was a bit above ambient temperature coming out the bullet vents. The compressor, of course, runs continuously even when full heat is on in an SY2 to dehumidify the air before processing it further.

34.4 mi traveled climate control set to full cold as soon as the 24 mi measurements were taken and left this way for the remaining 10.4 miles

208.2 F TH
206.1 F TP

having the AC running without the heater core taking some waste heat out of the equation (or at least not nearly as much) results in temperatures that are significantly higher.

Any time I stopped I did notice that the temperature would increase after the car was stationary for a short while, just like it did on my last trip, but I didn't bother recording these. I did not turn the car off on this trip so there are no post-parked heat soak on starting readings.

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 926
Registered: 5-2012
Posted on Saturday, 22 August, 2015 - 12:31 am:   Edit PostDelete PostView Post/Check IP

Hi Brian

I also went for a longer, 35 mile drive yesterday. Ambient temperature was 88F. I did not use the aircon (mad dogs and Englishmen) and left the heater turned off. The drive included a 20 mile section at 65-70 MPH, the rest being stop-start in city traffic. Once up to temperature the gauge reading was, fairly steady at 208F, creeping up to 210F on extended waits at some traffic lights.

This has been really useful to me. I now have a datum line for my engine temperature - 208F. From Brian's readings, I know I can safely go up to 218-220F. After that I'd start to get concerned.

Next drive I will remember to run the A/C and see how it affects the engine temperature.

Interestingly, even after my longer, "heat soak" drive the top of the thermostat housing still read 190F. I checked out the connections for the heater, but they return to the radiator and water pump at a sufficient distance not to influence the thermostat housing temperature too much.

Geoff