Topic: Engine re-bore measurement tool ????

[Toxic]

So I am looking for a bore gauge to measure the bore on my cylinders to see if I need a re-bore.  What are you guys using to get an accurate measure.

I found a dial bore gauge from Eastwood but I am questioning the accuracy of a dial gauge.
As opposed to a digital gauge.

I know I need something accurate to 4 decimal places.

I have a digital micrometer but that will only get me a reading on the top and bottom of the cyl.

Does anyone have any useful links?

thanks Gary

[MRieck]

Mitutoyo are good. I use an older SPI. You will also need a decent mic to index the bore gauge.

[Toxic]

ahh so I learned for my one time use I am better off to take the cly to a machine shop and pay them to do it.  Those guages are expensive.  And there is no point in getting a cheap one.

good to know

[Bodi]

Direct reading dial gauges are not accurate enough. You can get an idea of round vs oval holes but not exact measurements.
The accurate way is using bore gauges, you insert the gauge and lock it so it stays the length equal to your bore, then measure it with a micrometer.
The gauges each adjust to maybe a 1/4" to 1/2" range and most micrometers have only a one inch range. The gauges come in sets but I suppose you could buy just the one you would need.
There are also horridly expensive accurate direct measuring bore gauges.
Unless you have a machine shop there's no point in owning this stuff, really. Have an expert measure the bores. This will cost a pile less than buying the tooling to do it yourself accurately.

[bryanj]

I Bisagree Bodi I have a dial bore gauge that goes down to 1/10 thou increments. Set an accurate mic to the bore set the bore gauge to zero using the mic then use the bore gauge in the hole, If you set the dial to zero when the small needle is at 1-2mm you can then get accurate hole readings as below zero

[MRieck]

I Bisagree Bodi I have a dial bore gauge that goes down to 1/10 thou increments. Set an accurate mic to the bore set the bore gauge to zero using the mic then use the bore gauge in the hole, If you set the dial to zero when the small needle is at 1-2mm you can then get accurate hole readings as below zero

That's how I have always done it. My gauge goes to tenths too