broke_mofo

I'm just curious how difficult it is to rebuild an engine using one of those do it yourself videos. What tools are needed? What's the "famous $2 part" that I keep hearing about that can blow your engine if it fails?

Silver7

building engines is very easy. All you need is a shop manual. It will walk you through every detail.

silver93

lots of info on this - do a search

Mahjik

iTrader: (1)

Apex are generally what you hear causing blown engines. They aren't cheap but they don't cost an arm and a leg either.

As far as "assembling" an engine, it's just as simple as following directions. As far as making sure everything is within spec and/or replaced, that's something else. There is a reason these engine rebuilders get paid the big bucks.

BATMAN

here majik to ruin the parade..

personally its a Breeze.. just follow the instrucions.. just dont Try to port the Engine your self.. you might end up with a parifial Port. lol

DaedelGT

How many hours does it typically take? Just the rebuild, not the install etc.

silver93

I just did mine. The teardown took me around 5 hours or so. Marking the lines, etc... took time - and i wasn't in any particular rush.

cleaning: i would estimate 10 - 12 hours. (on all these times, keep in mind i worked relatively slow and triple checked everything).

assy: probably 7-10 hours.

HeX

I'm on my way to rebuilding the engine myself. I'm still in the process of buying all the tools suggested in the rebuild video by Bruce T. From the looks of it, it doesn't seem sooo difficult. Definitly go buy the workshop manual and the video. After seeing them you should gain some confidence. If you're planning of having all the tools and getting good brands, expect to pay around $1000. Well worth the money if you're gonna be working on the FD yourself. You're gonna save sooo much $$$$.

TailHappy

Call me a wus, but I saw a friend rebuilding his engine and it became immediatetly apparent that would be something I'LL never be attempting! I always heard how simple these engines are, but there's a LOT of small pieces in there. If there's ANYTHING on your car you're afraid of messing with, the engine might not be for you. On the other hand, a lot of people do it themselves. Just depends on how mechanically inclined you are, I suppose.

Kiflin

Well as long as you know the basics of the rotary engine you could probably just buy that rebuild video and it will tell you how to do it step by step. May be the best way if your planning on doing it yourself for the first time.

apneablue

I have never done this but really want to give it a shot...I don't think I would do it on my current FD though....I will probably buy a blown one and then try it.

As far as how difficult it is...I bet it's harder than the hose job.

es

I had the short block assy together in about 3 hours, but I had to assemble the rotors the day before. The oil control rings gave me a hard time since I used the Viton O-rings, & clearancing the side seals is a little tricky...

Blake

Don't kid yourself: doing it right is much harder than most people make it out to be. Not hard in the traditional sense -- as in physically demanding or even all that time consuming -- but in terms of skill and attention to detail. A proper rebuild will last 100,000+ miles, provided you don't ping it to death or overheat it. A hack job might last 5K, 10K, or even 40K miles. These engines are remarkably tolerant of clumsy rebuild attempts, but that does not justify them because it costs far more to rebuild an engine poorly two or three times than to do it properly once. My typical advice is for any prospective rotary engine rebuilder to take a class in piston engine rebuilding. Piston engines are far less tolerant of laziness, so you spend a lot of time clearancing parts and checking specs. You really need to be **** about the details and you will know immediately if you do it right, as the engines will either start or seize up from the get-go. Apply the same attention to detail in a rotary engine and you can be assured of it lasting for quite a long time.

One caveat is that Mazda's specs are no good if you intend to build an engine to rival the life of a brand new one (not that you can even buy one!). The main problem is their permissiveness in reusing parts that happen to be the highest wearing parts in the engine: the apex seals and rotor housings. Any engine built to Mazda's minimum specs will probably only last about 50K, even if everything else was done properly. Replacing those parts on every rebuild, plus having a higher standard for clearancing parts, will produce far better longevity.

I've rebuilt several rotary engines for myself, all under the experienced gaze of my friend Rob Golden of Pineapple Racing. I must say that with every effort, I learn something new. Not just tips and tricks, but MAJOR lessons that make me second guess ever doing the job without him there to observe and correct my novice fumblings. As they say: the more you learn, the more you know how much you have left to learn. And I'm not even talking about advanced stuff like porting, oil mods, etc.

BTW, I've got another engine project over there right now (for my rotary truck) that I want to put ceramic apex seals in -- good for ~25 ft lbs of torque across the powerband, even in an NA motor -- so I will likely start a group buy on those soon. First, though, I need to finish the group buy on the 6-puck clutches, so be sure to check that out in the GB section.

vudoodoodoo

Get the Bruce Turrentine video. I have it and it's pretty good.

cdk 4219

what if you get into the engine ang find that the housings are damaged? it seems to be a non serviceable item that can get costly. How do you actually change any of the tolerances of the engine with machine work, or is it all or nothing?

RX-187

So what all is needed to complete a rebuild? engine components, tools, knowledge of engine etc. -

93redFD

you need a huge socket for the flywheels bolt
Im very interested in rebiulding a rotary. How are you supose to know if certain parts are bad, thats whats stoping me from attempting the process. It takes engine builders way way too long to rebiuld one. Im not talking about dis/assemble the motor, its just the time they take just to get to the damn thing. I have been waiting sence Jan 9 03 and I still havent got my motor .

t-von

iTrader: (8)

So far I've had one attempt at a rotory rebuild. This was way back in 1995 on my 81 rx7. Blake is definelty right about using newer parts. I used the Hanyes manuel. I tried to cheap out and reuse parts on the engine (which had 150k miles). The damaged rear housing and rotor were replaced with a used housing and rotor from a separated junk yard engine. The rotor was rusted but I didn't care anyways. I replaced one apex seal and reused everything else. I did however use a new gasket kit. Anyways the engine started but ran like ****. Soon after the rebuild I bought a 84 model. Now 6 years later the engine in that car is shot ( my damn sister had the car in college and didn't put oil in it like I asked her to ). I plan on doing all of my own future rebuilds. So the engine in the 84 will give me another chance to do the **** right. Its all about repetition


Oh I got a question for ya Blake, while installing the apex seals in the rotor & housing, what do you use to hold the corner peace to the apex seal? During my last and only rebuild that damn corner piece gave me hell do to the fact that the mysterious assist piece (which was what the Haynes manuel said I should have used) never existed at the Mazda parts counter.

t-von

iTrader: (8)

So far I've had one attempt at a rotory rebuild. This was way back in 1995 on my 81 rx7. Blake is definelty right about using newer parts. I used the Hanyes manuel. I tried to cheap out and reuse parts on the engine (which had 150k miles). The damaged rear housing and rotor were replaced with a used housing and rotor from a separated junk yard engine. The rotor was rusted but I didn't care anyways. I replaced one apex seal and reused everything else. I did however use a new gasket kit. Anyways the engine started but ran like ****. Soon after the rebuild I bought a 84 model. Now 6 years later the engine in that car is shot ( my damn sister had the car in college and didn't put oil in it like I asked her to ). I plan on doing all of my own future rebuilds. So the engine in the 84 will give me another chance to do the **** right. Its all about repetition


Oh I got a question for ya Blake, while installing the apex seals in the rotor & housing, what do you use to hold the corner peace to the apex seal? During my last and only rebuild that damn corner piece gave me hell do to the fact that the mysterious assist piece (which was what the Haynes manuel said I should have used) never existed at the Mazda parts counter.

Blake

A drop of superglue is the typical method.

Blake

Mazda specs are in the factory service manual. There are also additional tips and suggestions in the Mazdaspeed catalog. As I said, though, you have to be a skeptical reader and make your own choices. There is no substitute for experience, but you can safely deviate in terms of not allowing as much wear as they indicate is acceptable. In other words, forget reusing apex seals, and do not allow any chrome flake on the rotor housings if you plan to reuse them (even better is to discard them and get new ones) -- Mazda permits 2mm chrome flake, which is absurd. "Step wear" on the side housings is another thing you can get picky about. Bearing and seal clearances are more tricky, as looser or tighter are not cardinal goals. There is a correct clearance range for different purposes and objectives and only experience can tell you where to deviate from factory specs. However, if you follow factory specs exactly, at least you should have a decent compromise. Properly measuring parts for spec requires quite a few expensive tools, like micrometers (inside and outside), certified straight edges, v-blocks, a dial gauge, feeler gauges, calipers, and more. Further, you need to know how to use them properly! This is why I suggest taking a class in piston engine rebuilding -- they will teach you to use these measurement tools and instill in you the importance of doing things right.