Need some main bearing advice

[Jeff_Ciesielski]

*Sorry for the long read*
So here is my problem. My car is a 90 TSI AWD, stock bottom end with some headwork done and balance shafts removed. I rebuilt the motor ~3000 miles ago and all of the clearances checked out at the time. Broke it in, and drove it from South Bend, IN to Seattle ( roughly 2200 miles ) without issues. Then about 250 miles later, I started to hear a slight clicking noise coming from the motor, I figured it was a belt hitting on the timing cover...It wasn't.

Slowly, over time, the clicking got worse, then it was two clicking noises I took everything off of the drivers side of the engine to see if I could figure out what the noise was, and it is definitely internal on the bottom end. Judging by the frequency and location of the noise I think that most likely a main bearing spun and caused another to die. So my question is, assuming when I tear the oil pan off next weekend I find a couple of trashed bearings and not something else, given that the motor is otherwise fine ( 150 compression across all cylinders) and I just rebuilt it, would it be better to:
1. Just build a new motor with the core I have sitting on my porch.
Or 2. Pull the transmission/oil pump, drop the crank and put in a new crank/bearings if the journals arent scarred up and plastiguage reads fine?
I know the second option seems like way more work, but honestly, I live in seattle, and my garage is small, so it would be easier to drop the trans and replace the crank than it would be to swap motors out. However, if I get a lot of negative feedback on option 2, I suppose I should start ordering parts :/

Thanks in advance
Jeff

 

[freeman 188]

ok just went through the same thing spun a rod bearing and had to rebuild the whole thing ,you have to get new oil pump, head gasket ,and so on which is a 1000 dollar fix ,so go with the first option maybe cheaper,

 

[jlr2196]

I do not believe it is a main bearing, possibly a rod bearing but that is usually a knock sound and becomes louder as you come up in the rpm. Check your oil pressure, does it seem lower than normal? Generally a main or rod bearing will cause a loss in oil pressure. You need to drain the oil and that will definately tell you if something is going away, you will have metal in the oil. You could just have a simple exhaust leak, that sounds like a ticking noise. Especially if it was freshly built, it is not uncommon for the nuts to back off a little during break in and need to be retightened. If you went all those miles I just can't imagine spinning a rod or main unless you reved it to the moon and even than I can't see it happening, these lower ends just don't seem to spin bearings. You could have a spark plug wire loose too, you would be surprised how many times I've seen that.

 

[Jeff_Ciesielski]

Well, Its definitely not a loose wire, I just replaced those due to one of mine literally disintegrating, plus I changed my plugs recently and made sure the wires were tight. Oil pressure seems fine I really need to get an aftermarket gauge to say for sure, but the stock one reads a little on the high side at all times, which I attributed to the BS removal. I have thought of an exhaust leak, but have thus far been unable to find one. I'll have to stop by my garage some time this week to check again, I'll also drain the oil and check for shavings.

 

[TOONAH]

It seems that a lot of DSM enthusiasts get spun rod and main bearings not long after rebuilding with the BS elimination kits installed. I am trying to analyze this and find the root cause. Hope it is not your main bearings. Why is it always #1 that goes first? Its the first one on the oil gallery. So please let us know the out come.

 

[freeman 188]

well mine spun #3 rod bearing after only 80 km on the rebuild , the way to find if it is a rod bearing is start it up, put it in gear ,hold the brake and give it some gas ,if the rods are bad the noise will get alot louder ,but it is easy to check the oil like they said ,good luck

 

[Jeff_Ciesielski]

I just have to wait till my wonderful 60hr workweek is up Plans for this weekend are changing the oil, checking for exhaust leaks, and if I get sparkles of doom in the oil, pulling the oil pan. Thanks for the input guys.

 

[Jeff_Ciesielski]

*UPDATE*

My oil has the sparkle of doom . There were also little metal chunks coming out, so it is definitely a bearing gone bad. That being the case has anyone here ever swapped out a crank in a car with spun bearings with good results? I'm not trying to half-ass it, but it is an otherwise new motor and I have a small garage, so installing a new motor could present some problems.

 

[freeman 188]

I had to swap mine when I spun a bearing ,the other crank I had for a spare, I took it to the machine shop to have it checked ,it looked good to me but it was beyond the service limit. they sent it out and had it turned 10 thou over ,cost $175.00 had it back in 2 days. now you know how much stuff your going to have to replace .was your block a stock bottom end ,because you should be able to get a used on somewhere in decent shape.

 

[force_feed]

its easier to pull the motor and put it on an engine stand.

if you're going to replace the crank with the motor still in the car, you still gota pull the tranny, head, etc...so might as well pull the engine out to make it easeir on you to rebuild.

Also when you start to rebuild, make sure you use plastigage to check all your clearance on your rods and mains.

 

[blcknspo0ln]

*UPDATE*

My oil has the sparkle of doom . There were also little metal chunks coming out, so it is definitely a bearing gone bad. That being the case has anyone here ever swapped out a crank in a car with spun bearings with good results? I'm not trying to half-ass it, but it is an otherwise new motor and I have a small garage, so installing a new motor could present some problems.

I'm in your shoes as we speak. I spun a bearing about 1.5 weeks ago and it took out my crank. By contrast, about 19/20 well-educated DSM peers have warned against cutting a crank, so I will suggest the same. I chose NOT to cut my crank and bought a used local one for $150. If you think about it, it's the same price as cutting a crank without the chance. I also second pulling the motor to do the swap. It will actually end up being much more difficult and consume more time trying to do the crank swap in the car. goodluck.

If you have a stock engine, just buy a used one for cheap. This way, depending on skill level, your downtime will be minimized. Pull the motor, swap the short block, put motor back in.

 

[crensinivon]

It also depends on how bad that bearing spun. You might have to get one of your rods recut. However pulling the engine and placing it on a stand is your best option. Only the nose of the car has to be pulled in the garage. I pulled plenty of motors while the vehicles were parked in the grass. Head Gasket swaps at apartment buildings that didn't allow motor work so on and so forth. It can be done.

If you pull the motor the car will still roll though.

 

[freeman 188]

you should pull your motor to have it hot tanked to get rid of the metal gone into the oil gallerys ,and good luck on cleaning out the oil cooler which is on with your oil filter ,not a easy task .

 

[crensinivon]

Yeah it's not. Mine cleaned up nicely though with cheap oil and a couple of hot cycles with a good filter. Just make sure you check everything thoroughly though. Any small amount of metal shavings will make it back to the bearings at one point in time or another.

 

[Jeff_Ciesielski]

Well, after having weighed my options, I'm thinking that I'm going to buy a stock shortblock as it will come with a warranty. I'm not looking to make huge power on this car, as there isn't anywhere to use it in Seattle anyway. I'll probably just end up cleaning out my oil pump with wd-40, and replacing my oil cooler with an aftermarket unit as its kind of beat up anyway. Thanks for the input guys