2Lucky2tha7

iTrader: (3)

First of all, I have a '91 N/A RX7. I just pulled my engine apart 2 days ago and found out that I SOMEHOW spun the rear rotor bearing. The damage looked terrible!! Obviously, it turns out that the debris from the destroyed bearing also took out the front rotor bearing and both stationary gear bearings as well as the eccentric shaft!!! I just rebuilt this engine a few months ago back in the winter and I've only got 7,000 miles on this engine before it finally blew!! I changed the oil every 2,500 miles (new filter every time), I ALWAYS checked the oil level, I used castrol GTX 10-30 oil, I didn't beat on the engine, and I replaced just about EVERYTHING during the rebuild. I am a VERY tedious person and tend to be a perfectionist. However, ever since day 1, I have noticed that according to the stock oil pressure gauge, The oil pressure has never exceeded 50 psi. At startup, it was always at 30 psi or more, and while cruising, it would read roughly 30-45 psi. Other than that, I could never get the gauge to read any higher than 50 psi, regardless of revs. I installed a used Turbo II oil pump (looked really good when I installed it), Racing Beat high performance oil pressure regulator, aluminum oil thermal pellet, a 3rd gen oil filter, and I am not using the front cover gasket, but rather leaving it out and using JUST the O-ring to make sure that this is not a leak area. These are the only changes that were made to the oil system.
I am currently in the process of trying to get it back together, but what holds me back is the fact that I am still very unsure as to why this happened in the first place!! The only possible culprit I can think of would be the oil pump, but after talking to Mazdatrix and Racing Beat Tech support, I still can't find any definite answers!! Their only advice is that the oil pressure I was getting was not adequate enough for rpms exceeding 4,000 rpms. My plan is to get another rotor, eccentric shaft, all new bearings, and a new oil pump to fix this. Does anyone have any insight on this matter.
My brother also has the same oil pressure problem with his '79 widebody turbocharged 13B first gen, and I'm about to replace his oil pump and get rid of the front cover gasket as well, and use only the o-ring for the oil passage.
Am I on the right track or am I still missing something???

Brian

2Lucky2tha7

iTrader: (3)

Well, I bought another rotor, eccentric shaft, new rotor bearings and main bearings, oil pump, and a few other miscellaneous things.

Syonyk

If you spun the rear rotor bearing, I'd look at the thermal pellet in the eccentric shaft as a likely cause. The thermal pellet restricts oil flow to the rear rotor in order to speed warmup for emissions reasons. If it's not working properly, the failure mode tends to be keeping the oil flow restricted.

Did you replace the stock unit with anything else, or just reuse the stock one? Most people (me included) prefer to replace the thermal pellet with a solid unit (available from most RX-7 places) that always allows full oil flow to the rear rotor.

-=Russ=-

2Lucky2tha7

iTrader: (3)

I had it stated above that I installed the aluminum oil thermal pellet in replace of the stock thermostatic one when I first built the engine. Unless there's some "strange" way that this can somehow be installed backwards, I can't see that this could've been a problem, unless, like I said, if I'm missing/ overlooking something.

MARTIN

You probably put it in the wrong way.

jhammons01

you can't put the thermal pellet in the wrong way unless you're a real retard.

I've been reading about motors on this forum for almost 11 months. Arron Cake is the only other one (from his website) I remember with this prob. Mostly its the same 'ol Apex seal story

Wankel7

What year is your front iron. What does that land look like where the oring goes? Maybe it is the wider one that is designed to have the teflon back up ring with an oring then the front cover gasket.

Man, if it dosen't feel right just stop....I had some weird oil pressure problem with a rebuild ( I didnt rebuild but a big name guy did it). I had to pull the engine at 2k.

When you put that used oil pump in did you use feeler gauges to make sure it was within spec?

Since you prob had all sorts of metal running through your oil system...make sure you flush out your oil cooler very well. Search on how to do that the right way.

Sorry to hear about your troubles man

I just buttoned up my first rebuild and will be starting it this weekend. So, I hope I dont have any bad stories to share :/

MARTIN

apex seal??? and yes you can put it on backwards. The only thing that couldve afftected only the rear part of the engine is the thermal pellet, or the bypass.

Wankel7

The long stem of the pellet goes towards the bolt.

Maybe you put it in in the wrong order?

Bolt, spring, pellet?

Also, I hope you read this on the front cover oring:
http://www.mazdatrix.com/faq/oring.htm

James

2Lucky2tha7

iTrader: (3)

As for the thermal pellet:
-Aside from the "obvious", I made sure of it's installation by checking the instructions that came with it from Mazdatrix. In this order: front pulley bolt with new o-ring, aluminum pellet with the long skinny protruding tip entering into the bolt, then the spring on the other side of the pellet. Basically, the spring is entering the e-shaft first.

The front iron is a '91, and thus is the later casting type. I was informed by Mazdatrix that if I leave out the front cover gasket, that I should use ONLY the White Nylon ring. I want to get another opinion on this to find out if I should use the nylon ring AND rubber o-ring--no front cover gasket of course. However, Mazdatrix did state that if I were to use both o-rings, that the rubber o-ring would get sucked into the oil passage, because without the gasket, the nylon o-ring gets crushed and pushes the o-ring closer to the hole of the oil passage.
As for the pump, I admit, I didn't thoroughly inspect it by using feeler gauges. I merely did a thorough visual inspection.
One last worry I have is that my oil cooler leaks from the "large bolt" on the underside of the cooler. It looks to be the regulator.

2Lucky2tha7

iTrader: (3)

Bolt, spring, pellet??

Didn't you mean:
Bolt, pellet, spring?

Wankel7

Yeah, I was just trying to trouble shoot.....maybe you put it in the wrong order....but you didn't

The large bolt on the bottom of the cooler holds in the oil cooler thermostat. It opens at 140F to allow oil to pass thru the cooler.

If you clean your oil cooler out you need to remove that thermostat and then plug the hole in side that area the Tstat went. To force cleaning solution thru the cooler.

James