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Datsun A12 motor

rambo64

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I have a problem with the timming setting on the A12 motor.I read the manual book say 5 or 10 deg advance and the rotor on no1 to the distributor cap and I set up and try to start the A12 with a problem it stop running and hard to start can some help on the right set up with the timming as I hope the cam and crankshaft timming is not out as this A12 motor was rebuilt.When the A12 is running and the timming light is on is shows more than 20deg advance and when you turn the distributor retarded the timming is just under 20 deg advance and not 7deg advance by the book.
 
You should start the process over and bring it to TDC on cylinder 1 and the set the distributor to point towards number one plug wire. The rotation of the distributor is counter clockwise. 18436572 is the Firing order. Once you have all that sorted out. it will start and run. Put your timing light on it and unplug your vacuum advance hose and plug off the carb port. Try setting initial to somewhere around 12 degrees BTDC to start off with. This should get you going.

 
You should start the process over and bring it to TDC on cylinder 1 and the set the distributor to point towards number one plug wire. The rotation of the distributor is counter clockwise. 18436572 is the Firing order. Once you have all that sorted out. it will start and run. Put your timing light on it and unplug your vacuum advance hose and plug off the carb port. Try setting initial to somewhere around 12 degrees BTDC to start off with. This should get you going.
You should start the process over and bring it to TDC on cylinder 1 and the set the distributor to point towards number one plug wire. The rotation of the distributor is counter clockwise. 18436572 is the Firing order. Once you have all that sorted out. it will start and run. Put your timing light on it and unplug your vacuum advance hose and plug off the carb port. Try setting initial to somewhere around 12 degrees BTDC to start off with. This should get you going.


The A12 motor is a 4 cylinder and we had put the no1 piston on tdc and the distributor to no1 is because the vacuum advance with the timming light shows more than 20deg so by removing the vacuum advance this will show the right advance
 
You should start the process over and bring it to TDC on cylinder 1 and the set the distributor to point towards number one plug wire. The rotation of the distributor is counter clockwise. 18436572 is the Firing order. Once you have all that sorted out. it will start and run. Put your timing light on it and unplug your vacuum advance hose and plug off the carb port. Try setting initial to somewhere around 12 degrees BTDC to start off with. This should get you going.


If the timming is out by 1 or 2 teeth from the cam to the crankshaft can this be a problem to the timming from the distributor and why is Advance more than 20 deg on the timming light
 
rambo, hope you mean that runs like a 4 cyl or not sure what we are talking about. With a 440 if you are 1 tooth off you got significant problems. Ignition timing will be way off. I had a timing chain set years ago that I thought was installed correctly while on the engine stand. Checked piston to valve clearance, way off. Drag motor, big cam. This timing chain set was hard to get lined up correctly, looked OK but 1 tooth off. If the cam is 2 teeth off you are likely to hit the piston with the valve. At idle(800+/-) your timing should be 5- 12*. Using a timing tape to see total timing(32 - 35*) is really valuable.
 
rambo, hope you mean that runs like a 4 cyl or not sure what we are talking about. With a 440 if you are 1 tooth off you got significant problems. Ignition timing will be way off. I had a timing chain set years ago that I thought was installed correctly while on the engine stand. Checked piston to valve clearance, way off. Drag motor, big cam. This timing chain set was hard to get lined up correctly, looked OK but 1 tooth off. If the cam is 2 teeth off you are likely to hit the piston with the valve. At idle(800+/-) your timing should be 5- 12*. Using a timing tape to see total timing(32 - 35*) is really valuable.
I am not sure if the teeth is out by 1 teeth because when we check the tdc on no 1 both valve on no 1 seem ok as the valve rod where lose and not tight which both valve where close when piston is on tdc could the vacuum advance be faulty as my son A12 motor is in a Datsun 120y 1975 we live in Australia.I just can not under stand why the timming light shows pass the 20deg timming which it should around 12deg
 
The A12 motor is a 4 cylinder and we had put the no1 piston on tdc and the distributor to no1 is because the vacuum advance with the timming light shows more than 20deg so by removing the vacuum advance this will show the right advance
Ahh ya posted an A12 im thinking a Lynch Road built Mopar.. my bad.

A12-1.jpg
 
LOL ... obviously there is more than one "A12" !!!!!
 
A12 Datsun in the ignition section of a Mopar site. :BangHead::BangHead: :poke:
 
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