If that's your side seal clearence, it wouldn't matter if you rebuilt the engine with brand new housings and apex seals as that's too much gap to make compression. Side seal clearence should be .002-.006max.

Some of you rebuild newbies also have the option to do a quick dry assembly of the engine just to do a compression check. Take the one rotor with the poorly clearenced side seals and install it in the front housing. Take the rear rotor with proper clearenced side seals and install in the back. Install only the inner coolant seals and NO sealant. Take about 4 tension bolts and torgue the engine down 20lbs. Hand tighten the flywheel and install the bellhousing and starter. Get a battery and jump the wires to do a quick compression check. Just make sure you have plenty of lube on the bearings. The only thing this takes is your time. Plus you will get really good with assembling the block.

A few months ago, I took an apex seal damaged housing and tig welded the face surface just to see if I could get that housing to make compression. The damage was on the compression side of the housing. Pre-damage repair showed 60psi. Post tig repair showed 85psi. My point in all this, you learn ALOT when you experiment.

 

Did I made the impression, that I would reuse those side seals?? If so, I really should reconsider my type of writing. Of course I would absolutely NOT use those side seals again! That was clear to me the moment I had the engine open and looked at them and moved them. Pretty much indeed.

But concerning your numbers of .002-.006max. - thats inch right? My numbers above are in mm, so most of them are in the "max spec", but obviously not good.

This dry assembly sounds good to me, I will consider it when I have everything ordered and at hand.

 

You miss understood my post. The point about doing the dry assembly with the badly clearenced side seals is so that you could witness the compression differences for yourself while still reusing the apex seals. With rotarys, if the apex seals are not bowed and the rotor housing aren't bad, your side seal clearence is what will effect the compression readings the most. Those measuments are in inches.

 

I think I missunderstood the other part.

What you meant was, that if I would put the bad sideseals in a "new" engine, it would not have any or bad compression, right? But here it would be important if you read my numbers above as inches or millimeter..

 

just fyi.. my current housings, which i have been using for the past 3 years, ~30k miles were deemed "unusable" by a professional builder, complete with flaking chrome. my center plate was also "unusable" with grooves that catch a fingernail. i have had zero problems other than coolant seal failure

 

Correct! The point of the dry assembly was to test the compression differences between front and rear with the existing parts you already had laying around as your on a budget. Your gonna need to order new side seals anyways so this could be a learning experience for you to clearence the one rotor to factory spec and just put the one badly clearenced rotor back in to see the compression difference. This test will let you know how good your apex seals are when making compression.

 

Any grooving or gouging is going to affect your compression and longevity of the motor. It may run fine for a while, but will never last as long or make as much power as a build done with better parts. Any builder recommending using parts that are in poor condition isn't very professional in my opinion.

 

^ This!

 

i agree as well. if i was a professional builder, i would recommend nothing but the best. but as a hobbyist on a budget.. i know compromises can be made with little or limited effect on performance

 

Can anyone say something about the condition of my housings (pictures on page 1)?


I'm thinking of buying better used ones at the moment.

 

I thought SVA was just a Japanese car importer? I didn't know they tried to rebuild rotaries after they get off the boat. There are a lot of decent specialists in the UK that could probably rebuild your motor for anywhere from £3,000-6,000 depending on how many new parts are required. Unfortunately, I'm not sure what's available in Germany in terms of rotary specialists...

Hayward Rotary
Steve Rivett
RX Motors
Oldone
Rotary Revs

Just to name a few in the UK.

 

"Trying" is exactly what they did. But this is no subject anymore, I'm rebuilding myself at the moment. I have no specialist around I would trust so I decided to do it myself.

 

The housings look pretty worn(evident by the shinny appearance) but probably reusable for a budget build.

 

Those housings are junk. throw it out, get new

those are not Mazda Apex seal, throw it out.

F**K those side seals, that's some garbage, throw it out.

I would say u should check the oil control rings, I bet those are junk too.

if i were u, I just gonna start checking the rotors and e-shaft to see if those are usable, if it does, just get all new seals, all 5 housings(some calls it iron), and rebuild the whole thing.


Things are getting expensive.

I recently (last week in fact) opened a "so called Japan rebuilt" engine, the side seal clearance was over minimum spec, rear stationary gear was leaking oil like **** cuz the oil seal was incorrectly installed. if a "japan rebuilt" can be this shitty ...

 

you could resurface those housings

 

I agree you could resurface those housings. Most of those marks should come out. Remember that the process doesn't add any chrome and won't fix the cracking around the spark plugs. In your case they appear minor. I offer the resurfacing service. The most I will take off is .002. Others go way further which I feel causes problems. Pricing is $150 per housing.

 

I would absolutely do that, if I weren't located in Germany..