johnnyg

I'll probably have a bunch of questions as this thing goes on, so I thought I'd start one thread and post them all here, along with miscellaneous ramblings regarding the status of the project. If you're reading this, I apologise in advance

My first comment is - what the hell am I doing?!! I've never pulled or rebuilt an engine before, but I did apprentice as a mechanic for a year (which mean I've done tons of oil changes, painted the parts department walls, and was the subject of many a prank, more than one of which involved the electrical output of the spark plug testing machine)

I started one week ago yesterday and have logged a total of about 8 hours so far. The engine is out and mounted on a stand, and I started tearing down the block last night. Everything is going so incredible smoothly that I feel like I MUST be doing something wrong! The flywheel nut came loose with a few zaps of my cheap impact gun and whopping 1/3hp 3 gallon air compressor, and the flywheel came loose with two "test" hits from a sledgehammer. These "hits" could just barely be called that, really - more like taps. Even the pilot bearing was no problem using a $20 puller from Princess Auto.

I pulled the exhaust manifold and at least now I've confirmed that an apex seal is missing. Tonight I should have a better look at the internals. I really haven't budgeted for new housings or irons, so I'm hoping they're undamaged and not too badly worn.

One question I have right now is regarding the fuel injectors. How do they come out, exactly?

BTW...the car is '91 NA and the engine had about 205,000KM (127,000 miles) on it when the seal blew.

WonkoTheSane

iTrader: (2)

Its fun to rebuild these engines, actually.. You'll enjoy it. The first engine I ever tore down was the one out of my 86 GXL.. couldn't have been any easier.

If the fuel rail is still on, remove all the hoses, and then gently pull straight up. You may have to spin the fuel injector back and forth a bit to get them to come out of the block. If you want to get them out of the fuel rail, gently rock them back and forth and they "pop" out. I'd recommend sending them in to cruizin' performance for a cleaning, while you have them out. These guys will put new o-rings on them as well as the pintle caps (the plastic cap at the end), and anything else thats broken. A very good maintenance issue for your engine, especially since it only costs 12 bucks per injector. And it will take you two weeks or so to get your engine back together anyway.

johnnyg

Thanks for the encouragement Like I said, so far it's been a breeze.

I was going to send the injectors to Marren. Does this place that you're talking about have a web site?

johnnyg

Is a rebuild video going to be worth the price? If so, which one - Atkins or Turrentine?

Aaron Cake

iTrader: (1)

Why would you send your injectors all the way to some US based company to clean them? There are many injection shops around Toronto that can do the job for about $20-$25 per injector. Just check the Yellow Pages for "injection service". Most diesel shops have gas cleaning rigs.

The rebuild video is worth many times it's price. I have not seen the Atkins, but the Bruce T. video is excellent.

WonkoTheSane

iTrader: (2)

Doh! didn't realize you were a Canajin. Sorry about that. Go with Aaron's idea of finding a shop on your side of the border.

I also haven't seen the Atkins video, but the Bruce T Video is awesome.. I got the version on CD, and just loaded them onto my laptop.. so I just brought that down to the basement while I was working. Way too easy

TwistedRotors

iTrader: (3)

Bruce's video is worth it's weight in gold!
-John

johnnyg

Thanks Aaron...never occured to me to look local for some reason. I guess I should ask in the Canadian section to see if anybody has experience with any of them. Marren has an excellent reputation though.

I would have ordered a video a while ago, but the shipping charges they both want are nearly criminal! Rotary Aviation charges $2.50 for US delivery, but $16.95 for POSTAL delivery to Canada. When I had my A/V shop, I could mail an entire DVD player to the US, insured, for $15 CDN! Atkins ships to the US for free, but wants $10 for Canadian delivery. Now I realise I'm just being stubborn, but why should I have to pay inflated shipping charges?

johnnyg

So what's the deal with lapping the irons? For years I thought it was something you just did when rebuilding a rotary, but just recently, two people have told me it's either unnecessary, or a bad idea.

WonkoTheSane

iTrader: (2)

The deal with lapping the irons is that if your irons go out of spec, there's a chance you can re-lap them to get them within spec again (I'm talking your "flat surface" spec). Depending on wear/damage it may not be a necessary step (like in my case). The only way I could see it being a bad idea is if your plates were so close to out of spec (depth wise) that lapping would put them further out..

I guess that every engine type that needs lapped has to have a different stand made for it (I.E: A 13B has to have its own stand, a 12A would have to have its own stand, a 6-cylinder would have to .. . . . ), there's a chance they'd have to make your stand and could put it slightly off-axis, and make it unusable.. I dunno..

The video will show you what to look for when you get your plates off, and if they need lapped, then send them to an experienced shop.

On a side note, if you want, shoot me a PM and I can order the video for you, then ship it up to the great white north.. might save ya 10 bucks or so.

fastrotaries

It is a Universally known Fact that Canadians can't clean injectors.....or play hockey....or grow weed....or be able to drink copious amounts of beer.

johnnyg

Geez, I must not be Canadian then

Of all the friggen things to get hung up on tonight...the eccentric shaft bolt at the front won't budge. I tried a good size breaker bar too and nothing. So now I have to either rent something better then the "Costco special" impact gun I have, or buy a new one (saw one on sale today for $100 - claims to generate 800lb ft of torque - yeah right!)

What really irks me is that I put that bolt on when I replaced the bypass pellet about 6 years ago! With the same air gun even!

Stanello

iTrader: (1)

Get a breaker bar, and a few buddies to hold the engine down. Torch it if you have to. It will come off eventually.

BTW, with the flywheel off, how are you locking the shaft in place so it wont turn?

johnnyg

I put the flywheel back on and I have a flywheel stopper.

I know it'll come off eventually, but to get held up by my own doing is just too much!

Stanello

iTrader: (1)

We broke a breaker bar, a rachet, and bent a gorilla bar and another rachet getting the front bolt off of an engine today. Heat it up and keep trying

johnnyg

Thanks for the advice...heat, and (probably) the help of a new impact gun, did the trick.

So now the engine is all apart. Unfortunately, I'm not terribly happy with what I've found inside. Much to my surprise, it did NOT break an apex seal. However, one of them is stuck really, really bad. I'm sure I'll be able to get it out, but there are other problems with that rear rotor - there are a couple of square/rectangular impressions on it that look as if something bashed into it. I've got to clean it up more to get a better idea, but one of these impressions is right below the opening of the stuck apex seal and may be responsible for it sticking. It hardly looks like recent damage though. I'll have to take some pics.

On top of that, the rear housing is too worn to re-use, and the front housing is marginal. I haven't measured anything yet, but that might leave me needing two good rotor housings and a rotor. Not good. It won't surprise me if the side housings need lapping either.

So at this point, what do I do? I still need to measure everything first, but am I going to be able to scrounge up the parts I need at reasonable prices, or should I just bolt the whole thing back together and get a Mazda reman?

johnnyg

I've now determined the cause of death of the engine. Something - still don't know what - got into the engine. It banged around a few times, then exited. Two of the collisions with the rotor were at the apex seal opening, and that clamped down on the apex seal, pooching compression - and pooching the rotor. I got the stuck seal out, but I can't get another in, nor will a corner seal fit on one end.

I over-reacted a bit on the condition of the rotor housings. I'd say they are both probably re-usable, but I'm going to send them to JHB Perormance to be resurfaced with Cermet B.

I haven't measure the irons yet, but I'm pretty sure they are going to need lapping.

So, my engine rebuild is probably going to end up costing me a bit north of $2500 CDN, but all things considered, that isn't too bad.

I took some pics of the damaged rotor and will post them soon.

johnnyg

Stanello

iTrader: (1)

mmm thats pretty smashed.

johnnyg

Looks like I dodged a bit of a bullet. With just over 200,000KM on the engine, I figured the side/intermediate housings would be past the wear limit. The side housings are within limits, and the intermediate housing is right at, or perhaps just a touch under the limit.

So, according to Mazda, they are all reusable. But what does that mean, exactly? Does it mean that there's no reason to machine these housings? If all components are to spec, does that mean the engine would make 'spec' power?

johnnyg

Check it out....wear limit is .039in.

RETed

Lapping, obviously, makes the engine "stack" narrower.
You need to compensate this by going with a thicker spacer in the front.
Taking too much off with lapping will decrease the depth of the water jacket o-ring grooves; if these grooves are too shallow, the o-ring will not seat right.


-Ted

RETed

Some of those parts are unusable.
In a pinch (no pun intended), you can remill the apex seal groove to stock tolerances.
It looks like you have access to a machine shop?
If so, try and get them milled.
Else, you need to replace them - good used rotors are relatively easy and cheap to find.

Did you find ALL the triangle corner assist pieces and all apex seal springs?
Those dents look like a triangle piece got loose or an apex seal spring.


-Ted

johnnyg

Which??? This is exactly what I need to know!

I thought of that, but as luck would have it, one of the corner seal openings got pinched too. Milling wouldn't correct that.

Do you have a source you could recommend? I've posted messages here, but so far, have come up dry.

Definitely got all the triangle assist pieces, but didn't actually count up the springs.

johnnyg

The question is, how much is too much? To get them perfectly flat again, I'd need to shave off 4 thous from 4 sides, for a total of 16 thous. Do you need to go perfectly flat? Can I only take off 2 thous?