How to confirm 12A is 79-80 not 81-85?
#1
How to confirm 12A is 79-80 not 81-85?
I am looking at a parts car and its a 79 body with a rebuilt 12A ... owner can't confirm its a 79-80 12A as opposed to later model FB 12A swapped into it . Other things have been modded so can't tell for sure like a header and newer alternator. Air cleaner has built in Carbon cannister but carb was also rebuilt and may not be 79-80 carb either
Would like to know how to confirm the Keg is actually a 79-80 ??????? what would be a sure indicator ?
Would like to know how to confirm the Keg is actually a 79-80 ??????? what would be a sure indicator ?
#2
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That's harder than it sounds, without taking things apart. most of the easy indications are covered.
FOMC, or Beehive oil cooler?
Wasnt there a tapped hole for the oil pressure sender on the 81+ motors, which is undrilled on the 80 and younger kegs?
The tension bolt count changed at one point , but you'll never spot it without removing the trans.
FOMC, or Beehive oil cooler?
Wasnt there a tapped hole for the oil pressure sender on the 81+ motors, which is undrilled on the 80 and younger kegs?
The tension bolt count changed at one point , but you'll never spot it without removing the trans.
#7
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If I recall correctly, the oil pressure sender was on the rear iron, driver's side, below the oil filter pedestal.
I know all the front irons bear a serial number stamped on top, about where the alternator goes, but I've never seen a reference that lists which engines went with which years, or which cars.
I know all the front irons bear a serial number stamped on top, about where the alternator goes, but I've never seen a reference that lists which engines went with which years, or which cars.
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#8
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the 74-80 rotor housings have extra ribs in the castings.
like these, although this is an older engine http://www.rotaryresponse.com/RHousi...rall72auto.jpg
the irons are different, the casting is more square, but its subtle, and really except the oil pressure sender, they are functionally the same
early SA engines also have pulleys that are creme colored, later pulleys are black.
like these, although this is an older engine http://www.rotaryresponse.com/RHousi...rall72auto.jpg
the irons are different, the casting is more square, but its subtle, and really except the oil pressure sender, they are functionally the same
early SA engines also have pulleys that are creme colored, later pulleys are black.
#10
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OK, this is a 1980 12a rear housing, driver side:
Arrow shows where the non-penetrating oil pressure sensor holes are:
The holes are in the casting, but they do NOT go thru to the oil journal. On 81-on engines, I believe, at least one is drilled thru and the oil pressure sensor goes in it.
(closeup, shot sideways.)
If somebody with a for-sure 81-later 12a could verify the sensor or get a pic of it, we'll have a pretty reliable way to detect early rear irons, without disassembly.
Arrow shows where the non-penetrating oil pressure sensor holes are:
The holes are in the casting, but they do NOT go thru to the oil journal. On 81-on engines, I believe, at least one is drilled thru and the oil pressure sensor goes in it.
(closeup, shot sideways.)
If somebody with a for-sure 81-later 12a could verify the sensor or get a pic of it, we'll have a pretty reliable way to detect early rear irons, without disassembly.
#11
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On the mazdatrix website there is a page w/photos explaining visual differences between the 79/80 Federal, 80Calif ERG equipped and 81-85 engines. Heres the address; http://www.mazdatrix.com/eng12aid.htm
#13
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Divin, here is a picture of the rear housing on my 84. Looks like a temp sensor on the left and oil pressure on the right.
Also note no "eyebrows" above the sparkplug.
Also note no "eyebrows" above the sparkplug.
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Also my 84 has "Mazda Automobiles" written on the pront rotor housing only....not the back.
I don't remember the "Automobiles" verbiage written on my 1980.
I don't remember the "Automobiles" verbiage written on my 1980.
#16
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Right now, it's got the following sections working:
Air cleaner base paint stripping
Steering gear cleanup and paint prep
350Z strut swap prep
Messy section that was just used for moonroof resto finished last week, which is where I parked that housing
Clean desk = messy mind, and all that.
#17
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And yes, the 80's rotor housings only said "MAZDA." The front housing was the first one that went NLA from Mazda, so perhaps your last build required that a later front housing be used.