12A Engine Problems after Rollover?

[tdw6974]

Looking at a 12A Engine to replace our rapping/knocking current engine. Am looking at one that was in a car that was rolled and ended upside down. What can I check/look at to make sure the engine is ok. I suspect the Rotary probably is pretty rugged but what should I check? Pull pan? At best any used engine can have problems as could any rebuilt engine. Thanks for any advice/help. Tom Weaver Truck Driver ailing ITA #63

[theenico]

About the only thing you can do (you won't be able to see anything with the pan off), short of disassembly/inspection, is to check the compression in the rotor housings. The further the numbers are away from each other the more likely it is that there is something wrong. If you don't have a way of checking the compression, then the age old method of crossing your fingers and hoping for the best is the next step
Another option is to use the engine as a core and have someone rebuild it. Tony Rivera redid one of ours for about $1500.

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Nico
KCRaceware (816) 257-7305
[email protected]

[Quickshoe]

Most of the 12a's that made it to the junkyard out this way ended up there because of an overheated motor.

Finding a 12A rx7 with a good body is bad news. Finding a rx7 with a totalled body most likely leads to a good motor. Must have been running when it was rolled/crashed.

[lateapex911]

Yup.....I'll second that...the best engine I've gotten out of a "pre-owned" car was the one pulled out of a car that was a little too intimate with a big oak tree....

Rapping ? Knocking?? Sounds like a stationary gear has become un stationary!

Been there, done that....



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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

[Hotshoe]

I have bought and sold a few motors and the best way to tell if one is good in a junk yard situation is to pull the thermal reactor ( exhaust manifold for you piston guys ) and turn the engine slowly by hand to where you can see the apex seal in the exhaust port.
Take a plastic tipped object ( I use a windshield installation knife ) and check to see if the seal will push in. I have seen these stuck before and have loosened them with some WD40.
I also check the top of the rotor housings for any sign of oil leaking (bad O ring seal between housings)
I have had a 95% success rate using this method.

Rick Thompson

[Weaver7]

Nico,Tony Rivera will do rebuilds? That doesn't sound like a bad price at all. Do you have a number that I can contact him at? Also what happens if the stationary gear goes can you just replace that and call it good or is a full blown rebiuld in order.

[Quickshoe]

I've never had a stationary gear come loose. But it appears to be common enough to have remedies available to prevent it. As well as it being an inspection item during teardown/rebuild.

I would imagaine having a gear walk out would wipe out the side housing. Probably too much so to have it machined. Can't be good for the rotor sides either.

Just a guess.

[lateapex911]

A good guess.... and after machining those side housings, isn't the gas nitrading compromised???

Modifications do exist for stationary gears that "walk", but as I recall, they suggest it isn't really needed for engines that don't turn 9K. I think a groove is machined in the rotor and a clip holds the gear in place.

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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]