Today I confirmed what I thought was going on…but got the wrong number than I expected. When I set my timing with a vacuum gauge and dial-back timing light, it ran best at 28* base timing. I been running at 12* when using only the timing light. I’m now 14* more than before and it’s starting and running great. I figure the only way to get this high of reading the timing ring has slipped on the harmonic dampener. I get out the piston stop and found that TDC is really about 8* ATC. I was expecting to see something around 8-12* BTC. Question is…Will the ring slip that much in just a few hundred miles? If the ring is that loose I would think it should be missing in action by now.
After you told me about thios jeff i done mine the same way i got up to 22" of vac at idle but when you reved it it was detonating without load so i ran mine back down to 14* base + vac advance roughly 27-28* And while it is possible for it to slip i would think if it keeps moving its on a course to come off jmho
I checked the timing mark again today and found out real TDC in now at 15* BTDC instead of 8* ATDC. The outer ring is still riding true with the hub. Looks like a new rebuilt dampener is in my very near future.
If you're that far off, it should start to develop a shake from the engine's balance being thrown off, unless the balance counterweight is in the center hub. All the stock balancers have the counterweight in the outer ring.
All you have to do is wait for it to come around again! Mine has been doing this for years! It doesn't shake or run out of true, so I'm not to worried about it. When I want to check my timing I just have that little extra step of verifying TDC and remarking the pulley. I think it slips because each time the AC compressor cycles has to put quite a load on it!
Weird those things are actually important? not to hi-jack but if your engine no longer has anything to check the timing is that something that is important to replace?
All I do is get number one piston on TDC, and then put a mark on the pulley at 0°. It will stay there for a few days. It's a little more work than just hooking up the timing light, but the timing can be set accurately. Once you have an accurate " 0 " you just add your advance ( 8-12° ) to it. I understand that you can get a solid single groove pulley, but I've not been able to find a double groove one! I don't want to replace it with the same kind that's already on it and have the same issue.
I think this thread has just answered a question that I have had about my car. The timing mark is off and there is a little vibration.... hmmmm.
I'm looking into getting this one. http://www.classicinlines.com/proddetail.asp?prod=DDC-250-RB1 The two-groove is heaver and will smooth out the longer crank better than a one-groove
