Stooopid Question
 

I have looked, but I can't seem to find one. I need a higher spring pressure (higher release pressure) water neck cap for an 88 13b NA motor. I have tried 3 rad caps and they all release under pressure, but the 14 - 16 lb Stant cap on the radiator never releases. So I guess I am looking for a 14 lb rad cap for the 86 to 88 water neck fill neck. Before everyone goes all snakey, the car doesn't overheat, only gets to about 220, but the cap releases any time I get the car over 200. I personally think its due to the fact that I have sealed the water pump bypass and the extra water flow may be lifting the cap off its seat. I don't know, its just a guess.

Anyone have any ideas as I am tired of cleaning the engine bay after every race day?

Eric

you have options here!

first is to switch to the non return style of filler cap adaptor, the part is N3C1-15-175, or you can just "borrow" one from an FD. then you simply run a fill cap, and not a pressure cap. several part numbers, KL15-15-205A is maybe the newest.

the v6 626 had a 1.1 bar cap, KL01-15-205. unlike a stant the Mazda caps will actually consistently hold the rated pressure. i've found the stant caps to be such poor quality that maybe 1/5 holds the pressure its supposed to.

there are also JDM 1.3 bar caps out there, Mazdaspeed and billion sell em, but they are $$ and not easy to get.

would it be easier to block off the cap plate and put a bleed screw on it?
or would that be un-safe on the track you run at?

Thanks, that's exactly what I was looking for. I will dig up a few of these caps and see what works the best.

The cap on the rad is an older race cap that I have had for years. It doesn't seem to release, only the top fill cap and then it sprays water all over the engine bay that's a beyatch to clean up.

Thanks again.

Eric

That would be fine, but I would still need a place to fill the rad. The car vents from the radiator, however that cap is about 6 inches lower than the fill cap.

Good idea and I will keep that in mind if I can't dig up a higher pressure cap.

Thanks,

Eric