Lost in the forest...time for a C4 rebuild
07-19-2020, 03:45 PM
#211
now your over thinking this. TDC on the crank is TDC and you setup the cams with the marks lined up to this is right. the gap will pass twice for each cylinder. 4 strokes intake, piston down, compression piston up, power piston down, exhaust piston up cam turns one time. firing order 1-6-2-4-3-5------ 1-4 6-3 2-5 matched cylinders you can't have it 360 out If you lined up cam marks plus it wouldn't run at all it would back fire, because the only thing 180 out would be the distributor. are you using 993 cams If so they have like a key way in the back? they use a cam timing tool that go's into the key and bolt to the three bolts where the power steering go's on and the drivers side has a plug you remove I put one picture of the tool at the next post.
Last edited by wallra; 07-19-2020 at 04:21 PM.
07-19-2020, 03:53 PM
#212
07-19-2020, 04:20 PM
#213
Race Car
Originally Posted by jburroughs12
Thinking through this more, since the crank rotates 360* “in phase” with the cams, the timing gap in the flywheel HAS to pass by at TDC irrespective of which cylinder.
07-19-2020, 04:21 PM
#214
Oh, I’m definitely overthinking this now! 
Just did a leak down, valves all seat, significant leakage past rings, which is to be expected.
I do have 993 cams, but they’re not a stock grind. I’m going to pull them today and get them cam doctored tomorrow to confirm specs therefore overlap measurement.
I’m running out of ideas here.
Just did a leak down, valves all seat, significant leakage past rings, which is to be expected.
I do have 993 cams, but they’re not a stock grind. I’m going to pull them today and get them cam doctored tomorrow to confirm specs therefore overlap measurement.
I’m running out of ideas here.
07-19-2020, 04:22 PM
#215
07-19-2020, 05:18 PM
#218
found this http://forums.pelicanparts.com/911-e...hout-tool.html the ground on the cams have nothing to do with the timing. the tools make it full proof thats was nice about the 993 cam no need for the dial indicator
07-23-2020, 10:24 AM
#219
Time to burn it all down!
The 993 factory cam tools really are awesome, really easy to use, and so simple a cave man can do it.
With that being said, the car STILL doesn't run right.
Here is where I think I may have screwed the pooch. The bolts on my crank pulley were all rusty and it really needed a good cleaning so I took it apart not thinking about the locating dowel. Shoot!
So, when reassembling the ending, we put #1 compression at TDC and reassembled the crank pulley so the red Z1 mark lined up properly. What it, and hear me out here, I was a dumb a** and it's a bolt off on the crank pulley.
That would explain why nothing we do is actually fixing anything; the initial reference point is, in fact, incorrect.
I'm getting spark at all 12 plugs, fuel at all 6 injectors, my DME is functioning properly, grounds are good, etc. We put a timing light on #1 last night and (according to my buddy who was in the engine bay), it looked like we are 10-15* out from the Z1 mark. I'd assume the car should probably run 10-15* advanced at idle, but I'm a simpleton, so could be totally wrong.
I'm plumb out of ideas other than putting the crank pulley together wrong. I wish it were as easy as just moving the distributor a tooth one way or the other to test, but if my Z1 mark is wrong, then that would mean the cams aren't in sync properly with the crank.
The 993 factory cam tools really are awesome, really easy to use, and so simple a cave man can do it.
With that being said, the car STILL doesn't run right.
Here is where I think I may have screwed the pooch. The bolts on my crank pulley were all rusty and it really needed a good cleaning so I took it apart not thinking about the locating dowel. Shoot!
So, when reassembling the ending, we put #1 compression at TDC and reassembled the crank pulley so the red Z1 mark lined up properly. What it, and hear me out here, I was a dumb a** and it's a bolt off on the crank pulley.
That would explain why nothing we do is actually fixing anything; the initial reference point is, in fact, incorrect.
I'm getting spark at all 12 plugs, fuel at all 6 injectors, my DME is functioning properly, grounds are good, etc. We put a timing light on #1 last night and (according to my buddy who was in the engine bay), it looked like we are 10-15* out from the Z1 mark. I'd assume the car should probably run 10-15* advanced at idle, but I'm a simpleton, so could be totally wrong.
I'm plumb out of ideas other than putting the crank pulley together wrong. I wish it were as easy as just moving the distributor a tooth one way or the other to test, but if my Z1 mark is wrong, then that would mean the cams aren't in sync properly with the crank.
07-23-2020, 11:10 AM
#221
That surely could explain things.
07-23-2020, 11:20 AM
#223
Dial indicator through spark plug hole is one option to try before a motor drop. If it looks like that's the issue the only resolution is to drop the engine, pull the pulley off, set to TDC compression #1, realign pulley, and pray.
And if it is off, I'll have to reset my cams...again...
And if it is off, I'll have to reset my cams...again...
07-23-2020, 03:34 PM
#224
here is a real easy way to set TDC remove #1 plug use a dowel and slowly turn the engine over till the dowel reach's the top then you'll feel TDC then look at the crank pulley mark and see where it's at. don't worry about compression stroke your just looking at the crank pulley to see If your off.
07-23-2020, 05:46 PM
#225
Race Car
You may want to print a paper degree wheel, tape/tack to the crank pulley and follow this TDC process to see how far off the mark is.
If it helps, I can loan you a Stomski TDC tool but it will take a few days to get there. Just let me know.
If it helps, I can loan you a Stomski TDC tool but it will take a few days to get there. Just let me know.