^ I agree. If the Semi PP wasn't done correctly, (beveled closing edge) it's possible the middle part of the apex seals could have gotten damaged.

 

Ok I'll check compression. When I deflood the engine it makes a pretty good whoosh. About the beveled edge, when building the engine I was very precautious about that and grinded a beveled edge all the way back to the surface of the rotor housing and ran the apex seals over it to make sure it was nice and smooth so I don't think it would be that, but I can check their surface through the exhaust ports and see what they look like. Thanks for the help guys

 

I pulled off the header to check the apex seals and they were all nice and smooth still and weren't stuck or anything. I checked compression with a piston compression tester and the schrader valve removed. The rear rotor was around 95psi and the front rotor was around 90psi at around 300 rpm on a cold engine. I noticed on the front rotor that one of the bumps looked a little less than rest but with the piston tester it was hard to tell, maybe 5psi difference. This engine has maybe 20 hours of running time and is still breaking in and I would think that 90-95 psi should be enough for it to run on.

 

Do you guys think this is sufficient compression to run on and start lookiing somewhere else or think that those numbers could be the cause of the problem? I went back up to work on the car. It started after a bit of cranking and I was able to keep it running around 1000-1500 rpms by working the throttle till it was warmed up. I then got it to rev up to around 3000 rpms. It stayed for maybe a couple of secs, backfired, then crapped out and slowly died. The car would almost start after that but never did. It seems that on the first starts it will run but after that it acts as though it's flooded.

 

That compression is good enough to allow the engine to run. Also your plugs may be fould. Check out my thread in the rotary performance section (spark plug experts need help). I was having very similar issues after only 5hrs of run time. I changed my leading plugs and all was well.

 

Sounds like you have a fuel problem. Make sure your fuel pressure is ok and you don't have a fuel filter plugged or a bad pump, etc. You said you had alot of fuel coming out of the exhaust, which means either too much fuel like from a stuck injector or ignition is not firing. Some things to check.

 

i tend to agree with T-von. the compression should be fine. put plugs on your list next. what type of plugs are you running now?

 

I'm just running stock 2nd gen ngk plugs, leading=7's and trailing=9's I think the codes are br7eq and br9eq. I'll be able to work on the car some more this weekend. I will try some different things with the ignition and megasquirt settings. oh and tvon I read that thread and it sound similiar, I think I have two more trailing plugs so that I can try using four br9eq plugs in the engine. Thanks again guys, I really don't know where to go next on this thing.

 

well, i'll start with suggesting the B_EV or B_EIX plugs, since i believe in them. however, since my semi-peripheral isn't running yet, i can't say how they perform in that application. so in the spirit of being thorough, i would try to see what plugs other semi-peripherals and big bridgeports run and maybe take cues from them.

 

Well I know that usually for BP and PP motors one runs colder plugs, 10 leading 9 trailing etc. This is just to reduce chances of pre-ignition on the hot plugs at higher power applications but will make chances of fouling plugs more likely at low rpm and rich conditions. So, that shouldn't be causing your problem, your warmer plugs should make the chances of them fouling less likely. This does seem very strange, I actually had a similar problem when I was first trying to get my bridgeport running, the bladder inside my fuel pressure regulator burst and fuel was pouring directly into the intake manifold through the vacuum hose :O . As you can imagine the engine would run like crap on only on rotor etc. and took me forever to diagnose. I just happened to pull the air filters off and look down the throttle bodies while someone cranked the motor one day and discovered it. I know its highly unlikely that this could be your problem but it seems you may have to think outside the box for this one . Also have you checked that your not getting rpm spikes on your megasquirt?

 

Haha, I'll check my fpr. About the rpm spikes, my tach in the car that is wired to the trailing coil will jump and bounce around while I'm cranking it, but the tach in megasquirt that i have wired to the leading coil is steady. I tried using all 9's and it didn't change much, I then put the 7's in trailing and 9's in the leading and it didn't really run any different, but there wasn't fuel covering the trailing plugs that time. I tried advacing and retarding the ignition and it didn't like that at all. I tried using a different distributor I have that the car has previously run on before and no difference. I have ordered a U4 chip for megasquirt. Thats pretty much the only thing for me left to replace in ms other than the flyback circuit but I'm pretty sure it's working. Could a vacuum leak cause it to run this way? Because I know i have one but I don't think it's very big. It's in my welds on the intake pipe of one runner, I have bought some bent pipe that I plan on redoing my intake with, but I wanted to get the car running again first. It seems like pumping the throttle is what keeps it running and when it I pump the throttle I can see the accel enrichment activate and add more fuel, but at the same time I'm opening the throttle adding more air so don't know which it needs to keep running (more air or more fuel?) It looks as though it just has way too much fuel. I've checked my injectors and there not sticking open. wow long post, sorry for the rambling just trying to think this through and make sure I'm not over looking anything.

 

have you made any headway with it?

i would tend to think so. i've had an occasion or two when trying to diagnose something all came down to a bloody vacuum leak. the only part that disuades me is the fact that it's obviously been there since you setup the engine, so why the sudden change in behavior?

 

Well, I wasn't going to say anything yet because I didn't want to jinx myself and I didn't want to look like a ratard , but I think the problem is I need a new distributor cap and rotor . I haven't gotten to check it yet, but I was working on the car lask weekend checking the spark and noticed that no mater what plugs I put in the trailing plugs had a lot weaker spark than the leading. I also thought I heard part of the spark jumping around in the cap. I took that cap and rotor off, they had some corosion so I cleaned them up and noticed that pin T from the coil had a gouge in it? I put it back together after cleaning and the trailing had a much louder and brighter spark put the plugs in and it fired up and idled by itself. I got out of the car and was working the throttle. I reved it up a couple times then really high and it cut out and died and then went back to acting the way it was. I have bought a new cap and rotor and I plan to do some tuning on it if it starts and runs good. I'm not sure if my wideband band is reading correctly though, but thats where I'm at now.

 

Once I get the car running decent I plan on making a new intake for it I have all the supplies I just need to do it. I wish I could wrap the intake around the engine that way I could run longer runners for the side ports and shorter one for the P-ports, but the water pump inlet won't let me. I've also got a pretty cool idea for a kind of drysump/relocated oil pan (probably already been done) that I would like to make once the I get the car going decently. I've also got some ducting work that I'd like to do. So many plans so little time and money

 

Well hopefully you have found your problem. One word of advice on the wideband, get the heatsink extender bung thingy or make your own, rotaries tend to eat those expensive lambda sensors quite quickly. I found out the hard way, mine was basically toast almost immediately after I got to an optimum tune, kinda annoying .

 

So that didn't fix it..... Man, this things a pain in the ***!
I pullled the distributor out of the block and was turing it and watching the spark, they all looked good and bright. What all can I check for in the distributor? ignitors, pick ups, anything else. Whats the best way to clean fouled plugs? Also would it be possible to use the stock 2nd gen cas and run just timing out of the stock ecu? I'm wondering if I should just pull the engine and see whats goin on inside?

 

Meths/kero and a toothbrush. Wirebrushes dont get in there enough.

 

My basic tuning instinct is that anytime you have to pump the gas (throttle pump) to keep it running as you have said it is lean- add more fuel.

If it was rich to start with and you pumped the gas (throttle pump) it should bog, pop and backfire and maybe catch itself as you are letting off the gas.

You are dealing with a poor compression (breaking in) high overlap (p-port) motor so perhaps even though it smells to hell of gas it actually needs more.

Only time my car actually got so rich it had a hard time starting/keep running is when one of my 1600cc inj were stuck wide open and it literally filled the exhaust/garage floor with liquid gasoline.

Every other time it has had trouble starting/running it simply needed more gas.

 

Ah- nvm. I went back and read the whole thread and not just the last page.

From your post on when it happened it sounds like it is possible you stuck a side seal when you decelerating with engine braking >.<

On your 2ndary ports it looks like the top edge of the opening edge (top outside of port) has too gradual of a radius and the unsupported side seal edge could hit it. I square that edge off more and put a radius on the closing line to scissor and lift the sideseal back onto the plate.

Anyways, I hope it is something else and easy to fix- awesome project.

 

Yeah, I searching yesterday and found a thread about a stuck side seal and sounds like that could be what it is. I do have somewhat lower compression one one rotor face on the front rotor. In the thread I was reading they were able to rev the crap out of the motor and got the seal to unstick, is this possible? I didn't think that I ported out past where the side seal runs but I did use some tight tolerances.

 

I did a little bit more researching and could it be stuck from carbon already? The car has only been driven 2-3 times the rest has been running the engine without a load so I wouldn't think it would have caused mechanical damage? Should I try to put some Atf, mmo, or oil down in the engine and try to work it loose or just go ahead and pull the engine apart?

 

It's real easy to find out if you have a stuck/broken side seal. Do a compression test with the schraeder valve out. Crank the engine over and watch the guage. If you have 2 good compression bumps and then one bad-low one, then you have a bad side seal. If you have two low and one good, then you might have a bad apex seal. You need to start with this test first. You should have three even bumps on the compression guage for each rotor. If you get this, then check your fuel system.

 

If your compression checks out fine, put in some new plugs. In my thread I actually tried cleaning that 1st set of plugs but that didn't help. I also checked for spark jump with each individual plug and they worked fine but as soon as put them back in the engine, it wouldn't start. It's almost like the fuel is killing the spark. My used BMW plugs got me running. They don't have to be rotary specific. Just the correct length to get the engine started. I just got my 20b back up and running and have been using the same used BMW plugs as before in the leading. I'm gonna keep them in there while I'm still doing my experimenting.

 

So i pulled the engine got the front plate off and this was the first thing I found (see picture). It looks like some blow by in the middle of the side seal, but just the middle. Could it just have gotten stuck to where the middle was down causing blowby? The side seal springs up and down fairly easily when pushed, but I'm gunna check the clearances again. I haven't checked the other side of the rotor yet I'm scared to pull it out, have the seals fall out and get them mixed up.

 

So I checked the clearances on the exposed side of the front rotor and they were around .002. Two of the side seals were sticking a bit on the ends when depressed. They would spring back but not all the way. I pulled them out and it seemed as though they were miss shaped from the groove a bit. I gently bent them back and sanded on them just a little bit to get the end shaped closer to the edge of the corner seal. They spring back better now. Two of the side seals are now around .002 and the side seal that looked as though it was stuck I sanded out to .003.