dbroad

I have a 91 rx7 vert with 90,000 mi on it . When I change my oil I notice at the bottom of the oil container a fine brass colored metal material . It looks like something is slowly wearing or grinding away in the engine . Any body have any ideas whats happening , thanks for any help thats given in advance

RotaryRocket88

iTrader: (7)

That is indicative of bearing wear, and not a good thing at all. The engine would need to be torn down if it is the case.

dbroad

thanks for the the info "88 rotary rocket", thats what I thought . I do my own oil changes and have noticed this issue for a few years now , with no change in performance at all . Any idea which bearings are brass, bronze in color. I'm not real familiar wth the inner workings of a rotary . In any case not a good situation I assume ....thanks again ....

Sean80501

I'm not completely positive, but I would say rotor bearings. They have a silverish outer metal, then a copper colored inner metal. One thing I check to check the condition of an engine when buying in parts form is that bearing. "Streaks" of copper start showing first, then more and more. Good luck bro!

7dust

iTrader: (14)

In most engines I have disassembled, it is the main bearings that go first - before the rotor bearings.

I assume this is because the main bearings have much less surface area than the rotor bearings. Also per engine revolution, the eccentric shaft is making complete revolutions more rapidly than the rotors.

Anyhoo, if you really were industrious you COULD inspect and / or change the rear main bearing with the engine in the car. However, if you are seeing the wear you are describing - chaniging this single bearing would be pissing in the wind since you cannot access the other engine bearings as easily.

Engine disassembly and rebuild it the only option.

DavebRN

Def have to agree with the bearing wear, same as piston engines.. if your oil is sparkly... not good

dbroad

I first noticed the fine brass metal after the first time I changed the oil after I bought it in Nov 08 , just a tiny bit of metal sparkles in the bottom of the oil collection pan . The same thing after every oil change since (2000-3000 mi). I have driven the car from florida to windsor ontario and back 3 times about 1200 mi each way without a hitch . Call me crazy but I will be doing it again next week , wish me luck guys .( ps to davebrn: looks like we're close by each other in windsor )

otis rotis

Its your bearing

959595rotor

your brassy material is comming from the Front main bearing you could replace the front and rear mains with new but I suspect you may have other issues with oil pressure ,you might also have blown out the oil pressure o ring between the front cover and block(supplys oil to oil cooler,and front main bearing ,I would recomend removal of the Engine and teardown for actual visual inspection ... then a full rebuild. I would also at that time also increase the oil pressure with 85lb oil pressure Regulater , as well I have used small copper o ring sized(same thickness ) as a flattened front cover gasket and used it to suround the factory o ring,similar to the one used in rotarys since the change up 1989 on the S5 Engine (Mazda had the same issues)

dbroad

thanks guys for all the great info and tips . wonder why my oil pressure is good and no over heating ? , any ways I will be looking to tear down as soon as I can