Date:         Sun, 30 Mar 2003 10:14:44 -0500
Reply-To:     Ben huot <huotx@VIDEOTRON.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Ben huot <huotx@VIDEOTRON.CA>
Subject:      About head temp & oil temp reading! Air cooled stuff (My
              Conclusion)

Hi guys,
Before a started my trip I didn't have much time to drive the bus very hard
and for a long period of time, as I know mechanic and I did want to be aware
of the engine condition for my 10000 miles journey I bought a Head temp
gauge & sender and a Oil temp gauge & sender from VDO, those where installed
properly following the instruction as to use the right wire gauge for the
oil temp sender and have a independent 12V source for my gauge.

I heard all kinds of story about those gauge, being not accurate, changing
with ambient temperature, stressing the hell out of you on a long run, being
not reliable, OK, now here is my version.

First let me tell you 2 little stories about why I was happy (and sometime
not) to have those gauge (even if they were very stressful, looking at them
every minute or so for 2 month, especially after what am going to tell you
right now).
-In Baja California I almost had a hard attack after filling my fuel tank
from a guy that sell fuel beside the road (no gas station in some remote
place in Baja), 5 minutes after refuelling I looked at my gauge like always
and ... 575F on the head and 260-270 on the oil temp!!!!!!!!! I cannot stop
the bus because there is no place to stop (the MEX1, only highway, as no
shoulder for the most part of it) and I have a 10 wheeler behind me, I
started to panic and drove as slow as I could for the next 10 horrible
minutes until I found I somewhat place to stop, at this time the head temp
gauge is at 600F & oil at about 270F, wile driving I had no smell, no engine
pinging and no real lost of power, I shot down the engine and as I make my
way to the back I am starting to smell a burned oil smell mix with something
else (am in the middle of nowhere), I open the rear hatch and... a plastic
bag is stock in the cooling fan grill!!!! It' yours to conclude if those
gauge save my day!

You won't like the next one.
In Arizona, I am witnessing an increase in head temp and a small one in oil
temp, I keep on driving as those gauge vary quite a bit, especially with
outside temp (Oil) variation, after 20-30 minute the head temp is going
toward the 475F marks, I stop the bus and try to find the problem, found
nothing, keep on driving, same problem is starting again! Reach a campground
and start looking seriously. Conclusion: Thermostat is stuck in the close
position!   At this time the head temp sender was on #1 cyl. (I switch from
1 to 3, 3 times in my trip)

This is what I have to say about my 2 gauge.
The exact lecture is for sure not very precise to a certain degree, but in
average it gives you a good idea of what is the engine condition, what you
need to look for is not those small variation but the big one. The head temp
DOESN'T vary with outside temperature as everyone were stating before my
trip, I know that what you guys were saying made sense but!!! I drove my bus
from -5F to 95F range. The oil temp will vary a lot (depending on the
location of this one, colder outside = colder reading) when the outside temp
change. Especially if you have the sender on the oils sump plate like me.

Here were my average readings. (You should know that my head temp is at 125F
instead of being at the100F mark when the engine is not running and cold?)
-Head temp at Idle: Head temp goes quickly down even after a 5 hours run, it
stays cold in traffic, between 250F and 300F, it will climb back up very
fast, the reaction of the head temp is instant as compare to the oil temp
who is slower to react.
-Oil temp at idle (after a long run in traffic): going slowly down to the
170F-190F ranges.
-Head temp on freeway (any outside temp): 400F to 440F, mostly in the 425F
area for most of the time (yes, it should be in the 375F-400F range).
-Oil temp on freeway: Well, at 32F outside ambient temp the oil temp is at
180F to 190F, at 75F outside the oil temp is at 200F to 220F, it did climb
to 230-240 at 95F outside temp. This gauge also act like an outside
thermometer, without opening a windows we did know that the outside temp was
going down when the gauge was going down!
-Head temp when Climbing (70F outside): if in third gear, temp is going
down, if in fourth gear, steady or going up a bit. (more rev = less heat =
fan spinning)
-Oil temp when climbing (70F outside): Going up in third gear and can reach
the 250F-260F range if the climb is long, doesn't climb as much in fourth
gear, same for heavy head wind.

Conclusion: use those gauges as a reference, a bit above or bellow the
center mark for the head temp gauge is fine. A bit below the center mark for
the oil gauge is fine. The #3 head cylinder temp as not much variation
compare to # 1 and 2.

Data:
Fuel use was 91oct when possible, no variation in power, temperature when
using regular, super or medium! I probably fill my bus more than 40-50 times
with all kind of Fuel Company and grade. Fuel consumption was on the high
side, at best I had about 15-16 mpg, at the end I was more like in the 12mpg
range (Carbs problems)

Oil was Castrol10W40 going down and 20W50 in the south. Change every 3000miles.

Timing was 8-10btdc (when possible) and 32-34 total advance (stock distributor)

Carbs sucks, period, they flooded the left side plug (#3 and 4) all the
time, jetting the solex didn't help much, I was fuel jetted X130 on the
right side and X127.5 on the left side, air regulation jet was .140 to.152
on the left side and .140 on the right side, at the best I had a brown plug
on the left side after 1500 miles and nice one on the right side.

Cheers, Ben
http://www3.sympatico.ca/huotx/engine1.htm