12A twin dizzy oil pump
12-12-08, 10:45 AM
#1
12A twin dizzy oil pump
Hi guys, I need a little help with my oil pump. I have a series 1 RX2 and the 12A twin dizzy has a scored oil pump. Apparently the oil pump is a bit of a strange one. See the pics of the oil pump. The pump does not mount to the front cast iron, but mounts to the inside of the front cover (timing cover in your boinger) and the pick up bolts directly to it. Does anyone know what the part number is for this, or better yet, where I can get a replacement.
It has the 12.5 x 40mm rotor set. Does anyone know where I can get the replacement rotor sets?
I contacted Atkins and they said they had never even seen one. Were these found in the 10As or something and Mazda just happened to slap one in my 12A?
Any help appreciated......
It has the 12.5 x 40mm rotor set. Does anyone know where I can get the replacement rotor sets?
I contacted Atkins and they said they had never even seen one. Were these found in the 10As or something and Mazda just happened to slap one in my 12A?
Any help appreciated......
12-12-08, 07:22 PM
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Hi guys, I need a little help with my oil pump. I have a series 1 RX2 and the 12A twin dizzy has a scored oil pump. Apparently the oil pump is a bit of a strange one. See the pics of the oil pump. The pump does not mount to the front cast iron, but mounts to the inside of the front cover (timing cover in your boinger) and the pick up bolts directly to it. Does anyone know what the part number is for this, or better yet, where I can get a replacement.
It has the 12.5 x 40mm rotor set. Does anyone know where I can get the replacement rotor sets?
I contacted Atkins and they said they had never even seen one. Were these found in the 10As or something and Mazda just happened to slap one in my 12A?
Any help appreciated......
It has the 12.5 x 40mm rotor set. Does anyone know where I can get the replacement rotor sets?
I contacted Atkins and they said they had never even seen one. Were these found in the 10As or something and Mazda just happened to slap one in my 12A?
Any help appreciated......
Twin dizzys have a lot of differences both 10a and 12a I put it down to production upgrades...
The pics there are a little small... Can you email me some slightly bigger pics and put a ruler in mm if possible on the part (size reference) I can then see if I have one which im pretty confident I do...
I have about 5 old very early series one 12a twin dizzys and one should have the part you need...
Mo Melville
12-13-08, 08:30 AM
#5
Strange oil pump
OK, so I'm going to give you guys some more detail, and the new pics should be bigger.
The first pic in my previous post shows the pump fron the front and the second is from the back. The 10mm bolt in the housing holds the centre plate in position. Its got 4 offset bolt holes, but the thing to notice is that the oil pick up mounts directly to the pump, not the front cast iron.
Pic 3 shows the front cast iron. The thing to notice is that there is nowhere to mount an oil pump.
Pic 4 shows the inside of the front cover. Here is the mounting point for the oil pump!!!!
Pic 5 shows the gears that drive the oil pump. There are NO chains to drive it, just gears (cogs). There is a big cof that fits over the top of the oil pump that meshes with these gears. Note that I have pulled the front counterweight forward so that you can see better.
Now, for the pics in this reply, I have attached a pic of page 51 from Racing Beat's catalogue where they state the oil pump rotor set sizes. Mine is not 15mm x 40mm as they state, but 12.5mm x 40mm.
The other 3 pics show the rotor set with a ruler showing that the rotor set is indeed 12.5mm x 40mm.
As it seems unlikely that I can find a new oil pump to match this one, I thought I could replace the rotor sets inside the pump for new ones. The engine has only done 69k km, all of these done by Mazda. The rotors are badly scored and covered in a brown substance. Carbon? The outer rotor to housing clearance is in spec. The inner rotor to outer rotor is out of spec, therefore a new rotor set should fit inside the existing housing and all be in spec, yes?
Racing Beat have rotor sets online (Mazda part number 0820-23-882A) but these are the 15mm x 40mm rotor sets.
I spoke to Mazda and they gave me a part number of N326-14-140 but could not tell me the size. It was for an 86+ RX7 which will most likely not fit. He also said it was unavailable, but may be able to source in Japan.
So, I guess what I want is either a new pump like this, or a pair of rotor sets in 12.5mm x 40mm to get the old girl up and running.
FYI, this is in a 1971 RX2, with 12A (as in the avatar).
Look forward to the responses to my comprehensive reply.
Cheers.
The first pic in my previous post shows the pump fron the front and the second is from the back. The 10mm bolt in the housing holds the centre plate in position. Its got 4 offset bolt holes, but the thing to notice is that the oil pick up mounts directly to the pump, not the front cast iron.
Pic 3 shows the front cast iron. The thing to notice is that there is nowhere to mount an oil pump.
Pic 4 shows the inside of the front cover. Here is the mounting point for the oil pump!!!!
Pic 5 shows the gears that drive the oil pump. There are NO chains to drive it, just gears (cogs). There is a big cof that fits over the top of the oil pump that meshes with these gears. Note that I have pulled the front counterweight forward so that you can see better.
Now, for the pics in this reply, I have attached a pic of page 51 from Racing Beat's catalogue where they state the oil pump rotor set sizes. Mine is not 15mm x 40mm as they state, but 12.5mm x 40mm.
The other 3 pics show the rotor set with a ruler showing that the rotor set is indeed 12.5mm x 40mm.
As it seems unlikely that I can find a new oil pump to match this one, I thought I could replace the rotor sets inside the pump for new ones. The engine has only done 69k km, all of these done by Mazda. The rotors are badly scored and covered in a brown substance. Carbon? The outer rotor to housing clearance is in spec. The inner rotor to outer rotor is out of spec, therefore a new rotor set should fit inside the existing housing and all be in spec, yes?
Racing Beat have rotor sets online (Mazda part number 0820-23-882A) but these are the 15mm x 40mm rotor sets.
I spoke to Mazda and they gave me a part number of N326-14-140 but could not tell me the size. It was for an 86+ RX7 which will most likely not fit. He also said it was unavailable, but may be able to source in Japan.
So, I guess what I want is either a new pump like this, or a pair of rotor sets in 12.5mm x 40mm to get the old girl up and running.
FYI, this is in a 1971 RX2, with 12A (as in the avatar).
Look forward to the responses to my comprehensive reply.
Cheers.
12-13-08, 01:05 PM
#6
A little more research
Mo, please let me know what you've got, with mileage if you know it. If not, can I get pics and wear measurements.
Blackrotor, I'll search for new parts if possible, but keep you in mind, thanks.
So I did some more research. I have a Haynes manual for the 71-73 RX2 from UK (see pic). It has a picture of all the engine compenents (see pic). On the LHS you will see a picture of the same pump I have.
The last pic states in part 11 that the early 12A twin dizzy had the pump I have. My chassis number is S122A-80433 which makes it pretty early; manufactured between March and September 1971 if Hollander is to be believed.
Also, if I could get the 15mm wide rotor set, could I just machine the rotor set down to 12.5mm at an engineers?
Very early, very rare = very cool?
Blackrotor, I'll search for new parts if possible, but keep you in mind, thanks.
So I did some more research. I have a Haynes manual for the 71-73 RX2 from UK (see pic). It has a picture of all the engine compenents (see pic). On the LHS you will see a picture of the same pump I have.
The last pic states in part 11 that the early 12A twin dizzy had the pump I have. My chassis number is S122A-80433 which makes it pretty early; manufactured between March and September 1971 if Hollander is to be believed.
Also, if I could get the 15mm wide rotor set, could I just machine the rotor set down to 12.5mm at an engineers?
Very early, very rare = very cool?
12-13-08, 07:18 PM
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Ok what you have there is the earliest 12TD direct drive oil pump... We have one for $40 that Jed my business partner will look over and get you a pic with condition report etc...
Mo Melville
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12-14-08, 06:15 AM
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One other point to make is when you do build the motor make sure you use "two piece" apex seals as they provide much better compression which is most apperent when starting... I can supply Jedd's email addy through pm if need be...
Pics and description to come in the few days!
Mo Melville
12-14-08, 08:13 AM
#10
Machining rotors?
Mo, I was talking about machining down the rotor set for the oil pump, not the rotors in the main engine.
I figured if I could get the 15mm wide rotor set for the oil pump (0820-23-882A) I could have them machined down to 12.5mm wide, then they would fit. They are both 40mm in diameter.
As far as 2 piece seals go, can you get 2 piece 6mm carbon seals? Mine are 1 piece.
Are we talking about the same thing?
I figured if I could get the 15mm wide rotor set for the oil pump (0820-23-882A) I could have them machined down to 12.5mm wide, then they would fit. They are both 40mm in diameter.
As far as 2 piece seals go, can you get 2 piece 6mm carbon seals? Mine are 1 piece.
Are we talking about the same thing?
12-16-08, 02:38 AM
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hi my name is jed and i am mo's engine builder and business associate
here is a pic of what i have.
what you have is an very early s1 rx2 12 twin dizzy. as they changed the design mid way through production of the s1. the pump you have is gear driven by baker light pulleys and is mounted to the timing cover. as opposed to the later type where they are chain driven and mounted to the front plate. these early 12as are a half way between an r100 10a and a late type 12a twin dizzy. i will sell the whole timing cover as a unit for $100aud. i thought i had just a pump some where but i cant find it. also it is only 10as that have 2 piece 6 mm apex seals and yes you can machine down the later type to fit.
cheers
jed
here is a pic of what i have.
what you have is an very early s1 rx2 12 twin dizzy. as they changed the design mid way through production of the s1. the pump you have is gear driven by baker light pulleys and is mounted to the timing cover. as opposed to the later type where they are chain driven and mounted to the front plate. these early 12as are a half way between an r100 10a and a late type 12a twin dizzy. i will sell the whole timing cover as a unit for $100aud. i thought i had just a pump some where but i cant find it. also it is only 10as that have 2 piece 6 mm apex seals and yes you can machine down the later type to fit.
cheers
jed
Last edited by Mo's; 12-16-08 at 02:46 AM.
12-17-08, 03:34 AM
#16
Thanks Jed
hi my name is jed and i am mo's engine builder and business associate
here is a pic of what i have.
what you have is an very early s1 rx2 12 twin dizzy. as they changed the design mid way through production of the s1. the pump you have is gear driven by baker light pulleys and is mounted to the timing cover. as opposed to the later type where they are chain driven and mounted to the front plate. these early 12as are a half way between an r100 10a and a late type 12a twin dizzy. i will sell the whole timing cover as a unit for $100aud. i thought i had just a pump some where but i cant find it. also it is only 10as that have 2 piece 6 mm apex seals and yes you can machine down the later type to fit.
cheers
jed
here is a pic of what i have.
what you have is an very early s1 rx2 12 twin dizzy. as they changed the design mid way through production of the s1. the pump you have is gear driven by baker light pulleys and is mounted to the timing cover. as opposed to the later type where they are chain driven and mounted to the front plate. these early 12as are a half way between an r100 10a and a late type 12a twin dizzy. i will sell the whole timing cover as a unit for $100aud. i thought i had just a pump some where but i cant find it. also it is only 10as that have 2 piece 6 mm apex seals and yes you can machine down the later type to fit.
cheers
jed
That is exactly what I have. They should have stopped using these pumps in January 71 but mine has it from approximately July 71. I guess they used what they had sitting around in stock.
I have managed to source some brand new 15mm rotor sets, which I will machine down and put in my pump housing. They were discontinued in 97. Last available anywhere?
Out of curiosity, what is the wear on the pump you have there? Mine is running at 0.18-0.2 between inner and outer rotor after only 69k km (43k miles). Spec is 0.01-0.09 according to Haynes.
Thanks everyone!
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