Solved? No, not yet.
I have not received any convincing definitive answers in posting this same question on multiple forums. I've got plenty of reccomendations to try to sell the car as-is non-running, keep cranking it trying to start it with it as-is (with carb issue as well requiring this to be correct first), or to simply replace the ignition system with another type (perhaps with that magic money from the tree in thier back yard). Yet no, in all this time there is still no convincing answer or explanation for the misalignment seen at the distributor.
It's been a long befuddling battle to figure out this ignition and cam timing with limited access for inspection, and limited information even with factory books.
Here are what details have been concluded so far:
Determining Compression Stroke
Access to visually confirm int/exh valve movement at #1 cyl is blocked by EGR cooler system.
Passenger side spark plugs (1-4) removed for easier engine turning by hand.
Confirmed piston movement at top of stroke at TDC using probe in #1 cyl plug hole.
Confirmed air flow when checking with finger in #1 plug hole as approaching TDC.
Getting 10psi on gauge at #1 cyl as approaching TDC when hand turning engine at crank.
Presumed to be set on compression stroke according to gauge and finger test.
New set installed when rebuilt, not stretched or worn.
Dots on timing gears line up facing each other at TDC on presumed compression stroke.
Cam gear has 42 teeth with 8.57* tooth angle.
Crank gear has 21 teeth with 17.14* tooth angle.
Distributor / Rotor
Distributor housing will not rotate to adjust timing, rotor must be pre-set to alignment.
Shaft is solid, no advance mechanism.
Shaft/Rotor sets down approx 12-15* to either side of specified alignment on dist. Housing.
Rotor has screw slots allowing for some alignment adjustment either direction.
Rotor will barely align when shaft is set down on either advanced or retarded tooth.
Rotor is at extents of slots to rotate and align on either tooth choice, rather than mid-area.
Shaft will nearly align to center on relative cam tooth at 30*, both before and after TDC.
Shaft will align exactly to opposite side of distributor at 180*. *See photo.
Shaft driven gear roll pin is good, and shaft driven gear cannot be reversed.
Shaft driven gear has 15 teeth with 24* tooth angle
Presuming cam drive gear has 30 teeth with 12* tooth angle.
Sealed Power #CS1008R [replaced by #CS1158R] Performance Camshaft; 302 firing order; Pro-1500 Perf. Cam; Hyd; Hydraulic; (050) Duration at.050 Lobe Lift; 204 Exh; 194 Int; 110 Degrees Lobe Separation; 0.448" Exh. Valve Lift; 0.424" Int. Valve Lift
So, with the most obvious things not appearing to be wrong at this point, I am left to suspecting some perhaps far-fetched possibilities. Some are doubtful, but still possible so I need to verify (if I can find the info) and eliminate these suspicions as I am not yet convinced this is the correct way that this vehicle s timing is supposed to be pre-set before attempting to start engine.
Suspicions yet to resolve:
Could the distributor shaft driven gear been put on the shaft backwards from the factory?
Or could the pressed-on rotor mounting plate be on the shaft backwards from the factory?
If rotated 180*, the crest of a driven gear tooth should fall in a 'valley' between teeth on the cam gear aligning exactly with mark on distributor housing, but currently, that same cam tooth is making the shaft driven gear fall to either side of that mark, which is what I have been seeing all along.
-I have yet to physically compare to another similar distributor to confirm or eliminate this.
Could what air flow I'm feeling at the #1 plug hole as the piston comes up. Be fooling me if cam is actually at 180* off? The cam specs are a bit confusing yet for me to determine; If cam is 180* out, would the valves opening/closing opposite of normal still cause this air flow?
The reversal should put the distributor shaft and rotor directly facing the alignment mark.
-Can the cam be rotated 180* in this engine to fix (or try-n-see)without damaging valves while lifters are still under spring load?. If not already possibly damaged if 180* off?
I ve encountered manufacturing/Q-C./Packaging errors before with timing sets & other parts. How likely could it be that the aftermarket cam timing gear alignment pin hole may be off? Or how likely could the pin on the cam or perhaps the cam drive gear may be machined that much off alignment and creating the issue seen with the distributor shaft placement on the cam drive gear at TDC?
-I doubt this one, but it's still possible.
Hey Benz220SEb, if you get notice of this. Can you please check your car for shaft/rotor alignment at TDC for me? Having another similar comparison would be so very helpful! Post a photo if you can looking down on the rotor showing the screws as best as possible to indicate the true shaft alignment relative to the housing. Perhaps this truly is the way it was set up at the factory.(?)
I need the "pros" to chime in on this one.
Images (Click to enlarge)
Monday, February 11th, 2013 AT 11:47 AM