RX7 overheating.... I think....

Could be an issue that manifests when the engine is hot. Something goes out of tolerance, then recedes when cool.

Something wacky I just remembered: there's black light dyes available for oil, coolant, etc. On two stroke motorcycles it's common to add this dye to the transmission lube, run the engine then shine a blacklight at the exhaust. Dye sparkles = trans lube getting sucked into the combustion chamber, i.e. bad crank seal. Wonder if this could apply to coolant systems as well? Remember, there's two seals on a rotary, the inner and the outer. If the inner seal is leaking when it gets hot, that could be your problem yet never show a thing wrong externally or when the engine is cold.

The coolant seals for the intake are another place to check carefully. I have found that some suppliers that I won't mention (cough Atkins cough) have supplied O rings of improper cross section for more than one area. Wound up sourcing the correct stuff through McMaster.

Oh yeah, something else if you need to go into the motors: the Mazda manual says Vaseline to install coolant seals. I question that; petroleum and rubber do not play well together. Hylomar works but damn it's messy. I have gone to Loctite 518, works like a champ, isn't petroleum based, easy to clean up. I stick with the gray silicone at the bottom of the housing 'legs', though; less likelihood of it getting sucked through the oil pump pickup screen.

The dye test was done with the car at about 220 F.

I am having some issues remembering where the coolant runs in the intake manifold. I know that it is not in my UIM (I have no coolant lines running to it). I can't think of where it would be on the LIM.

Do you have a picture of where the coolant goes to the LIM on an S4 NA engine?

Update after more testing...

I think I know why the second engine got hot... The radiator that we put in the car after the first water loss event...... Has a hole in it. Sweet.

The engine that was in teh car intially is testing good (pressure test).

I am not sure why the first motor was pushing out water (the one that tested good with a non-holy radiator).

If I can solve this, I think I will have some comfort level.

Well that makes a whole lot more sense!

Sure does!

Now I just need to figure out how an engine that is testing good and a radiator that is testing good AND hoses that are testing good still allowed water to be pushed out....

Glad you figured out the radiator was perforated, sorry that the radiator was perforated.

Does anybody track a 2nd gen on here? What temp does teh oil get to? Where do you measure it?

What radiator are you running?

Thanks!

Rob R.

Grm member imgon is a friend of mine and posted in this thread. He has tracked an 88 for the better part of 7 years. Maybe he will come back in to post, or better yet pm him as I know he is a busy man.

I run two driver cars for rallycross and typically race in hot humid weather followed by intense idling.

I let me engine run up to 210-215 degrees but I do have Viton coolant seals, vented hood and this guy:

Crossflow 24"w x 19"h overall 2 rows of 1.25

(I love my griffin) I still run the NA water pump too. I believe the turbo one is a bit bigger.

Just to be sure....

Do you have the rear iron coolant port blocked off? If you are eliminating the heater core I would run a hose from the rear iron to the pipe on passenger side for where the outlet for heater could would end up.

They say at high rpm the spinning will cause water pump cavitation, and I've beaten the piss out mine with a stock pulley, over-revving it to 10k and etc and I never saw any signs of cavitation. Cavitation usually means air bubbles exploding and damaging metal part. I have never seen any witness marks of that yet on the 20 or so rotaries I've torn down.

Are you running a fan shroud?

I am running the ford Windstar electric fan with the built in Windstar shroud.

Is it possible that running lean is causing this issue? Can running 13.7:1 from 5500 to 7500 causing my temp issues?

Is 230 or 240 the temp at which you shut the engine down?

My temp gauge is right near the thermostat. Is this an okay location? Should I expect to see higher temps at this point?

Thanks!

wvumtnbkr wrote: Does anybody track a 2nd gen on here? What temp does teh oil get to? Where do you measure it? What radiator are you running? Thanks! Rob R.

My oil temps are 220 measured at the pedestal under the filter.

Water temp should be around 190 and oil at 200. Hotter will cost you power and longevity.