Pinging

Engine troubles? Try here.
Post Reply
SAM. C.
Posts: 141
Joined: Mon Nov 06, 2006 1:08 am
Location: Brisbane, Australia

Pinging

Post by SAM. C. »

Hello all

I just chnged my oil from a castrol 15-40 to a Valvoline 20-50 as the temperature here is very mild. Since the change I can hear slight pinging under load which wasnt there prior to the change. Can i change timing to improve this?

Does anyone have any advice on how to get rid of this?

Thanks

Sam
Jim LaGuardia
United States of America
Posts: 1704
Joined: Wed Apr 14, 2004 3:42 pm
Location: San Bernardino Ca
Contact:

Post by Jim LaGuardia »

Ckeck the timing, it should be 3-5mm before top dead center@850-950 rpm.
Cheers, Jim LaGuardia
http://smg.photobucket.com/albums/v510/Goatwerks/
"Arch Magus of Machines."
SAM. C.
Posts: 141
Joined: Mon Nov 06, 2006 1:08 am
Location: Brisbane, Australia

Timing

Post by SAM. C. »

Hi Jim

I am sure it is more than that at the moment. To bring the mark closer to the timing spike do I rotate the distributor clockwise or anticlockwise?

Sam
Jim LaGuardia
United States of America
Posts: 1704
Joined: Wed Apr 14, 2004 3:42 pm
Location: San Bernardino Ca
Contact:

Post by Jim LaGuardia »

Rotate the distributor clockwise to retard timing :wink:
Cheers, Jim LaGuardia
http://smg.photobucket.com/albums/v510/Goatwerks/
"Arch Magus of Machines."
SAM. C.
Posts: 141
Joined: Mon Nov 06, 2006 1:08 am
Location: Brisbane, Australia

timing

Post by SAM. C. »

cheers mate

Sam
Erik712m
Posts: 1553
Joined: Sun Jan 21, 2007 7:52 pm
Location: Wichita, Kansas

Post by Erik712m »

Sam, Not sure if this would help but. I found this one late night of pinz snooping I believe its Dave Ds.

Timing in
Vehicle, mods RPM Degrees BTDC Degrees Advance Inches BTDC
710 Pertronix 800 17 0 0.75
710 Pertronix 2000 35 18 1.04
710 Pertronix 2500 43 26 2.25
712 Stock 800 4 0 0.125
712 Stock 2000 26 22 1.32
712 Stock 2500 31 27 1.75
712 Pertr, Civ cap & plugs 800 16 0 0.75
712 Pertr, Civ cap & plugs 2000 35 19 1.04
712 Pertr, Civ cap & plugs 2500 42 26 2.25


Dave's comments

Because the 710 runs so strong, I used the same base timing for my 712.
Though I haven't checked yet, I believe that the lack of total advance
after the conversion is due to weak springs in the distributor and I'm
getting premature advance at idle.

The truck is running strong and one side benefit is that the truck is
running a lot quieter.

Rob's comments (Stolen from http://www.dansmc.com/IGNITIONTIMING.html)
For those who are kinda clueless, like me.

When combustion occurs it does not take place instantly. It
requires a period of time. Depending on the RPM the
power stroke can be .05 of a second at 1200 rpm to .0057
of a second at 10,500 rpm. Now even though the time for
combustion at 1200 rpm is not

The reason that this small amount of time is important is
because the combustion process is not as much an
explosion as it is a controlled burning. The time available for
this controlled burning decreases as the rpm goes up. To
compensate for this, the point where the spark occurs, to
start the combustion process, must occur earlier. To
accomplish this weights and springs are attached to the
points cam. As the cam spins on its shaft, centifical force
causes the weights to move and turn this cam on its shaft,
advancing the timing of the spark, thus giving the
combustion process more time to occur as the rpm goes
up. Full advance is usually reached on most engines by
around 3000 rpm.

Most motorcycle engines with points have only a centifical
advance. A few have a vacuum advance. Newer engines with
electronic ignitions usually have an electronic advance.
Some engines have fixed timing with no advance at all. The
lower the compression ratio of the engine means more spark
advance is needed. This is because rapid combustion is
aided by a high compression pressure. Because the
combustion process takes place quicker with a high
compression ratio less time is needed, therefore less spark
advance. Conversely lower compression pressure slows the
combustion process, necessitating more spark advance.
Now why all this about compression pressure and spark
advance? Simply this, as an engine wears out it starts
leaking compression past rings and valves. This lowers the
compression pressure (ratio). What does this mean? You
got it, we need to advance the ignition timing as an engine
ages.

OK...Great...Now What? Well, if the engine is worn, lots of
miles or hard use, we need to advance the point at which
the spark occurs. This works best on large 4-stroke engines
although it can be done on small ones too, but it is harder
to do. I don't do this with flywheel magnetos ( Honda 50's,
70's etc. ) either, because it is a lot of work with that type of
ignition system. On many of the newer motorcycles you
just can't do it without major modification, but on almost all
points ignition machines and a lot of electronic ign. ones
you can.

Now when we increase the spark advance (the point when
the ignition spark occurs, at the sparkplug,
before-top-dead-center of the compression stroke [BTDC] )
we get more power BUT we also get more heat.
There is a point after which we get lots more heat and very
little extra power. We want to STOP before we get to this
point!

The drill is this...With the engine at normal operating
temperature and idling, advance the timing slowly. You will
hear the engine speed up.Move the timing back and forth,
advancing and retarding it till you get the highest engine
idling speed. Then back it off (retard it) just a bit. The
engine speed slows down just a little. You are still idling,
don't touch the throttle.

Go for a short ride and make sure the engine does not
"ping" under load. Then check the color of the spark plug(s)
to make sure it's not running too hot and you are done!
User avatar
David Dunn
United States of America
Posts: 2274
Joined: Wed Apr 14, 2004 7:08 pm
Location: Arcadia, CA

Post by David Dunn »

Erik712m wrote:Sam, Not sure if this would help but. I found this one late night of pinz snooping I believe its Dave Ds.

Timing in
Vehicle, mods RPM Degrees BTDC Degrees Advance Inches BTDC
710 Pertronix 800 17 0 0.75
710 Pertronix 2000 35 18 1.04
710 Pertronix 2500 43 26 2.25
712 Stock 800 4 0 0.125
712 Stock 2000 26 22 1.32
712 Stock 2500 31 27 1.75
712 Pertr, Civ cap & plugs 800 16 0 0.75
712 Pertr, Civ cap & plugs 2000 35 19 1.04
712 Pertr, Civ cap & plugs 2500 42 26 2.25


Dave's comments

Because the 710 runs so strong, I used the same base timing for my 712.
Though I haven't checked yet, I believe that the lack of total advance
after the conversion is due to weak springs in the distributor and I'm
getting premature advance at idle.

The truck is running strong and one side benefit is that the truck is
running a lot quieter.
Erik, your quoting is going to get you in trouble.
Back when I had my 710 and 712, I would bump up the timing to see how it would run, and then back it down if there was any pinging. The timing was set at 800 rpm for idle using a Snap-on digital timing light . The other numbers are what the distributor advanced to , at the given RPMs..... a easy function of the timing light, and the info is only good to compare to the factory figures in the owner manual . And only useful to someone that understands how the distibutor works. Those figures were done somewhere about 3BJL (3 years before Jim L :lol: ). From what have come across in gasser Pinzes since then, my 710M was an exception vehicle, many other Pinzes wouldn't run without pinging at those advances... and I am sure that on the yahoo group I had said to back the timing to where it would not ping under any condition.

I see the guy that bought my 710 every couple of months or so, and the last I saw him I had asked about it... he refered to it as his " go to" vehicle. :D

Dave
.
The Trojan Horse... the 1st Pinz used to covertly carry troops into battle .




ATL Pinzgauer XM 718K TUM(HD) 6x6 FFR (aka The Green Grail)
SAM. C.
Posts: 141
Joined: Mon Nov 06, 2006 1:08 am
Location: Brisbane, Australia

Timing

Post by SAM. C. »

Thanks Erik & Dave

That is useful info and an interesting lesson on how the advance works. My timing was set very advanced and it looks like the oil viscosity difference was enough to make it start pinging under load. I retarded my timing as per Jims suggestion whilst I was away this weekend and no pinging at all although I need to adjust my tappets as I do have a bit of ticking.

When retarded back to 3mm in front of the mark it didnt ping at all. Prior to this it was set over 10mm in advance of the mark. I was driving through patches of soft deep sand which drags like hell and it still didnt ping after the change.

Thanks again and will keep those settings on record.

Sam
Post Reply