Thermostat or not?

SLUF

SLUF

New member
My son and I have been racing a first gen RX-7 in IT7 and STU the last few years. We entered the POS-7 in the recent Chumpcar race at Hallett back in August. Everything was going just fine with few problems.

After ten hours and only a clutch problem the engine started to temp spike intermittently. We kept screwing with the cooling system components but just did not catch the problem properly. At hour 13 we finally had a terminal overheat and called it a night/day. Some further troubleshooting showed our thermostat had been sticking. (Yea we should have been all over that right away, I know!)

I have located another 12A for cheap and don't want to make the same mistake twice. Hence the question, thermostat or not? If we delete it should we just knock the guts out of one so there is some form of restriction to allow the water to spend time in the radiator? All our cooling components (hoses, water pump, radiator) were in new or nearly new condition. The car has been absolutely trouble free for almost four years with the exception of this issue. Any thoughts or comments are appreciated. (Even if its just to call us stupid!)
 
Summit sells three different restrictors for this exact application. I have heard most people use the middle size for rx-7s. I do not know the part number off hand but that are not expensive.
 
Gut the stock thermostat. You'll be left with a metal cage. Use that by itself. Make sure to plug the bypass hole underneath the thermostat. A 3/8" NPT plug should do the trick there.
 
Not worth the risk, like Chris said put the gutted thermostat or the red restrictor in there and forget about it. If your engine only takes one overheat to be completely junk, why risk it?

matt
 
Thanks for the input guys. I am leaning towards knocking the guts out of a stock one or the restrictor and giving it a try. First race is not till April so that will give us a chance to "overthink" another solution too!
 
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