gsmithrx7

Below are two pictures of spark plugs I removed from my engine. The leading plug on the front rotor has some kind of deposit on it, the other three do not! Does anyone know what it was caused by, or is it an indication of something going wrong with that rotor?

The second picture is after I carefully dragged the end of the plug across a strip of 400 grit sandpaper. It removed the deposit but is the plug reuseable after me doing this.

The insulators in the plugs are tan to brown in color and do not have many miles on them, do they appear to OK to reinstall in my new engine?

Fr
Front rotor plugs

After cleaning!

By the way, the engine that these plugs came out of seized up on me just driving down a city street!

j9fd3s

iTrader: (3)

those plugs look fine. that weird deposit that they get is due to the fuel/oil mixture, its weird but if you ran more oil (or less oil) you'd see less of those deposits

gsmithrx7

Thanks for the reply, so, something to do with the amount of OMP oil to this rotor is causing the buildup of deposits on only the leading plug?

Perhaps a partial blockage in the OMP lines feeding this rotor?

j9fd3s

iTrader: (3)

who knows, but that stuff should all be checked before it goes back on

gsmithrx7

It has the same deposits! they scrubbed off pretty easily.

What would cause these deposits to build up only on this rotor housing?

Here is a picture of the rotor itself.



I think this rotor will clean up and be reusable!

What caused this amount of carbon buildup? Was I running a bit rich? All the smog stuff and OMP was attached and it was my grocery getter! By the way, I am 69 now so no 7000 rpm lauches in the last 20 years.

Boogienoseface

Hope someone on here can chime in with this for you as i dont know for sure, but from my knowledge i would say the carbon buildup is from being too babied in rpm range. a great mod that ive been reading about lately and soon to do myself is direct fire ignition system which from what ive read burns up cleaner and less carbon. if you search DLIDFIS can read up on some good stuff on here and ausrotary and im sure elsewhere about it that has been known to run cleaner. wasted spark and what not, im no pro, but read a lot to try and keep up a little with these legends out here haha. 69 and still rebuilding the rotary, my hats off to you my friend and cheers great to see. I truly hope someone around here can chime in with some better knowledge than i have but my guess is carbon took over and carbon locked it. Hope to hear more on this as im just giving a moderately educated guess. And funny enough im pretty close to ware ma. what exactly are you working with for vehicle/motor?

gsmithrx7

As you noted I am getting a bit long in the tooth to be doing my own wrenching. But the story is interesting, I worked with another Gary Smith in the same dept. at a printing firm. He owned an 1985 RX-7, so when I was in the market to buy my first new car, I took his around the block and it was exciting to drive a real sports car! I went to a Chevy dealer and sat in the vette they had on the showroom floor and no salesman approached me! After 10 mins of being ignored me and my wife departed.

We then stopped into the Mazda dealership in West Springfield, on the showroom floor was a 1988 Black RX-7 GXL, as I walked around it from across the room there was an older man with a couple of young salesmen. He said from where he was, "Go ahead, get in it". That was all it took, it looked like a Star Wars fighter, had all the bells and whistles, leather seats, the works! I looked over at the man and still from where he stood across the room, he stated that it was last year's model, and he could make me a good deal. So, without even coming up to us he sold me that car! Oh, he was the owner of the dealership! Showed those young salespeople how it was done!

One of the lights in the logicon unit burnt out while still under warranty. I took it in to be repaired, the service manager decided he was not going to do it because the entire unit had to be replaced. Went out to Leo's office and informed him of my plight, he asked for the keys and left for the service area. He came back a few minutes later and told me to go have a coffee in the waiting room. Thirty minutes later I was on my way with a new logicon! That's service.

So this car has been my daily driver since then, the mufflers did not last long, four sets over the years, lifetime replacement after the original set got holes. The brakes got replaced three times, I have lifetime caliper replacement from Monroe, I don't tell them up front, so when they come up and tell me I need to replace ALL the calipers every time I get the rotors replaced I just smile and whip out my paperwork! Three times so far.....

The original engine threw a seal so I ordered a replacment online. It was from Atkin's, 3mm apex seals, street ported. I did not have the time to put it in until I was laid off during the great recession. Ran it until about five years ago when it seized up on me. Spun a bearing on the rear rotor, took out the stationary gear. Those 3mm apex seas that were to be more durable, see my other posts to view the wear!

I found a rebuilt engine on ebay and purchased it. Spent the month of August removing the seized engine along with the transmission. After 35 years everything needed to be replaced, so I will start with the fuel pump after I clean out the fuel tank, wonder what's going to be sitting on the bottom? I just found a rebuilt transmission for $1300 delivered. Mine was starting to vibrate a bit, since I removed the original one it makes sense to do the rebuild. All the wiring needs to be cleaned and checked; they break just looking at them! New oil cooler and lines, waterpump, I still was using the original radiator hoses! I reused the original antifreeze, just kept adding more when it got low! Kinda yellowish when I drained it out.
Unexpected problem, the frame where you are supposed to put the jackstands to support the car have rotted from the inside, the car had factory undercoating. Looked fine from the outside! So the frame collapsed and almost took out the fuel and vapor lines that run along the frame on one side!

I am refinishing all the nuts and bolts, most are corroded but serviceable. I wire brush them first, ordered a dozen small SS wire brushes. Soak them in lemon juice overnight, then wire brush them again. I spray them with "Rust Reformer" if they still show rust in the corroded areas. Then comes the engine primer, Hi Heat primer for the exhaust parts. Then the engine enamel top coat. Black or Silver. This is taking awhile, but I did not do this when I put the Atkin's engine in and everything was frozen and rusted! I just found out that if you use anti-seize on every nut and bolt you can take things apart without snapping them off! They have different kinds, I have to order some "copper" anti-seize for those pesky ground connections! Live and learn.

The car got side swiped on three sides while it was in storage, so I have some body work to do. Need to order some body hammers and dollies.

Thanks again for all the help from everyone, it makes it fun to work on the car. I thought I was just going to pop in the engine and drive down the road, no!

We appreciate these vehicles, even if nobody else understands why they are special. I got more compliments on my F-150 truck!

Have a great day!

Boogienoseface

A one owner rx7 thats pretty awesome and a good back story to it. And anti-seize is the best, i get it all over me and everything but works great. I know the pain of some storage wreckage, a metal fan fell on my 86 right on the windshield and got the hood too. best of luck on your build, these cars are definitely cool, and i love the fact that you can have a bunch of people walk by and probably think its just an old car but then you get that one car guy that gives you a thumbs up.

Cheers,
-Seth

gsmithrx7

I removed the engine and transmission in August. The exhaust system came out first. Who knew you could snap a 12mm manifold bolt with a breaker bar!

So, now I am still refinishing all the parts that I removed from the seized engine, they are in boxes all over my apartment. Can't find a damn thing!

Here is what I have to get the car road worthy. Rebuilt 13B N/A keg with a new clutch, rebuilt FC transmission, new drive shaft with rebuildable u-joints. That takes care of the drivetrain.

New mufflers and pre-silencer, and of course a header (I think it's the wrong size!).

Drained the old gas out of the fuel tank, thank you Mazda for adding a drain plug!







Also have a new oil cooler and SS lines.

I have 140k and 35 years on the fuel pump, do you think I should replace it, wonder what the sock filter looks like?

I still have the suspension to restore along with the rims and tires to deal with. Like I said, everything is worn out! At my age, what else can I spend my money on?

Oh yeah, all the electrical gremlins have to be delt with also. But it's a RX-7, way ahead of its time.

Anyone know what the two inspection covers are for? One at the top rear and the other is on the intake side at the rear also. All I can see is the space between the flywheel and the rear iron.

Have a great day!