mazpower

iTrader: (4)

I just picked up a free '86 base RX-7. The previous owner overheated the car and it hasn't started since. Several shops took a look at it and couldn't get it started, and that's why he gave it away. The car has been sitting for a year like this.

Background on me...I've got an '87 TII with Haltech, 60-1, all the goodies. I've rebuilt a couple rotaries and have experience with unflooding. I'm not a noob.

I towed the car to my place, and did an audible compression check. Neither rotor made any sound during cranking. I put oil in each chamber via the leading plug holes, and got instant whooshing. But when I check with a compression gauge, I get no bounces at all...like there's no force behind the compression. Even with the oil, I can't get the engine to remotely sound like its trying. Just a small hint of smoke from the exhaust.

I'm assuming because the engine was overheated that the coolant seals are gone. Would this be enough to cause complete loss of compression in both rotors? Or should I keep tinkering with it to at least get it fired up? I'm assuming I'm gonna need to tow start it...

I'm getting a used '88 N/A engine next month. All the current engine needs to do is fire up and move the car out of the driveway. Once I get the engine out I can tear it down and see what's bothering it.

BigTone

umm, if you have rebuild rotarites then you should know that zero compression is associated with blown rotors. You might have been told that the engine was overheated, but it sure sounds like a blown engine. And if the engine has all the goodies, it most likely blew because some idiot did not know how to tune it. I have had to put up with many overheated engines, engines so over heated that housings were cracked and could not be used again. But all most all those times, I could still get some sort of compression. Good luck with your car, but it sure sounds like you have blown apex seals, in which case there might not be many usable parts in the core.

Hopefully you can prove me wrong

mazpower

iTrader: (4)

Re-read the first post a little more carefully...the one with all the goodies is running perfect. Built it myself over the past 3 years. That was merely a reference before I got attacked for being a 'noob'.

The car & engine in question is a non-turbo 13B. I am getting 3 equal whooshes per rotor so I know its not a broken apex seal. This is more of either stuck seals, or both water seals are blown bad enough to lose all compression. I've never seen a rotary blown that bad so that's why I posted the question.

Scott 89t2

2 or more broken seals in each housing = no compression anywhere. it happens.

mazpower

iTrader: (4)

I've never heard of a completely bone-stock non turbo 13B blowing both apex seals. Not saying its impossible, but I could find no references on this website. Especially after being overheated. The gentleman who gave me the car is a friend of the family and wouldn't lie to give the car away...he knows I would have taken it even if the engine wasn't salvagable.

According to him the car was running well, and he started losing coolant. He tried to get it home but his heater hose let go and he overheated the engine. It hasn't run since.

Anyways, back to the question...can an engine completely lose compression from blown water seals? And, if the car sits for a year, can the seals stick enough to cause no compression?

mazpower

iTrader: (4)

bump

My88Se

iTrader: (10)

well, you could take the coolant cap off and watch for some big bubbles, with the spark plugs in of coarse. you could always pull off the exhaust manifold and look at the seals themselves.

stickgoat

Not sure if this will be of any help or not...

But the coolant seals in my '88 TII are gone enough that I have water mixing with my oil, have to regularly add to the radiator, etc..... yet I still have above average compression, and this is with 200k miles. And furthermore, the car has pegged itself out on the temp guage four times in one day. I've only had it about 5 months so I have no clue if it's overheated that bad before.

So I don't know. Seems logical that freshly blown seals that immediately get to sit for a year would make starting difficult, but...hmm..

Puzzling.

Mr. Gadget

Real simple, compression check verifis state of engine. Then you will know if it will start or not.

jon88se

if he overheated the motor and it hasn't run since that things is likely toast...you can't overheat a rotary like a piston motor, it warps the aluminum housings quickly on a severe overheat and pop goes your motor. a car a major problem after a major overheat is very lucky...

knight1976

get a mirror and visuall inspect the apex seals. pretty simple and it sounds like this is the info you are looking for. If ya wanna know if the apex seals are still there then pull hte exhaust mani and look. Otherwise youll never know just guess.

I happen to agree that there are missing apex seals in that motor.