cylinder bore gage equipment

[stinkity stoink]

I am trying to measure up the cylinders on a small block chevy I bought. I just need to see if I should just re ring the motor or bring it to a machine shop.
I have a 3"-4" micrometer to set the gage . I am just unsure as to what dial bore gage to purchase. I am like everyone else and can't justify spending the big money on a gage I will only use a handful of times.

I am not building a race motor or flying to the moon.

I see import brands , fowler (also import). Not sure what to buy.

I guess my budget is about $150.00
Thanks...

 

[billybek]

Why not buy a telescopic gauge set?
You already have the 3-4 micrometer that you will most likely measure the pistons O/D with, using a T-Gauge will use the same measuring device to find the I/D and determine your clearance.
It is a little more work than using a bore gauge and will require many measurements to determine if your cylinders are out of round.
I have a Mitutoyo bore gauge at work and it really visually demonstrates when you are out of round but the cost of it new is beyond your price point.
Perhaps someone local would lend you one.

 

[Mmfh]

If you want to save some money because this is a once in awhile thing, what about just buying your 4" mic and snap gauges.

Use the snap gauge to get the size of the cylinder, than mic the snap gauge to see what size the cylinder is.

If you feel you still want a bore gauge, I like my Sunnen gauges the best as they are accurate and have a setting fixture. Setting it is very quick and easy with the fixture.

I also like my Mitutoyo bore gauge, you use the mic to set it which takes a minute but its also very good quality and does a great job.

Here is one like mine, http://www.ebay.com/itm/Mitutoyo-511-163-Dial-Bore-Gage-0-7-to-1-4-Stem-Depth-4-/330713434868?pt=LH_DefaultDomain_0&hash=item4d000e8af4#ht_2332wt_1344

Those two brands are I think the best, shop around and you should be able to find the Mitutoyo for the price you want to spend. Want to save some money, http://www.ebay.com/itm/6-PC-TELESCOPE-PRECISION-MACHINIST-T-BORE-TELESCOPIC-GAGE-GAUGE-TOOL-SET-GAGES-/290676572778?pt=LH_DefaultDomain_0&hash=item43adac826a#ht_1100wt_1344
These will work just fine with a 4 to 5" mic for a 350, 4" bore. Which engine do you have?

Mm

 

[Fat50]

I use a snap gage and micrometers.
I just looked for a stock picture to show one and cant find a pic? Now i'm wondering if I've been calling this thing a snap gage for years and it's not....
I'll snap a pic and post what I use.

 

[Fat50]

This is what I use. This one covers 3.5" to 6". The rightside of the T slides into the leftside and you can lock it with the knurlled knob at the bottom. I find them at garage sales real cheap.

Check your local Sears, this one says Craftsman on it.

 

[Mmfh]

I use a snap gage and micrometers.
I just looked for a stock picture to show one and cant find a pic? Now i'm wondering if I've been calling this thing a snap gage for years and it's not....
I'll snap a pic and post what I use.

I have always called them snap gauges too. Actually after looking around a little I think they are called Telescoping gauges.

Learn something new everyday!

Mm

 

[bgott]

Does the block have a ridge at the top of the cylinders? High mileage carburated engines will usually have a ridge due to poor fuel control when cold. Fuel injected engines don't dump as much fuel so they don't usually wash down he oil and taper the cylinders. If you don't have a ridge and the pistons are in decent shape I'd just make a couple of passes down the cylinders with a *********** hone and do a re-ring job.

 

[DCarr]

a 3-4" gage micrometer wont measure over 4.000 so a 4" - 5" is needed. I have a Starret set up including their micrometer. Not a cheap set up to buy new, I got mine used for 302 $ from a machine shop auction.

 

[brownbagg]

sounds like an harbor freight run

 

[A_Pmech]

The shape of the hone pattern wear and the appearance of a ridge at TDC will make the bore / no bore decision for you. No need to measure, you can make the bore / no bore determination from 6' away if your eyesight is good.

As the others mentioned, if you feel the need to take a measurement, use a telescoping gage.

 

[stinkity stoink]

Thanks for the replys. I thought about the snap gages ,but if you dont have them set the same every time I think I will get different readings. That was why I was looking at the gage. I think I will get better readings.

By the way it's a chevy 305

 

[coldfusion21]

With a telescoping gauge you should be able to repeat your measurements within a thou or so pretty easily. A bore mic is obviously going to be more accurate, how accurate depends on how your setting it, kind of like the telescoping gauge.

I dislike cheap measuring instruments so I can't recommend a cheap anything even for a one time use. If your honestly never going to use it again have a shop inspect the engine.

 

[Murphy4570]

Snap gauges work if you know how to use them. There is a learning curve to them, as well as to micrometers. Measure more than once to ascertain the correct reading. Not a big deal.

 

[Shadowdog500]

A snap gauge will work.
Here is the proper way to use one.

 

[BillK]

ss,
My rule of thumb is that if you can catch the ridge at the top of the cylinder with your fingernail, it is probably at least .008" and the cylinders need to be bored. If there is no ridge, you might get away with rings. As much as I am a die hard Chevy guy, I hate to say it but there are not many small blocks with more than 70-80 k miles on them that dont need boring

 

[SGKent]

guys - I used to bore and hone engines for a living during the late 70's and early 80's. Fleet and racing. The two measurements most important are the bore near the top and bottom of the piston travel and also the piston width just below the wrist pins. Check the skirts and top for cracks. You also have to measure the ring land clearance to see if they are worn over spec. While I have gauges at home purchased online, none are really accurate enough to measure a bore. It is the nature of the bore and its ability to expand when pressure is put on it. How you hold the gauge in your hands will influence the readings enough to throw you off. My suggestion is if this is a one time event take it to the machinist, have them measure it and see what they say. A couple of passes with a hone will cross hatch it and maybe straighten the bore a little. Better than a bottle brush. If you are doing a dirt cheap job, just want to do it then you can bottle brush it maybe 4 strokes to get a 45+/- degree cross hatch and throw new rings on it - be sure to gap it. If you are burning oil or have blow-by be sure to check the valve guides too as they also can cause issues. Just keep in mind that in general used pistons over 100,000 miles are almost always worn enough to be false economy to keep them. Beware though - I took an engine to a machine shop in San Diego about 1986 as my friend's shop in San Bernadino was backed up three weeks. The shop in San Diego came highly recommended yet when they were done boring and honing my block, the clearances were worse than the worn out set I brought them except I was .020 over now. We ended up going to the next size over as I was pissed off big time. When I tell someone I want .0025 clearance that is what the gauge must say - not .0039.

Be sure to mark each piston and put it back in the same hole. Do not wire brush the sides. Use carb cleaner if the pistons are still together with the rods. Wiggle the rods to see if the wrist pins are worn. If you can feel it then wiggle then it is too much. Plasti-gauge the rods and mains. Don't trust the label on the box.

 

[billybek]

Not vouching for the quality or the accuracy of this bore gauge, but I stumbled across this the other day and thought about this thread... thhttp://www.eastwood.com/dial-type-cylinder-bore-gauge-kit-2-6in-range.htmlis

 

[stafford]

If it's gotta ridge, bore it, then you have a new motor again. It really doesn't cost that much more, you're already right there. Re-ring will not hold up like a freshly bored engine.
look at http://www.northernautoparts.com/ you can get a master kit on there reasonably, find a good machinist let him mike it, clean it and bore it. Money well spent. If you feel the need to you can upgrade some of the parts in the kit for very reasonable prices. Don't let anyone tell you not to buy that cheap assed kit, because it ain't no good because it doesn't cost 500.00 there's a heckuva lot of them out there running around.

 

[Rixter58]

guys - I used to bore and hone engines for a living during the late 70's and early 80's. Fleet and racing. The two measurements most important are the bore near the top and bottom of the piston travel and also the piston width just below the wrist pins. Check the skirts and top for cracks. You also have to measure the ring land clearance to see if they are worn over spec. While I have gauges at home purchased online, none are really accurate enough to measure a bore. It is the nature of the bore and its ability to expand when pressure is put on it. How you hold the gauge in your hands will influence the readings enough to throw you off. My suggestion is if this is a one time event take it to the machinist, have them measure it and see what they say. A couple of passes with a hone will cross hatch it and maybe straighten the bore a little. Better than a bottle brush. If you are doing a dirt cheap job, just want to do it then you can bottle brush it maybe 4 strokes to get a 45+/- degree cross hatch and throw new rings on it - be sure to gap it. If you are burning oil or have blow-by be sure to check the valve guides too as they also can cause issues. Just keep in mind that in general used pistons over 100,000 miles are almost always worn enough to be false economy to keep them. Beware though - I took an engine to a machine shop in San Diego about 1986 as my friend's shop in San Bernadino was backed up three weeks. The shop in San Diego came highly recommended yet when they were done boring and honing my block, the clearances were worse than the worn out set I brought them except I was .020 over now. We ended up going to the next size over as I was pissed off big time. When I tell someone I want .0025 clearance that is what the gauge must say - not .0039.

Be sure to mark each piston and put it back in the same hole. Do not wire brush the sides. Use carb cleaner if the pistons are still together with the rods. Wiggle the rods to see if the wrist pins are worn. If you can feel it then wiggle then it is too much. Plasti-gauge the rods and mains. Don't trust the label on the box.

All very good advice!

 

[Zeke]

Ever since I saw someone use a multi-point bore gauge, I've looked for that method. I'm not much of a machinist, but they just make sense. I have a set of telescoping gauges and I don't trust my measurements.

Like these:

 

[SGKent]

My experience is the lower one is not precise enough to bore a cylinder correctly but will give you an idea if you are going to need to bore it over size. The top one must have special calibration, I don't know how you would test it unless you had special standards.

I agree that in general if you can feel a ridge it needs boring but I also understand that many times a new cross hatch and re-ringing will get you another 60,000 down the road on a tight budget. The ridge has to be honed off / removed or you will crack the top ring and/or ring land.

 

[stinkity stoink]

Well . I tore it down and got a cheapo dial bore gauge.

I am going to get the block bored out. I tried to just clean it up and put a cross hatch in ,but the ring land up top still needs more. I feel if I keep going I could just screw up the cylinders so I am just going to punch it out to 30 over.

I am going to buy a master rebuild kit from engine tech. It is a little over $500 for my motor (roller cam) . I just need to figure out what main and rod bearings to order. I see stampings on mine ,but nothing that makes sense (not that I have done this before). I figure I would go with the size I have in there now (but new) than plastigauge and see how I am . does this sound about right.
I am bringing the block to the machine shop to do the cylinders, cam bearings , freeze plugs, clean the block and put the pistons on the rods.
The more I look at this it might not be worth it to do all this and just by a reman engine for about $1800.00

 

[Zeke]

I don't see where you'll get the satisfaction out of buying a reman.

Back to the gauges, if the multi point is not a good tool, how do you know that you're getting a true measurement to less than a thou when all you are doing is wiggling the telescoping gauge around to the point you think you found the widest spot?

The thing always gets stuck somewhere and I loosen the dial a bit and then it's all sloppy again. Rinse and repeat ad nauseum.

 

[stinkity stoink]

I put the dial bore in . Than point it to the bottom than the top. The point that it is the smallest is the bore size. Not sure if that is the right way or not .

My cylinders are not egg shaped ,but are out a few thousand. I set the dial bore with my micrometer that I measured the pistons with.

I understand the satisfaction of doing it myself, but I always get myself in trouble with some projects that way

 

[Zeke]

I guess you could set the inside mic with the outside mic and then use a feeler gauge to try and find the clearance. Just the transferring of measurements seems error prone.

 

[coldfusion21]

those multi point bore mics are nice, and can be used down to a few tenths but are hard to use accurately with a bore that is out of round, or rather hard to use to check to make sure a bore isnt out of round. A single point tool will allow you to take many measurements and determine size and roundness.

Even better a true bore gauge will have a dial and allow you to visually see the high and low spots.