Gouged rod journal... How screwed am I?

[jonheese]

Okay, so I've been prepping a 3.2L to swap into my '90, and in doing the rod bearings on it, I accidentally gouged one of the rod journals with the nut of the rod bolt (it's a long ******** story)...

When I first saw it, after I stopped swearing and punching myself in the face, my initial reaction was denial. "Oh, it'll be fine, just put the bearing in, torque it all down, and don't worry about it."

Once I got over the denial, I realized that there is pretty much no way that it's going to run right like this. I'm fairly convinced that it's going to spin the bearing as soon as I start it, and then I'll be really screwed because I'll have to pull the engine again and I'll be back when I am now.

So then I started imagining that I could take some garnet/emery cloth and just smooth it down, but after I really thought that through, I realized that all that would accomplish is to take the journal out of round, and probably not even get rid of the "bump" itself...

So, I guess the point I'm at now is that I've got two options:

1. Take it to a machine shop and have them fix (regrind/polish?) the crank.

OR

2. Start over with another 3.2 and pull all of the new parts off this one. (I really don't want to do this, because of the $$$ and the fact that this motor only has 68k miles on it and looks really nice and clean inside, except for that one rod journal, obviously)

My questions are these: If I have a machine shop fix the crank, do I need to bring them the whole engine or just the crank? Will it have to be re-balanced afterwards? Do they have to regrind all of the rod journals or can they just do the bad one? I'm assuming I'll need oversized bearing(s) then, right?

Am I correct in assuming that fixing the crank (if possible) would be cheaper than going with option 2 and ditching this engine?

Any advice is greatly welcomed... None telling me that I'm an idiot though, as I've already told myself that over and over and over.

Regards,
Jon Heese

 

[SHO_91]

SHO cranks are tough - forged and surface hardened. However, a re-grind will weaken it. No matter if it's the whole crank or just that one journal. Me, I'd rather not have second thoughts when shifting at 7k rpm...

 

[jonheese]

SHO cranks are tough - forged and surface hardened. However, a re-grind will weaken it. No matter if it's the whole crank or just that one journal. Me, I'd rather not have second thoughts when shifting at 7k rpm...

So you're saying this engine is toast then?

Would it be ridiculous to suggest a crank transplant (+ re-balancing) from another 3.2?

Regards,
Jon Heese

 

[1993MTXSHO]

how bad is it? can you catch your nail in it? I have had some pretty nasty little nics in cranks that really worried me and so far so good. But remember if you replace the crank you have to replace the mains as well. What I did with mine was sent it to the machine shop had them micropolish it and I just ran it, but the nic in mine wasn't a big dent like it looks like yours might be. Also FWIW next time put rubber hose on the rod studs before you even start moving the rod up

 

[K-Dawg]

What an idi-

Pick up a crank off somebody for cheap and throw it in this engine.

 

[sho_ted]

polish it out and run it.

 

[jonheese]

how bad is it? can you catch your nail in it? I have had some pretty nasty little nics in cranks that really worried me and so far so good. But remember if you replace the crank you have to replace the mains as well. What I did with mine was sent it to the machine shop had them micropolish it and I just ran it, but the nic in mine wasn't a big dent like it looks like yours might be. Also FWIW next time put rubber hose on the rod studs before you even start moving the rod up

Hmm... Well, I don't have fingernails that extend past my fingertips (chronic nail-biter my whole life), so I can't check that, but it sure looks like it'd catch a fingernail to me.

Oh no, I practically always use rubber tubing on the bolts to protect the crank. Here's the long story of how this happened:

Originally, when torquing down the first set of rod bearings, I forgot to reset my torque wrench from whatever I had torqued last (absent-minded, too much multi-tasking) and I snapped off one of the rod bolts on #1.

So, after I got done swearing, I knocked out the broken rod bolt, got a few new (used) rod bolts off a forum member, and proceeded to pull one of them back into the rod end using a short section of aluminum pipe (to draw it in, since the rod cap is too deep to allow me to thread on the nut).

So I got the replacement rod bolt in, and I proceeded to put the rod cap back on, but the damn thing wouldn't go on more than a couple of threads... So I concluded that that rod bolt must have been bent, so I pulled the half-inserted rod cap back off, and proceeded to knock the rod bolt out, this time with an old nut partly threaded on (to protect the garbage rod bolt? I don't know)... Well, in my eagerness to get it out of there, I hit it one too many times with the (small) hammer, and the nut made contact with the rod journal...

<commence screaming and swearing fit>

So yeah, stupid, tired idiot mistake.

Regards,
Jon Heese

 

[jonheese]

What an idi-

Pick up a crank off somebody for cheap and throw it in this engine.

Do I need to have the engine rebalanced after I do that?

I suppose I'd need main bearings then right?

polish it out and run it.

Really? Is this something I should tackle myself (well-rested and clear-headed, of course), or do I have to pull the crank out and take it to a machine shop (of which there are precious few anywhere near my very small town)?

Regards,
Jon Heese

 

[GoofSHO]

I've done worse, used a scotchbright pad to smooth it out and ran it. Ran Strong and Hard for many thousand miles. ended up spinning a different bearing....otherwise it'd still be running.

just my .02
B

 

[Off Road SHO]

Those kind of marks cause a small crater effect that you'll be able to feel by scraping it lightly with a straight edge. If the straightedge hangs up there, you have a crater that needs to be taken down. Dimple inward are not too bad, ridges and craters are. Depending on the height of the ridge, you might be able to use crocus cloth and mineral spirits and take it down.

The .003" oil gap that every SHO egine has had, in my experience, will cushion up to about .0025" of an obstruction. After that, you'll get a "hot" spot in the bearing heat and get "flaking" on the insert, a very bad thing for bearing life.

Tom

 

[jonheese]

You guys have no idea how much better I feel after reading some of these replies...

The funny thing is that by the time I opened it back up this afternoon to take the pics, I was picturing this gigantically huge dent in the crank, and when I saw it again, I was like, "Oh. That doesn't look too bad, does it?"

It's funny how your imagination runs wild when it's just you alone in your head thinking bad thoughts.

Thanks again.

Regards,
Jon Heese

 

[jonheese]

Those kind of marks cause a small crater effect that you'll be able to feel by scraping it lightly with a straight edge. If the straightedge hangs up there, you have a crater that needs to be taken down. Dimple inward are not too bad, ridges and craters are. Depending on the height of the ridge, you might be able to use crocus cloth and mineral spirits and take it down.

The .003" oil gap that every SHO egine has had, in my experience, will cushion up to about .0025" of an obstruction. After that, you'll get a "hot" spot in the bearing heat and get "flaking" on the insert, a very bad thing for bearing life.

Tom

Aha! Now there's a scientific analysis I can get behind.

I will try the crocus cloth/mineral spirits route (very gently) and see if I can get my caliper on there and see how much "bump" I've got.

Thanks, Tom.

Regards,
Jon Heese

 

[jonheese]

One more question:

With the crocus cloth, should I do the shoelace-wrap method to ensure a (somewhat) even pass?

Any other tips as to the specific procedure? Thanks in advance.

Regards,
Jon Heese

 

[ycode90]

Hand polish reassemble beat it up you won't be any worse off even if it breaks.

 

[cfamilyfix]

I think if you take it down, you'll still get some good mileage out of it. Like alot have said, just make sure there are no sharp or jagged edges to catch on. Good luck.

 

[jonheese]

Hand polish reassemble beat it up you won't be any worse off even if it breaks.

Except for the time/effort spent putting this engine in the car, just to take it back out again to replace the crank (or the entire engine)...

I think if you take it down, you'll still get some good mileage out of it. Like alot have said, just make sure there are no sharp or jagged edges to catch on. Good luck.

Yup, that's my current plan, though I'm not 100% confident that I'll be able to take down the high spot without taking the journal out of round... Oh well, nothing ventured, nothing gained, right? I'm pretty sure it ain't gonna last very long in its current state, so I don't have much to lose.

Thanks.

Any advice on the procedure for polishing the journal? Should I go with something like this?:

Many guys have used a shoelace to hold the abrasive [crocus cloth] next to the journal. Wrap a strip around and then loop the lace around once completely but without crossing itself. You should then be able to alternately pull on the ends of the lace to rotate the abrasive strip. The key thing/idea here is to apply an even pressure so you don't take the journal out-of-round. Clean thoroughly.

Regards,
Jon Heese

 

[Off Road SHO]

Jon,

If you have determined that there is in fact a raised bump, I would go get a small file called a points file. They might have one at the auto parts store. They are only 1/4" wide and a very fine cut; they were used to file the contacts of the ignition points in old distibutors.

Take one small, light swipe with the file and then re-check with the straight-edge. If the straightedge still catches on a raised portion, take another stroke with the file. Just in case you're not clear, one pass with the file, (in the direction of rotation, not across) then re-check with a staightedge. As soon as you can no longer catch the raised portion with the straightedge, you can then polish the journal with an oil soaked piece of crocus cloth.

The cloth should be the same width as the bearing surface of the journal and about 12-15" long. Slide one end around the journal and pull back and forth. You only need to do this about 6 times and that section of the journal will be polished. Rotate the crank 180 degrees and repeat on the other side of the journal with a new strip of cloth soaked in light oil. Kerosene, diesel or even paint thinner works just fine. Don't get carried away and polish it too much, cuz then it are belong to me! Good luck.

Tom

 

[jonheese]

Awesome, thanks for the detailed instructions, Tom.

I haven't yet determined for sure that it has a raised bump to it, but I will find out tomorrow when I dive back into this, and I'll certainly take your advice if necessary.

Regards,
Jon Heese

 

[rubydist]

Just to add a little detail - when a depression gets made like that, almost always there is a little raised lip around the edge of it - that raised lip is what needs to get taken off.

 

[Off Road SHO]

Just to add a little detail - when a depression gets made like that, almost always there is a little raised lip around the edge of it - that raised lip is what needs to get taken off.

Hey! no copying my posts. Just messin with ya.

Tom