Common Points of Engine Failure

[tweiss3]

I've been reading (in my never ending strive to accumulate information) of a few engine failures, and I thought (i searched) that it would be nice to have a single thread about the different types of engine failures. So far the few I have had are as follows.

1)Bearing failure for the e-shaft
- usually oil related, sometimes overheating and over reving
2)Apex seal failure, chipping, scoring
- detonation the cause?
3)Carbon build up causing the rotors to become un-ballanced
-it happens, but can be prevented mostly, also the water cleaning can fix carbon already built up
4)Seal/compression can be lost
-side seals, seal springs loose springyness, improper clearances, wear on the housings, apex seals, cold ass weather doesn't ever help, oil starvation (OMP failure or lack of proper ratio of premix)

Are there any others? Anyone care to go further into what causes these failures, and what can be done to prevent these? I'm just wondering, and of course, knowing failure points helps your maitnence, and your tuning/building knowledge.

[88turboii]

another problem i see a lot is coolant seal failure, but after tearing down the engine, there is nothing obviously wrong with the coolant seals. Its like they flatten out after a while or something. ive torn down about 4 engines, and have seen this on two of them. symptoms were overflowing coolant overfill and white smoke/running one rotor on startup

[tweiss3]

what would cause that, the extreme heat and torsion of the motor? Other than just age?

[PercentSevenC]

http://rotarycarclub.com/rotary_forum/showthread.php?t=9117

[TitaniumTT]

what would cause that, the extreme heat and torsion of the motor? Other than just age?

Overheating maybe, generally what happens with the S4/5 engines is the coolant seal support on the iron in the lower corners gets eaten away by corrosion. The steel piece actually falls away and the coolant/fire seal moves and looses contact. It lets exhaust gases into the coolant system when the engines running, then when you shut it down, the pressure of the coolant system pushes the coolant into the combustion chamber. Double whammy.

I tore an engine down about a month ago.... this was the CLEANEST engine that I have ever pulled apart that wasn't mine. This thing was mint.... coolant seal let loose as described above. It's cool though, bought the 'vert for dirt cheap becuase of that coolant seal.

[tweiss3]

dammit, i must not have gone back far enought, thanks

[chibikougan]

How about exhaust sleeve failure.

http://i19.photobucket.com/albums/b168/chibikougan/spring2008005.jpg

I know Brian had this happen I don't think his engine failed due to it. It was the opposite rotor also I think.

[chibikougan]

Whoa! Muscle Spasm

[TitaniumTT]

Yup, been there, been fucked by that. Rear rotor, sleeve failed, engine perfectly healthy... the three turbo's that the chunks went through...... not so much

[tweiss3]

How does that happen? Any way to prevent it?

[TitaniumTT]

I'm gonna go with high EGT's over a sustained period of 4k rpm cruising for 20+ hrs strait on puked turbo's thus the EMAP's where very high.


And I'll save Peter the trouble

Common points of engine failure = bdc/hc

:smilielol5:

[tweiss3]

so NA this shouldn't be an issue at all?