Racerxindy

Can't get a straight answer on this people say that the rotary has more compression when cold how can that be? No other engine is like that.

RIWWP

iTrader: (2)

All metals expand when they heat up. Different metals expand at different rates. The housings of a rotary expand away from the rotor more than the rotors expand to fill the gap.

This actually happens with all other engines too, it's just not something that affects most people. The engine block of piston engines expands away from the piston and piston rings, but piston rings can bridge the gap without a problem. There is far less apex seal material on the rotor tips, and a greater range of gap sizes that have to be bridged.

For example, F1 engines are technically seized when cold, they have to be warmed up through an external method before the internals will be able to move.

Racerxindy

So 60-70 psi on both rotor cold compression all 3 faces is a bad sign?

RIWWP

iTrader: (2)

Yes. Tehcnically it depends on the RPM, but only at like 170rpm cranking speed and lower will those numbers be above the failing line.

Racerxindy

I know it has first gen starter could that be why it's so low

RIWWP

iTrader: (2)

A starter from the original 2004s isn't automatically going to be a sub 170rpm cranking speed. They could still crank at 260-270rpm when new. The upgraded starter bumps that a bit, but is more for durability/lifespan than cranking speed. The Series2 starter is the one that can increase the RPM to 300-310.

A proper compression test records the cranking speed. If you used an analog compression tester, then there are all sortso f things that can go wrong, and you can't use it to get even a general idea of the compression. It is really a better option to get a compression test with a proper rotary compression tester. Dealers have them, most rotary shops, and some individual rotorheads.

Racerxindy

Can't find a rotary shop in Indy the one people told me about doesn't take calls lol

monchie

There is only one in Vegas, excluding the Mazda dealership of course, and i hope he doesn't leave Vegas, or else i'll be stuck with the stealership...

RIWWP

iTrader: (2)

Just take it to a dealer? About the same compression test cost, $120-180

Tofu*Monster

Good info thanks