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So this might take a little back story but the quick question is, why is this port filled with epoxy or something?
Back story: I picked up this car after it had been sitting for 16 years because the previous owner couldn't get it to pass smog. Alas, I couldn't get it to pass either even after some tuning and other emissions maintenance so yesterday I took off the TR, intake, carb, etc. I found what you see in the picture and am genuinely confused. To me it looks like they took an engine from another car and so that the intake manifold would fit since it doesn't have that port, they plugged it. As I'm swapping the intake, exhaust, carb, etc from my parts car which does have this port (it's an fb), should I clear it out or what? Any help or theories are appreciated.
Thats an exhaust port for the ACV valve used for emissions crap. Early 12As (79/80) didn't have these or an intake that would cover it. So common practice is to either cover it somehow or seal it up with JB Weld or the like. Since you have an SA, I suspect someone swapped in this engine at some point.
I can say that the 1979/1980 intake does not cover that port entirely. The 1981-1985 intake does. I found this out with my 1979. All original engine/intake/carb/etc and that port does not get covered. It's exhaust so I'm not sure why it's open. It doesn't make sense to me. I had a 1980 and put an 1984 engine in it and I filled that port. I'm torn if I should fill it on my 1979.
Just did some research on the different intakes and that extra port. It looks like the fb intake has a shorter intake port and the taller ones are a bit better for performance. Is this true? If those were to not match up I could see why that would be quite a problem. I'll check my other manifold when I get home today. No sensor by the way.
Just did some research on the different intakes and that extra port. It looks like the fb intake has a shorter intake port and the taller ones are a bit better for performance. Is this true? If those were to not match up I could see why that would be quite a problem. I'll check my other manifold when I get home today. No sensor by the way.
The early ports are better, bigger in the SAs.
The intake ports never really match the engine ports. The ports need to not match to provide a lip to reduce the reversion as the exhaust port closes duing the sweep into the intake port. Without this mismatch in ports, the car will not run well, especially at idle.
Cool info, both of my intakes have the same size ports so it wouldn't matter anyways. I confirmed the motor is a later year 12A so now I just have to decide between which carb/intake combo. I had the car running with the sa carb and such but if it would help emissions I might use the other set and clear out that epoxy. Would it hurt emissions much to block off the ACV set up and just run a line from the air pump to cat? The sa ACV wasn't working properly before so I'm not sure. The other carb has been rebuilt but it has a dead TPS and it's got a vacuum line that I can't figure out where it's supposed to go. Thoughts? Opinions? I'm trying to fix it this weekend so I'm hoping to avoid ordering parts.
that rectangular port is for the 81+ air injection system. the air pump air goes from the air pump -> Air Control Valve -> to this port -> to the exhaust ports. Mazda calls it 'Port Air"
the SA Thermal reactor system is different.
the 81+ cars will never ever ever pass smog without this air injection port working. engine in the pic is an 81-85
Well that was close. Yesterday I had just finished installing the new exhaust and put on the 81+ intake but I hadn't mounted the carb yet. Looks like I'll be taking it back off to drill it out. What's the best way to do that without getting a bunch of junk inside the engine? Drill holes and then knock it loose with a chissel? Good quotes BTW.
On a different note, the TPS sensor is frozen. Any ideas on how to get it unstuck and will the 81+ TPS work with the 80 ECU or do I need to fab a new mount for the 80 TPS?
Last question: The purge valve between the two cars is different. Since I'm keeping the rats nest for now, how should I run the tank and crank vent. On the fb they ran the two lines into each other but through the charcoal canister? Should I just do that or would a filter between the two lines work just as well? Thanks for all the help so far.
Its more of a switch that a sensor. It's either on or off but it uses the same connector and is mounted in the same spot. I got the newer sensor to work so now it's just the question if the ECU will work with it. I've removed the intake and are ready to drill the filler out. Thoughts?
Keep a shop vac running so it pulls as many chunks out as possible as you drill. There is no telling how deep that material was stuffed into the hole. You might get lucky and get it all out though.
Unfortunately I wasn't lucky at all. It goes down farther than I can get with even a small drill bit and my tap. It's still completely plugged but there probably isn't much left. I gave up and right now I'm installing the carb (a float was stuck so I've got to fix that now). At this point I just want to know if it runs. Thanks for the advice so far. I'll keep this updated if I make any progress.
If the engine is out of the car, put it on an engine stand and turn it post down.You could also try drilling a series of holes along the outside edge and space them apart. Maybe it will come out mostly in one chunk.
EDIT: Too late, just read your last post about trying to get it out.
Last edited by KansasCityREPU; 02-03-18 at 06:57 PM.
Thanks anyways for the idea. I'm thinking it'll need a rebuild to get the rest of it out.
I got everything installed and now the car fires up, runs rough for a few seconds and then dies. I've tried the mixture and throttle screw and they make no difference. I just finished puting the carb back together again so I'll give it another try. The float bowls have fuel and the floats are adjusted correctly. Anyone know what would cause something like this?
So let's just call it not having thought everything through... The reason the car would die consistently after being started was because of the shutter valve. Since the solenoids are open loop without power, the valve was getting vacuum as soon as the car started, thus killing the rear rotor and the car with it. The solenoid wasn't getting power since I'm still using the wire harness from the '80 and it didn't have that connector. I ended up putting a bind cap on it and it started up just fine. Right now I've got a lot of white smoke so that'll go on tomorrow's list along with trying to get it to idle a little lower. I've also since fixed the vents by picking up some hose and running them to the charcoal canister I stole from my parts car on the other side of the engine bay. The mystery vacuum line has also now been remedied along with flooding issues (a good knock with a wrench works quite well). Hoping it has a chance at passing smog even without that port. Thanks for all the help, if I find more issues (which of course I will), I'll update tomorrow.
Well it runs but there a noise on the passenger side of the engine bay that sounds like an exhaust leak but I can't find one. I wondered if the mismatch emissions systems could cause it but I've gone through and tested powering solenoids manually and nothing changes. Ideas? It kinda sounds like a plane.
The ACV port might, in fact, be passing some exhaust out into your engine bay now. Listen around the area where you were trying to remove the putty material to see if it gets louder there. It will sound like an exhaust leak.
The thing is that I'm using the 81+ intake manifold, which covers up that port. Thanks for the idea, but I think my exhaust gasket may be bad. I am however getting some water in the exhaust and I'm thinking it's from bad coolant seals in the intake. Once the car has cooled down I'll know for sure. I'm also still trying to figure out all the vacuum lines and decide what will still work with the older ECU. Right now I think the only things that match up are the relief and vacuum advance solenoids. The others I'll have to plug.
Here's a bunch of questions so get ready for the thought process... Ok, with the port-air port blocked off, should that affect at all how the car idles/runs? It should only affect emissions, yeah? As of now I'm having a lot of issues with the car idling rough and then it dying on decel. The only solenoids I have wired up (all of them are hooked up vacuum wise) are the relief and vacuum advance solenoids. When it does run it sounds like there's an exhaust leak or something else in sync with the exhaust pulses. The sound is coming from the middle of the passenger side of the engine bay, which sure narrows it down . The car also is leaking water from somewhere near the intake/exhaust. I'm gonna say this is thanks to me having made a gasket from a role of gasket material I had lying around. It was a good and clean gasket, but I'm guessing the cutouts for the cooling jacket ports were too small so the rubber O-rings had the gasket between them and the intake, causing a leak since it's a paper gasket. I found an actual gasket for the intake sitting in one of my parts bins, so when I take everything apart tomorrow or some other time this week, I'll use that. If anyone's got an idea of why it's running rough (I'm betting on a vacuum issue), please put it on the table, I'm looking for anything that might get this thing to run. I've also done some research on the emissions system from the '82 car and it looks like I might be able to rig the two systems together (I'll be experimenting more later this week). I might try putting the '80 carb on the newer intake just to see if it'll idle smoother. If it ends up I do need the port air to be cleared out, I do have another engine sitting on my bench as a last resort, like honestly, last resort. I'd rather not pull the engine if it might work as is. Timing is something else that's messed up. I can get the timing to stay correct if I cap off the vacuum advance solenoid (it appears it's not getting any signal so the vacuum is going through), but since the other emissions system had the leading and trailing separated and this one doesn't, it now shows that the trailing advance valve on the distributor is seized. Yet another thing to be fixed. The car does run better though when it's hooked up and the leading is advanced if that points to any clues.
Sorry for the messy update, but I'm hoping stuff is clear enough to get some opinions out there.
Any help appreciated.
Just had an idea. Would it be possible to clear out that port through the exhaust? Where does the ACV port go, besides into the exhaust somewhere, obviously. I'm gonna have to take stuff apart anyways so if it's possible, I'd like to give it a try. Also, at idle, where is air supposed to be going? Port air or split air, or does it depend? Our smog test in Oregon is just an idle test so once the car is warmed up, should I send air to port air or split air to get the best emissions. I might just rig a toggle switch so I can control the switching solenoid from inside the car. Thoughts, opinions?
EDIT: Did some more research on cleaning out that port and it doesn't look like you can get to it through the exhaust. Any other ideas on how to clear it out? The tool would have to be a bent shape since it's now so far down that my chisel and drill can't make the 90 degree turn. I didn't get a chance to work on it today and probably wont tomorrow either, but Wednesday I'll have some time. Any ideas before then would be awesome since while the intake is off again, I may as well take another crack at it.
Last edited by Benjamin4456; 02-05-18 at 08:27 PM.
That center piece is iron, right? You could cutoff 4 to 6" of the the business end of a metal drain snake, put it in a drill and rip up the JB Weld? Go in with a wire wheel (like a chimney sweep but smaller) after that.
Maybe you could back pressurize the exhaust with your shop vac on blow into an exhaust port, then debris blows out of the hole rather than falling into it as you work. Might have to rotate the e shaft by hand until it lines up the right way.
This job sounds like no fun
I would avoid heat. The JB Weld FAQ says the epoxy fails at 600°F and that sounds like it would cause warping.
02-01-18, 10:04 AM
. The car also is leaking water from somewhere near the intake/exhaust. I'm gonna say this is thanks to me having made a gasket from a role of gasket material I had lying around. It was a good and clean gasket, but I'm guessing the cutouts for the cooling jacket ports were too small so the rubber O-rings had the gasket between them and the intake, causing a leak since it's a paper gasket. I found an actual gasket for the intake sitting in one of my parts bins, so when I take everything apart tomorrow or some other time this week, I'll use that. If anyone's got an idea of why it's running rough (I'm betting on a vacuum issue), please put it on the table, I'm looking for anything that might get this thing to run. I've also done some research on the emissions system from the '82 car and it looks like I might be able to rig the two systems together (I'll be experimenting more later this week). I might try putting the '80 carb on the newer intake just to see if it'll idle smoother. If it ends up I do need the port air to be cleared out, I do have another engine sitting on my bench as a last resort, like honestly, last resort. I'd rather not pull the engine if it might work as is. Timing is something else that's messed up. I can get the timing to stay correct if I cap off the vacuum advance solenoid (it appears it's not getting any signal so the vacuum is going through), but since the other emissions system had the leading and trailing separated and this one doesn't, it now shows that the trailing advance valve on the distributor is seized. Yet another thing to be fixed. The car does run better though when it's hooked up and the leading is advanced if that points to any clues.
