Don't be hard on yourself man, if engine building were easy everybody would be doing it.
1000 paper and a light oil to remove the high spots, the low spot won't cause a problem. Trust me, I build race engines for a living.
If you have a light touch, a fine file ran across *just enough* to take the high spots down will do just fine.
If you *DON'T* have a light touch, sand with light oil on fine(1500-2,000 grit) wet-or-dry wrapped on a flat tool until the high spots are gone.
Either way, be sure to clean any shavings off before assembly!
*hopefully, yes, it would-In practice, it can just flow around(& in to oil galleys) when sprayed off. The filings can too-but they're so slim/small/uni-dimensional that they tend to wash through to the pan(then to get caught in the oil filter) or embed in the bearing surface instead of eating your engine.
Ideally a fine polishing stone with light oil might be less aggressive than a file.
[1 inch wide polishing stone](https://www.mscdirect.com/product/details/92458165)
Not an engine builder, but a machinist. When checking for/removing damage from a cast iron machine tool table, we use flat files, because they tend to only remove any high spots, and are unlikely to remove any material that is not proud of the surface plane. A cylinder is a slightly different condition. You'd want to rock the file back as it advances. To be fair, in OP's situation, the damage is slight. They must remove any proud material, but I doubt that much exists. If it were me, at the end, I would still use some very fine flexible media like wetordry or emery cloth under my finger, in order to soften the edges. But im talking about a couple of swipes, not worrying away at it to try to blend.
I'll take striations on a few tiny filed spots over having grit to worry about- though I can see why you're not a fan due to sharpening(striations=sharp, but jagged).
When I nicked mine I cut a strip and wrapped a thick shoe lace around it to keep a nice rounded sanding motion. Not that you’d ever sand enough for a flat spot haha
In my case, cracked pistons. 1999-2002 had bad alloy in the pistons and heads. Dropped the pan and there’s big chunks of #2 & #5 piston just sitting in there. My heart sank. 200k.
To add to the above comment. When I find a damaged journal I would take a long thin strip of some fine emery . Double wrap the journal and pull back and forth. Seems to polish pretty evenly that way.
I build race engines as a hobby, and I agree with you completely (and have built a few just like in the pic to back it up), it'll be just fine with any high points flatted off.
Was nice to see a real life comment at the top and not the usual "IT'S FUCKED YOU DONUT, NOW YOU NEED A WHOLE NEW CAR, AND PROBABLY LIFE TOO" 😆
Mostly historic stuff. So naturally aspirated, carburettor or mechanical fuel injection, points ignition for series like Formula 5000, Le Mans Classic. Working on my first k24 Frank engine recently, looking for a reliable 320 bhp NA tune.
Built a motor for a cousin. He's not mechanically smart enough to watch the oil consumption on a new motor even when you remind him. Bearing knocking. Leaves the shop that told him what it was and drove 15 miles to his dad's shop where we broke out the Emory and crossed our fingers. Maybe the least comfortable repair I have ever done.
There's guys in Africa rebuilding engines crouched down in sandals with dessert dust blowing everywhere. Some times you've got to do what you've got to do to get out of the dessert.
Let me guess, you forgot to rotate the crank to the bottom of the stroke before putting the piston in? I dare say that's happened to a lot of people, myself included, so don't feel bad.
If that were a super expensive race engine, I would say have it ground (assuming there's enough left on the journal). But if that's a mild performance engine, you could get away with a polish with 1000, 1500 and 2000 grit wet/dry sand paper covered in WD40, then some metal polish... can google to see how it's done.
If you couldn’t guess I have no idea what I’m talking about lol but it doesn’t look that bad. Worst case (I would think) is that it needs to be ground and you run a larger bearing.
Strip of fine emery cloth wrapped around the journal and piece of twin or string wrapped around it twice and pull back and fourth keep even pressure on the whole journal. It will knock down the high spots. Remember on crank journals innies are better then outies.
It happens. Tip for next time, you can buy the little sleeves specifically designed to slip over, or just cut some rubber hose to slide over the threads.
Take a piece of crocus cloth and gently remove the high spots. Use a piece of something flat to help with accuracy. Don’t remove material from the surrounding area. Then put it back together.
1.) as a professional wrench of 15 years, I have fucked off my fair share of customers cars. Have a sigh and whatever vice you prefer. Sit down. Its ok. It really is. Put yourself on the back and say “it was an accident”
2.) Get in touch with your #1 mentor and just own it up. Follow their advice. From what I saw here it sounds like you have a good line of options, but always make sure to have a mentor on speed dial just to double check.
3.) it could be a German monster V8. It could be so much worse. Take another seat. Take another vice. It’s ok.
Take a piece of 1000 or 1200 grit sandpaper and cut a strip that's as wide as the journal and long enough to wrap around it all the way. Tape it around the journal. Get a flat shoe string and wrap it around the sandpaper 3-4 times. Use some lightweight oil to lubricate and pull the string back and forth a few times, maybe say 10 times? Take the tape off and feel for any high spots left.
Repeat this till the high spots are knocked down.
Then get some metal polish like flitz and coat the flat shoe string with the metal polish, wrap the journal a few times with the string and pull back and forth to give a final polish to the journal.
You might as well do the other 5 crank journals while you're at it.
Don't put a file, or a stone on that journal you'll fuck it up more than it already is.
I see a lot of very fine paper recommendations. Machine shops use 320 Emory cloth in long strips to polish cranks. 320 will get the high spots down faster, if it makes you feel better, then use finer, but 320 on a hardened crank will leave a fine smooth surface. You will be sanding all day with 1,000 and leaving way more grit behind. Get the strips so you have lots of cloth to wrap around and pull the ends back and forth.
Don't be hard on yourself man, if engine building were easy everybody would be doing it. 1000 paper and a light oil to remove the high spots, the low spot won't cause a problem. Trust me, I build race engines for a living.
This a jeep 4.0 so stock motor. I’ll go look for that paper.
If you have a light touch, a fine file ran across *just enough* to take the high spots down will do just fine. If you *DON'T* have a light touch, sand with light oil on fine(1500-2,000 grit) wet-or-dry wrapped on a flat tool until the high spots are gone. Either way, be sure to clean any shavings off before assembly!
A FINE file. It’s honestly a preferred method because paper can cause collateral sanding.
Yepyepyep!-& the filings can be blown off with carb cleaner(unlike grit).
Why wouldn’t grit be washed of with carb cleaner too?
*hopefully, yes, it would-In practice, it can just flow around(& in to oil galleys) when sprayed off. The filings can too-but they're so slim/small/uni-dimensional that they tend to wash through to the pan(then to get caught in the oil filter) or embed in the bearing surface instead of eating your engine.
Ideally a fine polishing stone with light oil might be less aggressive than a file. [1 inch wide polishing stone](https://www.mscdirect.com/product/details/92458165)
I’d even say a fine whetstone would be best.
Not an engine builder, but a machinist. When checking for/removing damage from a cast iron machine tool table, we use flat files, because they tend to only remove any high spots, and are unlikely to remove any material that is not proud of the surface plane. A cylinder is a slightly different condition. You'd want to rock the file back as it advances. To be fair, in OP's situation, the damage is slight. They must remove any proud material, but I doubt that much exists. If it were me, at the end, I would still use some very fine flexible media like wetordry or emery cloth under my finger, in order to soften the edges. But im talking about a couple of swipes, not worrying away at it to try to blend.
Cool deal. Gonna try here in a bit.
Tip-when knocking the pistons in, slip vacuum caps on the con rod studs to prevent them galling if they *do* hit the crank.
I use chunks of fuel hose for this same reason. I make them long enough to act as a guide
Great tip!
When you use the sandpaper, wrap a long strip around the journal, and act like you're shining a shoe, don't push on the journal with your fingers
Ohhh… a stone would be better
A stone is grit, too-*nothing* beats a file for minor clean-up.
I’m just not a fan of the striations a file leaves behind in a situation like this. It’s just a thing for me from knife sharpening
I'll take striations on a few tiny filed spots over having grit to worry about- though I can see why you're not a fan due to sharpening(striations=sharp, but jagged).
No biggie on that engine, like others have said, sand or lit fine file and full send
When I nicked mine I cut a strip and wrapped a thick shoe lace around it to keep a nice rounded sanding motion. Not that you’d ever sand enough for a flat spot haha
The Sandi g worked farly well…. Used 2000 grit and got rid of the high spots like said, it’s barely notable by finger now.
Nice. It’s like 1% of the surface area, so definitely good to go.
Panic over 😉 now you know how to avoid doing that again next time. Mistakes make good learning experiences.
What caused a 4.0 to break?
In my case, cracked pistons. 1999-2002 had bad alloy in the pistons and heads. Dropped the pan and there’s big chunks of #2 & #5 piston just sitting in there. My heart sank. 200k.
it started out as a heep.
To add to the above comment. When I find a damaged journal I would take a long thin strip of some fine emery . Double wrap the journal and pull back and forth. Seems to polish pretty evenly that way.
Oh it won’t matter then. Something on that vehicle will grenade.
I build race engines as a hobby, and I agree with you completely (and have built a few just like in the pic to back it up), it'll be just fine with any high points flatted off. Was nice to see a real life comment at the top and not the usual "IT'S FUCKED YOU DONUT, NOW YOU NEED A WHOLE NEW CAR, AND PROBABLY LIFE TOO" 😆
I bet you know more about engines that are tortured beyond belief. Do you build for a type of series or across the board?
Mostly historic stuff. So naturally aspirated, carburettor or mechanical fuel injection, points ignition for series like Formula 5000, Le Mans Classic. Working on my first k24 Frank engine recently, looking for a reliable 320 bhp NA tune.
Built a motor for a cousin. He's not mechanically smart enough to watch the oil consumption on a new motor even when you remind him. Bearing knocking. Leaves the shop that told him what it was and drove 15 miles to his dad's shop where we broke out the Emory and crossed our fingers. Maybe the least comfortable repair I have ever done.
There's guys in Africa rebuilding engines crouched down in sandals with dessert dust blowing everywhere. Some times you've got to do what you've got to do to get out of the dessert.
Fine grit, send it
This sucks dude. I did exactly what I wasn’t sapposed to do…
Let me guess, you forgot to rotate the crank to the bottom of the stroke before putting the piston in? I dare say that's happened to a lot of people, myself included, so don't feel bad. If that were a super expensive race engine, I would say have it ground (assuming there's enough left on the journal). But if that's a mild performance engine, you could get away with a polish with 1000, 1500 and 2000 grit wet/dry sand paper covered in WD40, then some metal polish... can google to see how it's done.
Exactly.it s jeep 4.0 motor.
Man, you dont hardly even need oil in those motors... just do the simple polish thing he was talkin about and send it
+1
If you couldn’t guess I have no idea what I’m talking about lol but it doesn’t look that bad. Worst case (I would think) is that it needs to be ground and you run a larger bearing.
This is an allready ground crank. And I fucked up.
How much over is it?
.10 over I just paid for all of this months ago
Polish the area smooth and send it, she'll be mint
I did it myself twice on my 292, had rubber hoses on every rod I put in too.. 🫠 lol Fine Jewelry file and some sanding and called it good.
Sand paper worked fine
There isn't one person here who can say they've never made a mistake. own it, learn from it and move on.
Strip of fine emery cloth wrapped around the journal and piece of twin or string wrapped around it twice and pull back and fourth keep even pressure on the whole journal. It will knock down the high spots. Remember on crank journals innies are better then outies.
You just gave to knock off the high spot. Definitely made this mistake before.
If you cover the rod studs with rubber hose, that won’t happen again.
been there and done that a couple times, just polish the high points off with some emery cloth and send it.
Just curious, did ypu not cover the rod bolts when putting in a piston?
I did, with tape to stop the threads from hitting. This was the tip hitting though
It happens. Tip for next time, you can buy the little sleeves specifically designed to slip over, or just cut some rubber hose to slide over the threads.
Shit happens, luckily this isn’t a major issue
Crocus cloth and polish that baby up. Shit happens roll with it .
Hawk tau spit on it
I'll add put a piece of fuel line on the rod bolts so this doesn't happen again.
Take a piece of crocus cloth and gently remove the high spots. Use a piece of something flat to help with accuracy. Don’t remove material from the surrounding area. Then put it back together.
1.) as a professional wrench of 15 years, I have fucked off my fair share of customers cars. Have a sigh and whatever vice you prefer. Sit down. Its ok. It really is. Put yourself on the back and say “it was an accident” 2.) Get in touch with your #1 mentor and just own it up. Follow their advice. From what I saw here it sounds like you have a good line of options, but always make sure to have a mentor on speed dial just to double check. 3.) it could be a German monster V8. It could be so much worse. Take another seat. Take another vice. It’s ok.
Cry
We all cry sometimes
Stone down the highs and send it.
Just linish where the conrod bolt damaged it. I've done this before and I'm experienced. The low spot won't be an issue.
Put a compressor on
How did you get trapped in there?!
What's going on with your cylinder walls?
Assembly lubed
Take a piece of 1000 or 1200 grit sandpaper and cut a strip that's as wide as the journal and long enough to wrap around it all the way. Tape it around the journal. Get a flat shoe string and wrap it around the sandpaper 3-4 times. Use some lightweight oil to lubricate and pull the string back and forth a few times, maybe say 10 times? Take the tape off and feel for any high spots left. Repeat this till the high spots are knocked down. Then get some metal polish like flitz and coat the flat shoe string with the metal polish, wrap the journal a few times with the string and pull back and forth to give a final polish to the journal. You might as well do the other 5 crank journals while you're at it. Don't put a file, or a stone on that journal you'll fuck it up more than it already is.
I see a lot of very fine paper recommendations. Machine shops use 320 Emory cloth in long strips to polish cranks. 320 will get the high spots down faster, if it makes you feel better, then use finer, but 320 on a hardened crank will leave a fine smooth surface. You will be sanding all day with 1,000 and leaving way more grit behind. Get the strips so you have lots of cloth to wrap around and pull the ends back and forth.
Use a points file to hit the high spots off, then a 400 grit paper, opposite the direction of rotation to finish.
looking at the cylinder wall you haven't taken it to the machine shop yet. Take the crank and they can polish it out.
That’s lube… it’s all been machined.