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Removing rod bearings from 218


Cooper40

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Last year I pulled the #6 rod cap when i was trying to get the engine broken free and I discovered some flaking on the bottom bearing. So now I am going to be removing all of the rod bearings and I am wondering if I need to put some protective cloth or something between the crank and the bottom of the connecting rods (when the top bearings are removed). The bottom side of the crank will be fine but what about the top side. My plan is the remove all of the bearings and inspect them for wear. I will post pictures once I do. 

I will be doing this with the engine still in the car.

This is all new for me so any help is appreciated! 

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Been awhile since I've been in an engine but I would recommend that once you remove the lower cap place some kind of sleeve over the threads of the cap bolts , rubber/vinyl hose, masking tape, etc.  this will  avoid worries of bolt threads scraping the crank shaft as you push the piston up per Sniper's recommendation.  Just a thought. 

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I always use fuel hose, cut slightly longer than the rod bolts. Sized right, they stay on as long as you need them, and will keep the threads from dinging up the journals while you swap out the bearing inserts.

Usually a couple feet of hose is more than enough.

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Since the easiest position to replace the bearings is at the bottom of the stroke, two cylinders will have the best access, the other 4 will have severely compromised access.  Replace the bearings in the two at the bottom one at a time, rotate the crank until another two are at the bottom, do those and then rotate again to get the last two.  It only takes about 4 inches of fuel line that way.

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Again, its been a while....say your working on #1 piston....rotate crank so #1 piston is at bottom of stroke.  Remove lower bearing cap, protect cap bolt threads, push piston up off the crank, that should give you room to get the upper bearing shell off the crank or out of the bottom end of the piston rod.   Note that when #1 piston is at the bottom of stroke so will be #6 so do #6 next.  Then rotate crank 120 degrees and do #2 and #5, rotate crank another 120 degrees and do #3 and #4. 

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Not sure if it’s been mentioned but make sure you use engine assembly lube on the bearings during assembly. Otherwise it’s metal on metal when starting or even turning over with the starter. Not a good thing!

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When you say top bearings are we still looking at rods. You don't need to remove the crank to do rods or mains. Mains you just have to know how to roll in a new set.

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If you're finding flaking you'll also want to check the mains.  For a cursory main brg inspection I'd choose any except the rear main since that would disturb the seal and if it wasn't leaking before, pretty sure it will after if you drop that one to check it's condition.

 

I'll assume you have a torque wrench.

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2 minutes ago, Cooper40 said:

@Dave72dt I have a torque wrench but I will be torqueing with the engine still in the car. Is it possible to do the mains and fit a torque wrench in there?

 

With a socket extension, yes.

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2 minutes ago, Cooper40 said:

@Dave72dt I have a torque wrench but I will be torqueing with the engine still in the car. Is it possible to do the mains and fit a torque wrench in there?

Yes, you may need an extension to clear steering and suspension components.   

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As Hickory mentioned about "rolling in" the upper mains, the service manual I have that covers from 1946 to 54 shows a special tool on Figure 16 in the Engine Section. I never used one because I dropped the crankshaft for a regrind.  But instead of the special tool I figure I could fashion one from a cotter pin or nail or something. 

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Thanks @squirebill for the info. I think I have that same service manuel. I'll have a look at that page. 

I will pull the rod bearings for #1 and 6 rods and take the pics and see what you guys think. I'm not completely sure but I it kind of looks like the engine was rebuilt at one point because the cylinders looked really nice so the bearings that I get might need to be a different size. It might say on the back them right?

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Plasti-gauge and a micrometer are your best friends here.  Measure the crank throw bearing surface 5x at the same spot. Write down all measurements. Divide total by 5. This will get you a good number. 

Note the differences in surface wear near outer edges at crank counterweights. Expect more wear on the outer surface area due to thrust forces of the spinning crank.  I believe the crank naturally wants to walk backwards toward the tranny. 

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I roll bearings in about 15 times a year in the diesel world. For a special tool ive made my own buttons for work. Not sure if it would work in your car or not. I take a bolt and grind the head to the thickness of the main shell with rounding a slight arch. Then install the button into the oil hole on the crank and slowly turn the crank with a ratchet on the front. The button pushes against the main shell and rolls it out. Maybe at work tomorrow i can take a picture of one i made.

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I dunno, call me a snob but I's rather spend my tool money on real quality tools. Like Starret or Mitutoyo.  Yeah, they cost a bit more but are definitely quality tools. 

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