Howard Coleman

iTrader: (6)

re rotor housings...

here's 3 of the 4 spots where Mazda directs you to measure width. the 4th is at the top. as you can see it is around the lead plug area. i sometimes find it beneficial to switch rotors from front to rear to obtain better clearance.



here are a few housings back from honing:

Nakd n Fearless

iTrader: (4)

Use inexpensive sandwich bags to hold nuts and bolts during the rebuild.
Write a small note on scratch paper and place it into the bag.

DaleClark

iTrader: (55)

Bagging and tagging is the number one thing for keeping organized. I will say I have found getting the better Ziploc bags that have the sliding plastic tab to seal is a good idea. When you have super greasy hands they are easy to close up and it lose bolts.

more to come on this thread!

Dale

neit_jnf

iTrader: (17)

can you touch on engine removal and install part? I have a rebuilt short block and all the tools I think I need but doing it myself I find the idea of pulling the old engine to install the new one stressful.

twinturborx7pete

iTrader: (3)

I remember being 19-20 years old when I rebuilt my first FD 13B in my garage. I had a few friends come over and help pull the engine after doing much of what @DaleClark said. Essentially used the Mazda shop manual to do everything.

I even recall having some VHS tape I would run inside and watch for certain sections of the engine build when I’d get stuck. Don’t even remember what it was nowadays. Anyways I remember spending countless nights asleep on my garage floor.

Patience is definitely the key to this job. You do need to take your time and label/bag everything. Assembly and disassembly of the long block is 1000% easier on the engine stand. I think nowadays the wealth of information available would make this job easier than it was back in 2001-2002!

It was extremely rewarding when I turned the engine to check compression for the first time! Hearing the whoosh chug was amazing! Firing it up and breaking it in, even more amazing! To say, “I built that” was a source of great pride! It’s very nostalgic to me now as I write this!

SwappedNA

iTrader: (1)

I imagine that was quite the feeling and achievement. I've pulled countless engines, but as far as rebuilds go, I've just never trusted myself with a dial indicator or clearancing side seals.

Carlos Iglesias

iTrader: (6)

It's apropos that in Naval Aviation we say thatJust sayin...

twinturborx7pete

iTrader: (3)

Like many things mechanical, there isn’t any magic to working on the engine. It is about having the right tools and patience. Following directions on tolerances and torque specs. The engine is extremely easy to build once it is all cleaned up and you’ve laid everything out!

I thought pulling the engine out of the car was the most time consuming part and then dismantling it on the engine stand. Reassembly was much faster.

DaleClark

iTrader: (55)

I'll address this.

First, clearancing side seals. It's not particularly hard, it's just really time consuming. I usually prop my phone or laptop up nearby and watch YouTube while I'm doing it.

- Get the rotor clean. It needs to be as clean as you can get it. Use old seals to go through the grooves to get any old carbon out of there. The big one is using an old side seal on the side seal grooves, usually running one through with some WD-40 sprayed onto the groove will clear out any old carbon. This will also let you feel if there are any spots the seal gets hung up on. The apex seal grooves need a similar treatment and you have to get more creative to clean out the corner seal holes, sometimes a small screwdriver or pick can get there to get the carbon out.

- Get the oil seal springs and oil seals installed. The shop manual shows how the springs have to be installed for the direction of the rotor rotation. At this point I write F and R on the rotors with a sharpie to distinguish which is front and rear, this is important with the oil seal springs.

- Install the apex seals with no springs. This keeps the corner seals lined up.

- Install corner seals and springs.

Side seal time!

- Put a spring in with the 2 ends pointing up. This is outlined in the shop manual. I also put a coat of plain engine oil on all seals and springs during assembly.

- Get a new side seal and look at the 2 ends. Mazda typically sells them with 1 end finished and 1 end "flat". The finished end will be angled so it lines up nicely with the corner seal, it's at an angle. The other end is just squared off. This is the end you want to do.

- Hold it like a pencil and start rubbing that end on a piece of sand paper, drawing it back towards you. I also use a grind stone for sharpening knives, that works well to file it down. The big thing here is the side seal is ductile, you don't want to squeeze it so hard that you bend it out of its shape. If it gets too bent it will bind up in the groove.

- File and test fit, file and test fit. I keep handy 3 feeler gauges - .002, .003, and .004. Once .002 can slide in between the side seal and corner seal you know you are close. Once done, the .003 should slide in nicely and the .004 can't fit in there. The seal should also spring up and down all the way across without binding. If it does bind, figure out why, if it's bent or what.

You want to have some extras on hand, it's quite possible to go too far or goof something up. If you do go too far on one, that's OK, first try and see if it will fit in another slot. Each slot is slightly different in length. If it's too tight in another slot you are good, just file it down for that slot. It's only if it's too short for any slot or bent badly that you have to give up on it.

My method for doing it may not be popular but it works for me. I get a flap wheel bit on my Dremel and carefully get 90% of the material removed. This takes care since you don't want the seal to get too hot, you have to hold it so it doesn't get bent while doing this, and you have to watch for it going too far. That's the hard part is removing a good 2-3mm of material off the end in a fashion that's faster than just slowly rubbing it on sand paper but not too fast that you either go too far or damage the side seal.

As shown in the shop manual you have to hold the side seal at a 45 degree angle as you file it down, you want a good angle on the tip so it fits tight against the corner seal.

Expect to burn a whole morning doing all this - putting all the seals in the rotor, cleaning more stuff, and clearancing. Once done you should have 2 "loaded" rotors that are ready to stack up.

Cheap tip - you can re-use side seals. They wear VERY little compared to the rest of the engine. Test fit each one in each slot and find ones that fit the way you like, you will end up with a good handful that are too short for any groove but this will save some time and money. Mazda has a pretty wide range at the factory that they consider OK for side seals, I prefer to make it tight and consistent. Side seals will wear a bit on the bottom where they touch the spring, this HAS to go face down or you're going to have terrible compression. They also need to be cleaned well, usually a Scotch Brite pad and some WD-40 will get them all good.

I don't re-use side seals at this point in my life but I have on many FC engines I built in my youth .

Dial Indicator

The main thing I use this for is setting end play. The eccentric shaft can move back and forth slightly in the engine, this is normal and good. You want a certain amount of end play, too much and the engine is sloppy, too tight and you are loading the needle bearings which can burn up.

After you get the short block assembled and the flywheel on, you can use the flywheel to turn the motor over by hand and hear the nice chug-chug of compression. If you get that you are doing great, the engine is happy. Flip the engine so the nose is pointing up.

Leave the front eccentric shaft key off for now, stack all the components on the front of the shaft - counterweight, oil pump drive gear, MOP drive gear, needle bearings, and of course the end play spacer. The order is all in the shop manual and this is key to document when you take the engine apart. The needle bearings go around the spacer, this is why having an engine stand is great, if the engine is "flat" that needle bearing can hang off the e-shaft and the spacer can crush it.

Anyhow, with this assembled, install the front pulley hub (just the hub with no pullies bolted on) and install the front e-shaft bolt.

Get your dial indicator, it has a magnetic base that has a **** that turns the magnet on and off. Set it on a flat part of the front iron and lock it in. Then set up the arms so the tip of the indicator is straight above the front pulley boss and touching it. Zero out the pointer. Now use a pry bar on the counterweight to lift the stack up and see how much it moves, it's a VERY small amount. Look in the shop manual for the spec, if it's outside that range you need to get a different spacer. Each spacer has a letter stamped on the side and the shop manual will tell you which spacer you need.

The good thing is probably 90% of the engines I've done have used the spacer that came on the engine and were in spec.

The other thing to use it for, in theory, is checking wear on the irons. Really I've found doing a visual and a "fingernail test" is all you need. If you have grooves that your finger nail catches you need to replace or re-finish the iron. I'll have another post on how to size up all your parts to see what's good and bad.

Dale

DaleClark

iTrader: (55)

I had a lot of tips on the first page of this post and outlined the procedure. There are also a number of Youtube videos on the topic, watch them and get a good aggregate of how to do it.

Biggest tip is removing just the minimum to get the engine out and on the stand. There's no need to spend 2 hours removing the turbos, for example, in the car when it takes 5 minutes on the stand.

I can have an engine out and broken down to the rotors in 3 hours. That's from popping the hood to looking at apex seals. This is NOT a hard car to pull an engine on, tons of other cars are a royal pain. Hell you don't even have to remove the radiator . Mazda even put 2 hooks on the engine to hook the chain up to!

Dale

Jatt

iTrader: (2)

Combined with inspiration from you and @RotaryExtreme I am going to make the dive and do my entire build on my own. Just saw my builder's instagram page...it looks like he separated from the main shop he worked at and is going solo. I don't know how long it'll take for him to be up and running and I don't know how many cars he has in front of me. Communication hasn't been great, and although I am sure he will reach out, i just don't want to rely on that. After this work week, when I'm off for 5 days starting Wednesday, i'm going to get all the tools, engine hoist and stuff I need to remove the engine and build my car.

I *may* rebuild my engine if it's out and send it out to get street ported while the engine is out. Going to be searching during downtime during my shift tonight, tomorrow and the day after compiling a master list of tutorials/writeups made by members from everything ranging from installing a fuel pump, removing injectors, rebuilding injectors, installing an OEM brand new harness, installing a power FC, Greddy V-Mount and more. I may have to source some labor like boring out my secondaries (or primaries) on the stock injectors and will need new fuel lines.


Man, what am I getting myself into lol

zli944

iTrader: (2)

https://www.rotaryaviation.com/store...lace_DVDs.html

FYI, I actually bought and used these and they're VERY helpful. It's step by step, bolt by bolt on the engine disassembly and removal. I referenced multiple times after rebuild to make sure things were setup correctly.
I don't mind supporting some good info like that even if I could get this info some other place.

Jatt

iTrader: (2)

Just ordered, ty

DaleClark

iTrader: (55)

Porting your engine yourself

OK, figured with some comments that this would be a good topic to cover.

First off, PORTING SUCKS. It's slow, it's loud, it's dirty. I've done it on a few engines and I don't enjoy doing it.

If you ARE going to do it, seriously consider your use case. Many of the big ports are ZERO fun on the street, they are designed for race use for a reason. This is bridge porting, peripheral porting, and other hybrids of that. On a street car, do a STREET PORT, it's named that for a reason. I'm not going to go too far down the rabbit hole of ports and pros and cons, that's covered in depth elsewhere.

OK, so you are going to port. What will you need?

- Street port template. Pineapple Racing has great templates, their exhaust templates in particular are awesome, they line up super easy.
- Dykem or something like it. You can get it from McMaster-Carr, it's a dark purple ink in an applicator, you put it all around the port, line up the template, then scribe the outline of the template in the dried-out Dykem. I've heard of people using paint, Sharpies, etc. as well.
- Thick tape. After you get your outline, cover the rest of the face in a thick tape of some kind, multiple layers. Not if, but WHEN the grinder gets loose and tries to skip across the face of the iron it will be protected.
- Grinder. This is the tricky part. You can use an air-powered die grinder or an electric grinder. I've done it with a Dremel in the past, it's slow but it works. Air powered die grinders are VERY LOUD.
- SAFETY. You need to be wearing ear, eye, and breathing protection. Get a good 3M dust mask, most hardware stores have them, that totally seals against your face. Breathing in tiny bits of aluminum and cast iron isn't great. Eye and ear protection are a must as well.
- Grinding bits. You will need various shapes and grits, something to hog out the shape, something to refine it and polish.

Now here's where my knowledge comes to an end - as stated, I don't enjoy porting, and I don't really know the best bits or grinders to use. Maybe someone else can chime in. You need something that can cut through cast iron and cast aluminum well.

When porting, you want to stay SHALLOW. If you go too deep you hit a water jacket which means coolant will be pouring into your intake port - not good. At that point the iron is SCRAP. It's not worth hogging out the port deeply anyhow, I doubt you will make much more power.

Basically you want to go shallow and get the opening to the line as defined in the porting template. Then blend it in, again don't hog it out and go too deep. If you can get your hands on a junk iron to practice on, that's a great idea. Even an iron from an FC or FB will work for practice.

On exhaust ports, you want to make sure you leave a taper on the opening and closing edge. If you have a hard edge there it will grab the apex seal on the way by and dramatically reduce engine life.

There are some good videos out there on porting, read up and watch. To be honest I don't really know how much power you can get on a more "mild" setup out of porting. The FD already has pretty good sized ports. The FB had REALLY small ports and responded amazingly to a good port job, picking up a lot of power, but Mazda made the ports bigger and better over the years.

You can also just clean up the existing ports - get rid of casting roughness and any steps in there to smooth air flow. Don't know if it will make that much more power but it's something to do on a slow Saturday .

Also remember a lot of shops will port if you send the irons to them. The downside is shipping heavy cast iron parts ain't cheap and you have to wrap them VERY well, cast iron is brittle and a good drop from a UPS guy and the ear is broken off an iron, leaving you with scrap. But, you can have a pro do it and get better results than you most likely would.

Dale

j9fd3s

iTrader: (3)

i count the strokes on the first seal, and then the rest of the seals start out ~10 strokes short and then individually fit. i used to be really fastidious about getting them as tight as possible, but these days i go a little looser. you want it to be as tight as possible but not bind, i go by feel and then use the feeler gauge to make them all the same. if that makes sense. my set has an 0.0025" so if we insist on a number that would be it.

i also measure the side clearance, the groove to side seal clearance.

MarcZ55

What a great thread! As I go through the routine maintenance regularly fluids, filters (including fuel) hoses and belts etc.. I find myself wondering if I'll tackle the rebuild when the time comes. It's a little intimidating for sure but this thread is inspiring and a confidence booster. Thanks for posting this.

j9fd3s

iTrader: (3)

the actual engine itself is really simple, its about as difficult as the short block of a 4 cylinder.

DaleClark

iTrader: (55)

What engine hard parts need replacing?

This is a tricky one sometimes. I'll share what I have seen from first-hand real-world experience.

In general, FD engines fail in only a few ways. Broken apex seal from detonation, worn apex seal from mileage, or water seal failure from overheating. There are other failures but by and large that's 95% of the failures right there. Let's talk about these failures and what damage it does.

- Broken apex seal. Typically a small corner of an apex seal will break off, that piece goes around the engine and will typically score the rotor housing and damage the rotor face and apex seal grooves. 9 times out of 10 this means you need a new rotor and rotor housing. A scored housing won't build good compression obviously (the compression will leak through the scores) and those marks would wear apex seals down more quickly. Rotors many times have the grooves damaged and mangled by the broken piece and can't be re-used.

I have seen rotors that could be re-used before, one in particular had the piece of apex seal embedded in the rotor face and the apex seal grooves were OK. I cleaned it up, filed that groove down flat and took off any sharp points, and ran it - car did great.

- Worn apex seals. FD engine life is around 80,000 miles on a bone stock engine. Yes you may get more, you may get less, but on the average that's about where you may be thinking of needing an engine. As the engine wears, the apex seals lose height and spring pressure, side seals get more sloppy, corner seals lose spring pressure, this all contributes to lower cranking compression. This results in hard hot starts and lack of low end power.

Typically in this scenario you can put in new seals and springs and be back on the road again. I worked on an FC convertible here in town with 160,000 on the original engine, just put new seals in and it ran fantastic. Same goes for the engine in my RX-8.

- Bad coolant seal. This typically manifests as the car pushing all the coolant into the overflow tank, overheating, coolant buzzer going off, and champagne bubbles in the filler neck.

I've seen 2 failures internally that are typical - either a bad coolant seal from overheating, the seal was compromised and was letting coolant in, or the cast iron wall behind the coolant seal failed and broke off, removing support for the seal and the seal subsequently fails.

With a bad seal, many times you can be in luck - freshen up the engine, new coolant seals, and you're back on the road. With a broken coolant wall, you have to replace that iron with a new or used part and you're back in business, they typically can't be repaired.

If you do have a bad coolant seal, it's worth it to start the process sooner than later. I had an FC I worked on once that sat for a year with a bad coolant seal. The coolant pooled in the combustion chamber and rusted all the seals onto the rotor. I had to throw out both rotors and I think the irons were shot as well. If that would have been repaired soon after the problem was discovered it's very likely the hard parts could have been saved and a lot of money and hassle could have been saved as well.

So, what parts can I re-use?

First off, it would be nice just to chuck everything, buy new parts, and put it all together. But that's not very cost effective. I'm all about spending money WISELY on an FD, not just spending money to do it.

I typically, after the engine teardown, do a first pass of cleaning on things, enough to look at the parts and make a determination of what needs to be bought so I can get the parts on the way. Typically some brake clean and a rag is all you need at this step.

- Rotors. Look for gouges from a broken apex seal. Also look for evidence that the sides of the rotor touched the iron on the side, if you have bearing problems this can happen. Check the bearing, a lot of copper and you'll need to press in a rotor bearing. Handle rotors VERY carefully, they are easy to drop and if they hit the corner that can de-form that corner so you can't get a corner seal in, which makes the rotor junk.

- Rotor housings. Look for scores from a broken apex seal, pitting on the sides that touch the coolant seals from corrosion (typically from cars that never had coolant changed or ran straight water). Cracking around the spark plug holes and chrome flaking is also worth checking for. The smoother the surface is for the apex seal to seal against, the better.

- Irons. My rule of thumb is if there are wear lines on the face that can catch your fingernail, it's too worn. Surface should be smooth. Check all the coolant walls for corrosion or failure. Look for any physical damage like an ear that snapped off or something like that from rough handling.

- Stationary gears. Teeth should be good with no chipping or scoring. If you have a lot of copper showing in the bearing or it's scored or damaged, replace the bearing with a new one. Some copper is OK.

- Eccentric shaft. These are very rarely bad in my experience, typically they are only bad if the engine was oil starved and the bearings seized up or something. It should be smooth and shiny with no blueing from overheating. Threads on the rear for the flywheel nut should be good, and the hole for the pilot bearing should be good and not hogged out by someone doing a poor job removing a pilot bearing.

If you have a hard part and aren't sure if it could be re-used, post up pictures to the forum and voice your concern. You also have to find what your comfort level is, what parts are "good enough" and what parts are junk. Used parts will all have some measure of wear but many times it's not enough to worry about or affect the overall health of the engine.

Dale

DaleClark

iTrader: (55)

I'd say in many ways it's simpler. No complicated timing belt, no lifter adjustments, cam phasing, etc. Also you typically don't need to involve a machine shop either.

It's funny when you think about a piston engine - you have a timing belt, cams, lifters, valves, valve stem seals, all this stuff that a rotary engine does with simply a hole in the engine and no moving parts. The downside is you can swap out a cam in a piston engine to change valve timing whereas a rotary you have to open the engine to port it for the same effect.

The big thing to take away here is it isn't super hard, many people have done it, and there are tons of good resources to lean on for learning and for asking questions. If you can accept that you may screw something up and have to pull the engine and go back through it due to an error you made, you are good. In those cases you typically just cost yourself time more than anything else.

Dale

Pete_89T2

iTrader: (4)

IDK, I've built both, and I think the rotary is a so much simpler to build and less prone to mechanic's errors when compared to building a 4 cylinder, especially if it's one with multiple cams & lots of valves. Lots more stuff to screw up on the 4 banger.

twinturborx7pete

iTrader: (3)

As @DaleClark stated, it is important, if you are porting your engine yourself, to have proper safety equipment. The rotor housings themselves are coated in Chromoly, IIRC, which is a HUGE cancer risk if you start inhaling that mess. Generally speaking, inhaling metal is bad for you in any event.

When I would do the side seals, it was a nice grinding stone and sand paper that I used as suggested. It just takes patience and lots of measuring. It is like cutting hair, you can't put it back if you've gone too far.

Also would recommend the use of petroleum jelly in the packing/building of your rotors. It will hold most of the seals in place quite nicely when you are stacking them into the engine. Also remember that your apex seals should be installed with the springs once the rotor is inserted into the housing. You should get that beautiful "click" when you've got them in properly.

neit_jnf

iTrader: (17)

I've seen side seals used where the coolant wall broke but I don't know how good of a solution it is.

j9fd3s

iTrader: (3)

this one is a little funny, petroleum jelly is fine (the shop manual calls for it), but it smokes a lot, so you only need a little bit to hold the seal in, when you coat the whole engine in the stuff it'll smoke for hours.
since its only real job is to hold the seals in, anything sticky can be substituted, axle grease, Vics Vapo Rub...

neit_jnf

iTrader: (17)

now I wanna smell a fresh rebuild start with vics!!

twinturborx7pete

iTrader: (3)

Agreed. It should just be a dab. I've seen people grease them up thinking that was necessary, but honestly a small dot of it is all you need.