Ping Ping Ping Ping Ping

[AZstang66]

So after completing a 2bbl upgrade conversion on my mustang, it has very heavy pinging under acceleration.
It had very minor pinging before the upgrade, but only in 3rd gear on the highway when floored (so rarely).
200ci 3 spd, '66 mustang.
I replaced the older 1bbl Holley 1940 with a brand new Holley 2300 and adaptor from Summit.
Changed the distributor to a 1968 dual advance dizzy from checker, and replaced the points with a new Pertronix I setup.
Timing (for diagnostic purposes) is set stock at 6' BTDC, and still has the same problem when advanced or retarded.
The car starts right up, and doesn't ping while revved in park- only pings when under load/driving acceleration.

I checked the timing while revving the engine, and the advance is working. The plugs are clean and in good shape.
What's wrong!?!?

 

[Bort62]

pinging = too much advance.

so back the advance off a little. Sounds like you are getting too much advance under load.

 

[ASMART]

Your total advance could be diferent than before. Initial may be the same.

If you were on the edge before, letting more air and fuel in could make it worse since adding air and fuel will increase pressure just like raising compression.

Your new carb could be lean.

Good luck.

 

[The Plankster Prankster]

the other thing that helps is to buy better gas. but the root problem is the timing

 

[AZstang66]

I figured it was the timing, but what component/problem? dizzy? Everything is new!

 

[The Plankster Prankster]

i would venture to say that no one component is "bad", and that the problem lies in the adjustments. my advice would be to retard the timing about 10* from its current setting and take it for a drive, if that fixes the pinging, then i can almost guarantee that the vac advance is advancing too far/soon. in that case, there have been threads around here about how to re-curve the vac advance curve. this would probably be your best option in this case, but don't ask me about how
good luck--josh

 

[The Plankster Prankster]

forgot one thing: take a test drive with the vac advance hose disconnected/plugged and see how that is. it should be fine; if it pings in that condition you have WAY too much advance!

 

[rbohm]

8) timing is NOT always the problem. a lean fuel mixture can also cause detonation. adding a 2bbl carb can exacerbate a lean mixture if the fuel pump cannot supply enough fuel to the carb.

 

[63comet]

I am following this topic with extreme interest, my car did the same exact thing with a new rebuild. No matter where I set the timing (all the way to zero static) it still pinged under load and that was with super unleaded. I also unhooked and plugged the vaccuum line and that helped a lot but did not eliminate the problem and I had a lot less power. I also changed the harmonic balancer figuring that it had slipped, no difference. I also pulled the head and made sure I was at TDC, and I was. I changed distributors and no difference. Checking the plugs they show a dark brown or black coloring indicating a richer than needed mixture. I am at a loss as to what to do next also. So keep coming with the suggestions.

 

[fordconvert]

What are you guys running for compression? On a used engine carbon build up soaks up heat and acts like a glow plug, on the rebuild Im not sure other than if the builder did some strange things. To know whats going on with the timing you need to find out what your total advance is. Easy way is a advance timing light. An advance timing light has a dial on it that usually goes something like 0-50. You need the advance since you are going to be in the 30+ range and the timing mark only goes to 14 (ish). The cheap way is to figure out the distance per degree based on the timing gauge and put new marks on the pulley. Any used or rebuilt dizzy should be checked because I doubt they even care when they are rebuilding them anymore. A DUI may be an exception, it will most likeley do what it says it should do. I have had rebuilt dizzys with as much as 20* of extra advance because of the wrong parts or being put together wrong. One issue is most of the time the vac module is a 'universal' replacemnt and there is usually a way to adjust or limit the travel. The orignals were just built to have the proper stroke for the steup. The shop manuals didnt say what the stroke was just the part number of the modulator so the only way you can figure it out is to look at a factory manual that has the curves and start with those numbers. Most of the time people dont seem to run too far off of the factory curves so they are a good starting point.

 

[AZstang66]

Ok. I'll test drive it with retarded timing and no vacuum hose and let you know what happens.
I doubt it would be the fuel pump however. I replaced it about a month ago and the 1bbl still had the light pinging before too.

 

[66 Fastback]

First things first. Have you confirmed that the ring of the harmonic balancer has not slipped? You need to confirm that the indicated TDC mark is actually at TDC on the #1 cyl, otherwise you will be chasing your tail on trying to set timing and the reported timing figures will be meaningless.
Once that is done, you can dive into adjusting the distributor. It sounds like you have too much total timing. And since you have it under acceleration, you likely have too much mechanical or centrifugal timing. (again, assuming your timing mark reference point has not slipped). You may need to map out your advance curve by taking total timing and vacuum readings at 500 rpm inctrements, with and with out the vac advance connected. Hook up the vacuum motor to a vacuum gauge and pump and take note of when your vacuum motor starts to move and advance the timing. Also note the vac reading when the motor has travelled its full range.

You might be able to get by with trying to adjust it bending the advance spring tabs. Here is a post of mine from an earlier thread:

"I bought a rebuilt unit from Autozone for a '68 and installed in my '66. I think the rebuilt unit is probably set up at a more conservative timing map. I'll have to dig out some notes, but the advance curve was pretty sluggish and did not advance very much. You can adjust spring tension by bending the metal tab retaining the springs. The procedure is outlined in the shop manual. You have to line up the hole in the distributor base plate with the spring tab and insert a screwdriver to bend the tab in or out."

There is also a thread started by Jay (Montego Man) that goes into the centrifugal weights. Based on his info, I ended up tearing into mine and flipping the weights and changing the springs. See this thread.

http://fordsix.com/forum/viewtopic.php? ... istributor

You can get it sorted out with the recurving of the distributor, but you need to make sure your timing reference mark is correct. Your 6 degrees could actually be 15 degrees or more. Let us know what you find.
Doug

 

[AZstang66]

Ok.
I'm going to pick up one of AZCoupe's DUI Dizzys today. I was meaning to, and this problem sped it up.
Cross fingers and hope this solves the problem.

 

[66 Fastback]

Not to impair the sales of the DUI distributor, but unless the timing mark on the balancer is known to be correct, then the same problem may exist with the DUI distributor. You need to check the timing mark against TDC before proceeding.
Doug

 

[AZstang66]

Will do that while I replace the current dizzy.

 

[AZstang66]

Ok.
Now typing after more work is done to the car.
First I pulled the plugs (which were in pretty good shape, not too lean, dirty etc.) and checked the balancer's marks. They were spot on, so that wasn't the problem.
Also checked base of carburetor for leaks- none found.
I replaced the '68 pertronix with a new DUI from AZCoupe. Started up first crank then the timing was set to 12' BTDC with the vacuum plugged and at 600RPM.
Took it out for a spin, and it still pinged. No where near as bad as with the other dizzy, but still bad. The engine now has a loud ticking noise that varies with RPM. I re-timed it to 6' and that lessened it- only pinging heard was when in 3rd gear at about 1500RPM. Ticking still prominent. I then retarded it back to TDC, no pinging at all, but ticking noise still very loud.
The car also lacks power- it seems to be slower than with the 1bbl Holley/load-o-matic.

What's up now?!?!?!?

I know sixes tick, I've had 5 different engines and a few other 200ci cars that all ticked, but it was only when low RPM etc. This ticking is very loud and sounds like it would be bad for the engine/performance as opposed to the common ticking found in 99.9% of 200s.

I appreciate everyone's help!!

 

[jahearne]

Pinging or a ticking noise? Could it be a small exhaust leak?

 

[AZstang66]

I'm not too sure.
It 'ticks' like tick tick tick tick tick when i accelerate.
It isn't the rattle-kinda noise that pinging makes.

 

[fordconvert]

Have you changed your oil lateley? Maybe with all this messing around it got some fuel in it and is kinda thin? Just a thought..... Easy to check and eliminate.

 

[Anonymous]

'ticking' sounds a lot like an exhaust leak to me. Probably a bad exhaust gasket, but check your manifold while you're in there just in case something cracked.