What do you think of this big end journal?

Peteyoung75 · 2025-12-24T00:07:41-0700

Hi,
Following posts I made about 88 cranks a while ago I’ve found what seems to be a fairly low mileage crank (relatively). It’s been sat inside a seized engine for decades I think.
I’ve measured the journals and they are bang on 1.5
The machining inside the crank pins is pretty smooth
The journals look horrible as they are stained from being idle in all sorts of conditions for years but I can’t feel any surface defects.
I’d like to keep as much material in the crank pins as possible.
What are peoples thoughts? I’ll probably send it off for magnaflux and polish/grind but would be good to hear what others make of it as I’m relatively inexperienced.
Cheers,
Pete

What do you think of this big end journal?

Fast Eddie · 2025-12-24T02:43:31-0700

Don’t grind it unless it needs it. Clean and polish the journals then measure them accurately (or get them measured by a pro).

Peteyoung75 · 2025-12-24T03:02:17-0700

Fast Eddie said:
Don’t grind it unless it needs it. Clean and polish the journals then measure them accurately (or get them measured by a pro).

Thats my thinking too. Any recommendations on how to polish them?
I’ve measured them with a mic. I have gauge blocks and an indicator mic so I’m confident in my measurements.

concours · 2025-12-24T03:31:33-0700

Peteyoung75 said:
Thats my thinking too. Any recommendations on how to polish them?
I’ve measured them with a mic. I have gauge blocks and an indicator mic so I’m confident in my measurements.

What is an indicator mic?

Fast Eddie · 2025-12-24T03:32:48-0700

Peteyoung75 said:
Thats my thinking too. Any recommendations on how to polish them?

A good scrub with brake cleaner followed by a polish with very fine Emery cloth.

robs ss · 2025-12-24T03:47:36-0700

concours said:
What is an indicator mic?

I think it just means a mic with an analogue dial instead of the old, conventional vernier scale.
I don't think that they'd be more accurate at all.

...oh, and bah humbug to you all!

Peteyoung75 · 2025-12-24T05:21:31-0700

Indicating micrometers have a spring loaded moveable anvil and a built in dial guage. You can set up gauge blocks to the nominal dimension you want to measure and zero the micrometer on the gauge blocks, press a plunger in to move the anvil away from the gauge blocks, move the micrometer to what you’re measuring and release the anvil and read off the variation in dimension from the gauge blocks using the dial gauge. Same as a comparator dial gauge on a stand. Really accurate as using gauge blocks means you have standards bang on the dimension you want to measure.

Peteyoung75 · 2025-12-24T05:24:23-0700

Fast Eddie said:
A good scrub with brake cleaner followed by a polish with very fine Emery cloth.

Thanks. Any tips on removing an even amount across and around the journal?

Peteyoung75 · 2025-12-24T05:25:55-0700

robs ss said:
I think it just means a mic with an analogue dial instead of the old, conventional vernier scale.
I don't think that they'd be more accurate at all.

...oh, and bah humbug to you all!

Nope

marshg246 · 2025-12-24T07:59:23-0700

Peteyoung75 said:
Thanks. Any tips on removing an even amount across and around the journal?

Cut a strip of 1000 grit paper a little narrower than the journal and the full length of the paper. Using some thin oil (maybe WD40), wrap it around then go round and round. If 1000 doesn't clean it, you could try 800, but the goal is not metal removal, but cleaning and polishing.

Since you can't feel anything, if you're sure they are on size, you probably don't need to do more than clean and polish.

Peteyoung75 · 2025-12-24T08:06:38-0700

marshg246 said:
Cut a strip of 1000 grit paper a little narrower than the journal and the full length of the paper. Using some thin oil (maybe WD40), wrap it around that go round and round. If 1000 doesn't clean it, you could try 800, but the goal is not metal removal, but cleaning and polishing.

Since you can't feel anything, if you're sure they are on size, you probably don't need to do more than clean and polish.

Thanks, I’ll give that a go

Shelby-Right · 2025-12-24T10:11:08-0700

Get it crack tested, just use a zeroed mic on an oil free surface, it doesn't look too good to me, looking at the Pic, but maybe needs to have an automachinist look at it. Proper polish.

What do you think of this big end journal?

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