88 or 82 degree thermostat for 390SE
Discussion
Beginning to think it might have been a lot easier had I bought a 400SE as there seems to be no information for 390's whatsoever!
Anyways Rover would've used 88 degree stat I believe - wedge handbook which is supposed to be written around 390SE syas TVR use one that opens at 74 degrees instead of 82 (which doesn't amke any sense at all and is way too low as far as I can see).
So I'm stuck between deciding over stock 88 degree Rover or TVR large valve 82 degree as used in the Chim.
Does it even matter? The coolant temp sensor resistence map seems to suggest it does and too lower thermostat will screw with the ECU.
Which way should I jump?
Anyways Rover would've used 88 degree stat I believe - wedge handbook which is supposed to be written around 390SE syas TVR use one that opens at 74 degrees instead of 82 (which doesn't amke any sense at all and is way too low as far as I can see).
So I'm stuck between deciding over stock 88 degree Rover or TVR large valve 82 degree as used in the Chim.
Does it even matter? The coolant temp sensor resistence map seems to suggest it does and too lower thermostat will screw with the ECU.
Which way should I jump?
Wedg1e said:
Well just to be awkward 
my car runs an 82 according to my history file, yet the temperature gauge tends to hover around 88-90 most of the time so maybe there's a sensor/ gauge mismatch.
No mismatch - methinks, it seems your observations confirm exactly what my research and personal opinion suggests. - ie: my car runs an 82 according to my history file, yet the temperature gauge tends to hover around 88-90 most of the time so maybe there's a sensor/ gauge mismatch.HJ2 says - Lifted directly from 3rd last para of the reference PDF said:
..... if the owner desires. Indeed it's not uncommon to see the thermostat specified at 82 deg C which would give an engine operating temperature a few degree higher, at say 85 to 90 degrees C. .....
Your 88 - 90 is firmly inside my 85 - 90.But, as my PDF debates, IMHO about 5 - 8 degrees too low for an original spec 3.5 Efi Flapper.
With any variant tho', when the engine is hot, ask the following questions:-
- Does you engine run a tad rich with excellent idle speed and low rpm torque?
- Is the cruising mpg lower than you might honestly expect?
- Are the spark plugs and tailpipe blacker than you would like?
So today I put the 88 degree thermostat in and guess what I found when I opened the thermostat housing?
An 88 degree thermostat already fitted! Weird.
I replaced it anyway, ran her up and still running cool. So then I thought "timing!" and with my newly acquired pointer and marking spotting skills (cheers Dave) I discovered that at idle it was only 2 degrees BTDC.
Not at all right - ignoring the manual I plumped for just over 30 degrees all in which worked out just below 10 degrees at idle. Still got my intermittent Holding back issue but feels better anyway and runs at a better temp although still generally below 90.
As a result of advancing the timing my idle speed has risen so I need to have a go at that. I did notice that the fan seems to come in quite early and just wondered if someone's stuck a lower temp otter switch in. Sure I'll get to the bottom of it...
An 88 degree thermostat already fitted! Weird.
I replaced it anyway, ran her up and still running cool. So then I thought "timing!" and with my newly acquired pointer and marking spotting skills (cheers Dave) I discovered that at idle it was only 2 degrees BTDC.
Not at all right - ignoring the manual I plumped for just over 30 degrees all in which worked out just below 10 degrees at idle. Still got my intermittent Holding back issue but feels better anyway and runs at a better temp although still generally below 90.
As a result of advancing the timing my idle speed has risen so I need to have a go at that. I did notice that the fan seems to come in quite early and just wondered if someone's stuck a lower temp otter switch in. Sure I'll get to the bottom of it...
smash said:
So today I put the 88 degree thermostat in and guess what I found when I opened the thermostat housing?
An 88 degree thermostat already fitted! Weird.
I replaced it anyway, ran her up and still running cool. So then I thought "timing!" and with my newly acquired pointer and marking spotting skills (cheers Dave) I discovered that at idle it was only 2 degrees BTDC.
Not at all right - ignoring the manual I plumped for just over 30 degrees all in which worked out just below 10 degrees at idle. Still got my intermittent Holding back issue but feels better anyway and runs at a better temp although still generally below 90.
As a result of advancing the timing my idle speed has risen so I need to have a go at that. I did notice that the fan seems to come in quite early and just wondered if someone's stuck a lower temp otter switch in. Sure I'll get to the bottom of it...
The temp sensor and gauge is perhaps not 100% accurate, try a laser thermometer and calibrate it against a pan of boiling water.An 88 degree thermostat already fitted! Weird.
I replaced it anyway, ran her up and still running cool. So then I thought "timing!" and with my newly acquired pointer and marking spotting skills (cheers Dave) I discovered that at idle it was only 2 degrees BTDC.
Not at all right - ignoring the manual I plumped for just over 30 degrees all in which worked out just below 10 degrees at idle. Still got my intermittent Holding back issue but feels better anyway and runs at a better temp although still generally below 90.
As a result of advancing the timing my idle speed has risen so I need to have a go at that. I did notice that the fan seems to come in quite early and just wondered if someone's stuck a lower temp otter switch in. Sure I'll get to the bottom of it...
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