Timing not adding up....

[cny]

First off, I drove this car with absolutely no issues from Virginia to NY when I bought it in November of 2008. Then this past Summer it was used on the weekends (estimated about 1k miles). I installed my JRSC and am trying to time the engine to the 6btdc like specified in the instructions.

Now this is where it gets funny........I have the diagnostic port jumped and when I shine the timing light down to the read point the mark on the crank pulley is about 1" away (to the right) from the read plate. Adjusting the CAS moves it, but not enough to be put onto the read plate. It does however mess with the idle. By moving the CAS the idle can be anywhere from 500 all the way up to 1500 RPM's.

I am at a complete loss of explanation with this. I dont understand how the car did (and still does) idle fine and how it was running smooth with the mark so damn far away.

Here is a crude drawing for people who didnt understand what i just type......its been a long day and I am very frustrated at this point.

[Deliverator]

IIRC, some crank pulleys have two marks on them. One yellow, one white?

Others, like one that turned up at an ESR meet when we messed with peoples' timing, are too rusty to see any dots.

[cny]

1993's have a white mark.

From what I have just read, the pulley can slip, because there is a rubber center and this obviously making it impossible to read the current timing.

[cny]

I just bought a new crank pulley from Rosenthal, this should do the trick.

[Andy B]

Although this input may be moot, as you have already purchased a replacement pulley, I thought that for the benefit of anyone else I would give a quick bit of info on determining timing. Like you said, the pulley is on a rubber isolator, as are many vehicles. Also, the marks can become rusted over, worn down, etc. A simple way to determine timing is to simply pull the cyl one plug and use the piston position to determine TDC on the crank. It is best to use something made of soft wood (ie, pencil) that heaven forbidding you drop in, or a chunk breaks off, or any number off ways it can end up with debris in the cylinder, you don't really have to worry much about it, as it will be chewed up without damaging anything (I, and others I know have done this. It sounds scary, but really, some soft processed wood is just going to be chewed up and burned). Ideally you could access a dial indicator to determine precisely where TDC is, but a if you are watching very carefully, and turn slowly, it is very visible were the piston changes direction. At worst, you would be within a degree or two. I am unsure of the miatas markings being anything other than 0 degrees TDC, but if you need a different timing (for example, my vw bug is marked at 5 degrees ATDC), you can find TDC, and measuring out the diamater of the pulley, work out the circumference, and how many millimeters from TDC the timing position you need is.

Sorry for the long winded post, but I have had to work things out this way in the past many times due to simply not knowing the exact history of a motor, and being unable, or unwilling to use the timing marks present. It is much quicker and cheaper than replacing parts because of worn or faded parts. (sorry cny)

[longuyen88]

Originally Posted by Andy B

Although this input may be moot, as you have already purchased a replacement pulley, I thought that for the benefit of anyone else I would give a quick bit of info on determining timing. Like you said, the pulley is on a rubber isolator, as are many vehicles. Also, the marks can become rusted over, worn down, etc. A simple way to determine timing is to simply pull the cyl one plug and use the piston position to determine TDC on the crank. It is best to use something made of soft wood (ie, pencil) that heaven forbidding you drop in, or a chunk breaks off, or any number off ways it can end up with debris in the cylinder, you don't really have to worry much about it, as it will be chewed up without damaging anything (I, and others I know have done this. It sounds scary, but really, some soft processed wood is just going to be chewed up and burned). Ideally you could access a dial indicator to determine precisely where TDC is, but a if you are watching very carefully, and turn slowly, it is very visible were the piston changes direction. At worst, you would be within a degree or two. I am unsure of the miatas markings being anything other than 0 degrees TDC, but if you need a different timing (for example, my vw bug is marked at 5 degrees ATDC), you can find TDC, and measuring out the diamater of the pulley, work out the circumference, and how many millimeters from TDC the timing position you need is.

Sorry for the long winded post, but I have had to work things out this way in the past many times due to simply not knowing the exact history of a motor, and being unable, or unwilling to use the timing marks present. It is much quicker and cheaper than replacing parts because of worn or faded parts. (sorry cny)

I've done this using an extension rod on my honduh