Flywheel timing mark

[Rogillio]

On one of my 26 DB Coupes the timing mark for TDC is "I" (Roman numeral one?) and the other car the mark is "C".  Unless I'm missing it.  It this actually for TDC or "8 degrees before TDC"?

 

 

[Rogillio]

There was a line was below the "C" as it came around.  IOW the C was followed by a line ~ 1/2" later.  So my thinking is the line is TDC and the "C" is timing mark for 8 degrees before TDC and when the points need to start opening?

 

I'm trying to put the distributor back on.  Best I can tell, I just need to be in the right neighborhood and then the manual spark advance can be adjusted to fine tune it to the sweet spot for easy starting and for cruising as the engine is warm.

[platt-deutsch]

Just loosen the screw in center of the cam in the distributor and put it where you want it.. Not necessary to mesh the dist. to any certain place.

[Rogillio]

Just loosen the screw in center of the cam in the distributor and put it where you want it.. Not necessary to mesh the dist. to any certain place.

I nearly ruined that cam nut trying to get it off. I tried both left and right. I finally concluded it is not a nut by is machined onto the upper part of the shaft. Maybe the cam nut was a later design improvement?

The upper shaft and centrifugal spring assembly is pinned to the lower shaft.

It was pretty easy setting the rotor position to #1 once I put the flywheel timing mark visible in the hole. My problem tonight was the manual timing advance/retard bracket broke into 4 pieces as I tried to tighten. I called Meyers...the have one for $40. Cha-Ching!

[platt-deutsch]

On my 25 there is a nut in the center of the point cam and it is easily loosened with a large screwdriver and allows the cam to turn to any position you want. When #1 cylinder is coming up on compression use a screwdriver to know when it is at TDC (top dead center) and turn the engine 8 more deg. There will be a mark that is "I". With the spark lever retarded adjust so the rotor will send spark to #1 plug and the points are just breaking. Look at ampermeter to determine when points break with ignition on.

[GaryP65]

Hey... I have been following this and like some clarification.

I have taken off the oil pan to inspect things and I see marks. One is a C, the other is a fraction.

My questions are;

1-Which mark is to be visable thru the hole in the housing?

2-which ever mark is used, are the points to be open or closed?

I'm used to a timing light on my cars.....

[Rogillio]

Hey... I have been following this and like some clarification.

I have taken off the oil pan to inspect things and I see marks. One is a C, the other is a fraction.

My questions are;

1-Which mark is to be visable thru the hole in the housing?

2-which ever mark is used, are the points to be open or closed?

I'm used to a timing light on my cars.....

I can see a C thru the hole in the bell housing. What is the fraction? If it is 1/4 it might mean #1 and #4 are at TDC? I think there is supposed to be a mark after the C in 12* past TDC which is when the points are supposed to open. I'm not sure of this though.....I've read books multiple times and some things just don't make sense. There are 3 different procedures to set the timing based on the serial numbers and if you have a viewing hole. Mine seems to fit the A8xxxxx procedure but my car is A7xxxxx.

[MikeC5]

On this subject, I carefully re-set the static timing this weekend and started it up (also testing rebuilt starter/generator).  It runs fine but just for giggles I put a timing light on it to see how steady the mark was.  I set the lever to full retard at a slow idle and...  I see no timing mark.  Anyone else try this?  Is it because the centrifugal advance weights are too weak?

[hwellens]

Here is some info:

Tech book.pdf

[MikeC5]

Thanks.

[22touring]

But if you set the timing that way, you may not have enough advance for maximum power.  The way DB mechanics used to adjust the static timing in the olden days was to keep advancing it in tiny increments as long as the engine still ran well at idle with the advance lever all the way up. When it started to run worse at idle with the advance lever up than with the lever down, they would back it off to the previous setting.

[nearchoclatetown]

But if you set the timing that way, you may not have enough advance for maximum power.  The way DB mechanics used to adjust the static timing in the olden days was to keep advancing it in tiny increments as long as the engine still ran well at idle with the advance lever all the way up. When it started to run worse at idle with the advance lever up than with the lever down, they would back it off to the previous setting.

That is NOT how the Book of 

information explains how to correctly set the timing.

[22touring]

nearchocolatetown wrote: "That is NOT how the Book of information explains how to correctly set the timing."

 

No, the DB service manual doesn't say to do it that way, but that is exactly how savvy mechanics used to do it back in the olden days in order to get the maximum power from a DB engine.  Try it.  It works better than the factory method and is foolproof. The reason it is preferable to the factory method is because the factory method doesn't take into account wear in the distributor drive system.  My suggested method corrects for distributor drive wear.

Edited March 10, 2016 by 22touring (see edit history)

[MikeC5]

Hmm interesting...

[nearchoclatetown]

If you think your ear is better then doing the right way I guess it's OK for your car.

[22touring]

nearchocolatetown, why do you have to be so insecure and argumentative? I said nothing about listening with one's ear. Please stop distorting what I post.  Thank you.

[nearchoclatetown]

No argument, just bad advice on your account. First of all static timing is set with the engine not running. If the distributor is worn it needs to be repaired or replaced. If the engine timing is set your way it could lead to burnt valves or overheating or vapor lock. An inexperianced owner should follow the manual, that's why the factory wrote them.

[22touring]

No, you're setting up multiple straw men just because you're so insecure and argumentative.

 

Straw man no. 1:  I never claimed this was a method of setting static timing.  You injected this issue in order to distort the meaning of my post. Adjusting static timing is just a method of getting the engine to run in the first place.  Then you adjust the timing accurately with the engine running.

 

Straw man no. 2:  All distributor drive systems have some degree of lost motion, especially DB distributor drives with the rubber connecting disc. That's one of the reasons why you correct your initial static timing adjustment by then adjusting the timing with the engine running.

 

Straw man no. 3: Please explain to me how a providing sufficient ignition advance can cause a burnt valve. Only retarded timing can cause the engine to overheat, which might conceivably cause a burned valve, although I have never seen that happen.  But the point is, the savvy mechanic's method absolutely prevents retarded timing.

 

Straw man no. 4:  The savvy mechanic's method that I suggested is to make sure you have the optimal amount of advance.  Only retarded timing can cause an engine to overheat.  That would never happen with my method because it prevents the timing from being too retarded.

 

Straw man no. 4:  incorrect timing does not cause vapor lock.  That is a fuel issue.

 

I got this information from the Dodge Brothers news.  It has been repeated several times in that publication. I did not make this up!

 

Again, I reiterate that all the old savvy DB mechanics used this procedure for setting the final timing after it was set initially with the static timing method.  Please stop claiming to know more than all the mechanics who came before you.  Do you claim to know more than the very experienced DB mechanics who have written several articles on the subject in the DB news?  Again, please stop being so argumentative for no reason.  It simply betrays your rather unflattering insecurity.  Thank you.