I found another blowby spot on the other side of the front rotor on the same face as the other spot. I checked the side seal clearances on this side of the rotor and they were all .003. What could be causing the blow-by on these side seals?

 

Did you compression check it before you dissasembled it? Did you bevel the closing edge of your side ports to protect the side seals? Your side seal could be catching the upper portions of your side ports. You can also do a dry assembly of the engine and a quick compression check just to see how bad it's actually leaking in that spot. Make sure you lube the bearings well. Put the engine back together with about 1/2 the tension bolts and the inner coolant seals. Bolt the transmssion and starter up to turn it over on a bench. Then use your compression gauge and count the bounces. Wherever your weak compression point is, try to stop the engine the next time around B4 the reading on your gauge. This way you know it's facing the compression side. Now pull the engine back apart and inspect that section. I had to do this very same thing on my 20b recently because I was having a wired compression problem.



Edit: Since your in the experimenting phase, you may wanna start investing in the Mcmaster Carr- Viton inner coolant seals. You will save a **** load of money if you have to pull your engine apart on a regular basis.

 

It almost looks like there is a low spot on the side plate and that is causing it to lose a bit of compression right there. Are there any rust spots on the housings surface at the bottom of the intermediate housing?

 

Yes i did another compression check. I posted my first results in post #128 and I had said that one face was around 5psi lower than the rest, well the second test i did showed 95,95,95 for the rear rotor (like my first test), but on the front rotor I tried to pay close attention to just exactly where the pulses were at and two were 90(like on the first test) but one face was definitely atleast 10 psi lower, so I just went ahead and pulled the engine. I thought it might be because of the closing edge on my streetport but both sides of the rotor had blowby spots and the other side of the rotor passes over a stock primary port. I went ahead and pulled the rest of the motor apart and the rear rotor looks fine (it doesn't have any blowby spots on it and those side seals have the same clerance and same streetport). My side housings look fine too they still have the machined marks still on them. I'm still going to bevel the closing edge of my streetport some more myabe even the primary port, but i don't think that is the cause. This is really weird, I don't want to put the engine back together untill I can find some legitimate reason for what could have caused this because it will probably just do it again.

 

you see? he's a scholar of Ito ...

i didn't even think about this. you should get a dial indicator and check the housing. although, i suppose it doesn't explain why it's just one side of the rotor. i trust your judgment on the integrity of the seals, so i would reinforce trying another housing to see how it goes.

 

5 psi difference isn't going to be a factor, but like mentioned above make sure your irons are within specs. It's always best to have all the irons lapped when putting a new engine together. You will get the most compression and power this way.

 

Well, here are some more pics of what I've found it seems as though the stuck side seal has added a small groove to my front plate? Looks like it's either the side seal path or corner seal path. I couldn't get a good measurement on it, it wasn't over .002, but it still caught on my finger nail. I also found some strange groove in my front rotor housing. I took some pics of it, it's too far to the inside of the rotor housing to be the corner piece, I don't know what could have cause it? If an out of spec side plate is what caused the problem why would only one face have low compression and why would both side of the rotor housing have blowby or stuck side seals?The two outside side plates were from a low mileage Turbo2 japan engine and the intermediate housing i got came out of a previously running engine that looked like it had been rebuilt recently. Is this not kinda strange? have any engine builders out there since this before?

 

The first pic is very blurry and hard to see anything. It looks like your using solid corners seals? Are they factory solids or Atkins? I have heard some issues with clearances with the Atkins.

 

i've heard some of the big turbo guys reject the Atkins corner seals, but have seen very little feedback with the N/A crowd. any specific threads you can link? i have a set that i plan to try when my engine finally goes together.

 

Yeah, sorry the pics are blurry. My basement is dark and the lamp makes it hard for the camera to focus. I don't think the groove was real bad you can kinda see it in the pic but I'm still gunna try and lap my irons. Yes, I am using atkins solid corner seals, what clearance issues do they have with them? Has anyone seen a groove like that in the rotor housing? I'll try to get some better pics of it, I find that weird as I don't know what could've caused it. I guess maybe the the apex seals could've gotten in a bind or something, but why would the compression be good on two faces? I'm just gunna lap the irons, check all my clearances throw the engine back together real quick and see what compression I get.

 

Mazda has spent alot of time developing side, corner and apex seals for the rotary engine not to say that other companies cant make good products but they have been doing it and doing it well . Now changing the apex seals for racing i can understand but the corner and side seals is something i would not change .

 

Go onto Nopistons.com and go to the engine build forum and look in the FAQ and there is a thread by Judge Ito that explains the details. Basically the apex seal to corner seal groove needs to be checked as some corner seals have too tight of tolerance that can cause the apex seal to jam. You guys should be checking all of this on your pre assembly anyway, aftermarket or not.

 

^ Yep I'm also very picky about my side seal to corner seal clearence.

 

Are you using the fd corner seal springs? It can be a combination of the spring jamming into the corner piece causing that groove on the housing. Take a close look at the corner piece and you might see a nick on it.

 

Yes I am using the fd corner seal springs and my corner pieces have no nicks. They have slight wear on the side from the inside of the corner seal, also the wear in the rotor housing is to far to the inside for the corner piece to be causing it. It tried to take a pic of it but the batteries in my camera died.

 

I know the picture is horrible, but you can still kinda see what I'm talking about. the groove is to the inside of where the corner piece touches the rotor housing surface. If it did cause that it was majorly pushed in and I don't see how it could have even made 90 for compression on the other two faces

 

I am late to the party but what is the end play on the motor. If you get to much it can cause more wear on the middle plate.

 

I assembled the engine and compression tested it and this what the results were on the front rotor. I measured the endplay when I first put the engine together and don't remember exactly what it was but I remember it was in spec and the center plate still looks really good. The video show two pulses to be low and one high so I have something wrong with the corner or apex seal now. I guess I'll pull it back apart again. I will upload the rear rotor results here soon, it had fairly steady pulses. I think I'm about to give up and call it a loss.

http://www.youtube.com/watch?v=QjZoqbG2n24

 

Here's the rear rotor

http://www.youtube.com/watch?v=R2fGmS-9lJQ

 

Yea that compression isn't gonna work! Maybe it's those corner seals? For all we know the flat surface of the corner seal may not be flat and contacting the side plates flush. Also is your apex seal to rotor goove with-in spec?



Edit: I just went back to the beginning and saw you were running the 6 port side plates. Do you have the aux sleeves in place? Without the intake and sleeves, you will loose a lot of compression out those 5th and 6th ports. Remember, those ports are so late closing that the engine is on it's compression stroke before they fully close. So some of the air that is being drawn into the chamber is actually being diverted back out the 5th and 6th ports on the compression stroke. Your PP is also late closing and air is also be viverted back through your PP as well. I really think that were your problem is. I would try to find a set of 4 port plates and retest. You will also get higher readings with the intake bolted on when doing a compression check.

 

Yeah I know that compressoin isn't the best but I just threw the engine back together without using grease on any of the surfaces and the rpm it was spinning wasn't very fast either. I was pretty much just looing for even bounces and the front definitely was not even! About the side plates I started with 6-port plates but I screwed them up when I did that oil mod so I bought some turbo 4-port side plates from a jdm engine and thats what I'm using now. Yeah plan to pull the engine back a part when I get some time and go through and check all the clearances again paying special attenion to the front rotor. I switched the front and rear rotor housing when I put the engine back together to see if it would make any difference... I don't think it did. Thanks for helpin me with this

 

Do you have a set of stock corner seals to try?

 

I forgot to suggest this to you. You didn't happen to use too much premix did you? The 1st time when I got my 20b running in the car, I accidentally added too much and it got to the point where it wouldn't start at all. This was b4 my spark plug issues. I guess I was being too cautious with no omp so I had to drain the tank. New gas and it fired right up. I also did this again with my engine on the test stand and added too much to my little tank by not measuring. Same result no start! I hadn't been measuring just guessing. It turns out I've been adding about 1.5oz - 2.0oz per gallon. That's way too much. Too much premix will still run the engine initially but as the gas sits up, it starts to get really weak and fast. I last had my engine running a month and a half ago. I just got it back together and ready to fire up but it wont start now. I'm using the same ole gas I already pre-mixed a while back. I know there is too much oil in my gas because the last time I just poured what I had left in the gas container. I really think that's my problem again and could possibly be yours. I will know tomorrow when I get new gas. Just a thought.

Edit: I'm starting to think this is why I'm going through plugs so fast.

 

Yep! Once again my gas was wayyyy to diluted. Engine cranks and runs perfect.

 

Hope you're not using motor oil to mix in the fuel. Motor oil is not made to burn or mix. Pick a good two stroke motorcycle premix oil. I've used Bel-Ray GK1, and MC+1 with great results. No plug fouling or funny smoke. Now I'm trying Redline synthetic pre-mix @ 1 oz to one gallon. Also stays in susspension so it never really separates.
Burns clean and lubes well. A fave is Blendzall and VP12. Smells like a racecar!

GD