2006 Jetta w/ BRM conrod bearing failure

[Rezer]

I did a fair amount of work replacing engine components last year when my piston rings wore out, and everything went fine for about 10,000 miles when I started hearing an extremely faint ticking sound while on the freeway. I pulled over and by the time I came to a stop the engine had all but seized up.

I towed it home and the engine turned fine manually, the timing was fine, cam looked fine, so I tried turning it over with the glowplugs removed and it did so for about 3-4 seconds before seizing again. Pulled the camshaft, and it still would not turn a full revolution manually. I pulled the head expecting to see debris in cylinder #4 and an absolutely destroyed piston/valve, but all I saw was a very, very slightly dinged up #4 piston and valves that showed no sign of impact, but the #4 piston was visibly protruding ever so slightly more than the other 3.

I pulled the oil pan and found the #4 conrod bearing (all were replaced along with the main crank bearings last year) had spun around so both halves were on the top of the bore, so the ticking wasn't piston to valve contact...the connecting rod effectively got a little longer and it was piston to head contact. Fun.

At this point I'm working out what to replace, and the head and all pistons look perfectly serviceable to me. The crank is chewed up enough on #4 that I'm thinking it won't be worth trying to salvage without taking it in to get it machined, and I can probably just get a used crank with half the mileage for half the price.

So, onto the questions...

Is a conrod with this kind of bearing damage salvagable? It's not bent, but the big end has some obvious galling from rubbing on the bearing material, though I don't think it has chewed up the conrod material itself. Is it possible to get the big end back in spec with either basic tools at home (i.e. hone + bore gauge) or taking it to a machine shop, or is that just not possible once something like this has occurred? I'd like to avoid replacing it if possible since I just replaced all 4 conrods as a set, but if it's doomed to fail again...

Is replacing a crankshaft as simple as swapping it out, or is there some kind of gotcha in there that's going to make it especially difficult? Other than having to pull the transmission and replacing the rear main seal, that is.

Additionally, all 4 conrod bearings were showing extreme wear, which is strange to me since the car's never been more than half a quart low in the past year. Everything was checked to be in spec with plastigauge, assembly lube was used during assembly, and the car was turned over long enough before starting that the oil channels should have been flowing fine. The oil was drained and refilled after a few hundred miles of running. And the wear pattern is what I would consider deeply strange:

1 on the left, what's left of 4 on the right


It doesn't appear to be the result of contaminated oil, but like the top of the bearing was ablated away by the impact at the top of the stroke, no foreign material required. Here's a close-up of #2:

What in the world is going on here? Did I install these in a new and spectacularly wrong way? Or were they just garbage bearings to start with?

The main crank bearings, FWIW, still look pristine, and the cam and turbo are both undamaged.

 

[325_Guy]

What happened to cause the piston rings to burn up? Folks here are getting many hundreds of thousands of miles on these engines.

 

[pedroYUL]

Prothe parts?

 

[Rezer]

What happened to cause the piston rings to burn up? Folks here are getting many hundreds of thousands of miles on these engines.

Well when I replaced the head gasket previously I had used a green scotchbrite to clean up the block...my best guess is that somes abrasives from the scotchbrite ran down into the pistons and I didn't do enough to flush them out. I never said I was all that great at this, but it's why I was extra paranoid about potentially contaminated oil/bearings this time around. At that time the engine did have 320k on it though.

Prothe parts?

I'm unsure what that is?

 

[pedroYUL]

Where did you get your parts from, ebay, some unknown place?

 

[oilhammer]

I think your best bet is to try and source a good running used BRM engine and go from there.

Aside from cam wear, which I feel can be made to a tolerable length of time anyway, I've yet to see a single BRM lower end have any kind of issue ever, and I regularly see these with 300k, 400k+ miles on them. The lower ends are pretty good.

You clearly had some bad junk in the engine causing some oil starvation problems, but that is water under the bridge now. The whole thing is probably a boat anchor at this point. No sense in dwelling on it too much.

 

[Mozambiquer]

I would ask where the parts came from, but also, were the rod caps for sure in the correct positions? None of them swapped? Were the rod bolts torqued correctly and new?
Those fractured rods can't really be machined like the other kind of rods can be, so you'll at least need new rods (they're balanced as a set)

 

[Rezer]

Where did you get your parts from, ebay, some unknown place?

I just looked up the email and the conrod bearings came from a place called hansautoparts.com...I do remember them being quite a bit cheaper than other places but I figured as long as the oil clearance was in spec then how bad could they be. Pretty bad, I guess. I did a little looking around and found out this is the prothe you were talking about by another name. Luckily the only other thing I ordered from there was an o-ring...

I think your best bet is to try and source a good running used BRM engine and go from there.

Aside from cam wear, which I feel can be made to a tolerable length of time anyway, I've yet to see a single BRM lower end have any kind of issue ever, and I regularly see these with 300k, 400k+ miles on them. The lower ends are pretty good.

You clearly had some bad junk in the engine causing some oil starvation problems, but that is water under the bridge now. The whole thing is probably a boat anchor at this point. No sense in dwelling on it too much.

I see your point, but if the turbo, cam, lifters, and crank bearings are all perfectly fine, is that consistent with oil starvation? I was thinking the same thing until I saw that all 4 rod bearings (and just the rod bearings) were a complete wreck. If it's just an issue with a couple shoddy parts and not oil starvation, would writing off the entire engine still be the right way to go? I was tempted to, but dropping a couple grand for an engine which may or may not be in worse shape gives me pause.

I would ask where the parts came from, but also, were the rod caps for sure in the correct positions? None of them swapped? Were the rod bolts torqued correctly and new?
Those fractured rods can't really be machined like the other kind of rods can be, so you'll at least need new rods (they're balanced as a set)

No, I was aware of how these rods were built when originally assembling it and made damn sure the right cap went with the right rod in the right direction. And all bolts were new, torqued to spec, and checked with plastigauge before final torquing. However, as mentioned above the bearings were likely garbage to begin with.

 

[Windex]

Prothe strikes again....

So many needless tragedies.

Do a search on prothe or rothenbacher on this site. He's aknown seller of crap parts which have destroyed many engines.

Sorry for your loss. Get a used engine and move on.

 

[Mozambiquer]

I just looked up the email and the conrod bearings came from a place called hansautoparts.com...I do remember them being quite a bit cheaper than other places but I figured as long as the oil clearance was in spec then how bad could they be. Pretty bad, I guess. I did a little looking around and found out this is the prothe you were talking about by another name. Luckily the only other thing I ordered from there was an o-ring...



I see your point, but if the turbo, cam, lifters, and crank bearings are all perfectly fine, is that consistent with oil starvation? I was thinking the same thing until I saw that all 4 rod bearings (and just the rod bearings) were a complete wreck. If it's just an issue with a couple shoddy parts and not oil starvation, would writing off the entire engine still be the right way to go? I was tempted to, but dropping a couple grand for an engine which may or may not be in worse shape gives me pause.



No, I was aware of how these rods were built when originally assembling it and made damn sure the right cap went with the right rod in the right direction. And all bolts were new, torqued to spec, and checked with plastigauge before final torquing. However, as mentioned above the bearings were likely garbage to begin with.

That explains it... Hans strikes again. If the connecting rod bearing spun in the rod, it likely damaged the rod, which would need replaced. The crank likely needs ground as well.
I had ordered parts from him before I knew how poor quality his parts were. Thankfully I never ordered anything that was a safety issue.

 

[oilhammer]

Dang, that's twice in one month we've seen Prothe strikes here.

 

[325_Guy]

If it's just an issue with a couple shoddy parts and not oil starvation, would writing off the entire engine still be the right way to go? I was tempted to, but dropping a couple grand for an engine which may or may not be in worse shape gives me pause.

Yes. The bottom ends on these engines lasts virtually forever. You could go to a you-pull-it on half-off weekend and spend $100 on an engine you pull yourself and be miles ahead.