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Tool question: Engine bore gauge


jgerock
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For those of you who tear into engines on a regular basis, what brand and type of bore measurement device do you use? I know there is a wide price range on tools, but would like something that the ShadeTree mechanic can use and maybe loan it out to fellow club members.

I borrowed a "snap" gauge and used digital calipers when I re-did the top end of my 73 in 2008. Note I took many measuresments and did a "just to get by" job since the engine didn't have too many miles since the previous rebuild.

boresizecheck.jpg

I was going to borrow a co-worker's tools this week, but he is on vacation, so I'm thinking of buying a telescoping bore gauge from either Sears or Eastwood.

Any thoughts about this one? Any and all advice appreciated.

http://www.eastwood.com/dial-type-cylinder-bore-gauge-kit-2-6in-range.html

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No offence meant but you dont need one. Your machine shop will remeasure no matter what you say. And with higher quality equipment.If they wont do it for free find another shop.......Machine shops seem to know the spots for wear and how to read the bore....

I agree with your comments, but for a quick measurement of cylinder bores and/or old grubby pistons, I'm not in a position to haul the block & pistons to a machine shop.

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The Eastwood gauge is pretty cheap and will work for the most part if all you want is an idea of where you are with the engine. The suggestion that your machine shop will measure with much better equipment is absolutely true as well. At this point I use mine more to figure out if an engine has been bored before or how much wear is in it. Still very handy.

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heh- you beat me to it.

But an inside mic takes a little bit of practice to use,

and if you're not careful, you can score a bore.

I hate those inside snap gauges, but you can get

a 'has it already been bored?' indication from them.

Which saves cleaning up a 90.10 mm block.

t

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It is really not worth buying cheap "precision" tools. I have found good prices on quality precision tools at www.tooldiscounter.com. There is a nice Mitutoyo 511-166 Dial Bore Gauge there for just over $300. In other news, www.emaxaction.com distributes CDI torque wrenches (a Snap-On "value" brand). I bought two different ones there and am very happy with them. They have a 1/2" drive, 20-150 ft. lb click type (CDI 1503MFRMH) for $175, plus a 10% Internet discount.

Fred 74tii

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Measure the bore, what for?

The way I've always seen done and have fit pistons in bores, especially "old grubby" pistons is to remove the rings, invert and slide the piston in the bore with a long feeler gauge 90 degrees from the pin axis. It's the skirt to bore clearance anyway. If the clearance is outside the service clearance, your outa luck unless you want a noisy engine that happens to run at high rpm.

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Jim - you are right about the piston skirt to bore clearance.

But until I either measure the I.D. of the bore, O.D. of the piston skirt or scrub the carbon off the piston top I have no clue what size pistons are in the spare engine.

I used the last method today (89.47mm) and will measure the clearance as the project advances.

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Jim - you are right about the piston skirt to bore clearance.

But until I either measure the I.D. of the bore, O.D. of the piston skirt or scrub the carbon off the piston top I have no clue what size pistons are in the spare engine.

I used the last method today (89.47mm) and will measure the clearance as the project advances.

I think his pistons were out of the hole already and why not if the engine is being torn down.

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Measure the bore, what for?

The way I've always seen done and have fit pistons in bores, especially "old grubby" pistons is to remove the rings, invert and slide the piston in the bore with a long feeler gauge 90 degrees from the pin axis. It's the skirt to bore clearance anyway. If the clearance is outside the service clearance, your outa luck unless you want a noisy engine that happens to run at high rpm.

Lot's of reasons.

Measure for wear top to bottom, out of round. There are plenty of reasons to measure the bore. As well as if you measure your way and it

s out of spec, you'd measure to see where to go from there.

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Measure the bore, what for?

The way I've always seen done and have fit pistons in bores, especially "old grubby" pistons is to remove the rings, invert and slide the piston in the bore with a long feeler gauge 90 degrees from the pin axis. It's the skirt to bore clearance anyway. If the clearance is outside the service clearance, your outa luck unless you want a noisy engine that happens to run at high rpm.

Lot's of reasons.

Measure for wear top to bottom, out of round. There are plenty of reasons to measure the bore. As well as if you measure your way and it

s out of spec, you'd measure to see where to go from there.

Experienced mechanics know the wear is in the top 1-2 inches below where the top ring stops travel. If it is out in this area there is no need to be mucking around in the other areas.

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Experienced mechanics know the wear is in the top 1-2 inches below where the top ring stops travel. If it is out in this area there is no need to be mucking around in the other areas.

Actually experienced mechanics know you don't just measure the top. The majority of the time the bore wear is in the top but there are issues to check farther down as well. But nice try. Especially when dealing with older engines. If you're not thorough you mind as well not even do the job.

A good example is measure the whole bore on one engine bored with a torque plate vs. one without. It can be very important on some engines, especially where the bore isn't supported at the bottom.

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