Yep, thats right. Just got my freshly rebuilt 302 all ****oned up and dropped in my A Tudor late last week. Drove it around town about 20 miles. 20 miles into a road trip the next day at freeway speeds, my stomach sank as I heard the dreaded knock. I pulled over and had her flat bedded home. Pulled the oil pan last night and found bearing material in the oil. Re-checked the torque on the rod bolts and main bolts to be sure. All were in spec. Also checked the end play. Again, all in spec. Started pulling the rod caps and found a nice groove and quite a bit of material missing from the #4 rod bearing. It also made some very small ridges on the freshly polished crank journal. Randomly checked a couple more and the bearings looked good. So now the questions are: What could have caused this? Can I get away with replacing the one bad bearing, or should I just replace them all? Can I use an emory cloth to polish out the small ridges on the crank journal? Any precautions I ought to take to keep this from happening again?
Probably caused by trash left in the oil galleys by the rebuilder. Better yank the crank (the engines not yours) and get it turned to the next undersize. If it still mic's ok it could run a while with new bearings but if its been knocking its doubtfull.
You might be able to get away with replacing the bad bearing, but that all depends on how much damage was done, to even attempt this everything would still need to be in spec, also check how badly out of round the crank journal is. I have done this in the past sometimes successful and other times not but since the damage is alrady done what do you have to lose right.
Most likely debris in the oil p***ages or debris on the bearing shell at time of ***embly. Possible the crank was knicked at tiem of ***y, will also cause this type of damage. Debris + RPM + Time = Knock and Damages you see.
I heard the knock for under 20 miles. Probably 10-15 at most. The ridges are very small, but can be felt by running your finger over them. I was really hoping to not have to pull the crank.
Just one spun? I got away with changing only one rod bearing on a Ford 300 inline six in a Belt Loader once... Airline budget crunch ;-) I'd say take it out and have it pulled apart if the engine builder is going to cover it but if not, take all the rods off it, and main caps(the timing chain in your 302, and trans will hold the crank up) and check all the p***ages with any pressurized cleaner rotating as required(Trans Cooler/Line Flush works good, or a solvent nozzle w/regular cleaning solvent) Dress/Polish journal(s) as required... x2 on the plastigage. I'd check 'em all to be sure... Check the oil pump for FOD/Trash Re-***embly w/Lubriplate or Equivalent... Pre-oil before firing it back up. I've heard of worse lasting 100K miles Good Luck! I'm the west metro, feel free to PM
I don't care what eveyone says. If theres bearing material in your oil, that whole engine should come apart. You have to clean EVERYTHING and get all that out or it will just happen again. I work at a machine shop and see this daily...people try to do a quick fix with metal in the engine....will wipe the whole thing out in aother 20 miles. The oil will ****ter those little copper flakes EVERYWERE inside. My .02
The best course of action is as Chris surmised.........take it apart. Probably something in the crank took out the bearing and at this point anything other than total dis***embly and a thorough cleaning would be inviting another failure. Sorry man.
I just went thru the same deal, Brand new engine ate a cam and ruined the bearins ... I was dso pissed i just "FIXED IT" and went another 60 miles and spund a rod bearing & hurt it even more !! Yank it out and go back to the machine shop..... Did they ***emble the engine ???
Was the engine plasti-gauged before you did the final ***embly? I would pull the intake and try to flush all the oil p***ages atleast if your not going to pull it apart.. I had a 302 eat some push rods. Long story but the push rods werent hardened and they were rubbing the guides. I managed to flush everything out with no problems. The filter did its job. I ended up pulling the pan just to check and see what was there and it was only on the top end.
If you had the crank turned the most likely cause is debris left in the oil holes or in the oil holes of the block that came dislodged and pumped out on the bearing after warmup. Chris has got the ONLY REASONABLE solution. the engine should come back apart, everything miced for size, through cleaning, and most likely at least that one journal ground down to the next undersize. I would take take all of the rods to the next undersize to keep the bottom end uniform but economics might dictate otherwise. If you do a half- ***ed polishing and put it back together with a new bearing I'm predicting it won't last any longer that it did the first time. Frank
I did an olds 455 engine in a jet boat years ago... polished the crank with crocus cloth threw one new bearing on the bad journal and we beat the **** outta it the rest of the summer.. It can be done but it depends on the damage to the crank.. Dave
well i guess it goes without saying, but i'll say it anyway! this is the only mistake that matters. whatever ***embly error was made is now moot. when it comes to rebuilt engines, there are only two options, do it yourself, or go to a reputable rebuilder. never trust a private party selling a fresh motor. the motor needs to come all the way apart, inspect it closely to judge the rest of the work to determine if the other machine work is salvageable.
If you used synthetic during break in it will destroy bearings in a heart beat. also if the crank was turned before were the correct bearings used. sometimes you ask for one thing another gets sent.
Of course you have no idea what your bearing clearances were. But as far as breaking one in, I run one for 15-20 minutes in the shop. If it's not a roller cam engine, you run it at an elevated RPM during this time to break in the cam and lifters to each other. Recheck everything and then it's time to go for a drive. Once everything feels right under load, it's time to do a series of WOT blasts and engine decelerating in between them to seat the rings. Once you've done this, brought it home for a final check and then change the oil and filter, no further break-in should be necessary. I highly recommend an oil temperature gauge for any performance engine. Critical during break-in and still very important beyond, IMO.
pull it apart and build it....not a whole lot of money envolved. SBFs are cheap enough... Do it right...
Take the rod cap off on the other rod thats with the spun one & check to see if theres a ridge in the middle.You seemed to do the right thing by shutting it off & towing it with the caps off the crank mike to journal & see if its worn or just has some slight grooves in it.It its just slight try a new bearing on that one rod.also try blowing out the oil holes. The damamge is already done, if the cranks not bad try it, it could mean having the car not drivable for the season or using the car. The "bandaide" is always worth a shot!! Its a quick fix if theres no damage.Just run it in the driveway at about 1500 RPMs for a short time & then keep it local.If the pans down clean it all out & refill it with oil. Always go for the easiest method first!! Keep it running at all costs with a minimum of h***le.LOL jimV
I agree with Chris and Desoto...pull her down and do it right. I have gone thru the same thing, spun number 5 rod in my old 289( just enough to crush the tang, and no scarring), shes coming to a bare block
Gotta agree with him on this! I ran the rod shop at a shop here in town for many years and saw it all, and I usually saw the guy back for a rebuild after his patch job didn't work, one thing to check which I didn't see mentioned, Make sure the oil holes on the crank are "chamferred" If they have a sharp edge on them they have the potential to s****e away that layer of bearing material and it will go thru the blood line of your motor. Just an opinion though...Ken
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