CJ love

[turbohunter]

BTW
On the subject of main bearings. When you go to buy them it is a bit confusing to the uninitiated. There is no Federal Mogul anymore. They are now branded as Speed Pro. Aaaaand Speed Pro is also the name of inexpensive parts. If you don’t know that FM became SP it can be confusing.
But such is the way of today’s corporate bs.
This has been a public service announcement.

[turbohunter]

Spent Sunday measuring mains.
I’m finding that I’m not liking my bore gauge. I of course bought a Summit brand about a year or so ago and am finding it’s a bit hurky jerky and the measurements are not what I think they should be (probably me).
I’m going to have to spend a lot more time here. The learning curve is steep.

Just went out a used a little WD40 on the action and it seemed to smooth out.

[turbohunter]

Think I’m getting a new bore gauge.
I can’t duplicate any numbers. I’m working on my technique which at first was part of it but I’ve been at it now for a couple days and I can’t get the same measurements from one pass to the next. I think I’ll invest in a better tool and see if it’s me or my gauge.

[RustyCrankshaft]

How much are the readings off and what brand bore gauge? Even a cheap (like a Fowler or other import) dial bore gauge should be fairly repeatable but not maybe to a half tho like a good bore gauge will.

If you're off a couple tho every time it might be technique.

[turbohunter]

Just went and looked. No name on the tool but the instructions say Eastwood.
It’s some ummm, you know deal. Anyway I’m going to invest in a good one and keep working on my technique.
I have a solid .002 via caliper but I’m not going to trust that. I was able to get a .002 reading once on #1. But not twice and not on another. Came close but horshoes, hand grenades and atom bombs are good close.
Oh forgot to answer how much off. As much as .009.

[Barry_R]

BTW
On the subject of main bearings. When you go to buy them it is a bit confusing to the uninitiated. There is no Federal Mogul anymore. They are now branded as Speed Pro. Aaaaand Speed Pro is also the name of inexpensive parts. If you don’t know that FM became SP it can be confusing.

Actually that info is incorrect.  Federal-Mogul acquired Sealed Power and Speed-Pro in +/-1996.  Speed-Pro was/is the high performance brand for the Sealed Power product line and has been so since somewhere in the 1970s.  Standard replacement ent bearings are manufactured, packaged and sold under the Federal-Mogul brand.  The high performance engine bearing line manufactured by Federal-Mogul has been sold under the Speed-Pro brand since +/- 1998.

I know this because.......I am one of the guys that "did it"....

[turbohunter]

Why incorrect? You can’t buy a FM 125M, it’s Speed Pro or Sealed Power.
But thanks for clearing it up.

[jayb]

If you want a good dial bore gauge, figure on spending some dough, and get one that measures in tenths of a thousandth.  I've got a Mitutoyo that I'm very happy with.  I started off with a Fowler, and didn't get reliable results.

https://www.ebay.com/itm/MITUTOYO-511-753-2-0-6-0-Total-Range-0001-Graduation-Dial-Bore-Gage/273768609822?hash=item3fbde1781e:g:7d0AAOSweTlcj~dF

[blykins]

Two things I can see happening here:

1.  On some of the budget bore mics, there's a little spanner nut on the very end.  It's shaped like a disc and has two little holes on it.  I've seen those little nuts loosen up and do screwy things to the results.

2.  The jist of operation is that you measure the OD of the journal with an outside mic and then set your bore gauge to the mic.  When you set the bore gauge to the mic, you have two axes of movement there and you need to zero both of them.  So you get the anvil and plunger inside the outside mic, hold it still and move it up and down until you find the shortest distance between the micrometer anvils, then zero your dial.  Also, you can "twist" the bore gauge in the other plane of rotation and you will need to zero it there too. 

If you've ever watched a machinist or engine builder check clearances, you'll see them insert the bore gauge and then give it "the wiggle".  The wiggle is finding the shortest distance, or the point where the bore mic is perfectly perpendicular to the part they're measuring, whether it's a cylinder or a bearing housing diameter.  I guess what I'm trying to say is that you can't just put the bore gauge in and get the right number, you have to find the shortest distance.

If you watch this video, you'll see me check it.  I do it a lot slower than normal because I'm looking through the camera to see if it's showing, but it shows the movement. 

https://www.youtube.com/watch?v=TRUSzF4fCt8

[turbohunter]

Thanks guys
Yes I’ve got he technique down and have watched guys do it so I’m getting pretty sure of what I’m doing.
Brent I’ll look into your comment on the end nut that sounds promising.
The one thing I’ve learned so far is that you need tools that make YOU the only factor that can change.
So investing I will go.

[Barry_R]

Why incorrect? You can’t buy a FM 125M, it’s Speed Pro or Sealed Power.
But thanks for clearing it up.

You could never buy a F-M branded 125M for the past 25 years.  Always been a Speed-Pro part.  At least since I sorted out the branding strategy in +/- 1996.

Now thats not true for Australia - or for the occasional packaging department F up - but those are separate subjects for another thread.

[blykins]

Thanks guys
Yes I’ve got he technique down and have watched guys do it so I’m getting pretty sure of what I’m doing.
Brent I’ll look into your comment on the end nut that sounds promising.
The one thing I’ve learned so far is that you need tools that make YOU the only factor that can change.
So investing I will go.

FWIW, I've got a $500 Mitutoyo bore mic (the one in the video) and I've got an $85 economy bore mic that I bought from MSC back in 1999.  They read exactly the same.  However, the Mitutoyo has a higher resolution. 

[turbohunter]

Why incorrect? You can’t buy a FM 125M, it’s Speed Pro or Sealed Power.
But thanks for clearing it up.

You could never buy a F-M branded 125M for the past 25 years.  Always been a Speed-Pro part.  At least since I sorted out the branding strategy in +/- 1996.

Now thats not true for Australia - or for the occasional packaging department F up - but those are separate subjects for another thread.

Interesting, thanks Barry.
Us guys that haven’t been doing this don’t have a clue. If you look in the dyno section for bearing brand names there are many FM 125Ms listed. That’s all my psa was meant for, as info for noobs.

[RustyCrankshaft]

Thanks guys
Yes I’ve got he technique down and have watched guys do it so I’m getting pretty sure of what I’m doing.
Brent I’ll look into your comment on the end nut that sounds promising.
The one thing I’ve learned so far is that you need tools that make YOU the only factor that can change.
So investing I will go.

FWIW, I've got a $500 Mitutoyo bore mic (the one in the video) and I've got an $85 economy bore mic that I bought from MSC back in 1999.  They read exactly the same.  However, the Mitutoyo has a higher resolution.

I think some of the import stuff from a good supplier like MSC can be ok as your experience shows. I've got some MSC and McMaster import tools I keep on the truck and have had good luck with a lot of it. But it can be a bit of a crapshoot with import stuff - I've had some real crap too.

I've got a Mitutoyo and a Brown and Sharpe dial bore gauges and you know what you're getting when you buy those (and the price tag that goes along with them).

[turbohunter]

I went for the Mitutoyo since everyone likes it.
But while I wait for it I decided to take apart the one I have and at least clean it.
It was readily apparent why it was unreliable. There was rust in the main shaft affecting the plunger. It was pretty filthy and the end was, shall we say, not quality.
So I cleaned and lubed it as well as run a file across that end.
It’s much better but still not consistent although the degree of inconsistency has diminished to 3 to 5 thousandths instead of 9. I think the fact that it is not graduated into the .0001 and the quality is just not there make it unusable for precise work.
Can’t wait to try it against the Mitutoyo.
I know you builders may have gone through this when you were wee little engine gurettes. But for us old guys that are just getting back into building/assembling engines again this could be useful. I’m going to keep documenting my mistakes as well as victories as a learning tool.
The lesson from this one is, don’t buy cheap precision tools.