I think I got the goody out of that one.

bwolfie said:

I have tried to contact QPD several times. Now answer and they don't reply to emails.

Click to expand...

I think they are old school, did you try a carrier pigeon?

[quote="Dances with Shrapnel"
By the way, that case of beer you left in the paddock was excellent![/quote]

LMAO, the statement from Dances with whirly bits flying through the air:
The important things in life are what count. Everything else is just noise.
Cheers,
CNN

Dances with Shrapnel said:

comnoz said:

It is no surprise that the left piston seized first as that is the cylinder that normally runs hottest on a Commando.

Click to expand...

So I'll ask. Why is it that the left cylinder normally runs hottest on a Commando?

By the way, that case of beer you left in the paddock was excellent!

Click to expand...

It is said the left side runs hottest because it receives less oil. I do know the left side piston needs to have around 1/2 thou more clearance to live.

So I never did find out who left me that case of beer. Glad you enjoyed it. It would have been tough to get it in my luggage for the trip home.
Plus I am sure you will have a case waiting for me next time. Jim

comnoz said:

The cases look pretty good aside from a little shrapnel blasting.

Now for decisions. Maybe it is twingle time. Jim

Click to expand...

Jim
What case halves are you running on your bike? Where is the web embossment at the main bearings? Are they Maney crankcases?
CNN

comnoz said:

Dances with Shrapnel said:

comnoz said:

It is no surprise that the left piston seized first as that is the cylinder that normally runs hottest on a Commando.

Click to expand...

So I'll ask. Why is it that the left cylinder normally runs hottest on a Commando?

By the way, that case of beer you left in the paddock was excellent!

Click to expand...

It is said the left side runs hottest because it receives less oil. I do know the left side piston needs to have around 1/2 thou more clearance to live.

So I never did find out who left me that case of beer. Glad you enjoyed it. It would have been tough to get it in my luggage for the trip home.
Plus I am sure you will have a case waiting for me next time. Jim

Click to expand...

Consider that reciprocity case of beer a given. Probably need to visit Pueblo so you can see my arms waving while I explain the motor I want to build next.

The business card I found on the case of beer had written on it "from Bill to Jim" and "Thanks". The card described a business which specialized in draining swamps, flooding swamps, rigging elections, monkey wrenches, used rugs, concrete overshoes, meteorites, art forgeries, dynamite, rubber chickens, cannons, indian rope tricks, call girls and defiling virgins; the usual stuff.

CanukNortonNut said:

comnoz said:

The cases look pretty good aside from a little shrapnel blasting.

Now for decisions. Maybe it is twingle time. Jim

Click to expand...

Jim
What case halves are you running on your bike? Where is the web embossment at the main bearings? Are they Maney crankcases?
CNN

Click to expand...

They are just stock MK3 cases. The webbed cases were only used for a couple years. Jim

Thanks for the words about the injection system - still food for thought.

comnoz said:

CanukNortonNut said:

comnoz said:

The cases look pretty good aside from a little shrapnel blasting.

Now for decisions. Maybe it is twingle time. Jim

Click to expand...

Jim
What case halves are you running on your bike? Where is the web embossment at the main bearings? Are they Maney crankcases?
CNN

Click to expand...

They are just stock MK3 cases. The webbed cases were only used for a couple years. Jim

Click to expand...

Well there you go?
Jim,
Thanks for the clarification on the cases. Again... I am taken for the "Dumb as a Post award" when it comes to the mk111 commando. I'll just stick to Right hand shift models so don't mind me.
Cheers,
Thomas
CNN

Jim I didn't doubt the example piston was detonated on, though appreciate the conditions that did it , I wanted to know what part of the piston damage piontable-outable as evidence of detonation. At my level it just looks like a regular used up half trashed piston from other causes. In other words what is it about the example piston that would imply detonation destruction if ya didn't know the history of its over advanced spark racing or lean burning lugging? We do enjoy your full frontals of a beautiful construction.

comnoz said:

Click to expand...

It still puzzles me that the other piston seems to be unscathed as far as detonation evidence. I think there was something other than just lack of octane alone at work there.

It still puzzles me that the other piston seems to be unscathed as far as detonation evidence. I think there was something other than just lack of octane alone at work there.

Click to expand...

I've same suspicions but don't know enough to say why, except I note the piston knurling which I've had done to take up some piston slackness. Of course any part can have flaws in it so hard to say if just luck of the draw in life time. Has crank run out been checked yet after finding the DS race loose?

comnoz said:

Dances with Shrapnel said:

comnoz said:

It is no surprise that the left piston seized first as that is the cylinder that normally runs hottest on a Commando.

Click to expand...

So I'll ask. Why is it that the left cylinder normally runs hottest on a Commando?

By the way, that case of beer you left in the paddock was excellent!

Click to expand...

It is said the left side runs hottest because it receives less oil. I do know the left side piston needs to have around 1/2 thou more clearance to live.

Click to expand...

I think you are right about that. That's what Axtell told me back in the early '70s when I first got hooked on racing Nortons. He also specified an extra 1/2 thou for the left piston. At the time he preferred Hepolite Powermax pistons for the 750, and fit them at .0040" on the timing side and .0045" on the drive side.

Ken

BitchinBeezer said:

comnoz said:

It still puzzles me that the other piston seems to be unscathed as far as detonation evidence. I think there was something other than just lack of octane alone at work there.

Click to expand...

Click to expand...

I can definitely say that after the seizure but before I added octane booster the engine was pinging on both cylinders under acceleration.

I can clean the carbon off the right piston but what kind of damage would you be expecting from a few seconds worth of detonation other than seizure -when running a forged piston.

Right up until the piston grew too big for the hole there wouldn't likely be any damage evident.

Now if this was a water cooled engine especially with cast pistons which could be run with sustained detonation without seizure then I would expect things like craters in the top of the piston and maybe broken ring lands but with an air cooled motor with forged pistons, the first result of detonation is likely to be a seizure. Jim

hobot said:

Jim I didn't doubt the example piston was detonated on, though appreciate the conditions that did it , I wanted to know what part of the piston damage piontable-outable as evidence of detonation. At my level it just looks like a regular used up half trashed piston from other causes. In other words what is it about the example piston that would imply detonation destruction if ya didn't know the history of its over advanced spark racing or lean burning lugging? We do enjoy your full frontals of a beautiful construction.

Click to expand...

The result of detonation on a forged piston in an air cooled motor is the same as if the piston had been fitted with inadequate clearance. That is because detonation causes inadequate clearance by heating the piston beyond it's normal operating range.

When a piston is fitted in a cylinder the necessary clearance is what is required to make sure the clearance does not reach zero
when it is exposed to it's maximum heat for whatever it's use is.

For example a forged low silicone piston in a Norton requires .0065 clearance to maintain more than zero clearance when used at full throttle, full load on a hot day in a normal hot rod or road race engine.

That same piston cruising down a level highway on a cool day may be running with over .004 clearance as a piston temperature can easily vary by more than 300 degrees depending on the load and ambient conditions. There ain't no thermostat.

Anything you do that would heat the piston to a temperature beyond what the clearance was set for will reduce the clearance to less than zero and a seizure will be the instant result.

Detonation is very good at making a piston hot because it scrubs the boundary layer of air from the top of the piston. That boundary layer protects the piston from the 1500 degree fire in the cylinder. As soon as that boundary layer is blown away by detonation the piston temperature skyrockets and clearance goes away. To put up with the heat from detonation you would need a huge amount of piston clearance. Jim

Oh ok then, could of just told me to look at the piston sides and not the crown for the end result of over heating by detonation blasts. Heat will limit Peel's deal and now more concerned as ever plus .005 more on LH, ugh. Really don't think its lack of head oil flow as Harley really spent a lot of money experimenting moving a Lot more oil through head to find head temps stayed the same but oil temps seriously soared to point they trashed oil cooling in that area. There is a reason they sell various octanes to protect public's engines but part of travel adventure is the risk taking & hwy bandits.

Someone left me a nice intact fiberglass or some type composite narrow waisted classic Triumph gas tank on my pile of parts for sale yet nothing missing in trade form my pile, so took it as a good will gesture and really handled and thot about it for Peel but its too antique Triumph for me and no knee grips so left it in the wide open for fate to take it where wanted.

I suspect ya might be thinking about some water or water/methanol spray uses now and then.

Ethanol injection could be a good thing with a boosted engine. It is a pain to deal with however.

The one thing I am going to do is make another attempt with a knock sensor. One thing I have now that I didn't have before is the ability to program the ECM to listen for knock only at certain RPM ranges. That may help me to avoid false triggers.

Even if I am not able to stop it from triggering on normal engine noise at times I could use it to turn on a warning lamp without retarding the timing. There are several extra outputs that cold easily be programed to turn on a light. That could alert me to listen and see if it is ping and back out of the throttle.

Methanol is the alcohol of choice for a reason, not ethanol, though could be done its a real bother as you state.

The only way to get knock sensor to work in many engines is to Only listen in the short time window interval when the valves are closed so not ringing engine just before TDC and shortly after in the zone detonation occurs. Sounds easy in a single but don't know if possible on 360' twin with a mate working its valve train ringing. Its very very common for modern engines to shut off knock sensor above some rpm [upper 4000's lower 5000's] d/t normal freq sounds triggering a cut back yet everything fine. I suppose a super duper spectrum analyzer and processing of known normal and known detonation examples might work a digi brain but I'm getting realization only a human ear might pick it up, but even so may be too dang late to matter.

What's the main engine question here anyway, a longer boring life or a $horter more exciting one?
I'm trying not to relate-flash on your riding so far on faith and noises which has beat my psyche to a pulp much shorter. Though not voluntary its still something you endured that rest of us can get a psychic lift from.

comnoz said:

The one thing I am going to do is make another attempt with a knock sensor.

Click to expand...

Have a look at "Ion sensing", it was discussed in the Megasquirt forums now and then but it will probably still involve a very hefty learning curve.



Tim

Tintin said:

comnoz said:

The one thing I am going to do is make another attempt with a knock sensor.

Click to expand...

Have a look at "Ion sensing", it was discussed in the Megasquirt forums now and then but it will probably still involve a very hefty learning curve.



Tim

Click to expand...

Thanks, I will have to research that a bit more. I remember reading some stuff about it before. Jim

Jim may be one of the very few that could possible get ion sensing to work as expected in our engines as its very tricky to calibrate for a standard stock engine on standard fuel and standard operation conditions. Change or aged HT leads, change or age of spark plugs, change or age of coils, change or age of fuel and change of environmental conditions will all screw with proper ion conduction detection and mess with the desired purpose to avoid detonation w/o over richening a/f and retarding spark to about stall out. Also each CR and cam profile will skew ion conduction almost beyond calculation. Read about the Harley's leading the way for us again, which implies better have more than enough octane inhaled for all conditions or else...

http://www.hdforums.com/forum/engine-re ... ained.html

Review of the technical and hardware issues to incorporate and over come, not a cheap hobby horse solution for any of us.
http://www.vems.hu/wiki/index.php?page=IonSense