lateapexer
lateapexer New Reader
6/21/14 7:10 p.m.

Looking at a 2006 RX8 has a replacement engine because the original was hydro locked and cracked a rotor. The replacement is a used engine with no provenance, not sure of year etc. The seller maintains that the engine hydro locked because it had a mazdaspeed cold air intake that sucked water in during a torrential rainstorm. Is it even possible to hydro lock a rotary and is this remotely feasible? A negotiating point or a run away signal. The car is way overpriced $10,000 and 60,000 kms.(36,000 miles?)

tomtomgt356
tomtomgt356 GRM+ Memberand New Reader
6/21/14 7:27 p.m.

It is possible to hydro lock a rotary. You are still trying to compress an incompressible fluid. $10,000for an 8 with 36k miles isn't bad, but the motor could have a lot more since you don't know the history.

nicksta43
nicksta43 UltraDork
6/21/14 7:30 p.m.

I don't think what happened to the original engine would be relevant at all.

cwaters
cwaters Reader
6/21/14 7:35 p.m.
nicksta43 wrote: I don't think what happened to the original engine would be relevant at all.

Except in so far as you need to be careful not to drive in big puddles with that intake.

lateapexer
lateapexer New Reader
6/21/14 7:46 p.m.

Does it sound reasonable that the cold air intake could allow enough water to enter the engine? The seller tells me that there is approximately 27,000 miles on the replacement engine, but I can't verify this. Would the year of the engine matter much?

amg_rx7
amg_rx7 Dork
6/21/14 11:43 p.m.

That does sound odd.

Can you do a compression test to check the health of the current motor?

I would think that for $10k, you should be able to find a less sketchy option.

BoxheadTim
BoxheadTim GRM+ Memberand UltimaDork
6/21/14 11:58 p.m.

The year of the engine probably doesn't matter that much but for that sort of money I'd insist on a proper rotary compression test. People have been known to kill an engine in fewer miles than that.

Duke
Duke UltimaDork
6/22/14 6:19 a.m.
lateapexer wrote: Does it sound reasonable that the cold air intake could allow enough water to enter the engine?

Hugh Betcha. Voice of experience here, though not on a rotary. And I was even using a version I had shortened by 5" to lift the filter up to what I thought was a safer place.

Curmudgeon
Curmudgeon MegaDork
6/22/14 7:04 a.m.

The original engine's method of execution is immaterial except that yes you'd want to keep it from happening again. $10k is highway robbery. And yes you want a proper compression test run.

Don49
Don49 HalfDork
6/22/14 7:06 a.m.

+1 on a proper rotary compression check. That will tell you everything you need to know.

glueguy
glueguy GRM+ Memberand HalfDork
6/22/14 7:32 a.m.

So I may not be the normal car owner, but if I had a very low mileage sports car, and enough car interest to add an aftermarket intake, I would think that I would have pretty decent documentation on the replacement engine. You may not know the history of the engine, but there should be some pretty solid receipts from an identifiable source plus the install.

Standard sniff test applies - is this the best example I can find for $10k? Only you can answer that, or the dollar figure that would make you answer yes if the first answer is no.

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