quick question. i've replaced rod bearings for the guy next door(spun #6). i've put in the stock size bearing, but there is still a little slop in the 6 and 5. he doesn't want to spend the cash in fixing it right. he's thinking of just getting rid of it in a few months, and wants a quick fix for now. he asked if i could put a bigger bearing in it. i would have to go with a undersized bearing correct? not too sure about it. thanks

The bearings come in increments of .010", and that's probably a lot more than the 'slop' you currently have in the bearings.
To be sure just measure the clearance with plastigauge.
I'd just suggest runing a really thick oil to quiet it down (SAE 50).
(BTW you'd need oversize bearings for an undersized (worn or reground) crank)

Hope this helps

the crank has a few ridges in it. you can feel 'em when you drag your finger nail across it. right now theres 10w40 in it. when he brought it to me you could really hear it knocking. now you hear it once its warm and at a high rpm. i was thinking going with a .020 over.


http://www.superford.org/registry/vehicles/detail.php?id=1394

You can also get rod and main bearings in .001, .002, etc, sizes. Use platigauge and get it the best you can.

IMO if he's putting out the money for new bearings anyways (regardless of size,) tell him not to be such a cheap ass and grind the crank. What, fifty bux? At least that way he won't have to worry about whether or not it will last him the few months he needs it, and he'll be able to feel good about not ripping off the person who buys it from him down the road if he does decide to sell it.

The bitterness of having something you're not happy with LONG outlasts the joy of having saved a buck.

$50 plus gaskets and bearings, plus someone has to pull the motor and tear it down. If you are going to do all that for free, then you are a better neighbor than I am.

BTW, I would emphasize that there is absolutely no guarantee that the motor is going to last a day, let alone months.

the motor won't have a problem lasting if just the bearings wore out from mileage. I put .oo2 over size in my 4.9l that had 240,000 and received another 130,000 out of it before i sold it and bout 4wd.....If the crank has fine grooves in it then there could be some issues..

the motor won't have a problem lasting if just the bearings wore out from mileage. I put .oo2 over size in my 4.9l that had 240,000 and received another 130,000 out of it before i sold it and bout 4wd.....If the crank has fine grooves in it then there could be some issues..

My personal opinion as well, but my previous statement still stands. Would you pay for parts and provide the labor if it does not last? Huge liabilty there :shocked

yep, i totally agree with the liability, and if he wanted that kind of work done he would have to pay me to rplace bearings, not the easiest to do with motor in vehicle....

Just check your clearance with plastiguage, determine what size you need to get it into spec, (prolly .001-.005), .010 would be too much, .020 and that engine wouldn't even crank over. If you do indeed need something that big its time to get the crank ground. But I think you'll be good with .002 or so, but just check it and make sure.

EDIT, I just noticed I made that sound wrong...I didn't mean that .001-.005 was sped, I ment that you need to decide what out of those sizes you will need to install to get your clearence in spec, sorry if I made it sound different...

Pull the crank, have it turned, and buy new bearings. From the sounds of it the motor isn't going to last. How's the oil pressure?

BTW--Bearing clearances are usually .001-.0015, or something similar. .005 would be too much.

the engine had major issues when he brought it to me. here's a list of crap i already fixed and or found:
bad spark plug wire
cracked spark plug
intake manifold leak ( all but one bolt was loose)
exhaust manifold leak ( same as above)
vaccum line not connected
electrical connectors cracked and exposed
distributor cap is loose ( you can actually wiggle it back and forth)
muffler is total shot ( can see right thru it)
and the rod bearings. #6 was spun pretty good. you can't see the ridges but you can feel em. when i replaced them the first time they were all pretty much loose, and now just the 5 and 6 can still move. :banghead
the oil pressure sits right at the "m" in normal and drops to the "r" after about 5 minutes. he paid me 100 bucks for about 4 hours of work and it not that hard to drop the pan again to put in another set of bearings. so, a safe beat (for the cheat guy) is to run what .002 oversized bearing? :shrug
o'yeah the engine is outta 83 F150 4x4 and it's the inline 6. a little backround on the truck. the guys wife bought it for him as a birthday present. while bringing it home the engine blew it in. so, the person she got it from slapped another engine in it for her. now they are driving around and that engine blows so, now he get this engine from a junkyard... puts a few hundred on it and the bearings go out.
i told him i'll go ahead and put another set bearings in but if it was me i'll go ahead and tear into it. pull it and go to town replacing everything, but he wants to go cheap. :twak
thanks for all the good info.
http://www.superford.org/registry/vehicles/detail.php?id=1394
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88 Eddie w/351 sitting on some 33x12.50x15's

I'd just got .001 oversize, that should fix ya up, but plastigauge it first to make sure!

I'd just got .001 oversize, that should fix ya up, but plastigauge it first to make sure!


definately plastigauge it and see if it is within ford specs...if not but a oversize that will bring it to specs

cool beans "i'll do it"
o'yeah did i forget to tell ya that i took the end caps off with a 3/8 drive ratched. yepper nothing torqued to spec here.

http://www.superford.org/registry/vehicles/detail.php?id=1394

Woah!
I never knew they sold bearings in .001" increments!

cool!
(well... cool for all the cheap people)

Woah!
I never knew they sold bearings in .001" increments!

cool!
(well... cool for all the cheap people)

:goodfinge hahah. i did that on my truck just because everythign was in good shape and i saw no reason to yank the crank :toothless

mmmm "yank the crank".
autozone has 'em pretty cheap. the plastigauge is only $1.79. .001 over is 3.89 and .002 is 3.17,both which are not instock.

well fellas, after all that. i replaced all the bearings with .002 over and it took all the slop outta the #6 and #5. started it up and once it got warm it started knocking again. :banghead if the guy would of listened to me the first time and had everything turned and reconditioned it would of been fixed.
with it knocking i got the case of da ars and went out picked put .020 over and put it in. the knocking went away, but not for long. the neighbor drove it around and it started all over again. now, he wants to spend the money to get it done right. :boxing
here's a pic of the #6. this is just from moving outta my garage to the side of the house. it's a little blurry
http://www.superford.org/getfile.php?id=109599&toggle=fullsize&f=IMAG0014.JPG

thanks agin for all da good info.

http://www.superford.org/?vID=1394

here's a pic of the #6. this is just from moving outta my garage to the side of the house. it's a little blurry


thanks agin for all da good info.



:shocked that should be the wear on that after maybe a 500,000 mile engine....none of mine looked like that after 250000miles....definately more probs than just putting new bearings in...there must be a burr somewhere. anytime a bearing is wore down to the copper is spent and needs replacement