In head T-stat conversion

[johndemar]

To those of you that have done this I have a question before I go randomly ordering parts.

What did you use for the lower hose? Currently have the original set up with the external stat. Will the lower hose from a '74 work?

I seem to remember reading something that a hose from a '74 TC special coupe fit well.

Both Vick and IAP sell the same hose for both the 73 and 74 and Bayless sells the hose for the '74 TC coupe.

Did the '74 have the alternator on the passenger side? If not, that may be another issue to overcome.

John

[So Cal Mark]

I'd advise against that conversion for a couple of reasons; first, there isn't any bypass so you get zero circulation until the stat opens and second,the bolts holding the water outlet tend to strip very easily. Since that outlet will be taken off more frequently, your chances of needing thread repair increase greatly.

[mbouse]

i had the same thoughts, once upon a time.

dont do it, said all the 'sperts; you'll just be asking for more heat related issues than you could shake a stick at.

[johndemar]

i had the same thoughts, once upon a time.

dont do it, said all the 'sperts; you'll just be asking for more heat related issues than you could shake a stick at.

Fiat switched back and forth with the internal and external stats. Do the cars with the in head thermostat really have cooling issues? I'm really only considering it because it would make a cleaner look.

[mdrburchette]

I've got one 1608 with the original setup and one 1608 with the conversion. I was concerned about hot spots at the back of the head or a spike in head temps with the internal thermostat but I checked the temps while the car was warming up and I couldn't find any concerns whatsoever. I've not had to replace the internal thermostat so I don't know how I'll like the process of replacing it or if I'll have the problem Mark is talking about, but it does clean the engine compartment up a bit. Also, all the racers run the internal thermostat.

[johndemar]

I've got one 1608 with the original setup and one 1608 with the conversion. I was concerned about hot spots at the back of the head or a spike in head temps with the internal thermostat but I checked the temps while the car was warming up and I couldn't find any concerns whatsoever. I've not had to replace the internal thermostat so I don't know how I'll like the process of replacing it or if I'll have the problem Mark is talking about, but it does clean the engine compartment up a bit. Also, all the racers run the internal thermostat.

Thanks Denise.......If I do this (and I'll still have to find a hose that works) I was going to use anti-seize on all of the bolts and be careful with the torque specs on them. Hopefully that will address the potential thread problem.
Did you use an infrared tester to measure the head temps?

[karhawk]

I've got one 1608 with the original setup and one 1608 with the conversion. I was concerned about hot spots at the back of the head or a spike in head temps with the internal thermostat but I checked the temps while the car was warming up and I couldn't find any concerns whatsoever. I've not had to replace the internal thermostat so I don't know how I'll like the process of replacing it or if I'll have the problem Mark is talking about, but it does clean the engine compartment up a bit. Also, all the racers run the internal thermostat.

Thanks Denise.......If I do this (and I'll still have to find a hose that works) I was going to use anti-seize on all of the bolts and be careful with the torque specs on them. Hopefully that will address the potential thread problem.
Did you use an infrared tester to measure the head temps?

The hose we used was Gates number 21897, you have to cut about 4 " off both ends, match it up before cutting. The clean way is to use the early outlet and make sure you use two rubber gaskets top and bottom to the GM t-stat, also Fiat made a gasket with a slit in the center that the t-stat slid into. We just blocked off the T on ours and utilized the same upper hose. To avoid having to burp the system we drilled a 1/8" hole in the flange of the t-stat.

Chris
Oakland, Ca.

P.S.
We used a 160 degree t-stat so it opens a little sooner

[mdrburchette]

I did use an infared thermometer and, if memory serves, the fan came on with the hottest temp being around 190. I was especially concerned since I wasn't sure I had all the air out of the system after a radiator repair and actually found the head sender to be faulty after using the infared thermometer. I'm not sure which engine FIat used the internal t-stat with so I can't help you with the hose to use.

[So Cal Mark]

Fiat didn't switch back and forth, only the early cars had the stat in the head. Once they switched to the external unit, all of the Spiders used it. Other than some minor esthetics, why switch from one that is so accessible?. On a race car, I wouldn't use a stat, just a restrictor in a hose so there is one less item to fail

[mbouse]

Both Vick and IAP sell the same hose for both the 73 and 74 and Bayless sells the hose for the '74 TC coupe.

i am betting if you asked these mentioned parts suppliers, they too would recommend against the conversion for the same reason i mentioned earlier.