Too cool 2600 spider

[Redmerlin]

I have a 2600 spider and I cannot get sensible readings on the oil and water temperature gauges - at first I thought they didn's work atall.

All I get is


Water Temp

On start moves to 120F

After 20 minute run moves to about 140F

Oil Temp

On start bottom of scale

After 20 minute run moves to 120F

Any Ideas?

Thanks

Ian

[rogerspeed]

In the northeast US I owned a Red 2600 for one year back in the late eighties and put 10,000 miles on it. The car would never get much over 160 and I drove it hard. I imagine with all that alumimun arround a relatively small displacement it radiates heat quite well. In fact when operated in winter below freezing at high speed the engine temperature would actually drop unless one used the blind on the intake in front of air cleaner. You might also want to check that the mixture is not too rich which will also promote cool running.

[Steve O]

Since you undoubtedly are running a thermostat, I would question the accuracy or the gauge in the dash. It is simple to check if you have access to a pyrometer, (either the infrared kind or the older thermocouple probe kind will do.) You get the engine warmed-up, and then take a temp reading in a couple strategic locations, i.e., the thermostat housing (which is the outlet on the intake manifold where the upper radiator hose is attached), center of the top of the cylinder head, top of the radiator, etc. Any auto repair shop, and most well-equipped shade tree home mechanics will have a pyrometer these days, and taking a few readings should take all of about one minute.
If you find the temp readings are consistent with the gauge readings, then I would replace your (screw-in type) thermostat, which is the same as twin-carbed 105s like the Duetto. If the pyrometer readings are a more normal 160-180 deg F, then either re-calibrate your brain to compensate, or find an instrument repair shop to re-calibrate the gauge.
The first, and most important step is discovering at what temperature your engine is actually operating. Then you'll know what needs doing.

[Redmerlin]

Steve 0 / rogerspeed

Thanks for your advice , Yes I do understand that the 2600 spider is massively overcooled, designed to run hours on end at 100mph in 100F plus temperatures. The oustide temp here in the UK is about 50 -60F (10-15C) - So clearly well cooled - after a run I can put my hand flat on the rocker cover and hold it there with no burning ! which suggests no more than 140F (60C).

The only problem with this is if I fully cover the radiator there is no obvious change in indicated temperature.

I too suspect the thermostat - the car has been stored for 10 years and it may have failed open - so far I have been unable to remove it , till I can find a 1 9/16 inch ( or 40mm ) socket

Just for the record

Temp senders give the following

On bench

Water temp sender at 50F (10C) gives 2.20 Kohms , in close to boiling water 200F gives .492 kohms

In car

Water temp sender in stone cold car gives 2.55 kohms in warm car 1.54 kohms - on a linear scale this is approx 120F - so the gauge is probably working

Voltage to gauges is only 11.3 volts that seems low

Thanks for your help

I'll report back on the thermostat swap. If this fails its on to the pyrometer ( my hand was cheaper)

Cheers

Ian

[Steve O]

On my 1964 2600 Sprint, which too did not want to give up its old non-responsive thermostat, I sprayed WD-40 liberally around the threaded area, let that soak for about an hour, then used hefty channel-lock type pliers to carefully thread it out of its long-time home.
Large cooling capacity not withstanding, the engine should run at a 'normal' temp...as you know, that's what the thermostat is there for. Shuttering the radiator should not be necessary to achieve this.
Parts lists show a unique Alfa part number for the 2600 thermostat, which is of course unobtainable. I took the obvious alternative and used a Duetto part (perfect fit, and readily available from IAP, Centerline, etc.), with anti-seize compound on the threads, and my 2600 now operates at the identical 160F winter/spring /summer/or fall -- whether trapped in traffic on the I-15 on a hot August afternoon, or cruising full speed in January. Oil temp follows along, remaining slightly lower unless run for long periods at high speed, (but never goes higher than the coolant temp.)