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Spun Front Stat Gear Bearing

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Old 11-27-2007 | 11:11 PM
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teknics's Avatar
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Hey,



Alright had a 13brew built formy fd.



at about 30 miles the t04r that was on it (and was brand new) apparently destroyed its bearing, car smoked horribly for the whole maybe 30 minutes that i ran it with the turbo in that condition on it.



I ripped off the t04r, sent it back, bought a t04z put it on.



motor made it about another 1000 miles. Then as i was driving it,. break-in style, i heard a loud knock,knock,knock drove it back to my shop where it died in the parking spot, and enevr turned on again.



I noticed the eshaft pulley spinning ovally rather then straight and round.



Motor finally got ripped out and torn down, apparently the front stat bearing was destroyed, which subsequently destroyed almost everything but the rotor housings.



So far the builders have only thought of oil contamination and low oil as possibilities.



I know my oil wasnt low, i babied the car as this is exactly what i DIDNT want to happen. checked the oil and coolant every morning and night (i work at a shop).



Oil level was never low, onyl thing i noticed was the 20w50 became thinner then i thought it should be pretty quick and it had a pretty noticeable fuel smell to it. I did have good oil pressure at all times tho.



Is the only possibility here oil contamination? would the blown turbo really cause so much damage? I changed the oil immediately after the turbo incident, saw no metal in the oil when i drained it, and i specifically drained it into a pan to check for metal as a "just in case".



Any ideas? im now probably either selling my car or trying to get a secondhand motor unless someone can provide me other possibile reasons for this failure? apparently the front bearing really got destroyed as in pieces of it were missing.



kevin.
Old 11-27-2007 | 11:35 PM
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Jesus man you have the WORST luck ever, sheesh. I seriously doubt the turbo did it, but then again the timing of it is strange. However what killed your turbo probably was what did your engine in too. Did you have your oil cooler cleaned before this engine went in? What afsr were you seeing during your " break in"...
Old 11-28-2007 | 12:11 AM
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afr's were kept around 11-12 IIRC, i think maybe i started tuning it to 13:1 for off-boost before this happened. seriously its been 6 months since ive seen the car so ive forgotten a lot.



BTW I'm not questioning anything I'm just trying to find out more info about my failure. i know the engine builders visit this forum, i dont want you guys to be upset i posted this but i just was hoping someone could give me some more clarification on why something like this would happen since its basically going to make me sell the stupid car.



I flushed out the cooler as best i could, but didnt have it professionally cleaned.



kevin.
Old 11-28-2007 | 11:11 AM
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only time ive seen this, was when a marginal bearing got used in the rebuild, but even then the motor went for a couple years...



did you tear it down? that might give you a clue
Old 11-28-2007 | 01:43 PM
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could it be possible that the upper oil passage in the dowels got partially plugged by silicone or something and limited the oil being supplied to the front main bearing and turbo? causing both their failure, makes sense that the BB TO4Z wouldnt be as affected as the TO4R
Old 11-28-2007 | 05:59 PM
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the motor was torn down, apparently pieces of the front bearing were even missing. it was apparently such a catastrophic failure that nothing could be deduced from the tear down except that the front bearing started it all., motors met irons and whammo.



like i said i always had good if not great oil pressure and was not low on oil, only oil related thing i noted was a distinct fuel smell and in my opinion a thin viscosity, it was 20w50 going in and wouldnt look like 20w50 soon after. and i mean it only ran for maybe 1k miles, and i changed the oil twice i think so in maybe 500miles 20w50 oil was becoming almost watery.



all new bearings were used when the motor was built, everything was new except housings were cermet and irons had like 20k on them.



kevin.
Old 11-29-2007 | 10:50 AM
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Originally Posted by teknics' post='888783' date='Nov 28 2007, 05:59 PM
like i said i always had good if not great oil pressure and was not low on oil, only oil related thing i noted was a distinct fuel smell and in my opinion a thin viscosity,

kevin.




I kind of agree with rotary1307



Hydrodynamic wedge is key.. so if the oil contaminated with fuel, it will eat bearings. If the viscosity is low, the hydrodynamic wedge is ****. How is the FD block set up, the oil pressure begins at the back and works it's way to the front? And the turbo oil feed is connected to the front iron right? Or am I way off base here?



Anyways, what kind of oil jets did you have in the eccentric shaft? Pressure is measured at the back iron (good pressure like you said), and if you had huge jets, you'd see gigantic pressure drop up until the front iron, where the contaminated oil with low pressure is creating virtually no hydrodynamic wedge while the oil composition is eating the front bearing, and the low pressure would also destroy the turbocharger (not sure about fuel contaminted oil injuring turbo bearings, but suspect same as injuring mains)



That's my take on it, but if the FD block produces, measures and distributes oil differently then what I think, then my argument doesn't matter.
Old 11-29-2007 | 11:27 AM
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Why would you have a motor built for you?



That oil was getting beat up...
Old 11-30-2007 | 03:37 PM
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Adhesion and coadhesion of oil really sucks *** when fuel is in it..





Just take some new oil, dip your finger in it then hold your finger in the air with the tip downward and watch the perimeter of oil on your finger.. It will stay "built up" (like a rounded shape) around the edges of the dry part of your finger for some time, and drip really slow. It sticks to your finger pretty good and sticks to itself really well.



Get some old oil or even some fuel contaminated if available and do the same thing. Before you can hold your finger up it would have dripped already and you can see the perimeter of the dip on your finger has already lost the build up section and is just totally flat and wet.



The oil can't stick to your skin and it can't stick to itself so it just falls apart.



Same deal on bearings.



Plus if there was excessive clearance it's too hard to build hydrodynamic wedge. And I don't believe the way the system is setup on a rotary engine that excessive bearing clearance will show a low oil pressure reading on the gauge. It's too bad the motor is fucked already, you could have put a gauge on the front iron and ran the engine to see what the pressure was at the front.



The only reason I can see for such a catastrophic front bearing failure would be a gigantic clearance (incorrect assembly). New bearings can take some oil / fuel contamination abuse. And new bearings are speced properly for size by the builder. If the bearings are new, there's no reason for that to happen. I just picture your eccentric shaft flopping around like a **** in a shirtsleeve because of too much clearance at the front main bearing, so no matter what shape your oil was in you lost all your oil pressure trying to create a wedge at the front stat gear and blew your turbo. And the whole time your gauge (at the beginning of the oiling system) says everything is perfectly fine.



I could be wrong about the oiling system though I think I need to re-read that oil line mod that the race guys were doing to equalize pressure throughout the motor. I know mazda changed between model years, but one starts full pressure at the front and slowly loses pressure until the back, and the other is the other way around.
Old 11-30-2007 | 06:34 PM
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teknics's Avatar
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i think the fd has the pressure at the front and it goes to the back. i could be wrong.

'

my whole confusion is...why would i have a distinct fuel smell in my oil plus the viscosity breakdown so rapidly?



all seals were brand new, all of them. I was running decently rich for the first couple of days but i tuned that out relatively quickly and was cruising at like 12:1 maybe 13:1 IIRC for the break in, was about 2 weeks from getting a full tune when this happened.



Hopefully nothing happened to the new ball-bearing t04z i put on there in between the orig. to4r blowing up and the engine blowing up.



gonna send it to BNR to flush out the turbo, hopefully he can tell me for sure that its still good.



kevin.



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