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mark1122 wrote:

What is the duration? what was the recomended LC for the cams?
Do u have any head porting done?
You could advance the timeing a bit (start the spark sooner) to try to avoid the ping . What is it set at now? Dana S? stock?
Or you could try a little more overlap on the cams.
Just a thought.

duration with normal valve lash approx 280 degrees. recommended LC's 106-108
no head porting
Pinging is in my case no ignition problem......
I'm using Dyna S
I'm indeed thing of retarding the intake cam to get rid of the pinging. I do have a 0,040 squish ridge so that should be enough :dry:
engine is actually really faster than a z1000 overall so I geuss head porting is not always necessary

martijn wrote:

mark1122 wrote:

What is the duration? what was the recomended LC for the cams?
Do u have any head porting done?
You could advance the timeing a bit (start the spark sooner) to try to avoid the ping . What is it set at now? Dana S? stock?
Or you could try a little more overlap on the cams.
Just a thought.

duration with normal valve lash approx 280 degrees. recommended LC's 106-108
no head porting
Pinging is in my case no ignition problem......
I'm using Dyna S
I'm indeed thing of retarding the intake cam to get rid of the pinging. I do have a 0,040 squish ridge so that should be enough :dry:
engine is actually really faster than a z1000 overall so I geuss head porting is not always necessary

Pinging is all about compression. if u have to much psi, u have too much heat, for a given octane level to deter.
If u change the ignition timing u can start the flame path sooner. If the flame starts at the wrong time with too much heat in the cyl, (high compression) u will get spontaneous combustion ahead of the flame.
Or u can retard the cam timing to increase the overlap witch will decrease the cyl pressure.
I’m just saying that low squish doesn’t mean no ping do to ignition timing. Just that u should be able to run LESS timing if all else were =. But it is a test till pass #, not an assumed #.
There can also be other factors at play. Did u massage all of the edges on the pistons? These can cause hot spots as well.
So in the end we cant assume it is cam timing alone.
This is not meant to be persuasive, as much as let you know some alternatives.
What do u run the timming at? have u tried other #'s?

The age old question, Is it pre-ignition or detonation? Both can be gently finessed to a point.

martijn wrote:

no head porting
Pinging is in my case no ignition problem......
I'm using Dyna S
I'm indeed thing of retarding the intake cam to get rid of the pinging.

I had the same problem with pinging in the midrange.

Before retarding the intake cam, which may help the pinging at the expense of reducing your torque. You might want to consider adjusting your igintion advance curve.

If you are getting good midrange torque (volumetric efficency) with a 10.5:1 piston kit then it is normal to have pinging in the midrage with the stock ignition advance curve. My stock weights and spring brought full ignition advance at 2200 RPM. Way too quick for my setup. I lightend the weights and ordered a range of springs from Lee Spring Company. After a few days of tweeking I was able to get my advance to start around 1800 and full advance at 4000. It didn't cost too much but it was a lot of work fiddling, tweeking, grinding soldering, etc

The easier (more expensive) route is to buy a Dyna 2000. It will give you a good advance curve out of the box - and a rev limiter. That's handy. It may also have the ability to create a custom curve with a PC and serial port.

hey Mark 122,

you're right.. there can be other problems. I tried several jettings. less pinging was with 127,5 mains and 22,5 pilot. But that was way to rich. So I'll try the BS34's Some people already told that the VM's had midrange tuning problems. Apparently thats why the made the CR models?
About timing: it's stock, full advance is 40 degrees. I've tried even retarding 20 degrees.. still pinging which occurs in mid from 5000 to 7500 rpm's.
We do have a high ocatane feul in europe ( ron 98). I did nothing with the pistons. The first set up was 108-110 LC's which , as I recall, had no pinging. But it was very agressive at 8,5k.. It went as a rocket to 11K and bellow 7 k it was sloppy almost a kz650....
I reached 11k in forth gear.. a bit scared on a dutch dyke...

davel wrote:

martijn wrote:

no head porting
Pinging is in my case no ignition problem......
I'm using Dyna S
I'm indeed thing of retarding the intake cam to get rid of the pinging.

I had the same problem with pinging in the midrange.

Before retarding the intake cam, which may help the pinging at the expense of reducing your torque. You might want to consider adjusting your igintion advance curve.

If you are getting good midrange torque (volumetric efficency) with a 10.5:1 piston kit then it is normal to have pinging in the midrage with the stock ignition advance curve. My stock weights and spring brought full ignition advance at 2200 RPM. Way too quick for my setup. I lightend the weights and ordered a range of springs from Lee Spring Company. After a few days of tweeking I was able to get my advance to start around 1800 and full advance at 4000. It didn't cost too much but it was a lot of work fiddling, tweeking, grinding soldering, etc

The easier (more expensive) route is to buy a Dyna 2000. It will give you a good advance curve out of the box - and a rev limiter. That's handy. It may also have the ability to create a custom curve with a PC and serial port.

I've got a 900 head on my engine and once had over 200lbs compression from carbon. Never had pinging. The timing is set way back from the fire mark and it runs good that way. I do remember taking weight off the advancer arms once. Don't really know why I did that but, I do know if I set timing even eight inch back from the fire mark it would waay to advanced. 1015 kit is in the motor. my personal opinion most people would'nt realize the timing can be set back that far and the motor may run even better. :blink:

Retarding the cams will change your power band, maybe for the worse. Buying cams with a later intake closing points, costs money. A good flowing head will cool the mixture, but costs money. Possibley the quickest and cheapest way is to add an extra base gasket or two. Reduce the compression a touch and save those high dollar parts you have invested your money in. It is best to run your cams in there stanard position and keep your timing close to stock. If you don't like your current parts, please put them in a brown box and write my name on it, I will gladly pay the shipping. You guys are hearing what is called the "death battle", better to give me the parts, rather then waste them. I will give them a loving home.

kzz1p wrote:

Possibley the quickest and cheapest way is to add an extra base gasket or two. Reduce the compression a touch and save those high dollar parts you have invested your money in. It is best to run your cams in there stanard position and keep your timing close to stock.quote]

Sorry but but that just wont work. :silly:
If u add a gasket u will increase the squish clearnce. and that is a big no no.
poor squish = detonation for sure.
less is always better.

kzz1p wrote:

Possibley the quickest and cheapest way is to add an extra base gasket or two. Reduce the compression a touch and save those high dollar parts you have invested your money in. It is best to run your cams in there stanard position and keep your timing close to stock.quote]

Sorry bud but that just wont work. :silly:
If u add a gasket u will increase the squish clearnce. and that is a big no no.
poor squish = detonation for sure.
less is always better.

mark1122 wrote:

kzz1p wrote:

Possibley the quickest and cheapest way is to add an extra base gasket or two. Reduce the compression a touch and save those high dollar parts you have invested your money in. It is best to run your cams in there stanard position and keep your timing close to stock.quote]

Sorry bud but that just wont work. :silly:
If u add a gasket u will increase the squish clearnce. and that is a big no no.
poor squish = detonation for sure.
less is always better.

Sorry Mark I disagree. Less squish equals higher compression therefore adding to the problem. Is there problem preignition because of pressure or hot spots. Or is it detonation because of ignition timing? Most motors have large squish areas, and most builders not even know what squish is. My line of thinking is by reducing the presure in the cylinder you do two things. one, stop the fuel from combusting before it's ready, two slow down the flame travel speed. Better to have poor squish then a empty wallet. I will use a stock Z1R turbo for an example. It has above average cylinder pressure and above agerage V/E. What does that motor know about squish? Nothing..............................

Okay I'm just not done yet. In my book there is a bottom line here. In the old days you could buy any parts and just put something together. Well we live in a new time! Today you must build around the current octane levels. In california our gas sucks, this limits what you can build or how you build it. The day of the 10.5:1 in a street motor is almost dead, rather we like it or not. A guy can't just buy some 10:1's and small bolt-in torque cams and ride it like days gone by. If you lucky, you can use 10:1's with big cams. Then everyone is complaining about no bottom end torque. I think as builders we need to change our line of thinking to stay with the times. Myself I can't tell the different between a 9.5:1 or 10.5:1 motor while riding it. The same may apply to low squish in high compression street motors. We may be going to squish in low compression street motors before we know it. Once agin I don't really know a dam thing

this is fun.
you are right, but you are also wrong.
why do we have squish?
To improve the flame travel and speed it up.
if u tighten the squish, u increase the presure. yes
but we will improve the flame and the pro's will over ride the cons.
This comes from Kevin Cameron.
U will get more detonation from a 9:1 with poor squish than a 10:1 with good squish clearance.

if u want to reduce the presure u are better served to change the cam timing. no cost involved . no risk.
the gasket just wont work.