Folks,

Not even the magazines have given you these tests and a window to see this information.

The first chart is full camshaft advance vs. full camshaft retard... (the 2 extremes of the VVT actuator)

The second chart shows the same 2 runs with my programming added to contrast the two extremes... (my cam timing)

The third chart shows the gains that I achieved by adjusting the VVT.

Obviously, proper cam timing is essential to peak performance, but having this variable makes the best of both worlds... especially when I can adjust the settings to make the best spread of the power at all rpms.   

I chose to use my tuned file for these tests because it shows the effects better at the extremes and also with the raised rev-limiter.

VVT works by throttle position vs. rpm on this bike

See the attached stock ECU table... (resolution redacted of course)
There are others that control it's function too, but this one shows the basic programming.


Knowing how this system functions makes it easy to understand how a botched valve adjustment can lead to a blown engine.


Example;

Mechanic installs C14 intake cam one tooth advanced by accident.... under light to moderate throttle he would notice nothing wrong and could use the bike indefinitely like this as long as he never gives more than 50% or more throttle.....

Once the throttle is opened more than the amount needed to push the cam into full advance position, there would be mechanical valve to piston contact and failure.
 
Once there are broken parts in the cylinder destroying things and jamming things cam(s) valves ....etc... and cannot rotate due to mechanical interference, the weakest link will give in.... at high rpm, all kinds of things will shear off and get destroyed.

The key here is that there are 2 of these failures that are documented here on this board and also on COG and the common link is that they both failed after valve adjustment. One failed immediately.....

The other one took longer, I suspect due to gentle riding habits.

One was due to his own mistake while adjusting his own valves.

http://www.zggtr.org/index.php?topic=22436.msg278038#msg278038

http://forum.cog-online.org/concours-14-zg1400-general-chat-and-tech/died-and-won't-start/


The other paid a mechanic to do the valve adjustment...

http://forum.cog-online.org/concours-14-zg1400-general-chat-and-tech/2009-c14-went-into-limp-mode-last-night/

Follow up here:

http://forum.cog-online.org/concours-14-zg1400-general-chat-and-tech/found!!!-nybiomed's-'09-nonrunning-issue-has-been-determined!!!/



Horrible story for both of them.... 


Thanks,



Ivan



Ive added another page to my website that has all this info on it as well for everyone:

http://www.ivansperformanceproducts.com/ZG1400_vvt.htm

 Interesting information.  In reviewing your dyno charts, with your pre - selected area of 3000 rpm, I see you show a gain of 15# TQ @ 3000 rpm. 

  Here's another dyno chart (mine), using stock vvt timing, that also shows a 15# TQ @ 3000 rpm gain. Yes, it had a slip on... but as your own charts show at 3000 rpm the slip on runs the same as stock at 3000 rpm, so no net gain at that rpm.

   15# TQ @3000 rpm gain is impressive to say the least, no matter who the tuner is.

  Steve

I feel silly about the other thread now, all my speculation about how VVT works.  But, hey, it led to this, which is great.

I love seeing the VVT table- is that a stock table??  I wouldn't have expected any cam advance at such low RPM (1200!) even with tons of throttle.  Yes, it is only a tiny, tiny bit, but still- mind blown.  There is 24 degrees to work with, it looks like at "normal" riding (maybe half throttle) at "normal" RPM ranges (maybe 3-5K) it is around 1-6 degrees.  Much more than I would have predicted.

By the way, the manual implies that midway in the VVT pressure is "neutral", neither advanced nor retarded.  Now I think that is another English nuance error.  Midway, is half-way advanced, or 12 degrees.  I suppose it depends on perspective.

One was due to his own mistake while adjusting his own valves.

http://www.zggtr.org/index.php?topic=22436.msg278038#msg278038

Ivan, I saw your post on the other forum but was not certain you were referring to me. Thanks for your diagnosis, great to have some light shed on this failure. What confused me is how the having the intake cam out of phase resulted in the exhaust side damage?

EDIT: after posting the above I went and saw your reply to my post over there.  A couple of questions. Would further dissambly help determine the exact cause.  Also I have been wondering if a failed or improperly assemble  tensioner could be the cause .

Once you see how things work, it's just common sense how parts fail. 

If you pulled the head on the old motor, you probably would find at least one or more broken intake valve heads... once the head pops off, the stem can fall into the cylinder and will end up jamming into things... it's even possible for parts to migrate to another cylinder in extreme conditions when an engine tangles up it's parts.

Most likely the pieces of the intake valves got caught in the exhaust valves... got all smashed up by the pistons, got locked up and stopped the exhaust cam.... hence shearing off the bolts as the weakest link between the cam chain and the sprocket bolts.

Edit: 2/23/18, after some discussion with you, I do not think that this applies to you, your failure is due to something else.... disassembly of your cylinder head will give a lot more info in your case.
________________________________________________________________________________________________________



Many years ago (1999), I had customer's ZX9R blow it's motor on my dyno after I installed one of my jet kits...

The cause of it was the locator tab on one of the clamps that holds the carb to the head
see attached photo that I took from ebay today

One of the clamps popped off when I took the carbs off, and during the handling of the clamp when re-installing it onto the intake boot the locator tap popped off (weak spot weld) and fell into the #4 cylinder unknown to me at the time.


When I started the bike it was just quiet as a mouse... I revved it a few times and took it around the building to my dyno room at my old shop... rolled up onto the dyno, strapped it down.. got everything set up, and proceeded to make the pulls... on the 2nd pull it blew at 12000 rpm.

Apparently what happened was the little tab embedded itself in the piston crown... when it came out, it got caught in one of the exhaust valves, the head came off the valve and broke the other 3 valves in that cylinder... the head split... the valve head ended up in another cylinder... There was so much damage to the rods (bent) and the crank/clutch gear teeth were bent due to the force when the head split. What was most amazing, the cam chain didn't break !!

My insurance was very good about paying for the parts and labor at the time, and the customer was fixed up and running fine 3 weeks later... he wasn't even mad at me and is still a customer till this day.

That was the only direct experience with a blown motor that I have ever had... other than an Indian 2 stroke that broke a piston on a friends dirtbike when I was about 13.


Ivan

I feel silly about the other thread now, all my speculation about how VVT works.  But, hey, it led to this, which is great.

I love seeing the VVT table- is that a stock table??  I wouldn't have expected any cam advance at such low RPM (1200!) even with tons of throttle.  Yes, it is only a tiny, tiny bit, but still- mind blown.  There is 24 degrees to work with, it looks like at "normal" riding (maybe half throttle) at "normal" RPM ranges (maybe 3-5K) it is around 1-6 degrees.  Much more than I would have predicted.

By the way, the manual implies that midway in the VVT pressure is "neutral", neither advanced nor retarded.  Now I think that is another English nuance error.  Midway, is half-way advanced, or 12 degrees.  I suppose it depends on perspective.

Max,

Speculation can lead to lots of bad information, rumors and twisted 1/2 truths   

Yes, that's one of the stock tables..


Ivan

Thanks for the detailed reply Ivan. I will pull the head win I get a chance.

Lather,

The only other way that enough force could be put against your sprocket bolts to cause them to shear off would be if the cam seized in the head. (no initial valve contact)

The cause of this scenario happening would be from either mixing up the numbered cam caps, or one or more of their locating dowel pins being missing
(both will cause improper cam to cap clearance/alignment)

Improperly installed/damaged oil supply pipes/o-rings.

It's also entirely possible in your particular case if you used aftermarket shims when doing your valve adjustment on the exhaust side that don't fit as snug as the originals.... possibly it "spit a shim" and caused one of the exhaust valves to hang open and get destroyed to start the chain of destruction.


Ivan

Lather,

The only other way that enough force could be put against your sprocket bolts to cause them to shear off would be if the cam seized in the head. (no initial valve contact)

The cause of this scenario happening would be from either mixing up the numbered cam caps, or one or more of their locating dowel pins being missing
(both will cause improper cam to cap clearance/alignment)

Improperly installed/damaged oil supply pipes/o-rings.

It's also entirely possible in your particular case if you used aftermarket shims when doing your valve adjustment on the exhaust side that don't fit as snug as the originals.... possibly it "spit a shim" and caused one of the exhaust valves to hang open and get destroyed to start the chain of destruction.


Ivan

I did use some aftermarket shims and also noticed some slight damage to  a coupl oil pipe o-rings

As I mentioned at some point a couple of ex shims WERE beat up pretty bad. If spit shims are a known issue that seems to me to be a likely cause. Thanks for your comments

Was the cam seized in the head?

Just to butt in here for a second- the C-14 uses 'under bucket shims', I did not think it is even possible to 'spit' those, is it? Shim over buckets have a whole host of problems and can and do get dislodged but I though under bucket shims were immune from that? Plus there should be no appreciable wear on them as other than rotation, they should not ever actually move against either side (valve stem or inner bucket). ?? The shims fit quite radially snugly into the under side of the bucket so it would seem impossible for them to do anything unless the bucket separated from the valve stem by a lot, and I cannot imagine that happening unless a valve struck a piston and was already bent.

This is a question and please do correct me if this is not correct because I would really like to know.

Brian

Lather,

The only other way that enough force could be put against your sprocket bolts to cause them to shear off would be if the cam seized in the head. (no initial valve contact)

The cause of this scenario happening would be from either mixing up the numbered cam caps, or one or more of their locating dowel pins being missing
(both will cause improper cam to cap clearance/alignment)

Improperly installed/damaged oil supply pipes/o-rings.

It's also entirely possible in your particular case if you used aftermarket shims when doing your valve adjustment on the exhaust side that don't fit as snug as the originals.... possibly it "spit a shim" and caused one of the exhaust valves to hang open and get destroyed to start the chain of destruction.


Ivan

If there is "looseness" in the circumferential fit of the shim, it can "rattle" around and damage the retainer... in a high rpm situation, it's possible for a loose fitting shim to climb out of it's seat and find it's way out of the retainer well.... The more clearance, the more chance there is.

I've seen it on some bikes during valve adjustment... (beat up retainers)

I've also seen it on bikes that were blown up by their owners for various reasons. (on top of the retainer)

I never use aftermarket shims for fear of this... I'm not saying that all shims besides OEM are bad... I just don't know other than what I have seen.

All of this applies to shim under bucket..


Ivan

I've never seen any reference to the possibility of bending a cam during installation - which can happen. The cam needs to be placed in the saddle (journals) and when the caps are placed on the bolts are "walked" down evenly from one end of the cam to the other. Never just bolt a cap down, then move to the next and bolt it down. Bent cams will gall and wallow out the journal, thereby wrecking the head -  and who knows how much turning resistance is involved, of course dependent on the run out. Steve

Was the cam seized in the head?

No sir it was not and there were no signs  on the bearing surfaces. Away from desktop now but should be able to find pictures tonlght if you are interested.

I would prefer to see pics of the head when you remove it... otherwise there will be speculation.

Facts are best.   

Working on adapting a non abs zx fork to mount abs sensor now but when thatsdone off with her head. And in reply to Steve one thing i am religious aboutis bolt tightening sequences.

No sir it was not and there were no signs  on the bearing surfaces. Away from desktop now but should be able to find pictures tonlght if you are interested.

Here's an easy to to see if you have bent valves. If the cam is out, lay a straight edge on the bearing saddles from one side of the head to the other side. A square, or a piece of pipe that rolls true would be fine. Then measure the clearance from each valve to the bottom edge of the straight edge. If you have any bent valves, you're going to have significantly more clearance than on non bent valves. Significant meaning more than .010" difference... more like .100" . this is because the high side of the valve is on the seat and holding the stem down.

  If the cam is in the head and you can rotate it, do the same thing, check the clearance on the base circle. If it exceeds significantly the clearance that should be there, the valve is bent. Steve

Working on adapting a non abs zx fork to mount abs sensor now but when thatsdone off with her head. And in reply to Steve one thing i am religious aboutis bolt tightening sequences.

 It's surprising how many folks actually don't know that. You would have seen galling had a bent cam been the issue, I looked at your pics and didn't see any, but of course I can't see all the way across the saddles either. Though I think you stated there was no galling. Steve

Just pull the head and take lots of pics...   

Also put all the intake valves in a cordless drill if they look ok.

I do appreciate the help from you two pros. Will get head off soon and post pics.