Measuring squish through the spark plug hole

[mike wilson]

Thanks for the sketch. If I'm correct, this is a section of your combustion chamber across the top of the piston (avoiding the valve pockets) _after_ you have modified the head?

 

The apparent ring around the periphery was something best removed. I am not, however, convinced that you have introduced an effective squish band. General concensus seems to indicate that about 30% of diameter is needed before this is acheived. If you look at a two stroke head you can clearly see it. There are other, complicating, factors with four strokes. I think that removing areas where mixture can do untoward things is probably the best you can hope for with the standard head.

 

This is all conjecture based on your drawings. I have been unable to find engineering drawings of the V11 motor, nor have I ever seen one dismantled.

 

mike

[motoguzznix]

Mike

 

This sketch is the stock head before I did any mods.

 

At the time of dismounting the heads, I removed only 0,5 mm from the heads as this was enough to get the target CR. When removing further 0,5 mm from the head and using a thinner 1,2 mm head gasket as intended (instead of the then unsed 1,6 mm), the valve pockets for the intake valves should be deeper to have enough clearence. The time for the engine assembly was limited, so I put it together at this state. This will be done when the heads come off next time when I replace valves and guides.

 

Even with the ring area too small for effective squish, there might be reduced pinging as the ring around the periphery with then only 1 mm height will contain a too small amount of gas to burn from itself.

30 % of the diameter would be a ring of 13,8 mm around the bore. This is hardly possible with the Guzzi engine.

 

In case you really would find some engineering drawings of the V11 Engine, I would not trust in the fact that the really produced engines will follow these drawings.

[Guest ratchethack]

Haw haw!Coming from someone who'll happily have a 2000 word dig at anyone who disagrees with his point of view,that's priceless.

. . . . .

I dont like it when people put one another down,but a healthy debate is nothing to be feared,as long as personal insults are not used.Purely from a personal point of view,I prefer the direct approach,call a spade a spade,etc.

. . . . .

Well, I'll tell you what, Big J. One of the most valuable aspects of this or any other Forum is the wealth of information that it provides to our common area of interest -- the V11 Guzzi. Of course, arguments and disagreements will ensue. Such is the nature of the Forum.

 

I find that there are essentially two kinds of posters: One kind of poster actually brings information to the Forum that may be of value to others. That information can be the poster's experience, however he chooses to present it, or it can be references to outside information. References can take the form of copied outside information in the post, or links to outside sources on the Web. I'm sure you'd at least agree that when making a point, one's point is usually made much stronger when backed up either by direct experience, or credible expertise from outside references, depending on the strength of the experience and/or backup reference(s)? IMHO, some of the very best information available here contains both.

 

The other kind of poster typically brings NO information to the Forum of any kind, other than opinion and speculation. This kind of poster invariably offers little or no direct experience, nor ANY form of outside reference to credible expertise. The woods are full of empty opinions, but unfortunately, they usually represent little or no value to anyone.

 

On a Web-based Forum, experience and credible references are all we have with which to separate valuable, accurate information from worthless opinion and useless speculation.

 

Ernst has answered my inquiry in this thread with pretty convincing evidence, as far as I'm concerned, that he's been on the inside of the V11 cylinder head. This is what I asked for in my opening post on this thread. To me, his measurements would be a good indicator that he's not dreaming things up or speculating. Furthermore, his measurements would seem to be a pretty solid basis for his conclusions, as well as for the modifications he has made and intends to make in the future. In all my years on this Forum, I have yet to see these measurements until Ernst posted them. I consider this valuable information, and since I have no reason to doubt what he's provided, I'll consider it valid until I discover any reason to invalidate it. It's the "trust but verify" principle.

 

Now as usual, we have people who disagree for whatever reason with the experience of others. Again -- what continues to amaze me the most is the ridicule and scorn that people heap on the information provided by others, whether by direct experience or outside reference -- WITHOUT PROVIDING ANY BASIS FOR THAT RIDICULE AND SCORN -- no basis for disagreement at all -- no experience, no evidence, and no outside reference whatsoever. My observation has been that those with the most negative points of view toward the information provided by others very often seem to have a consistent track record of providing ZERO evidence and ZERO backup for their points of view.

 

I'm just using the direct approach here -- calling a spade a spade, as it were. So if you don't like it when people put one another down, and personal insults aren't y'er cup o' tea (as you've indicated above) what exactly is your point above, Big J?

[dlaing]

 

I'm just using the direct approach here -- calling a spade a spade, as it were. Now you indicated that you hadn't had your heads off, If I remember correctly? So if you don't like it when people put one another down, and personal insults aren't y'er cup o' tea (as you've indicated above) what exactly is your point above, Big J?

A fine example is when I have posted photographs that are far more accurate than Motoguzzinix' first drawing, you have scoffed at them.

What kind of hypocritical poster does that make you?

On many miserable threads we have been through much of my criticism of your posts and what type of poster you are. Lets not do it again.

Please, lets not force Jaap to move this valuable thread to the banter forum.

Why don't you get back to the topic and post the picture you drew?

Maybe you don't have a drawing program or a scanner.

[mike wilson]

This sketch is the stock head before I did any mods.

 

OK

 

Even with the ring area too small for effective squish, there might be reduced pinging as the ring around the periphery with then only 1 mm height will contain a too small amount of gas to burn from itself.

30 % of the diameter would be a ring of 13,8 mm around the bore. This is hardly possible with the Guzzi engine.

"Will contain" is maybe too strong but I think you are right that it should lessen the probability of audible detonation. Your second point reinforces what I have been saying about squish in four strokes. Unless the head is designed with that form in mind, it can be difficult (if not impossible) to provide any functional form of it by reworking. Concentration on providing a clean combustion chamber shape, free of as many potential sources of detonation as possible, is a more useful use of energy.

 

In case you really would find some engineering drawings of the V11 Engine, I would not trust in the fact that the really produced engines will follow these drawings.

Not even approximately? 8-))

[Guest ratchethack]

A fine example is when I have posted photographs that are far more accurate than Motoguzzinix' first drawing, you have scoffed at them.

What kind of hypocritical poster does that make you?

On many miserable threads we have been through much of my criticism of your posts and what type of poster you are. Lets not do it again.

Please, lets not force Jaap to move this valuable thread to the banter forum.

Why don't you get back to the topic and post the picture you drew?

Maybe you don't have a drawing program or a scanner.

OMG, no...... Dave, have you been stretching out with y'er FEEEEEEEEEEELINGS again? (Now THAT'S scoffing.)

 

Here we have the introduction of some real misery. By all means, let's nip the lunacy in the bud here and not let this discussion drop into dreckfest. Dave, get a grip. Your photo of pistons provided little value to the shape of the combusion chamber compared to the concept that Ernst illustrated in his drawing. Need I repeat that it's the relationship of the shape of the combusion chamber to the shape of the piston crown that defines the squish band? Did you consider my pointing out this fact to be scoffing?!?!?! Where do you find any hypocrisy on my part?? Why would you now be asking for my version of what he's already provided?? What possible value could this represent to anyone?? Exactly what kind of a poster are you implying I am, and where's your evidence?

[dlaing]

OMG, no. Dave, have you been stretching out with y'er FEEEEEEEEEEELINGS again? (Now THAT'S scoffing.)

 

Here we have the introduction of some real misery. <_ by all means let nip the lunacy in bud here and not this discussion drop into dave get a grip. your photo of pistons provided little value to shape combusion chamber compared concept that ernst illustrated his drawing. need i repeat it relationship piston crown defines squish band did you consider my pointing out fact be where do find any hypocrisy on part why would now asking for version what he already possible could represent anyone exactly kind poster are implying am evidence src="%7B___base_url___%7D/uploads/emoticons/default_knownothing.gif" alt=":huh2:">

Sorry to confuse you.

It is always a dis-pleasure to incite your rude rantings.

Get a grip you lunatic!

I did not mean the photos of the pistons.

It was concerning other threads.

[Guest ratchethack]

A fine example is when I have posted photographs that are far more accurate than Motoguzzinix' first drawing, you have scoffed at them.

I did not mean the photos of the pistons.

It was concerning other threads.

Oh, I see. The "fine example" of my hypocrisy exists in "other threads"?

 

Now, how ever could I have missed that in what you said above?!

 

Perhaps this was on another dark and purply planet, far far away?

 

Hmm. The nitrous oxide index has been quite high on Remulac lately, hasn't it?

[big J]

There was no technical point,it just struck me as funny.Now you're havin a dig at Dave again-

"WITHOUT PROVIDING A BASIS FOR THAT RIDICULE AND SCORN"

 

Amazed yet?

 

What struck me as even funnier,in all the time it must have taken to poke about with bits of solder,think about and type up the topic,wait for replies,etc,etc....You could have pulled off the head and had a look yourself.

 

You already said you can do it easy,so why not?

[Guest ratchethack]

There was no technical point,it just struck me as funny.Now you're havin a dig at Dave again-

"WITHOUT PROVIDING A BASIS FOR THAT RIDICULE AND SCORN"

 

Amazed yet?

Yep, I'm amazed. Truly and thoroughly. A certain level of mastery of the obvious is called for here.

 

I've not ridiculed Ernst's drawing, or his point of view, Big J. Ernst provided the basis for his point of view with what I consider to be his own convincing evidence, and I've simply pointed this out. I have no need here to provide a basis for what's already been provided.

 

Now Dave seems to've got something or other wound around his Remulacian Space Sprockets over photos he provided in some other thread "that are far more accurate than Motoguzzinix' first drawing" that I allegedly - and hypocritically - "scoffed at". I don't have any idea what he's talking about. . . .

 

Do you, Big J?

 

Yep, (Part II) I'm amazed quite a bit of the time. . . . .

 

Much of the time, it's quite amusing. Sometimes, I just like to watch as stuff unfolds. . . . .

 

....You could have pulled off the head and had a look yourself.

 

You already said you can do it easy,so why not?

I've worked on lots of cylinder heads of my own vehicles. One of the many things I learned early on is that a casual heads-off "inspection" can be unwise. By my experience, many things can happen when a cylinder head comes off and goes back on, not all of which are good things. There's usually some level of risk involved. The old adage, "If it ain't broke,....etc." often applies, and has been repeated often enough, including in this thread. I think there's often some wisdom in that. I don't like to waste head gaskets or effort, either.

 

As I've said previously in this thread, in the interest of maximum up-time, I like to know what I'm doing and where I'm going far in advance of having the heads off, and be ready for the kinds of things I'm most likely to find when I get in there. The way things are going, it might take me awhile just to learn what I think I ought to know before I take 'em off.

 

Forewarned is fore-armed, as they say. Hence, this thread.

 

So far, I've only had 2 days of down-time since I got the Guzzi, and I sorta like to keep the up-time going as much as possible. . . . .

 

BAA, TJM & YMMV

[dlaing]

Now Dave seems to've got something or other wound around his Remulacian Space Sprockets over photos he provided in some other thread "that are far more accurate than Motoguzzinix' first drawing" that I allegedly - and hypocritically - "scoffed at". I don't have any idea what he's talking about. . . .

 

Do you, Big J?

 

 

Here you go...apologize, and we'll drop it and move on to more important things

 

 

From the sloppage sheet prototype? thread:

Dave. You've obviously got lots of time to take so many pictures of your dipstick. If you post any more, people will start bidding on it.

 

They don't show anything of any value whatsoever WRT oil level.

 

With all due respect, what you "suspect" here but haven't shown isn't very interesting.

 

If you don't trust the work of the Pro's who've done this countless times before and you really want to duplicate the efforts that Greg, Pete, and God-only-knows how many others who've done this for decades, why don't you do what they've done long ago and take off the sump. Put a straightedge across the block and get the measurement that Greg posted way back in posts #50 and #76. This is the only way y'er going to have any indication at all about what you've got y'erself so wrapped around the driveshaft about.

 

Then you can take all the photos you want from the inside with the dipstick screwed down in place and post them here with circles and arrows and explanations about how wrong everyone has always been. [sigh]

 

Where's Arlo and the "Group W" bench?!

[Guest ratchethack]

Here you go...apologize, and we'll drop it and move on to more important things

From the sloppage sheet prototype? thread:

Uh, Dave. . . . . this may come as a bit of a surprise to you, but the rest of us dropped it and moved on to more important things so long ago that we've forgotten and no one cares.

 

But since - amazingly enough, with resurrected apologies to Arlo Guthrie - y'er evidently still stuck back on the Group W bench with the 8 x 10 color glossy photographs with the circles and arrows and the paragraphs on the back explaining how each one was to be used against us -- frankly, now I'm curious.

 

By what possible stretch of y'er other-worldly, nitrous oxide-addled imagination are you now demanding an apology??!!

 

Please provide the basis of your demand. Be concise, try your very best to be rational, and please do make a sincere effort to use the logic that we find so helpful and necessary here on the blue planet -- that's the one with the clean air and the Global Warming Fraud -- not the dark and purply one with the toxic nitrous oxide atmosphere.

 

Enquiring minds are now shifting into Intergalactic hyperdrive.

[dlaing]

Uh, Dave. . . . . this may come as a bit of a surprise to you, but the rest of us dropped it and moved on to more important things so long ago that we've forgotten and no one cares.

 

But since - amazingly enough, with resurrected apologies to Arlo Guthrie - y'er evidently still stuck back on the Group W bench with the 8 x 10 color glossy photographs with the circles and arrows and the paragraphs on the back explaining how each one was to be used against us -- frankly, now I'm curious.

 

By what possible stretch of y'er other-worldly, nitrous oxide-addled imagination are you now demanding an apology??!!

 

Please provide the basis of your demand. Be concise, try your very best to be rational, and please do make a sincere effort to use the logic that we find so helpful here on the blue planet -- that's the one with the clean air and the Global Warming Fraud -- not the dark and purply one with the toxic nitrous oxide atmosphere.

 

Enquiring minds are now shifting into Intergalactic hyperdrive.

If you don't know now, you never will.

I guess I'll move on without your apology.

You'll get the respect you earned.

[dlaing]

Ratchet

 

I took some measurement from the head design when they were off, I will post this soon.

 

Mike, Hubert, Skeeve

The combustion chamber shape resulting from that head design is not favorable, as shown in the following sketch:

 

 

These big pockets let me doubt about the serious work in the factory on the combustion chamber shape. Previous Guzzi heads were not of that design and used a large squish area.

 

If I I did not appreciate your inaccurate drawing and if was more like Ratchet, I might write something like the following:

Motoguzzinix. You've obviously got lots of time to draw many pictures of your piston. If you post any more, people will start bidding on it.

 

They don't show anything of any value whatsoever WRT squish. homer.gif

 

With all due respect, what you "suspect" here but haven't shown isn't very interesting.

 

If you don't trust the work of the Pro's who've done this countless times before and you really want to duplicate the efforts that Ratchet and God-only-knows how many others who've done this for decades, why don't you do what they've done long ago and take off the head. Put a plasticene across the piston and get the measurement that measurements you need. This is the only way y'er going to have any indication at all about what you've got y'erself so wrapped around the driveshaft about.

 

Then you can draw all the pictures you want pic.gif pic.gif pic.gif you want with lots of illegible numbers, post them here with circles and arrows and explanations about how wrong everyone has always been. [sigh] whistle.gif

[dlaing]

Readying myself for more insult...

and the same image without Ernst's drawing overlayed:

http://img167.imageshack.us/img167/1339/forratchettq4.jpg

Note the straight lines I drew should be within a mm of Ernst's measurements.

I did not write the numbers next to the straight colored lines, but they correspond to Ernst's drawing's numbers.

You can see that despite the ugliness of his drawing with measurements, it is pretty faithful to the measurements listed.

The lines do not follow the photos perfectly, but I think it helps visualize better than the drawings alone. Sorry Ratchet, if you don't appreciate it.

I did not know how big the pistons were, but going off the 77mm number, I ended up with the pistons being about 90mm.

Unfortunately the Mike Rich piston photo did not line up as well, but still, GREAT MINDS can see what Mike is achieving.