'84SE - 5&6 Port Operation & Exhaust
11-10-14, 01:29 AM
#1
84SE-EGI helpy-helperton
Thread Starter
'84SE - 5&6 Port Operation & Exhaust
Hey guys - got the LIM off of the engine today (221k original miles), and am replacing the 13b engine after getting such low compression that it won't restart when warm. Removed all the ancillary stuff to reach the core and on removing the LIM found the following port condition: (Sleeve #1 is front rotor, #2 is rear)
Overall intake and exhaust manifolds:
Sleeves:
And closeup of the exhaust manifold:
Based on the coloring of the exhaust and the lack of any carbon buildup on the #1 sleeve - it seems to me that this sleeve wasn't operating at all in most of the last 10 years since I rebuilt these. This could lead to the overly rich condition in the #1 chamber, as evidenced by the white burn residue on the exhaust side. Also note that the #2 sleeve is heavily carboned-up which is what I expected after cleaning the '6'-ports back in 2004.
I'm thinking the front '6'-port actuator was stuck or otherwise not seeing pressure. Any thoughts?
Overall intake and exhaust manifolds:
Sleeves:
And closeup of the exhaust manifold:
Based on the coloring of the exhaust and the lack of any carbon buildup on the #1 sleeve - it seems to me that this sleeve wasn't operating at all in most of the last 10 years since I rebuilt these. This could lead to the overly rich condition in the #1 chamber, as evidenced by the white burn residue on the exhaust side. Also note that the #2 sleeve is heavily carboned-up which is what I expected after cleaning the '6'-ports back in 2004.
I'm thinking the front '6'-port actuator was stuck or otherwise not seeing pressure. Any thoughts?
11-10-14, 09:51 AM
#3
84SE-EGI helpy-helperton
Thread Starter
Interesting you mention coolant, Jeff - as I was losing a few cups of coolant every trip (20-40mi) and had to keep topping off the radiator before drives.
Part of the reason for the engine swap was that as it was gradually losing compression, it was also drinking just about every fluid on every trip. Before starting off, I'd have to add coolant, add engine oil, add power steering fluid, and of course gasoline - as I was down to about 12-13mpg - which was a frequent reminder that the original engine was on it's last legs.
On the #1 '6'-port induction sleeve, that's exactly how it looked when I reinstalled both of them back in 2004; I cleaned them both to that level of spotless, scrubbed out all the carbon crap in the bores and the #1 sleeve was just as clean when I took it out yesterday as the day I put it in! The other sleeve looks like it's had 20k+ miles on it, and was a bit harder to remove from the engine block. Sleeve #2 was well-oiled and just slid out, rotated smoothly and I'm thinking the actuator is bad.
Studying the pressure hole configuration on each actuator - is there a specific actuator for Front/Rear intake? I'm going to bench test it this evening the way it's run for the past 10 years and see if it's a bad actuator. If one gasket gave out and wasn't sealing, BOTH actuators wouldn't work as it would never build the 1.8psi opening / 2.2psi full open pressure due to loss, right? TIA,
Part of the reason for the engine swap was that as it was gradually losing compression, it was also drinking just about every fluid on every trip. Before starting off, I'd have to add coolant, add engine oil, add power steering fluid, and of course gasoline - as I was down to about 12-13mpg - which was a frequent reminder that the original engine was on it's last legs.
On the #1 '6'-port induction sleeve, that's exactly how it looked when I reinstalled both of them back in 2004; I cleaned them both to that level of spotless, scrubbed out all the carbon crap in the bores and the #1 sleeve was just as clean when I took it out yesterday as the day I put it in! The other sleeve looks like it's had 20k+ miles on it, and was a bit harder to remove from the engine block. Sleeve #2 was well-oiled and just slid out, rotated smoothly and I'm thinking the actuator is bad.
Studying the pressure hole configuration on each actuator - is there a specific actuator for Front/Rear intake? I'm going to bench test it this evening the way it's run for the past 10 years and see if it's a bad actuator. If one gasket gave out and wasn't sealing, BOTH actuators wouldn't work as it would never build the 1.8psi opening / 2.2psi full open pressure due to loss, right? TIA,
11-10-14, 10:29 AM
#4
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what we can see from pics:
both rotors are running ok, the front looks a little leaner/hotter/using coolant/tired injector/bad metering nozzle. a good running rotary will have a light brown colored exhaust sleeve, and usually you can spot the problem, as the bad rotor will be black...
the sleeves are still pretty clean, the average one i've seen is basically full of carbon, and not a light coat, which implies that yours are open enough to get some flow through them*.
the actuators are the same front and rear.
they are fed by a pipe with 2 banjo bolts, and there are gaskets between the actuator and the intake, so there are places to leak, and i have actually seen a plugged 6 port pipe, easy stuff to check while its apart. in fact you're ahead to check everything you remove while you're changing the engine, easy to clean/fix now, harder later
both rotors are running ok, the front looks a little leaner/hotter/using coolant/tired injector/bad metering nozzle. a good running rotary will have a light brown colored exhaust sleeve, and usually you can spot the problem, as the bad rotor will be black...
the sleeves are still pretty clean, the average one i've seen is basically full of carbon, and not a light coat, which implies that yours are open enough to get some flow through them*.
the actuators are the same front and rear.
they are fed by a pipe with 2 banjo bolts, and there are gaskets between the actuator and the intake, so there are places to leak, and i have actually seen a plugged 6 port pipe, easy stuff to check while its apart. in fact you're ahead to check everything you remove while you're changing the engine, easy to clean/fix now, harder later
11-11-14, 09:56 PM
#5
84SE-EGI helpy-helperton
Thread Starter
Yep, will do new gaskets (homemade from cork board - as OEM hard to find) and will bench test it with a pressure gauge this weekend. Still waiting on the light flywheel and clutch parts from Mazdatrix, and thinking about replacing the water pump while the engine is out, too.
And, replacing all vacuum hoses with silicone tubing,... and, running new fuel injection hoses to the rail,... and...
There's a lot left to do now that I can look at everything in the open!
And, replacing all vacuum hoses with silicone tubing,... and, running new fuel injection hoses to the rail,... and...
There's a lot left to do now that I can look at everything in the open!
11-13-14, 05:13 PM
#7
84SE-EGI helpy-helperton
Thread Starter
Haven't decided on replacement engine colors, yet - I'd just be happy to get rid of 30 years of caked on grease, oil, and dirt!
It's a mess and I need to get the engine core out before I can get to cleaning anything in the engine bay. I'll post before/after pics, eventually.
It's a mess and I need to get the engine core out before I can get to cleaning anything in the engine bay. I'll post before/after pics, eventually.
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