My Mazda RX-7GSL-SE build log with the occasional balsa inclusion

Bob,
Don't run anything yet...I need to get the bigger pictures pulled down and look for all visible fuel connection joints. I'm not a fan of running a new pump on an old tank for reasons previously indicated. Now if it were a $30 local part house pump AS A CHEAO test? Or will the old pump clean up and run? Sure...waste away.

How much effort to drop the tank at this point? This way you are done playing with the fuel system.

Yes, run cheap clear vinyl Lowe's line from test gas can to pump, and pick up after the fuel injectors with more cheap vinyl line back to the gas can. This way you can see fuel and whatever getting pumped to throttle body. You would be surprised just how much fuel is recirculated in a fuel injected vehicle.

I'll come back after dark tonight  to pick this up. I also want to see if I can find the fuel system block diagram so I'm not making broad generalized suggestions. Now if this were British ie Zenith Strombergs, I'd have a very narrowly focused and direct path to running...in the same style as I usually do-cheaply and effectively.

Thanks Bob, I guess that dual rotor and the phase offset is what caused them to run so smoothly…. I know they had a great reputation for that…. Interesting project…. I’m following along….

The fuel pump shown above is an after-market el-cheapo at about $40.  No big loss if it gets hurt.  OEM replacement is a hefty $452.16 dollar job.  Might smart a bit if I jam it up.

https://mazdatrix.com/product/fuel-pump-rx7-84-85-13b/

The thing is.......the folks on the RX-7 forum (I'm not a member but my son is) all say, go for this pump.  Pressure regulation is a big deal on these for best performance.

This pump works.  My idea is to keep the intake side connected to the cars tank and dump what's pumped into a container and analyze that.  There is an OEM fuel filter that I thoroughly cleaned between the tank and the pump.  Not a cheap filter either, new replacements (which I have) are $54.  But I'm saving that for when the car is finished and running properly.  

I will probably find a way to put this hi-tech in-line filter between the tank and the OEM filter.  

Bob,
I did some quick sniffing around after dinner. But before I mention what I found, I wanted to dissuade you from employing that glass filter. Sometimes the glass breaks (oops, engine compartment fire), sometimes the "filter" collapses enough to allow junk to bypass the screen and continue where you don't want it. It also is hard to retrofit into places the OEM doesn't intend on an aftermarket/gerry-rigged filter to go. Nothing beats an OEM equivalent in the OEM fashion, unless one is completely redesigning the whole enchilada.

OK...back to pump diagnosis, and tank checks. That pump is triggered by the fuel pump relay by the computer AFTER the Air Flow Meter senses the passage of air. In short, the pump doesn't run full time unless the engine is breathing full time.

As an example, I had a Merkur XR4Ti (European Ford Sierra brought stateside) with the mid-80s Thunderbird TurboCoupe engine and Ford's EEC-IV engine controls. One pin on the distributor module turned on the fuel pump relay ONLY when the distributor was turning. The module was responsible for the check and switch function. On a parallel circuit from the computer, the pump relay was energized to provide a quick fuel system purge/pressure cycle. Turning Key-On/Engine-Off/No-crank and listening provided the sound of the pump briefly turning on, and then off (bleed/prime). Once the distributor module failed, the car would only fire off immediately after every key cycle while Key-On/(bleed/prime) Engine-crank (run), until the initial system bleed ran out of "prime," which took only a second or two. I couldn't go far with Key-On, prime/bleed, Engine-crank (run)...stall; Key-On, prime/bleed, Engine-crank (run) stall; Key-On, Engi...well, you get it.

Fortunately, Ford used a standard 4-pole relay like I described earlier, with the energizing poles operated by the momentary computer bleed/prime OR the distributor module "pump run." Once I learned how the relay was triggered (and when), I created a jumper wire from the 12v hot (switched by relay) to the pole that ran to the pump. I only needed to place the jumper in, and crank/run the engine. I called it a poor man's anti-theft device because of a thief didn't look for the relay, or my jumper, that car wasn't going anywhere! Once I replaced the distributor module, I also reinstalled the relay. I had no more problems running the car after that.

I read on the RX-7 forums that the fuel pump relay does a bleed/prime also, and shut off until the Air Flow Meter senses air drawn into the engine. In short, if you want the pump running full-time to check the tank for trash, or to check initial fuel pressure, then you will need to "hotwire" the pump so that it continuously runs. The OEM Mazda relay isn't a standard four-pin relay, nor is it cheap! My quick check says this is the way it works for the mid-80s RX-7. In short, this is something that could park an uncommon car like yours until, well, now! So, with all that said, maybe this is why the car seat for so long.

Jumper a pump, check your fuel system, and if satisfied with the condition of the tank and lines, then by all means, restore proper fuel connections and listen for the prime/bleed cycle before cranking the engine. If you CAN identify the cycle is as expected, then go ahead and crank the engine.

I also like to check the ignition system by removing the plugs and laying them on the block while connected to plug wires. Then crank the engine and observe for spark on all plugs. If I see spark , I screw them back in and continue thread-testing the engine's controls (air metering/measuring, fuel-management, ignition management) and engine operation.

Phew, I know that's a mouthful...it hurt my fingers to tap all that out on my phone! I'm no Mazda expert, but shoot me a PM if you want to save a bunch of typing. We can take this to voice this weekend if you like.

Ciao for now.

Thanks for the "firehose" explaination Jim, it took me a few minutes to digest all of it.

It is a complicated system, not like MG world where everything is old school and simple.  Perhaps why they have such a great following.  They also have a great parts structure, with most everything being reproduced in India and China.  I miss that with this RX-7 as Mazda no longer supports it.  Thankfully, some of the more common replacements, like my just received brake master cylinder are being reproduced with maybe more to follow.  Mazda made a lot of RX-7's, perhaps they will develop a following like MG has.  

That glass filter belongs to my son.  He just removed if from a classic Studebaker Hawk

Wiki picture (I had a 1951)



that he is helping a friend with that shares the same rusty fuel tank problem.  They went through the same ordeal, rust in the tank and the lines.  They thought they had it sorted, but Mark put the filter in just after the fuel tanks pickup.  Took it for a ride and the engine quit.  They checked the filter to find it clogged, thankfully that clog never reached beyond the tank.  The owner has ordered a new tank, which I think is in my future.  

Putting the pump on hold for now until Mark has time to help me.  Hitting the front rotors and calipers this morning.  

Thanks for the help Jim, hang in there with me.  

No problem, Bob.

I wish we lived closer together.

Since moving south to high humidity, I've learned steel tanks rust fast. I've de-rusted all of the old vehicles at my house...the TR6, my FIL's TR6, the two Hondas (1965 S-90, 1983 CB1100F), a friend's VW Bug, an old tiller, and both tanks in a recently sold Shadow..and flushed trash out of a pile of old machines and other old vehicles.

All of my antiques have been POR-15'd after a muriatic acid flush, the Bug and Shadow were sealed with Red-Kote (available at O'Reilly's). I'm on the fence regarding which I like more. Any time I do this much work to a tank, I'm replacing all lines, including steel ones, and cleaning carbs before soaking/cleaning jets. Por-15 can be used to seal those new, acid-etched leaks from outside the tank. Soak heavy cloth in Por-15 and apply it to the holes from outside the tank. Do this the day before sealing the tank on the inside. Plastic wrap laid down over the remaining Por-15 in the can, then closed-up with the can's lid will keep the Por-15 stable until the next day...but I wouldn't stretch the time out more than that (it was about 12-16 hours apart for the TR6).

Formula 409 and boiling water do a great job of stripping goo and sludge from tanks, carbs, and intake manifolds. Once the heavy petroleum was removed, then then tanks were stripped of rust with acid.
The $25 hand sand blaster with the last cycle of the refrigerator baking soda will make aluminum and other metals shiny. Don't do this over your lawn...the high salt content will kill your grass. I missed that part until a corner of my lawn turned brown. But the S-90 carb looks great! So does my son's '94 Jeep Grand Cherokee intake manifold. Wash the pretties with 409 first, then soda-blast them. An old toothbrush and aluminum polish will "soften" the "matt-flat/blasted" appearance without a whole lot of effort. So will doing the same with the rotary cleaning brushes available in a kit at Walmart, Lowe's, or any other retail store.

Feel free to ask questions regarding any/all of the above.

New or used gas tanks run from $500 to $1200.  POR 15 on ebay is $24, Red-Kote $42.............

New or used tank $500 plus........POR-15 $24..........thinking I will clean it myself or have a radiator shop boil it out and POR or Red-Kote it.

Removed front calipers and rotors.  Pads look almost new.  No wear.  Rear's were trash.  Work to do, but cold in the remote garage.  Snow predicted today.



One bolt impossible to get to. Can't use a socket, boxed end wrench only wedged on with a screwdriver and beat with a hammer...








Vinyl gloves don't offer much protection when using the wire wheel at 29 degrees F.  

Bob,

Cleaning out a tank can be hard, arduous work. I can tell you each time I did it, I thought "never again." But once completed, I breath a sign of relief. In this instance, a job well done will provide years of rust-diminished service, if not "rust-proof"

I do have ways to mitigate the effort of the work so it isn't too difficult. In fact, you have the woodworking tools to make the 3-axis frame for the tank. I did mine with a circular saw, decking screws, and some scrap 2x4s and plywood.

I would be glad to share, and believe your current (this one) may be a good place to share those processes. Let me know if you want the clutter. Otherwise, I'll share via email.

Thanks Jim, maybe email is best. I will PM it to you if you don't have it already. I post a lot of pictures. Saves me explaining. I figure members can always use the - choose not to view or exit buttons if loading is a problem.

Completed one caliper today. Front, they do not twist in like the rears so a little different reset tool. After cleaning them out I put a little brake fluid in the chamber to keep the seals from drying.

Buried..............

Struggled with these clutch slave cylinders bolts attached to the engines block right next to the firewall for two days. Penetrating oil soaks. Not much help. Buried beneath hoses, clamps, and flex lines. Can't see.....12mm, 13mm, 14mm? Settled on 12mm a couple of extensions and a hammer to set. Hit them with an impact air tool set at about 40psi.

Whew. Alternative was pulling the engine. Mark got the master a few days ago.





Ought to be able to hang brakes soon.

Man, you guys really have to deal with some serious rust.  Must be the salt on the roads.  I doubt that there has ever been salt put on any Aussie road.  The experts tell us that salt is bad for you.  

I see all these American YouTube clips on car repairs and the major part of the repair is fixing rusted parts, or removing rusted in bolts.  Must be very tedious.
I mean, we still get rust, but nowhere near that much chassis rust.  Must turn minor restorations into major ones.

Hi Oldenginerod,

With all the salt/wet winter here in Toronto, Canada. Cars just melt !

Enjoying this thread,
Thanks,
Dave

Oldenginerod wrote:I see all these American YouTube clips on car repairs and the major part of the repair is fixing rusted parts, or removing rusted in bolts.  Must be very tedious.
I mean, we still get rust, but nowhere near that much chassis rust.  Must turn minor restorations into major ones.

It's why many here prefer to buy their older cars and body parts from the lower western states, where the air is drier with less precipitation, and minimal driving on salted roads. Like Australia, bodies there will have minimal rust.

OTOH, when I lived in Hawaii, all my vehicles suffered from "island cancer". The salt laden air from the sea and Tradewinds could rust out a car body in less than a decade. There were companies like Z-Bart, which would for a fee, spray some form of antirust coating inside doors, fender pockets, under chassis, inside various nooks and crannies of the car. Some places required drilling holes where they could insert their spray wand inside. In the early 1970's, One of those rust proofing companies had an early 1960's Plymouth Valiant station wagon with their company logos on the doors. It was their way of advertising that their system works. Apparently it did. I never bothered, because I never bought a new car in Hawaii. Nowadays, I think the newer cars have have better metal treatment than back then.

Rust repair work, especially to have it lasting is tedious and can be expensive. The simple backyard knock and grind rusted hole edges, place window screen over and fill with plastic filler is only temporary. Shortly after, the rusted edges return and one is back to square one.

Here in New Mexico, none of my vehicles have ever shown island cancer. When I got rid of my 14 year old 1984 Dodge Aries purchased in Southern California, although it needed serious repainting, had no rust holes.

Hi GG, I know the roads are not salted here in Oz like other places, but cars here used to rust pretty badly back before the japanese cars started coming here in the roughly late 60s. The locally australian made Holden, Valiants, Fords were all pretty bad for rust. Possibly that was as expected for old cars. But the japanese imported cars and then the locally made Toyotas and imported european cars didnt seem to rust as badly as the locally made product. Of course many would argue this, but I owned many holdens and they were always rust buckets. A friend of mine was Toolmaker for Mitsibishi here when they made cars here. Interesting point is they made two sets of press tools/dies for making car models. One set of tools/press dies was made from different steel as that run of cars used sheet metal with a higher carbon content. The cars made with the higher carbon content were cars made for export out of Australia. The ones with the lower quality steel were sold locally and were rust buckets. The joke was, the exported car could be bought overseas for less than the price being asked for the cheaper version in Oz where they were made. And they wondered why we didnt buy them!

All cars I can think of are now imported into Australia and they dont rust like most of the Australian made cars for local consumption did.

Another reason many of the locally made cars rusted may be because in Oz it is said people tend to keep cars much longer than in other countries where they get turned over more often.

GaryB
'Yabby'

Yabby wrote:Another reason many of the locally made cars rusted may be because in Oz it is said people tend to keep cars much longer than in other countries where they get turned over more often.

When they gave life time warranty on parts, they didn't expect people like me who tend to keep their cars for a long period of time. I kept the 1984 Dodge Aries for 14 years, got rid of my 1990 Dodge D150 pickup and 1992 Dodge Caravan minivan in 2005, 1976 Ford Pinto in 1985. Still have the 1999 Chevrolet S10 pickup we originally bought for our son as a college vehicle.

Regarding domestically made vehicles in AU, weren't factory production basically based on Detroit methods? I don't think they did much painting on inside surfaces sealed by unibody construction welding and seaming. Exposure to water moisture and condensation would cause those surfaces to rust from the inside out.

Regarding lack of rust on Japanese cars of the late 1960's, in Hawaii, it seemed to make no difference on country of original. All including European cars suffered from island cancer. My 1967 Datsun PL411 Bluebird sedan and 1970 Mazda 1800 had rusted out holes in the doors. My 1968 Hino Contessa (Japanese Renault rear engine) didn't have much rust, but was short lived because I totalled it.

Actually, this RX-7 spent it's whole life in middle South Carolina, no salt but not exactly the Southwest USA regarding humidity.  It's downfall was 15 years of sitting.  Seller said it was a "garage find" but I suspect much of that time was spent outside.  However, the body itself is rust free, it's the underpinnings that suffered.

The upside is, that rust is surface, easily removed - (well, if your not doing it!)   by media blasting and just good common old elbow grease.  (See a couple of pages back - my MG axle housing pictures.) NOT my favorite part of this.  

I'm no stranger to rust.  My 1959 Corvette.  Check the frame just behind the front tire.  North Carolina car with a rusted frame that had been boxed with welded steel.  Frame sagged so much the previous owner ground away the fiberglass door edges to get them to shut.   Required a new frame.

Edit add.......And......and I had to rebuild the door edges with fiberglass and resin, if you think that was easy.............







Mark and I (he was 12 at the time) did all the work.  Each suspension piece was removed, sandblasted, primed and painted. In comparison, this car (RX-7) is a piece of cake.

Same car today with a new very happy owner.

[quote="GallopingGhostler"]

Yabby wrote:
Regarding domestically made vehicles in AU, weren't factory production basically based on Detroit methods? I don't think they did much painting on inside surfaces sealed by unibody construction welding and seaming. Exposure to water moisture and condensation would cause those surfaces to rust from the inside out.

Regarding lack of rust on Japanese cars of the late 1960's, in Hawaii, it seemed to make no difference on country of original. All including European cars suffered from island cancer. My 1967 Datsun PL411 Bluebird sedan and 1970 Mazda 1800 had rusted out holes in the doors. My 1968 Hino Contessa (Japanese Renault rear engine) didn't have much rust, but was short lived because I totalled it.

Yes, you are probably correct GG as the cars used to start rusting on the corners of the door panels and progress through the panel from there. They used to rust badle eventually around windscreens then into the boot and rust the wheel wells out. The chassis not so bad, but the panels, doors, rusted badly and quickly.

The cars I recall not rusting were mazdas, imported and local toyotas, BMW, Merc, later nissans, honda, volkswagon, hyundai. Most cars are now pretty good in this respect

Working outback is very dry but the sand and dirt is quite salty as the centre used to be an ocean. Vehichles in the centre used to rust faster than expected in the dry climate, but the roads/tracks were terrible. Everything is pretty much sealed now, so its all pretty good and the imported cars better made.

GaryB
'Yabby'

There is a time when a tender touch is called for, other times it's time to get brutal.

Clutch slave cylinder fitting.  Guess I have done about a hundred of these fittings in my lifetime.  This one brought me to the brink!







And no, even with that it didn't come easy.

Looks like aluminum line in a steel or cast housing. Dissimilar metals are never a good thing. Guess you know that already!

I have started using this product after I nabbed a can from the aircraft mechanics in Guam. We used it on salt air corroded hardware and pipe and it freed everything up. By far the best penetrating oil I have used to date. It has a hefty pricetag, but worth every penny.

Cribbs74 wrote:Looks like aluminum line in a steel or cast housing. Dissimilar metals are never a good thing. Guess you know that already!

With a little directed heat, (butane torch) the other end unscrewed fine.  I had to climb into the engine compartment (bracket mounted on the firewall) to get the correct push/pull position on two wrenches to try to unscrew this one to no joy.  Despite smoking heat and penetrating oil it would not budge.  I have a complete set of SAE SK flange (tubing) wrenches but no metric so I had to use an open end 10mm.  

Afraid of rounding it off, I cut the flex tubing and snaked the hard line out of the bracket then vised it up (above) and manuvered a boxed end over the fittings and heated it again smoking.  Rounded it off.  Called for the vice grips.  Let go with a snap not a groan.  People that deal with this stuff know the difference.  I'm just happy the tubing did not twist.

New tubing?  Nope......it will go back on the same way it came off...with vice grips and maybe a little anti-seize.  No way I would ever be able to duplicate those bends.  

Now to reassemble all that stuff, bleed it and see if the clutch is rusted to the flywheel.  May not be, the slave piston was rusted in position.  Berryman soak just to see.



Edit add.............Kroil, I live by the stuff. A little behind each ear attracts the ladies...

Tell that to my wife! She gags every time I come back into the house after using it.

Cribbs74 wrote:Tell that to my wife! She gags every time I come back into the house after using it.

Don't try PB Blaster then (my son's favorite) it's even more gross.  Comes out....excuse me........ a little like snot.  I like WD-40's penetrating oil with the collapsible straw but you better get it aligned correctly or you get more on your hands than the target. Haven't tried the CRC yet.

Ok, so it will stop, new calipers all the way around now,



but will it go...............

Should know tomorrow when I hook-up a remote fuel tank to the fuel pump to bipass the presently rusty fuel tank.  I had bought new fuel line that I thought would fit (metric) but it's way too small.  Thought of this tubing that I had in the shed.  Still too small but a little heat from a heat gun softened it and when it cooled it shrunk around the fitting on the trial original pump which is the same size as the reproduction presently fitted.  Won't even need a clamp.

In truth, I'm not holding out much hope.  I have no idea what shape the injectors are in.







Judging from the diameter, this thing must suck the petrol.