New snag in project Astrid: rod bearing

[veektor]

Thanks for the link, abscate!

I've had to put Volvo aside to focus on some house repairs, which gave me a lot of time to think through different solutions to my blown engine problem. One of my goals is to keep the costs down, but as I am trying to sell two houses almost at the same time (long story), I am very limited on time to troubleshoot and repair. I definitely don't have time to pursue strategies that are likely to result in rework. Replacing just the bearings alone sounds like an opportunity to revisit the crankshaft again, because I am not confident about the crankshaft condition, and whether I need standard bearings, or oversize +0.25mm, or maybe even +0.50mm. Not getting this aspect right is practically begging to do this over in the near future. Here are the options as I see them:

• Replace only the 5 bearings, keep the crankshaft: 5 x $40 - $200. High probability of not getting bearings sized correctly.

• Replace the whole engine from Pick-n-Pull: $150 + time investment of searching for the suitable donor and the actual removal from the yard

• Dissect an engine from below, removing the crankshaft with connecting rods and pistons (examine each bearing to be intact prior to removal). Crankshaft $25 + Rod and Piston $8 * 5 = $65. This was my thought for hedging between a total engine swap and replacing just the bearings. I figure if I pull the crankshaft with rods, I will have less chance of size mismatch between bearings and crankshaft journals.I am well aware that pulling the combo from the junkyard may work from below, but piston installation will have to follow the appropriate procedure from the top.

• Buy an engine from full service salvage yard: $600-$1000. Saves me the time of hunting for the right donor, but still have to pull the engine out to do the swap

If any of this sounds like incoherent rambling, that's probably because that's all I can do when I can't be working on the car hands-on. Please let me know if there are other options available that I am not thinking of at this moment.

[abscate]

You just open up the bearings , measure the journals with a micrometer you can borrow, and then buy the right size.

It is good to be careful and use Plastigage to check the clearance of the new bearing and confirm its right. You are deep in the heart of the engine but its pretty simple stuff in there once you get to it.

I would do that before doing all the hassle of a swap - particularly because the bottom end of a Volvo engine is known for its toughness.

[veektor]

Well, I don't have a mic, but I did pick up a green and red Plastigage from O'Reilly this morning. The #2 crank journal doesn't look mirror shiny, but doesn't feel terribly scored, either. I'll see what the Plastigage tells me about the crank/bearing clearances and go from there. Thanks for all the technical and moral support!

[abscate]

You need to measure the journals , plastigage with a used bearing doesn’t tell You much. You don’t know if the journal or the bearing has worn

If the journals look good and mirror like, I would risk buying a set of new mains and plastigage those. I bet you’re crank is good to go.

[veektor]

You need to measure the journals , plastigage with a used bearing doesn’t tell You much. You don’t know if the journal or the bearing has worn

If the journals look good and mirror like, I would risk buying a set of new mains and plastigage those. I bet you’re crank is good to go.

Again, good points, I will try using plastigage with a new bearing when they arrive. I will polish the journal on #2, all other journals look good.

I used plastigage this morning on one bearing that did not spin (#3 this time, decided to remove the oil pickup to take a peek), and got 0.025mm clearance measurement (torqued to 20Nm or 14.5 ft/lb). I've been looking through the repair manual PDF, but can't seem to find any clearance values yet.

I also removed the bearing shells on #4, ones that started spinning and shifted to the side. The bearing looks pitted very badly, and I realized there was a chunk of metal in the oil hole on inside the journal. I got a picture of the pitted bearing, but not of the metal chunk. Tried to pull it out with a pick, but it only retreated further into the center. I placed an order for 5 new STD size bearings, can't imagine even the worst one needing a whole 0.25mm plus size, but now I'm more worried about chunks of metal floating around the oil passages.

[veektor]

Ha! Seek and you shall find! Advanced search through the PDF document yielded the specs. Now I need to find a micrometer and I'll know for sure, though I still doubt 0.25mm upsize would be needed.

Big end journals

Diameter, standard 1........50.000 +0/-0.016
Bearing recess width........26.0 0.1 mm
Maximum out-of-round........0.004 mm
Maximum taper........0.004 mm
1 The variation in diameter for each bearing journal must not exceed 0.008 mm.


Diameter, bearing recesses
Designation

B5254T2
Big end (mm) 53.000 -0/+0.013
Small end (mm) 21.000 +0.011/+0.005
Max. ovality in the bearing recesses 0.006
Length big end-small end (mm) 147

[SuperHerman]

You are in a pickle here. The problem is those bearings all spun for a reason - no oil. What other damage may have occurred is unknown and cannot be known without pulling the head and inspecting the head, cams and journals and cylinder walls and piston rings.

Were it me I would find the cheapest standard sized bearings you can find - assuming your crank looks fine (the one photo that shows it looks good) and assuming your rods look good - and just swap out the bearings. You cannot do anything more without pulling the crank and rods to get them to spec as they require machining. Plastigage will just tell you what you will end up with, but without throwing more money at the engine for maching there is nothing you can do. Remember you don't know what the pistons and rings look like or the top end.

QUESTION: Can you pull a couple main crank bearings for inspection? One at a time?

That is why I say get in and out for the least amount of money, change your oil and filter afterwards a couple times to factor for metal floating in the system which will be caught by the filter.

Do the bare minimum and hope the rest of the engine is solid. If the crank and rods visually look good move forward with the cheap route. You will know pretty quick if it is burning oil and tapping like crazy that the rest of the motor also took a beating. Rod bearings, if that is all you swap out are about $50 - so you can be in and out for about $125.00 (plus lots of love).

Other option like you said is to get a used unit that is working - do the oil pan and related seals while it is out and go from there.

[veektor]

I've been thinking about that chunk of metal in the crankshaft all day. My conclusion is that the only way it could have gotten into the oil passage is from the journal of the spun bearing, because it was too big to pass through the oil pickup mesh. This means that metal chunks are probably limited to the crank, which is good news for the top end (provided oil starvation didn't cause too much damage), but bad news as I proceed with replacement of rod bearings. Who knows how many of those chunks got into the crank, and if they are eating away at the main bearings already. I don't know if I have the gumption to unbolt the intermediate part of the crank case to inspect the main bearings. I will ruminate on that for a couple more days. The rod bearings will be arriving on Saturday.

Herman, how did you arrive at that $125 figure? The cheapest rod bearing I could find was Glyco at FCPEuro at $39.xx, and I went with 5 of them, knowing that they will let me return whichever I decide not to replace. I'm still trying to make peace with that purchase, considering that a complete set of 6 rod bearings for my Jeep Cherokee would only cost $11 on RockAuto. Considering I've owned my BMW for over two years, I should be used to paying premium for the parts made of unobtainium, but it still stings.

I kind of feel like that air traffic controller from the Airplane movie who picked a bad day to quit sniffing glue. Only I'm trying to get two houses prepared for sale, while dealing with a blown engine. My wife is already at the point where she throws a conniption when I take a glance at the Volvo, let alone get underneath it. Replacing bearings with engine in the bay is the only option for me right now, as much as I am aware that engine swap, or a proper rebuild on the engine stand would be the wiser man's approach.

Maybe if I kept sniffing glue I wouldn't have all these problems.

[abscate]

Anyone who spells conniption correcly will persevere and further.

Dont sweat the chunks - we used to detonate VW engines all the time, wash them out with hose, put used bearings in and drive them another 50k miles

Its not something beautiful and complicated like a cell

[SuperHerman]

Veektor: I looked at Pelicanparts and saw the set was $51.00 - I think you may have bought 5 sets.

So rod bearings $50, oil pan/pickup refresh gaskets/orings around $15, oil filter $7, anaerobic sealant $15, and oil $20.

You need to see how hard it is to pull a main bearing to see if you can get a look at their condition. A set is $116 from same place.

I agree with abscate - you need not build perfection just an operational vehicle. It is never going to be factory unless you strip it down to the bolt and machine everything to spec. Budget approach best in my mind as you have no clue on top end and piston condition.