Tore down this core tonight and thought I'd post the pics. This was an original 148k mile 04 6 port manual trans. Two owner, last owner has had it since about 60k he said. He reported that he does nothing special except change the oil every 3k and "run it hard".

It came to me because he knew it was starting to get tired and he had scored a deal on an 07 wreck with 70k miles and a mazda reman already installed, so he paid me to swap the newer motor in and I got to keep this one as part of the deal.

I drove the car just prior to removal of the engine. It started a bit slow but idled fine and drove fine, except that it was slow overall and had some misfiring in the 4-7krpm range. Rather than troubleshoot it the owner just wanted to do the engine swap, so we chalked it up as a tired engine that probably needed coils and plugs, and I just pulled it out.

After I got it out I noticed that the plug wires were on wrong. They had both T coils connected to the rear rotor and both L coils connected to the front. So that explains the slow start, lack of power, and misfiring.

 

broken apex from the misfire do you think ?

 

That's my guess, with the misfire being due to the plug wires being backwards, although it's kind of a chicken and egg thing. It could have been that the rear rotor housing wore and flaked in response to the broken apex seal which was caused by misfires. Or it could be that the housing flaked first for other unknown reasons and as it got worse the seal finally broke as it had to jump over and over the bad areas. I'd lean toward the first theory, though.

 

big side seal gap - is that within mazda spec ?

 

0.15? hell no.

broke the apex ... O_O

 

thanks for sharing your teardowns rr

 

wow--sparkplug wires that messed up? And it still ran and cranked pretty good?
He must have had pretty good gas in his area --for 147K miles he really doesnt have that much carbon build up ( except the areas around the problem areas)?
Wow look at the wear of the stationary gear bearing --still for that mileage--kinda expect that?
Coolant passageways look good and the exhaust port looks pretty clean?

Thanks for taking the time to post these things. We all learn from this.
lesson--get the sparkplug/coil wires on right!!

 

hmm for 148k it looks pretty normal, actually it reminds me of a 12A, everything looks alright, but is worn out.

 

lol, nowhere near it. Most every renny I tear down, regardless of mileage, has 15 thousandths of clearance. I try to build with 2.

The guy is local to me. We have 87, 89, and 93 gas...no idea what he was running. But the fact that he said he "ran it hard" is why there's not a ton of carbon.

The bearing wear is expected on this engine, and in fact this level of main bearing wear at that mileage is very low. Normally I see more bearing wear than that on an 80k engine.

 

That's what I "aim for" on my last FC rebuild, did Mine and got it @ 2 to 4(the most) on all side seals. Engine started on first crank. and ran really well

 

someone here said "run hard" doesn't do ****, I WON'T NAME NAMES! *please don't hurt me!*...

hahaha, I wanna know who did the spark plugs so he/she can be fired.

 

Is that bearing wear from using 5w20 or is that just normal on these engines? I have seen a lot of 1st gen. and 2nd gen. engines apart that had no brass showing. I have used 20w50 in mine since I got it, and it only had about 25k on the reman. engine when I bought it. We all appreciate you posting things like this.

 

I don't know what oil he used, I'll have to ask if I ever hear from him again.

Main bearing wear is very common for 3rd gen rx7s and rx8s. The rx8s are the worst by far.

 

and lots of people throw their 0.02 in saying oh Mazda knows best we all know nothing ... and it's right to use 5w20.

 

What I tell people is that mazda does an awesome job of designing a car for the first 85%, and then they totally f*** up the remaining 15% with bean counting, attempts to do too much with an otherwise simple design, and various other compromises and afterthoughts. The whole 5 weight motor oil thing is right up there on that list with "let's mount the fuel pulsation damper on the lower fuel rail right against the block, what could go wrong?" and "let's install a 226 degree fan switch on this twin turbo rotary engine, it'll help with emissions and mpg".

 

Ouch. Thanks for sharing, I love seeing tear downs. I would be curious to know what oil weight he used if he changed it every 3,000 miles. It's funny to me when I read from others that bearing wear is NOT an issue on RX-8's.

Aside from my least engine (died at less than 30k of a coolant seal failure), every Renny I have seen torn down has had bearing wear down to the copper and all of them except one that I can remember were well maintained using factory spec oil for the most part.

 

 

^ I need to tray that for a couple of cycle and test it. I found that at the local NAPA stocks it.

 

I wanted to get that in NYC for quite some time, but even the dealer don't stock that and has to be special ordered (forget about the god-forbid ridiculous price tag they try to put it on)

oh well

 

lol, u have no idea how many times I got bitch at for the same reason:

"WHAT DO YOU KNOW? DO U HAVE AN ENGINEERING DEGREE?"


burn baby burn ! Wakakakakaka

so much steam coming out from the hood ... oh wahts dat loud pinging noise I just heard ?

and they are STILL doing it wrong on the RX-8, *Sigh*

 

I was referring to 1st gen. and 2nd gen. rx-7's. The only 8's I have seen apart are online so far.

 

More than likely they stock the regular Eneos 0W50, not the new Sustina brand which is different

have you priced Redline oil lately? This was less even with shipping from the link below

you have to page all the way down to get to the Sustina brand: http://matrixsyntheticoils.com/store..._oils_atf.html


.

 

I was referring to RR's post.