no compression
 

Hi, i am a new member, i just save enough money to buy my dream rx7,even i am a auto tech, but i don't know nothing about rotary engine:scratch:.
I had my car for one week and something gone very bad on it, car had no power and i check and had no compressor on the first rotor. I am going to take the engine apart, anyone can please give me some advice on what i should look for and what kind of part i need to overhaul the thing, thank you

How did you check the compression? If you have no compression, a seal or seals have failed and that will require a rebuild. I would advise you to purchase a rebuild video before you attempt to disassemble the engine. Mazdatrix.com has a good one and there are others. Rebuild kits are available from several sources including Atkins Rotary (http://www.atkinsrotary.com/index.php?pag=5) and Mazda.

Before you even turn a wrench, do 2 things: 1 Describe what happend, in detail including prior known history of the car when the engine quit and 2. Download the carb manual and the fsm for the modelyear of your car along with the 85 FSM.

One link for the FDMs is here: http://foxed.ca/foxed/index.php?page=rx7manual

The other and more reading material are in the above link and the ones that follow
.

http://www.wankel.net/~krwright/cars/rx7/manuals.html

Attention: newbies. READ THE FAQs,

Upgrade your beehive oil cooler here. https://www.rx7club.com/1st-gen-archive-71/cooling-oil-how-install-fc-oil-cooler-1st-gen-write-up-pics-478521/

My toy. https://www.rx7club.com/build-threads-293/unvieling-12a-bp-widebody-462184/

I check the compression with the spark plugs out with a compression gauge on and cranking the engine for a few second and it should 0 and i did the same to the other rotor and i am getting around 90 PSI, thank for your sources to get the video and part sources and i just got a repair shop manual from a friend that work at a mazda dealer

Which spark plugs did you take out? If you took out all 4 plugs, you will not get a valid compression reading, if any at all. Take out one of the plugs in each housing, either the leading (lower) or training (upper) and check the compression again. Hold down the button or remove the schrader valve in the tester while someone cranks the engine and watch for 3 even pulses--one for each rotor face.

BTW, proper compression tests of rotary engines require a special tester, but you can get a general idea of the health of your engine using a conventional tester.

Hi, GO48
I recheck the compression like you told me, i got 70 PSI at the front training (upper) spark plug hole and only 5 PSI at the rear training (upper) spark plug hole, so is that mean my Apex seal only or my housing gone too. I also looking at some of the part price to rebluid my engine, some of the company show 3mm OEM Apex seal, is that true Mazda make 3mm Apex seal?

Well, 70 psi is marginal at best, but 5 psi indicates a serious internal engine problem, probably one or more failed apex seals. The only way to determine the extent of the damage is to disassemble the engine and examine the parts. Like I said previously, get a rebuild video to get an idea of what a rebuild entails. And also get a copy of the factory service manual from one of the links in the appropriate FAQ at the beginning of this forum section.

Rebuilding a rotary engine is not difficult, but it is very different from rebuilding a piston engine. As far as the parts go, I would suggest you discuss that with the people at Atkins Rotary after you disassemble the engine.

Hi GO48, I live in Canada and i found a rebluid shop near me in canada, and they tell me they use 3mm OEM Mazda Apex seal, so i am thinking to send them my engine to get them to rebluid for me, price is $3600 canadian with 3mm Apex seal (OEM Mazda), but is there really a 3mm OEM Mazda Apex seal out there in the market, or the rebluider is lying to me?

The rebuilder is not lying to you about the 3mm OEM Mazda apex seal. I'm not entirely sure about it, but I'm almost sure that older rotary engines came with 3mm seals rather than the typical 2mm seals that you see nowadays.

By the way, if you're from Canada(like myself) and would like some help finding parts or a good rebuilder. Let me know and I can help you.

private message me on the forum if you need to get a hold of me.

Mazda Motorsports sells optional 3mm ceramic apex seals but I have no idea if they ever used 3mm seals in stock engines.

Thank you for your help, i order the DVD from atkinsrotary and hope to get this done soon and I also going to change color on my car while i had the engine out, after i am done i will show you some picture of my car

Good luck!