Moss Motors, Ltd

enfo, motorbill et al

here goes!  more ideas- as stated the farther the piston goes the more accurate the measurement. true

you would need a ladder to read the thing- false (i've got an idea!)

the pressure of the column of water would cause leakdown-false

 

Listen to this- --- You connect a long clear  hose to the  spark plug hole. It is full of air not water except for a little column of water that is stuck in it a fair distance down the line. (like when you bleed brakes and its mostly air in the line but there is a short column of fluid and then more air) Go through the motions as described before by me going back and forth past top dead center and marking things except you use one edge of the bubble of fluid as your reference point instead of the top of the column of water idea. similar to a bubble level used by carpenters. you could do this with the tube coiled or laying on the ground or on a bench. Since there is no pressure caused by the weight of the column there is no leakdown! Plus the ladder gets to stay in the garage. The surface tension on the water would keep it from dribbling out of the hose. Kind of like keeping fluid in a straw by holding your finger over the top end.

one problem- without the ladder i think labcoats would be overkill.

 

LCJUTILA
 

I haven't had this much fun on the internet in a while.

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Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)

Guys-

More thoughts...

If you don't like my last idea because we don't get to use the ladder or labcoats here's some fine tuning on the manometer idea addressing the leak- down issue. Motorbill will be shakin' and bakin' because we'll need his precious stopwatch!

1)  Set up the manometer.

2)  Put the crank at something like 110 degrees btdc.

3)  Rotate crank toward tdc to cause the water to rise. Stop after short distance.

4) Get Motorbill (we're gonna need his stopwatch)

5) Observe (May need magnifying glass- Oh Boy!) and Time any drop in the water level and also the amount of the drop. This is a measure of the leakdown rate! (I still think it will be neglible)

6) Do the back and forth mark and measure monkey motion as described earlier and TIME THE OPERATION.

7) Adjust results using leakdown rate factor times time to complete operation.

 

Are you guys gonna shoot me down or should I take some aspirin for my sore shoulder from patting myself on the back?

 

P.S. Bayless- If you do this operation and it works you are gonna be the BIG DOG at  cocktail parties and club events when people start telling stories!
 

Brilliant!!!

Only problem is that by the time we get done screwing around with all this water the cylinder will have rusted and we"ll need to rebuild the thing anyway, at which point we can just use the mechanical piston stop method. Brilliant!

Oops. Will the static leak down rate of the water be the same as the semi-dynamic rate effected by moving the piston over the surface of the imperfect bore? (I got a million of 'em. Go ahead and try me again!)

You know what they say. The optimist sees the glass as half full, the pessimist sees it as half empty. The engineer, on the other hand, sees the glass as inappropriately sized for the volume of water involved.....    Cheers. My wife says I gotta stop this or she's leaving with the dog.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motorbill-

I said about 47 postings back that I felt there isn't going to be any leakdown in the first place, and if there is a dollop of 30w would fix it! All this other stuff is to make you disbelievers happy. The amount of water that will be displaced amounts to about a cupfull. That cupfull is going to be piled up in a quarter inch diameter tube which is going to generate about what... 2psi pressure? (At the most)      You could generate more pressure blowing into the tube yourself! You'd pop your eardrums before you could generate any appreciable leakdown. Wasn't this engine just rebuilt? Its gonna work guys- get the lab coats!   Wind that stop watch!

LCJUTILA 

LCJ,

Mine's electric.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

LCJ,

Look, there's only one way to do this. We've both got to agree to meet at this guy's house at a time certain and tie him up while we do the whole thing YOUR WAY. Then, we'll rip the cylinder head off and use the reliable piston stop method (my way). I'll bet you a case of Guiness we'll find you're off by at least fourteen one hundredths of a degree. Ha!!! I'm packing my lab coat right now...

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motorbill-

Wasn't Fort Collins over run by indians in 1872 or something after it was over-run by white guys? They won't like me there. Im descended from the pilgrims. (Don't let the name fool you)

LCJUTILA 

LCJ,

I'm originally from the northeast, but I'm descended from Cherokees and Seminoles. UH OH.........

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motorbill-

That explains it!!!

 

(My wife is part Cherokee )

LCJUTILA 

Well, in spite of the fact that we do have some pretty brilliant ideas here, we are talking about lab coats and all. That does imply the scientific method which is: formulate a plan to test the system then verify it. In keeping with that methodology, I guess we could try the various manometer methods and the physical piston feeler, if possible then estimate which method was more accurate. The verification part would, of course, be pull the head and use the positive piston stop to finally determine which was right. I may do that but not this week. It's too darn cold in the garage with all this global warming stuff. I think I'll just have another beer for now.

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Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)

Enfo,

Ya gonna suck that beer through a quarter inch hose from the top of a ladder?

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

I guess maybe I've already sucked too much beer. The answer suddenly came to me today as I was discussing something else and it is so simple that you guys are gonna feel embarrassed, almost as much as I am. Turns out that I know a guy who has a 50's Anglia that has the same motor I have, including the original timing cover. All I have to do is go look at his motor and note where the mark is then put one on mine at the same place. Duh! Now where is that smilie beating his head on the wall? Or better yet, the one bashing his palm up against his forehead?

 I probably better go finish his XK140 for the imminent Concours before I ask to check the Anglia though.

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Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)

Efoperfect-

Look back 47 postings or so and you'll see I suggested that you make a clay impression of the original timing cover and transfer the marks . I'm not saying I told you so I'm just saying...............Hmmmm, maybe I am saying I told you so in some round-about way.  Anyway, Would the clay impression idea help at this point? 

By the way, that's good news and congrats!

LCJUTILA 

I suspect it would. It's been a very long time since I had that cover and I don't remember the layout. May or may not be practical to get an impression but I'm sure I can find some way to locate the point.

Yep, your suggestion back then should have triggered to memory of that local Anglia. Funny though that we were discussing something entirely different, the up coming Jaguar car show, when that just suddenly popped into my mind.

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Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)