Nick in crank journal, machine shop or??

[Sir Dodge alot]

Hello again & greetings, long time I have not consulted the masses of FCBO, I have a question(s) regarding the patient today.

I'm finally getting off my @$$ and doing a rebuild on this 1965/1966 Chrysler big block 361, have disassembled most of the block down to the crank/cam & the timing chain still being the final stragglers.

After turning the engine over with the pistons out of the way, I've nicked part of the journal with the connecting rods bolts.

Is this damage on the journal machine shop territory to get it regrinded to accept undersize bearings? Or can I just emery cloth this sort of damage?

And if so, what emery cloth "grit" can I use for this type of damage?

This engine being my first rebuild/project engine, I guess it's the first to receive crank damage also lol.

The singular scratch on the journal was not from me to my knowledge.

Enclosed are the photo(s) I have managed to take the best of my photography abilities,
The nick with the 3 gashes going across will catch my finger nail.
Thanks and looking forward to favourable responses, or bad news either way.

 

[MONC440]

If it was for my own use I would use a really good fine flat file then fine emery to smooth it out. I have done budget rebuilds that had worse. That being said for piece of mind if you have the time and money send it to the machine shop for a .010 turn.

 

[MONC440]

Also when you reassemble put some 3/8 hose on the rod bolts when you install the rods and pistons in the block to keep from nicking the crack again.

 

[Sir Dodge alot]

If it was for my own use I would use a really good fine flat file then fine emery to smooth it out. I have done budget rebuilds that had worse. That being said for piece of mind if you have the time and money send it to the machine shop for a .010 turn.

Appreciate the response, I'll make some time to take the crank to the machine shop if I doubt the damage.

Thank you.

 

[Sir Dodge alot]

Also when you reassemble put some 3/8 hose on the rod bolts when you install the rods and pistons in the block to keep from nicking the crack again.

That's the ironic thing, I knew about protecting the journals with fuel line over the connecting rods bolts. Figures I don't learn my lesson til bad something happens, go figure huh?

After the first piston I pulled out damaged the crank, I proceeded to put rubber fuel lines over the other connecting rod bolts; FACEPLAM.

 

[MONC440]

That's the ironic thing, I knew about protecting the journals with fuel line over the connecting rods bolts. Figures I don't learn my lesson til bad something happens, go figure huh?

Been there done that. It is easy to forget during disassembly.

 

[Sir Dodge alot]

Been there done that. It is easy to forget during disassembly.

Yes sir! Alright I guess I'm swinging down to the hardware store for some emery cloth.

 

[CBODY67]

What size are the connecting rod journals now? IF they are close to being .010" Undersize, putting standard bearings on them will not be good. So getting a "10/10" turn can be good, all things considered. Correct bearing clearances and all. To me, their current size would be more of a guide than just smoothing the nicks and putting "Std" bearings back in there.

Your judgment call.

Just some thoughts,
CBODY67

 

[Davea Lux]

Your shaft was showing some wear without the nicks. I would have it turned.

Dave

 

[Sir Dodge alot]

What size are the connecting rod journals now? IF they are close to being .010" Undersize, putting standard bearings on them will not be good. So getting a "10/10" turn can be good, all things considered. Correct bearing clearances and all. To me, their current size would be more of a guide than just smoothing the nicks and putting "Std" bearings back in there.

Your judgment call.

Just some thoughts,
CBODY67

According to the block machine stamping, the crank journals have been ground down 10 thousandths with undersized 10 thou bearings, I'm now considering the machine shop route and probably ground the journals down another 10 thou to get 20 thou undersize bearings.

I will confirm the bearing sizes once I have a caliper or a micrometer.

Thanks for your input I'm now considering getting the crank Turned.

 

[Sir Dodge alot]

Your shaft was showing some wear without the nicks. I would have it turned.

Dave

That's the plan if the weather holds up.
Machine shop time!

 

[Big_John]

According to the block machine stamping, the crank journals have been ground down 10 thousandths with undersized 10 thou bearings, I'm now considering the machine shop route and probably ground the journals down another 10 thou to get 20 thou undersize bearings.

I will confirm the bearing sizes once I have a caliper or a micrometer.

Thanks for your input I'm now considering getting the crank Turned.

View attachment 722758

That nick is easy to fix. As one very good engine builder once told me, it's now a nice pocket for oil. In other words, it will never hurt anything. If you did this putting it together, you take some fine emery cloth and cut a piece that fits the crank when wrapped around it. Then you get a leather shoe lace and wrap that around it and see-saw that so it spins the emery cloth.

That said, that crank needs polishing at minimum. The way to do this is to mic the crank and see how much wear there is. Calipers aren't accurate enough. The shop will do this and polish then mic again. I'd say it probably needs to be ground.

Don't go too much by the markings on the block. I've seen them to be correct and I've seen them wrong too. Then there's a lot that happens in 60 years and you never know what's been done.

 

[Sir Dodge alot]

That nick is easy to fix. As one very good engine builder once told me, it's now a nice pocket for oil. In other words, it will never hurt anything. If you did this putting it together, you take some fine emery cloth and cut a piece that fits the crank when wrapped around it. Then you get a leather shoe lace and wrap that around it and see-saw that so it spins the emery cloth.

That said, that crank needs polishing at minimum. The way to do this is to mic the crank and see how much wear there is. Calipers aren't accurate enough. The shop will do this and polish then mic again. I'd say it probably needs to be ground.

Don't go too much by the markings on the block. I've seen them to be correct and I've seen them wrong too. Then there's a lot that happens in 60 years and you never know what's been done.

I've happened to buy some 800/2000/3000 grit wet/dry sandpaper last night. I'll see if I can scrounge up some spare shoelaces.

As for the Micrometer, I'll have to source those.
Much obliged for the advice!

 

[volksworld]

320 wet or dry paper, wrap a strip around the journal ...I've always used cloth covered vacuum hose to wrap a loop around it for polishing but probably anything kinda clothesline sized should work....clean the hell out of the oil holes with the proper oil passage brushes...when in doubt bring it to the machine shop to have them mic it and get their opinion

 

[Sir Dodge alot]

320 wet or dry paper, wrap a strip around the journal ...I've always used cloth covered vacuum hose to wrap a loop around it for polishing but probably anything kinda clothesline sized should work....clean the hell out of the oil holes with the proper oil passage brushes...when in doubt bring it to the machine shop to have them mic it and get their opinion

Yes sir, to be honest the machine shop is the last place I'd like to go to, if I lose some oil pressure that's alright too, I intend to use some 15W-40 diesel oil once everything is said and done, I hope.

 

[CBODY67]

If the journals sling too much oil, it can overload the oil rings, which can then result in higher-than-needed oil consumption. Using thicker oil is not a good way to compensate.

 

[Sir Dodge alot]

Got around to getting some Micrometers and mechanical dial calipers, here's what I was able to measure the crank connecting rod journals.
The readings are:

Connecting rod journals #1 #2
2.370
Connecting rod journals #3 #4
2.370
Connecting rod journals #5 #6
2.370
Connecting rod journals #7 #8
2.370

The crank big end journals doesn't seem to be oblong so I guess that's good?

 

[Sir Dodge alot]

If the journals sling too much oil, it can overload the oil rings, which can then result in higher-than-needed oil consumption. Using thicker oil is not a good way to compensate.

OK, appreciate the advice sir.
If that's the case I'll be looking for a oil that is high on zinc, maybe not the same viscosity grade.

 

[Sir Dodge alot]

That nick is easy to fix. As one very good engine builder once told me, it's now a nice pocket for oil. In other words, it will never hurt anything. If you did this putting it together, you take some fine emery cloth and cut a piece that fits the crank when wrapped around it. Then you get a leather shoe lace and wrap that around it and see-saw that so it spins the emery cloth.

That said, that crank needs polishing at minimum. The way to do this is to mic the crank and see how much wear there is. Calipers aren't accurate enough. The shop will do this and polish then mic again. I'd say it probably needs to be ground.

Don't go too much by the markings on the block. I've seen them to be correct and I've seen them wrong too. Then there's a lot that happens in 60 years and you never know what's been done.

This is what you were talking about about right?
Grabbed some spare shoelace with the emery cloth, very therapeutic and tests your patience!

Used the 800 grit for about 5 minutes then swapped to 2000 grit. The nick is barely feelable with the finger nail.

 

[volksworld]

really shouldn't be doing that in the engine...should be doing that with the crank on an engine stand, followed by a thorough cleaning of all the passages...all the grit is going into the oil holes which connect the rod bearings to the main bearings...recipe for disaster