Replaced rod bearings and now crank won't turn
 

A few weeks ago my 03 cooper S spun a bearing. I have the oil pan off currently and repaired and damage done from the bearing. The bearings are from summit racing and the brand name is kings. I checked and double checked that they where for my motor and resemble the OEM bearings perfectly, although slightly thicker. I assume because they are brand new and the older ones are worn? From here I began to install them, one rod cap at a time, and made sure they faced the right way when reinstalling. The first time I put the bearings in I put them in dry and torqued the rod bolts evenly. The crank turned fine before touching it but would not turn even with a breaker bar on the crank pulley. I took them out and tried again, this time with assembly lube on the inside face of the bearing and again nothing. So I thought to disconnect the rod in which the bearing spun to see if it was just that rod journal holding it up and again nothing. Next I backed all the bolts off a tad so they where not tight to the crank and then the crank turned easily. Any advice on what this could be seizing the crank for ? Or what to do from here ?

Moving you to the Stock Problems/Issues area.

Engine is still in the vehicle correct?

repaired damage = resurface crank journals? If so, then you buy oversized bearings to match the amount removed (I believe). If you didnt resurface crank and bought oversize bearings they will contact the crank and cause it to bind

Assuming you put the caps back on the right rods (don't ask me how I know this), I think the most likely is wrong (over) sized bearings. It's hard to measure them with the necessary accuracy, but Plastigage would give you a cheap and quick read on this.

yes, the motor is still in the car

Wrong sized bearings makes the most sense to me, although I can't find any "smaller" or thinner bearings. I'm thinking OEM bearings should be but BMW/MINI isn't clear with the specs.

What was the King part number??? Should be CR4600XP if the XP series. No XP at the end if standard King bearing. There should be NO number at the end i.e. 025 etc.

You may also have bearings from a standard Cooper...but not sure how you managed to get those on the rods--2mm smaller.

you should also be checking clearance with plastigauge it will tell you without a doubt if you have the right sized bearings, I do this even if I know I have the right bearings.

whoever repaired the journal damage should have told you what size bearings to use

the bearings I got are not XP series, but I see the ones you are talking about on autoplicity, but website doesn't specify if they are for the S or Base model. Will the XP series work on the S ?

Yes the XP's are just a better bearing. What part number did you buy? Should be on the box!!! post a picture of the box label.

dont have the box handy at the moment, but the summit racing part number is: KGB-CR4538CA05 and the kings part number is: CR4538CA05

OK....so that is the right bearing number (in the none XP series) BUT...the 05 at the end indicates that it is for a crank ground 0.5mm smaller (second undersize).

You need the Summit part#KGB-CR4538CA which is for the stock size journals...since you have not removed the crank and had it turn/machined to a smaller journal size.

NO WONDER IT WONT TURN!!!!!

Or for extra money the CR4600XP. Summit part#KGB-CR4600XP if you want a better bearing. But since your just cobble it back together just get the 4538's

how do you machine the crank without removing it, how was the repair done?

Whatever you do, you need to use plasti gauge this is engine building 101

Plasti gauge doesn't do s^!t if the bearing are 2 sizes too small!!!!

Looks like he is just doing a patch job to get it back up and running...not sure if that is really a good idea but ???? to each his own.

it's obvious you do not know what it's for

I use it all the time...but he bought bearings that are for a crank that has been machined 0.5 mm undersize...DID YOU MISS THAT DETAIL!!!

Plasti gauge won't tell you that...will it??? It will simply tell you that there is not enough clearance!!!

for those that do not know, plastigage tells you your clearance, it would have told my.mojo immediately that he had a problem and basically zero clearance

instead of trying to rotate the crank with the wrong size bearings, possibly scoring the journals again

But it won't tell you that there is 0.5mm too little clearance!!!

I've already given him the correct part number...when he get it..he can then use the plasti gauge!!!

the stuff I use goes way below .5mm also it will tell you if you have no clearance it'll squish it beyond the measuring gauge

also see here for clearances

https://www.northamericanmotoring.co...es-needed.html

You are right...that's what you want to hear...so there it is!!! Even though your blowing smoke...

I give in to your mighty knowledge...you can help him out from here on out!!

GOOD LUCK My.mojo

patch job ? Negative. When I say repair the damage I don't mean that the surfaces where destroyed, crank is fine and rod cap needed minimal deburing. Thanks for your help and effort on this though !

Also, just ordered the XP bearings, I'll post how it goes when they get here

I agree with you, although I didn't try to force the crank to turn, as soon as I realized it was tough to turn I realized something wasn't normal and stopped. I knew trying to muscle it would possibly lead to more problems as you mentioned

You may want to order new rod bolts and have a really good look when you fit the new bearings...plasti gauge may or may not help.
You may have distorted the rod journal or stretched the rod bolts when you torqued them with the thicker bearings...be careful!!
Only removing the rod/piston and using a bore gauge will tell you if you have distorted the journal.

BTW...no offense meant by the "patch job" but it has been know to happen!! People then sell the car on to the next guy.