Too much advance on my Durasparc II

[Anonymous]

Has anybody had experience with excessive pinging on a 200 ci 6? Does anybody know what typical numbers of total advance timing should be?
The engine is stock but I have replaced the distributor on my 67 Mustang with a Durasparc II. The centrifugal advance was on the "13" tab and after some experimentation I reduced the gap and ended up with about 6 deg total mechanical advance. I also had to limit the vacuum advance to about 6 deg as well. My static timing is set to 12 deg for a total amount of advance of 24 deg. The engine no longer pings but I can't help but think that this value is extremly low as some of the figures I read about are in the 40 deg range.
Thanks

 

[Lazy JW]

The first thing to check is to verify the TDC marking on the timing pulley. These pulleys are known to have a problem with the outer ring slipping relative to the inner portion. This would cause your timing to be WAY off.
Joe

 

[fordconvert]

Is your engine stock? Cam? Comperssion? The 60's 200 were 9:1 stock. With everything in GOOD to GREAT shape they should run fine on 87-88 gas, but if its got a few years on it and has some carbon and other sludge built up in it that could be the cause of your pinging. Try a tank full of 91-93 preimum and see if it changes. Hot carbon and sludge will 'suck up' the air fuel mixture which tends to lean out the mix which adds heat. The added mix to the carbon build up makes it 'glow' hotter till it gets to the point where it will sort of pre ignite the fuel on its way into the cylinder.

 

[Anonymous]

The engine is stock and has about 22K miles on it after a rebuild. I use the best gas I can find at 94 Octane.
How do I tell if the pulley has slipped, do I check TDC on piston 1 with the spark plug removed or is there another way?
Is 24 deg total advance unusual?
Thanks for the replies.
John

 

[66 Fastback]

Yes you need to pull the #1 spark plug and place a long rod or screwdriver etc in hole. Rotate engine by hand slowly making sure that the rod/screwdriver does not bind and watch it's motion up. You need the piston at TDC on the compression stroke. You may have to pull the valve cover and watch the valves to confirm which stoke is TDC with the valves closed. However, Since your car has been running, I think you can just pull the distributor cap and look at the rotor, and when it is pointing to the near the #1 wire post on the cap, then you should be on the compression stroke. You may need to rotate the engine both ways and note when you see the rod/screwdriver stop rising make marks for both, and then split the difference. The rod will move very litttle during the upper part of the crankshaft revolution.
Mow compare the mark you make on the balancer with the groove that is machined into the balancer ring.
Doug

 

[Anonymous]

Thanks Doug I'll check it out.

 

[JackFish]

If you put your finger over the spark plug hole you can feel a puff of air on the compression stroke when you turn the crank.

 

[Lazy JW]

... You need the piston at TDC on the compression stroke...

Nope.
It matters not for the purpose of checking the timing marks for TDC. The piston comes to TDC on both the compression stroke AND the exhaust stroke. The piston/rod assembly is tied to the crankshaft and therefore MUST remain relative to the crank pulley. Unless something slips, such as the harmonic balancer.

The positive stop method using a bolt in the spark plug hole will give more accurate results.
Joe

 

[66 Fastback]

Joe is right. I don't know what I was thinking. However, to verify the that the disttributor is in synch with the piston, then you would need it to be on the compression stroke and the distributor rotor oriented to the #1 post on the distributor cap. I guess, I've gotten used to working on my old motorcycle and timing it statically. It has a wasted spark and fires on each revolution, so I always have to make sure to locate the compression stroke. Old habit that I carried over to cars.
Doug

 

[mkgcars]

For reference, the '65 Ford manual specs for 200 w/automatic indicates:

12 base
14 @800 rpm
17.5 @1200
24 @1600
31 @2000
39 max (typically around 2500-2700)

I know my previous car's 200 had about 48 total advance at 2500 and ran on 87 without pinging. Had loadamatic, with holley 1 bbl, with base timing at 12.


So, 24 total would be low.
If the balancer hasn't shifted then question is, when is it pinging? At idle or low rpm would be my bet.

With the addition of the mechnical advance you may want to try backing off on the base/static timing. Try setting the base at 8 or 10 and see how it goes. Then you can probably increase the mechnical to it's full 13(x2) advance. Example: (base)8 + (mech 13x2)26 + (vacuum)6=40.

Update us on what you find.
Be interesting to see how it works out.
matt

 

[Anonymous]

for the record I have mine @ 12* base and then have the vaccum direct from manifold and am pulling about 20* at idle and have not even the slightest hint of pinging

 

[james singleton]

LAZY JW , If I understand the "positive stop method using a bolt in the spark plug hole", it does not matter if you are not exactly @ TDC when you install the bolt as long as it is close to TDC. You then make a mark (on timing scale) opposite the timing notch on the pulley/harmonic balancer. Then turn the engine 360 degrees until it touches the bolt; and make another mark opposite the timing notch. You then split the difference between the two marks (example: 1/4 inch divided by 2 = 1/8inch from either mark)? Is this correct? I am guessing that even though you made a mark when the engine is not necessarily @ TDC to begin with on the compression stroke, that the difference between the two marks automatically makes up for this? Am I correct or way off base? Help clarify this if you would. Also where did you get a bolt with spark plug type threads? My local auto parts store acted as if these are not threads you would normally find at an auto parts; and they usually have most everything!? Thanks! P.S. I have a new engine with a older pulley/harmonic balancer with rubber in the middle and thought I should verify TDC.

 

[addo]

It's a fine metric thread, in an unusual size. You might get it from a place like McMaster-Carr, else it could be overseas only (there are a couple of pretty flash European bolt makers).

That limited availability is one reason people tap a more common thread into a spark plug shell.

You've got a good grip on the TDC finding method. Try to set the stop bolt very close to top, so the marks are easier to average. Use a thin, flexy 6" rule to wrap over the balancer when dividng this separation.

For safety's sake disconnect both battery leads when taking these measurements!

Regards, Adam.

 

[Lazy JW]

James,
You have it figured correctly. I used a spark plug, broke the insulator out of it and threaded the inside with a tap.

I like to have the stop adjusted so the marks are about an inch apart. When you get too close to TDC you have a LOT of mechanical advantage and it is more difficult to "feel" the stop. Go very slow and careful, you won't have any problem.
Have fun,
Joe

 

[james singleton]

Lazy JW & Addo, thanks for the info on TDC. Joe, one question on breaking the insulator out of an old spark plug. You say to tap the center of the broken spark plug; do you then install a standard bolt that fits through the middle of the spark plug? Is that correct? Thanks, Jim

 

[Lazy JW]

Yup. Just find a bolt size that will get a few threads. Those insulators can be stubborn sometimes.
Joe