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Measuring a cylinder wall score


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Yes it would. A experienced mechanic can accurately measure a cylinder using a bore gauge or inside mike. An inexperienced user has trouble keeping the gauge 'straight' that is at right angles to the cyl wall. One way to help is to take one of the piston rings removed from a piston removed from the engine. Place it inside the cyl. Now take the piston and turn it upside down and push the ring into the bore. Using the ring for reference now measure with the gauge. Do this in at least 3 places, directly under the ridge, at the bottom of the ring wear area and in between the 2. This also a good way to measure the bore. Place the ring where you want it. Then use a feeler gauge to measure the end gap of the ring. Do this in at least 3 places. First tho make sure the bore is clean and carbon free.

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You guys are not answering his question. He isn't asking how to measure his bore, he is asking if it is possible to measure the depth of the score mark(s) in his cylinder walls to determine if an overbore will clean it up, or if he needs a new (different) block.

 

There MUST be a way to measure this, but I don't know what that might be.

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416oj-X4vHL._SS500_.jpg

 

http://www.amazon.com/Precision-Dial-Bo ... 216&sr=1-9

 

Sorry man, I don't think there is an easy way around one of these, or handing it over to a pro. You are talking about thousands of an inch, not many backyard tricks that get that precise. You could use the bore gauge to measure the thickness not in the score, and then drop the gauge into the deepest part of the score and getting a measurement. That's the best I can tell ya.

 

Might be also one of those things where the machinist might just have to punch it out in steps until it goes away.

 

Rob L.

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don't know if it would work or not, but I would use a dial indicator with a small point and attempt to measure the depth of the score depth as compared to the "normal" cylinder wall. You should see the dial move from "zero" as you cross the score.

 

The other thing to use is your finger nail around the score and a a fealer guage to compare the score to with your nail. Use a .020 or .030 feeler guage and see how it feels compared to your score in the cylinder.

 

Above are just my thoughts. YMMV.

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You need to find an inside micrometer with pointed anvils or a spring caliper. Measure from outside the score, then inside. The difference will be the depth of your score.

 

Doing a quick search i found some inside spring calipers that should work well & get you an idea of how bad it is, this will not be terribly accurate, but should be enough for you to know if it's still usable...

 

http://www.mcmaster.com/#spring-calipers/=92me03

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If the score isn't big enough to measure don't worry about it.

 

I can feel it with my finger through a rag, and I can definitely get my fingernail in it.

 

You need to find an inside micrometer with pointed anvils or a spring caliper. Measure from outside the score, then inside. The difference will be the depth of your score.

 

Doing a quick search i found some inside spring calipers that should work well & get you an idea of how bad it is, this will not be terribly accurate, but should be enough for you to know if it's still usable...

 

http://www.mcmaster.com/#spring-calipers/=92me03

 

The spring caliper might work, but I'm a little confused as to how you actually get a reading off of it.

 

This might work, eh?

http://www.google.com/products/catalog? ... 8gIwBzgA#p

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Are you talking about the upper ring ridge where the piston stops at its uppermost travel, or are you talking about a linear gouge in the cylinder wall that goes top to bottom? If it is a top to bottom gouge, or score, then youll most likely need a machinist to try to measure it and with his experience know if it can be machined out or not by boring the cylinders. Same goes for the upper ridge... if the cylinder has a lot of wear, it is most likely tapered due to the most wear being in the upper part of the cylinder. Assuming taper is not out of spec, you could use a ridge reamer to remove the ridge, and throw new rings in it. But I still think an experienced machinist will have to make the determination either way.

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your upper photo looks to be in excess of .030, the lower... maybe .010-.020...

 

if you don't have any actual tools to measure the inside use some feeler gauges pressed into the ridge. this won't be very accurate at all but you can probably get a ballpark figure within .010-.020. and you won't be measuring the width of the bore, only the difference between the ridge and non ridge.

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What about lightly buffing the cylinder wall with steel wool, then applying a light coat of oil ... not motor oil, but thin stuff, like 3-In-1 oil ... then take a glob of fast set epoxy or J-B Weld and press it into the score and hold it 'til it takes a set?

 

Then pull it off, allow it to harden, and then you'll have a ridge to measure the height of rather than a groove to measure the depth of.

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Suggestion. Take a piston ring and push it into the bore. Place it over the worst looking spot. With a light under the cylinder you can see the score better. Find something you can slip under the ring and in the score. Piano wire would be great but not many people has access. Cut a 1/4 wide strip off one side of a .005 feeler gauge. See if it will fit. Don't want to cut up a feeler gauge? Use a strip of paper. Thread will do. Just get something that will fit snug. Then you can remove it and measure it. If the score is .005 or less, don't worry about it. Over that, bore it.

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What about lightly buffing the cylinder wall with steel wool, then applying a light coat of oil ... not motor oil, but thin stuff, like 3-In-1 oil ... then take a glob of fast set epoxy or J-B Weld and press it into the score and hold it 'til it takes a set?

 

Then pull it off, allow it to harden, and then you'll have a ridge to measure the height of rather than a groove to measure the depth of.

 

I was thinking maybe something similar to that. I can give that a try, the plan tomorrow is to drop the pan, and get the pistons out so I have access to the entire cylinder.

 

Suggestion. Take a piston ring and push it into the bore. Place it over the worst looking spot. With a light under the cylinder you can see the score better. Find something you can slip under the ring and in the score. Piano wire would be great but not many people has access. Cut a 1/4 wide strip off one side of a .005 feeler gauge. See if it will fit. Don't want to cut up a feeler gauge? Use a strip of paper. Thread will do. Just get something that will fit snug. Then you can remove it and measure it. If the score is .005 or less, don't worry about it. Over that, bore it.

 

There is no way in hell it's even close to .005. If I reuse this block, it will be bored out. I'm just trying to figure out if it's even too deep to bore out. I'm still looking for a different block, in case it's not worth it to use my current one, and it'll be a few days before this one comes out anyway. Trans will probably be coming out Sunday.

 

your upper photo looks to be in excess of .030, the lower... maybe .010-.020...

 

if you don't have any actual tools to measure the inside use some feeler gauges pressed into the ridge. this won't be very accurate at all but you can probably get a ballpark figure within .010-.020. and you won't be measuring the width of the bore, only the difference between the ridge and non ridge.

 

Ridge isn't really the issue, I'm sure a bore would take care of that. My main concern is the giant vertical gouge.

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This is the big one you can feel in one spot

62242_442837569059_762289059_5056361_2274598_n.jpg

 

These ones you can't feel

60342_442837744059_762289059_5056365_1959574_n.jpg

Your worried about those little things??? I'm betting they aren't any more more .005-.007 deep. Boring that cylinder .020 should be more than enough to clean um up.

Of course that depends on how much wear the cylinder has. The piston ridge looks pretty deep so if it's worn any more than .010 over you'll probably need to go .030 to get the scratches out and to make sure the cylinders are straight and round again.

 

Good luck with it. :thumbsup:

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