Hey Guys,

I have a few flywheel/timing questions:

1) I normally time the engine by seat-of-the-pants, but just for a reference, how far off Z1 is 5 Degrees (No mark for 5 Degrees on the flywheel)?

2) How far advanced is too far?

3) The flywheel size is always referred to as 215mm. Does this measurement reference the diameter of the flywheel, or some other aspect of its design? If I knew the circumference, I could figure out where 5 degrees should be.

Thanks,
Justin

can you just measure mark the crank fan pulley? little tight in there?

total advance is a function of compression ratio , cam duration.

34-35-36 total depending on what you have.

I haven't check the pulley on the crank, and I don't want to start the "Access hole in the Firewall" debate. But I could line up the mark on the crank pulley (if I can see it), and then mark the flywheel. Does the stock 914-6 crank pulley have the marks for 5 BTDC? My engine originally had the marelli distributor which I believe called for 5 ATDC (I dont have the manuals here), so will my crank pulley have the timing mark located at 5 ATDC instead of BTDC?

My total advance is 35, I was wondering what is "too far advanced" for running at idle? 8 or 10, or is it too hard to say because it differs for every engine?

Thanks.

the books say 1mm/deg -on the crank pulley-. i know it's tight but it shouldn't be -too- bad to measure off 5 deg BTDC (5mm) there and transfer a mark to the flywheel. the spec book shows 911T gets timed to 35 deg total advance, 6000 rpm, at operating temp (180F oil) - S and E want 30 deg total advance.

static time is mostly to get you in the ball park, then check for total advance at the specified conditions for your engine and let the static time fall where it may...

if you can get close you should be able to feel the notch on the crank fan pulley with your thumb nail. my 911 2.4 t is marked for 5 degrees AFTER tdc so you really need to know the motor to make sure it is a stock pulley for that motor.

i would do the mirror and flashlight trick and see what you can see.

That's good to know, the engine specs are where it gets a little difficult for me, I only have limited information of how the engine was rebuilt. To the best of my knowlege its a 2.0 with E P/C and T cams. Here is the only build info I have (I think I have a receipt/part number for the P/C's, I don't know if they are 2.0 or 2.2):

as much as anything, it will depend on what dizzy's in there -- the original /6, a 911T, E, or S...
if eveyrthing else is up to snuff, try for 35 deg and listen for pinging under load using the gas you'd normally run. if you hear any, back it down to 30 deg total advance. neither of my 6's nor my 911E have any dizzy hoses so i can't advise you on those if you've got 'em but i can poke through the manuals if need be for some hints.

the original /6 engine came with T cams -- E cams really wake it up - especially if you've got the E compression too...

I have the original marelli in a box, I'm pretty sure it's an E or S since the redline is now 7200, but I can check the part number tonight (no vaccum advance of any kind).

Either way, if I use the mark on the pulley, I'll get an idea of where 5 degrees is in relation to Z1, I may just have to transpose the mark to the opposite side of Z1.

For now I'll concentrate on Full Advance, I had always been shooting for 35, I'll try 30 and see what I get.

Thanks Again,
Justin