I would have it turned. I have the same issue with my "low milage" '03 Escape engine. You may want to try polishing the journals with some Crocus cloth. I tried this but can still feel some of the scoring with my finger nail.
Crank is going to the machine shop this week, and I will also have to pickup the corresponding bearings. I picked up stock size before opening up the engine
Well then it's another $90 for all the bottom end bolts. Better than a new engine 20k from now though. Might as well do the mains as well while you're in there. Not what I wanted to hear. I guess I'll try the cloth. Any ideas on crank turning pricing.
Depends on the shop, $75-$100 is about what it went for in Tucson for a minor polish job like that.
Can you just have it polished and use the std. bearings I have?
For future reference TH says.
...advice/old test.Rub across the main and crank journals with a penny or copper coin....if they leave a copper deposit in grooves then the crank needs a reground and oversize bearings.Watch out with the oilways too....Don't forget the 'sand in block' issues of a LOT of Escape 3.0 and some other 3.0 blocks....lot of used 'junk' out there....with sand in the main feeds to the main bearings....
I would try hand polishing it before going all out and having it returned.
I am. Found this advice on a web search.
Polishing crankshaft journals:
1) Get a 30" length of leather shoe lace. $3.50 at Wal-Mart's outdoor dept. or any shoe repair shop.
2) Get the appropriate sized OD mic that reads in .0001" (tenths), eBay $15.00 or so. Starrett, Brown &Sharpe, Mitutoyo, etc. Get a good one. It'll last you until the second coming or you loose it in the divorce decree whichever comes first.
3) Get one (1) sheet of crocus cloth. $1.50 at your local FLAPS. You may need to call around some. 3M makes it and ALL auto parts stores used to carry it. In the olden days it was 50 cents per sheet. Keep looking; you'll find
some. One sheet will do about 5 cranks. FYI crocus cloth is jewelers rouge (iron oxide) on a cloth backing (like emery cloth) and is used to polish jewelry.
It has the smallest (finest) grit commonly available for polishing anything.
4) Get a wooden paint stirer at your local Home Depot/Loew's store. Get three; they're free.
5) Get a flat piece of 3/8" steel or a flat file that will fit between the throws of the crank. New file $10.00. Any old worn out file flat file will do nicely. Cost = free.
6) Mike each crank journal (both sides and every 90* around it. You want to know up front any taper and out-of-round condition of each journal before you begin. Write the results down for each journal !!!!!! Don't ASSUME anything.
You 'll never remember what they were after you started.
Depending on the length of time that the crankshaft was left in the salt bath has determined how deep the nitriding is. Usually it is only .0002" to .0003" deep (about 1/10 the width of a human hair). You should only need to take
less than .0001" off of each journal to make them shiny. Thats 50 millionths per side here! Even if you take .0002" off of them its still only .0001" per side so you're still OK.
7) If you have a lathe use it to hold the crank as you spin it at high speed for the mains. Nice but not necessary. Be careful here! Use the crocus cloth backed by your free paint stirer and then the file. The file just lets you
push harder and control the cutting action of the CC. The corcus cloth will do the polishing of the journals W/some light oil. The idea is to get the journal shiny and not tapered. Stop, wipe the journal clean and measure it often.
If you find a taper (or more likely you start to make one) push harder on the big side to take it down to size.
No Lathe, No problem.
8) For the connecting rod journals tear off a strip of crocus cloth and using the leather thong wrap it around the journal twice so that it completely holds the CC on and both ends of the thong comes back to you. It helps here if
you use two pieces of old broom handle to make handles like the old pull starters on lawn mowers. Your call here.
9) Add some light oil and polish away by pulling the thong back and forth causing the CC to spin completely around the journal(s). Check as you go! Write the diameter(s) down!
10) Do the same for the mains if you don't have access to a lathe. Be thinking about getting one though. They are almost as handy as money. Actually handier on late Sunday afternoons and just before all final late night thrashes!
Been there, done that, got many T-shirts!
When all of the journals are shiny record each diameter so *IF* you have to selectively fit bearings you know EXACTLY what you need and where you needed them.
Don't forget to clean the crankshaft completely and grease the nice shiny journals IF you are NOT going to rebuild the engine immeadiately.
Cliff notes:
Get some Crocus cloth from a local Napa, get a shoe lace and wrap it around the crank and cloth twice so it will polish evenly.
These cranks are quite hard, much harder than old school cast cranks with standard nitriding.
I was going to mention it before, but forgot. You will be sanding all day with that setup before you make a serious dent. That polishing info you put up is good, but it isn't for getting out the journals. That is just for very light stuff.
IMO you will spend a lot of time on it, then either give up and have it polished or just run it the way it is.
That's kind of the lead-in to my last post.
I wondered if you could really polish the gouges out of a crank by hand as hard as they are. I guess I'll just have to pull all the caps and take a look.
I don't know a whole lot about bearing dynamics. But I can see two things happening with throwing on a new set of bearings over a grooved crank.
1. The groove traps oil and makes no difference.
2. The groove allows for a release of pressure on that point, creating higher pressure on either side.
Those are my guesses, any advice from the experts?
A rod bearings main purpose of existance is to trap particles and prevent damage to the rod journal. That being said, these bearings have lived their life harshly and it's evident on the crank's rod journals. Unfortunately, just inspecting the crank's main journals involves all new TTY bolts for the block, so regardless, might as well spend the extra $50 and replace the bearings. Judging by the rod journals, I would care to put money on the mains being scored as well. As for regrinding the crank ... if you can feel it with your fingernail, time to machine off .25mm and move up to the next sized bearing ... but that's just my opinion. Remember, you can only do it right once
Yeah, well the polishing with Crocus cloth did nothing for my journals. I dropped off the crank this past week at a local reputable speed shop. They were running a race engine on the dyno as I was leaving and it was like music
Just waiting to hear how much material they removed so I can pick up the correct oversized bearings. In the mean time, with the warmer weather I plan on starting the head porting and injector relocation.
Scott took his back to LQK and exchanged for one with 15000 miles. Paid an extra $100. I'll tear it down tonight to have a look. If this one is scored I'm going to flip.
