Exhausting RX

While still living in Ohio, I picked up an old 1982 RX-7. It was pure nostalgia. It was the same color as my 2nd car, an 1983 RX-7. I loved that car and drove the shit out of it.

I enjoyed driving it, but from the first test drive, I had hated the sound of the exhaust. What’s hilarious is that when I bought it, I told the seller that I’d probably swap out the exhaust immediately. He froze, stared at me hard and said “Do NOT change the exhaust!” He did not elaborate, but I assume he spent way too much on it.

It wasn’t that the sound was too loud, but that at highway speeds, it would drone. Just a mind numbing hum that resonated your brain cells. It was the main reason I didn’t drive it much. Well, time to fix that.

What took so long? Money. It’s not that I didn’t have the funds for it, but I wanted the same one I had put on my first RX. I knew it would bolt up and sound good. Plus, there weren’t many other options that weren’t custom jobs, and I was not about to let a muffler shop with no experience with rotary engines slap something together.

How bad was the cost? Almost half of what I paid for the entire car. Yeah, $1300 for $2800 car. It wouldn’t have been so bad of I had bought before the pandemic, but at the time I thought $1000 was outrageous.

Fuck it. It’s what is preventing me from driving the thing. Fix it or sell it.

And I don’t sell my cars.

Due to supply issues, I got the header first. Which wasn’t useful as the current system was a single pipe and the new headers were dual. Finally, after almost a year and a half, I bought the rest. Why so long? When I had bought the header during a visit to their shop in California, they had put my order (unpaid) on a giant stack of orders. They assured me they would call when it became available. They lied.

I started noticing the two remaining sections were available on their website mid-summer, but it seemed every time I remember and grabbed my wallet, it would show out of stock again. Damn it! So the n3xt time I saw it available, I bought them.

Just after Thanksgiving, the parts arrive and am excited, but have a lot going on. When I finally get time prior to Christmas, I lay all the pipes out…and realize I’m missing the header to engine gasket. Shit. And it’s a weird one. Local part store shows it available “within 24 hours”, so I run down and order it. “Special order, shipping extra.” Shut up, whatever, here’s my money. 24 hours my ass. Stupid Christmas. It takes a week

Our last week of work for the season, and all I want is to get this thing running. In the hours before work, I put it up on jacks and unbolt the current system. From the cat back, it’s solid. Until I take a sawzall to it. Cut it in the middle of a straight section in case I want to reuse it. Sure.

Unbolt the thermal reactor. It’s what Mazda calls the exhaust header that is also heavy as hell to absorb a bunch of heat from the motor. It weighs a metric shit-tonne.

Since I’m still waiting on that damned header gasket, my mind begins to wonder. On top of the motor is a pile of solenoids and vacuum hoses, affectionately called the rats nest. It’s a bunch of emissions shit. Ironically, if the engine is tuned right, it doesn’t do much. It’s a common thing to remove the rats nest, as long as you don’t have to run the car through an emissions check. Not here!

I find a few write-ups on how to yank it all off. It is mostly straight forward and you end up using 12 vacuum caps of various sizes, but it looks MUCH cleaner when done.

And now the gasket shows up. Yes! I check the exhaust manufacturer’s website for install instructions. There are 2 files; one for the header and one for the rest. Whatever. Header instructions are easy, remove old, clean, install, torque in stages starting with bottom nuts first. Easy!

Start reading instructions for the second half. Item 1, install header with new gasket but do not torque yet. FUCK! Did I miss something on the first set that said wait? Nope. Bunch of dicks.

Whatever. I leave the header torqued and install the center section and muffler. It’s a good thing I bought the new hanger set as the previous own bastardized the stock ones. Ironically, there is very little rust for a car from Ohio.

It takes some grunting and a lot of swearing to get things lined up. A couple of heat shields need adjusting, as stated in the instructions. There was a missing bracket that the instructions say was supposed to be included, but it’s a simple straight piece with 2 holes, so I measure and fab it up.

Back under for final torque. More grunting and swearing. This getting older just makes the pain stick around longer. And god damn do I miss my lift! But it’s finally done. I look it over a third and fourth time to make sure all connections are made and no tools are laying around the engine. I leave it up on jacks so I can feel for exhaust leaks.

At this point, I realize I should have put the battery on a trickle charger. I had the battery disconnect thrown, but I don’t think the battery was well charged the last time I moved the car. I attach the charger and turn the key on. Fuel pump starts pumping away. Good sign. Hit the key, click, click, click. Voltage at 10v. Bad sign.

But I’m used to old, dead vehicles, so I grab my battery starter charge pack. One of those tiny, under seat package batteries. They work amazingly well. Hook it up and hit the key. It cranks a few times and stops. Knowing that a cold rotary engine will take several attempts to get going, I wait patiently for the charge pack to go green again and try again. And again. Then I decide to just give the motor a visual inspection while waiting for the green light a 4th time.

I immediately smell gas. This isn’t unexpected as I’ve been dumping fuel into the carb at every start attempt. But then I notice the back of the carb is wet. Finger swipe confirms fresh fuel. Shit.

Turn the key off and pull the air cleaner. Yup, fuel leaking out the top of the rear bowl. I clean up the carb, mop up the fuel and turn a fan on. I give the carb a few taps to hopefully unstick the float and it’s needle valve. Turn on the key and listen to the fuel pump tick away. This is the normal operation and it works as intended. Fuel into carb, bowls filled and excess fuel leaves via return line. Seems fine. Then I crank the throttle a few times. Some fuel goes into the carb, but then it starts leaking again. Shit, again.

As luck would have it, a few years ago the accelerator pump had started leaking but you could only buy the entire carb rebuild kit. So I had a kit minus the accelerator pump, not where it was leaking. As I remove the carb for a rebuild, I keep telling myself that this is good luck.

I strip the carb down while I can’t see anything wrong, I install new needle valves and seats. New gaskets all the way around and I check the float measurements. Maybe the new valves and seats are a different dimensions, but the floats are considerable off. Bend the floats to spec.

Clean(ish) and reassembled, I throw the carb back on the motor. Hook up all the cables and hoses and double check. Fingers crossed, I hit the key. On try 2, it hits once. Promising. At least the charged battery seems to be working. On try 3, I crank it longer than usual as it is starting to hit. Tapping the throttle and encouraging it to run. It finally clears its throat and starts running with the choke on. Yes!

It take a bit more attention, but it finally runs on its own. I actually shut it off as I had left the air cleaner off. Good thing I checked, because I had left one vacuum line off. Oops. Better yet, no fuel on the outside of the carb!

Fire it up again, starts on 2nd rotation. Happiness! I let it run until it gets warm. This is fun because I know I had dumped a ton of raw fuel through the system when the float was stuck. Plus it’s a new exhaust, so all the light oil on the pipes is burning off. When it got to temp and the choke kicked open, it died, but I knew the idle screw had been moved and hadn’t set it yet. As expected, the exhaust is smoking…both from the inside and out. I let it sit for a while.

Whatever…it runs! As much as I’d love to tune it, I need to pack for a trip to see family. Stupid family commitments.

I roll it into the garage. As I’m closing the garage door, I notice a drip. And it’s not water from the exhaust. It’s slick. My hands are so dirty, I can’t tell what it is. So I start looking under the hood. Oil dipstick is in. Oil filter is on and not leaking. Engine looks fine. Check oil cooler and hose. Fine, but then I see it. Coolant on the front skid plate. Looking up I see where the drip came from.

The top of the radiator is pooling at top seem.

Son of a bitch!

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