[T2] CHT with Dakota gauge

[Sami Dakhlia]

Thank yo all for the feedback. I guess it's time for me to stop
pretending the readings are false and save for new cylinder heads. But
first I will need to figure out WHY it has been running so hot. AFAIK,
nothing major was changed since I've had this engine, so it most
likely has been running hot since day 1. Now I did replace the old
wobbly dual vac distributor with a new SVDA last summer. I timed the
new distributor at 7.5 BTDC (as opposed to 5 ATDC for the dual vac.)
Other guesses:
- When installing the thermocouple ring under the spark plug, I did
not realize that there is a slight recess in the head. The ring got
stretched to an oval shape. Took it back out, and used pliers to put a
proper 90 degrees bend at the base of ring. Still, it's possible that
there is some leakage at the plug now and that the hot exhaust is
contributing to the high readings. BTW, I did pull the plug again
yesterday morning and found that it was snug, but not tight. Inspected
it and saw nothing remarkable; put it back on, properly tightened; the
temp reading were a tad lower yesterday, by about 10-15 degrees on
average.
- It's a '75 bus with the original fuel-injection system. The bus
originally came with a 1.8 liter engine, but the new one is a 2 liter
engine. I worked on the assumption that the airflow meter and CPU
would not care. Maybe I've been wrong.
- Either way, I would guess that it's running too lean.

Am now in San Diego and will head back to LA on Monday. Any advice on
simple measures to take until then?

Cheers,
Sami


On Wed, Aug 19, 2015 at 9:22 PM, c.dreike <c.dreike at verizon.net> wrote:
> Sami,
> I have a Dakota Digital CHT gage on my type 1 engine. TC's on #1 and #3. I
> can swap connectors in the cab to check both sides. Currently 1 side reads
> about 20F higher than the other. Not sure which side is which just yet.
> However the temp reading on the Higher one runs tops 390 running really hard
> on the freeway. Usual speeds 60-65mph temp runs in the 340-360 range. I need
> to do a little trouble shooting to figure out which reading goes with which
> side of the engine and which one is correct.
> The sensors are of the ring lug type that fits on the spark plug threads.
> Plug tips look perfect.
>
> I'm running fuel injection with a Mexi-bug throttle body/intake manifold and
> a Megasquirt controller. Used the automatic tuning option to set up.
> I also have a wide band meter. A/F ratio runs at about 12.2:1 at WOT, medium
> load on freeway runs around 12.6-13:1, foot off throttle at freeway speeds
> 13-16:1. Maximum spark advance is currently 34 degrees. Thinking about
> dropping that to 32. Have fully electronic ignition (No Dizzy!!).
>
> Anyone have thoughts on the AF ratio's? Or the advance?
>
> Thanks,
> Chris
> 64DD Kamper Kit
>
>
>
> On 8/19/2015 8:13 PM, Sami Dakhlia wrote:
>>
>> I lied about the thermostat: cable got loose, which would explain the big
>> temp variation. As for the level, still no explanation. But the gauge
>> already reads 340 at idle, so I'm not going to worry.
>> Sami
>>
>> On Wednesday, August 19, 2015, Sami Dakhlia <sami.dakhlia at gmail.com>
>> wrote:
>>
>>> hi Volks,
>>> Installed a Dakota Digital cylinder head temp gauge (hat tip to R.
>>> Atwell)
>>> and took off this morning on a trip from the Bay Area to Santa Barbara.
>>> Holy $h!t! The readings are much higher than I thought was the norm.
>>> Basically cruising at 55 mph, with
>>>
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