RX 7 hot starting

[central]

Having trouble starting when the engine is hot. It's a 92/93 RX 7 (import). I hear this is a common problem. Any tips?

[Mave]

Hmm, maybe the start of tip wear problems? (get a compression check by someone who understand rotaries), or hopefully needs new plugs. Good luck

[Rex-7]

have you been losing coolant lately?
hot starting problem is one of the sign for water seal failure. this can be checked by(note doing this when the car is stone cold):
1, remove water cap(not ast cap).
2, check level(fill up if required).
3, start the engine with the cap off.
4, look for lots and lots of small bubbles, the sort you'd see from fizzy drinks.

what happened? if no.4 symptom is showing(hopefully not), there is a good chance the water seals are gone.

[IainT]

Mave said:

Hmm, maybe the start of tip wear problems? (get a compression check by someone who understand rotaries), or hopefully needs new plugs. Good luck

Spot on. Hot starting problems are usually a sign of low compression.

The hot oil, being less viscous than cold, doesn't form as good a seal at the tips and thus exaggerates any wear that isn't an issue when cold.

Cold start problems and excessive smoke on start up are often signs of water seal failure.

[central]

Thanks guys. It's a mate's car not mine, supposedly with a re-built engine. I'll pass on the info.

[IainT]

central said:

Thanks guys. It's a mate's car not mine, supposedly with a re-built engine. I'll pass on the info.

Copmression test is the way forwards, needs to be a rotary tester though. Most mazda dealerships can do this for a small fee or check out the specialists on www.mazdarotaryclub.com.

Check what grade oil he's using, too thin might cause these symptoms, should be 10w40 mineral (e.g. castrol gtx).