[DallasSprint]

Fellows:
Have a 59 Giulietta Sprint Normale, running too cold. Had the original 750 manifold and in-line thermostat, was told thermostat open too fast, order new from Centerline but after a couple of months of wait no thermostat. Replaced manifold with a later 750/101 manifold an a new 180 deg later type thermostat. Run better during the summer, however, as soon as the ambient temp. went to below 65 deg. starting to run too cool. I have blocked the rad. with cardboard and now it is up to 180 deg. Is there a better permanent solution?. I was thinking to install a restricting ring at the output of the thermostat but do not know were to start, thanks, Enrique.

 

[Dennie Cliff]

Enrique, you can test your thermostat by placing it in a pan of water on the stove and monitor the water temp with an accurate pyrex glass thermometer. Note the temp when the thermostat opens. Could it be that your water temp guage is inaccurate? These aluminum engines are great for shedding heat. Dennie

 

[750sprint]

Enrique, I would verify your engine temps and accuracy of gauges and related senders before going the Rube Goldberg route. These engines are slow to heat up, but eventually get there. I am betting you have gauge or sender problem. As a side note, some of the very early 1955 Sprints had a radiator blind that was controlled by a cable/chain linkage into the cab interior.

 

[DallasSprint]

Thank you guys for the prompt response:
As you can see on the pics. I added a thermocouple and meter so I can monitor the temp. as I drive. I have piece of towel (not shown on the pic.) wrapped around the thermocouple to avoid external cooling. The reading that you see on the meter is on degrees Centigrade, did this to check the instrument gauge, that to my surprise is very accurate. Today, before noon, I drove for about 20 miles, the ambient temp. was about 70 deg. and the instrument gauge read, at highway speed, 190 deg. and down from there to about 180 as I slowed down. All this with the rad. blocked. I could do away with the cardboard on a day like that but tomorrow it is going to be about 40-50 deg. and should be back on. It is not an easy task to go back and forth with the cardboard. Perhaps the rad blind would be a good idea, but a lot to fab. Still open for suggestions, Enrique.

 

[DallasSprint]

Here are the pictures, thanks.

 

[DallasSprint]

Closing this thread

I got a new thermostat. Tested the old and the new thermostats and they both show to be good. Installed the new. Yesterday I went for a 80 mi. test trip with the new thermostat and NO rad. block. Gauge temp. looked good at 165-170 deg. during the trip with a 30's deg. ambient temp. Why the difference? I can only think would the new thermostat had a faster response. I will wait to summer and see. Can figure how to test for the response time without a chart driven instrument to measure temp. and time at the same time. Thank you all, Enrique.

 

[kuni123456]

I use an inline thermostat on my 101 Sprint Veloce and it works great without a radiator blind. I used to have another inline thermostat that never worked and the engine always ran too cool. I think that the engine runs much better when the water temperature is at 180 degrees just like my two Milanos.

 

[DallasSprint]

KUNI:
I agree, they run a lot better at 180 deg. I would had continued to use the in-line thermostat but after waiting two months for one, not to mention the $80 they want for it. I had the opportunity to find the newer manifold for the 54mm thermostat and I went with that, however even the less expensive ones have their problems that I didn't anticipate but I needed to buy a new one to solved the problem. I think that the fast response of the new one is what helped. The speed of start closing after the temp. has been reached is more critical on these small engines. Perhaps on larger engines is not that problematic. Thank you for your input, Enrique.

 

[kuni123456]

I know that the earlier 750 intake manifolds used an inline thermostat and the later ones had a thermostat in the manifold. The Veloce intake manifolds use an inline thermostat. I had a thermostat that never worked and always was open. I replaced it when I restored the car.