Has anyone else had the issue of the timing marks on the eshaft pulley being off? While working on my S4 last weekend I followed the procedure for finding TDC by marking the position of the apex seal in the rear leading and trailing holes and finding center between those two marks. The TDC mark I obtained using this method is much more than 5 degrees away from the stock leading mark on the pulley. My TDC mark is about 15-20 degrees ahead of the stock leading mark, roughly the same distance between the stock leading and trailing marks. I checked for TDC again to make sure I did not make a mistake and my marks were the same when I re-checked.

For the time being, I advanced the timing about 5 degrees from the stock leading mark. The car runs much better with this advance, however, I am finding it hard to believe that the stock pulley could be off by this much so I am hesitant to advance any farther.

I searched around a bit and some people seem to suggest that S4 and S5 pulleys have different timing marks, however, reading the FSMs for the S4 and S5 shows that the leading and trailing marks should be the same between the two motors (5 deg ATDC, 20 deg ATDC.) Unless the S5 has the timing pointer in a different location, I don't see how this could be an issue. Has anyone else had the issue of the stock timing marks being this far off?

 

You can't have messed up timing marks....The pully only goes on one way.. Unless somebody grinded off the old ones and put on a new one.... The timing marks are physical indentions on the pully. There are 2 marks. One is for rotor 1, second is for rotor 2.. I think. can't remember which is which.

 

The two marks are for checking leading and trailing on ONE rotor, the front to be exact. There are no marks on my pulley for the second rotor. Still does not explain why I am getting the results I am getting.

 

i never did the process of finding TDC, if you dont mind me asking why did you go through this. Did you motor not run good after you set timing?

 

I had the front cover off to replace a failed O-ring. When I put everything back together I had issues stabbing the CAS on the stock marks, so I checked TDC to verify the marks were correct, despite the fact that the pulley could be installed only one way.

 

any possibility the pulley has been removed and is it possible to put it on in the wrong position. Im not looking at the motor now and cant recall how it looks. ARe there 4 bolts that hold it on. is it possible to put it on wrong? im not sure just try to help

 

The bolts are staggered, so the pulley could be installed only one way.

 

o well seems like you can disregard that possibility. doesnt help now but next time they say to mark the CAS to where you removed it... sorry i cant help sure someone can

 

Let's start with some theory, then on to help you out.

The eccentric shaft has a keyway in the front. The front hub will only go on one way because of the keyway and key. This same hub is held on by the big screw where the thermo pellet and springs go inside. Once the hub is on, the four holes will only allow the pulleys to go on one way. The marks are leading and trailing marks for number 1 rotor, as you spin clockwise standing in front of the car, looking at the engine. BTW, the individual pulleys also only align one way.

The timing marks are (as you turn the engine clockwise - think of the fuel going in at the top left, making its way around to the spark plugs, and then leaving at the exhaust on the bottom left): Yellow - 5 degrees ATDC (After TDC), Red - 20 degrees ATDC.

Unplug the Crank Angle Sensor, make sure ignition is off. Turn the engine clockwise with a socket on the hub bolt or the hub bolt on another accessory (slowly, especially when compression builds), and bring the first mark (yellow) in line with the pointer on the front cover. Pull the CAS out, align the punch mark on the gear at the bottom with the raised triangle on the shaft, and reinsert crank angle sensor so that it is around the middle of the range of the slot near the top of the front cover. A tip I've read here is this: Since there is always a possibility of the gear turning too much on the CAS when you put it into the geared wheel around the eccentric shaft, some people have removed the CAS cover at the top and placed a mark (felt pen) to show when the CAS is ligned up at the bottom.

Let us know what happens.

EDIT: BTW, make sure the needle bearing didn't fall out of place and off the spacer when you removed the front bolt. Check endplay of the eccentric shaft. Worst case scenario, if you start her up and hear a loud whine inside the front cover, shut her down. FSM in my sig. Have a good look.

 

None of that is relevent to my original question.

Why does TDC keep end up being more than 5 degrees away from my stock marks. No, nobody ground off the original marks or any nonsense like that. I'm looking for input from people that have had similar problems, not people that want to recite the FSM to me.

 

Another question would be why you/anybody would think that the method of finding TDC that you mentioned..........would result in actually finding TDC? I mean dead spot on TDC.

And nope, I've given up finding TDC spot on./dead on. Gave up. There's also talk about how the marks on one engines pulley won't work if you put it on a different engine. THEY say that, not me. I always assumed we were in the industrial age where you build a item and the parts are interchangable b;t any unit in the line. Like I say, THEY say that. Both forums.

 

After reading the trailing/leading method on team FC3s, I was hesitant of it's accuracy. It's not that I am looking for TDC +/- .005 deg, but rather looking to see if it's common or not to have this issue. Normally I would not worry about it, but upon the observation that my car ran "that much" better with 5deg advance over stock, it makes me wonder how accurate MY stock pulley really is. Obviously, from the responses I am getting nobody really cares and just relys on the stock pulley for accuracy. Now, I tried to be consistent as possible when looking in the plug holes, and my marks were dead on every time, not to say that I am exactly on TDC, but it gives me a good idea.

Someone over on the megasquirt forum was posing how their S4/S5 aftermarket pulleys had the timing marks in different places, so you would think that the pulleys between the S4 and S5 are different. The S4 and S5 run the same base timing stock, so for the differences in pulleys to be true, the S4 and S5 front covers would have the timing pointers in different spots. I am not familiar with S5 front covers, so I don't know for sure if that is even a possibility.

Mabye someone who knows could post up if the timing indicator on the front cover is the same between S4 and S5. If they are different, the timing marks on the pulleys would be different.