2G Spun rod bearing questions.

[Spicyorange]

Now before anyone tells me that I HAVE to have the crank polished at least, and the rod re-sized...
I just want to know if anyone has EVER had any luck just throwing a new bearing in, with the crank in the car still.

I am REALLY sick of working on this car, I've owned it 2 years and put less than 300 miles on it chasing problems, I finally got it running last tuesday, and it ran mint, for the first time ever! (I found a problem with the flywheel that caused a BAD vibration) Then wednesday the f'ing rod bearing spun. I've heard from a couple people that if everything looks ok in the motor and the clearances look ok, that I could possibly throw a bearing in it and get away with it. I'm not looking to get 100,000 miles out of it, But I would atleast like to drive this car through the winter, until I can afford/have the patience for a 6-bolt swap. please let me know if you have ever had any success doing this.

Nick

 

[ivanr4g63]

With the crank "IN" the car still...? as in "without taking it off the block...?"

I don't see how's that posible, if my brain is working properly when you spin a rod bearing most likely the piston rod is damage too, but if NOT then the crank 'must' be at least polished to a mirror finish to ensure smoth functionality otherwise you'll keep messing up the bearings, now if you "FEEL" like the clearances are fine, you should use some plastigage and confirm according to the factory specs and max allowed clearances, if they look ok then go for it, but I definetaly don't recomend it.

Now, if you spin a rod, you may have metal shavings all over the block, you gotta make sure you clean the block and oil pump from this kinda of debree, otherwise the whole rebuild process will be flush down the toilet.

We understand how frustating it could be to keep working on your car and never driving it, my advice is Do it right, and it'll last longer, but... if money is tight, or you don't have the time, or you simply are fed up with the car then sell it, get your self a Beater car, save and buy another "better shape" DSM other than keep dumping money into this headache builder.

 

[Spicyorange]

Well I bought the car as a basketcase, and put it back together and it seemed to run right, so I went through the hassle of converting it into 97+ bodywork, and painted the entire car pearl orange. This took a lot of time and work. But I felt it was worth it. So I don't wanna sell it. But since I've owned it I've had the timing side all apart twice and the tranny out twice. I really don't wanna pull the motor out and apart again. I was wondering if this would worlk

And yes I mean leaving the crank in the car. unbolt the rod cap, slide piston up a little, replace bearing, plastigage, if it looks good, slap it back together. as long as the crank and rod are not scored up.

 

[bigjdog84]

Generally there is a reason why bearings let loose; improper oil pressure, bad clearance, detonation, etc.

You may want to get to the bottom of WHY it happend.

Have you actually removed the oil pan and taken a look to make sure it is infact a rod bearing? The vibration from your flywheel problem could easily spin the crank off kilter and eat up the thrust bearing. I'm betting your problem is going to be a bit nastier than you originally thought.

Now to answer your question about putting in another rod bearing.
Just replacing it more than likely won't last. Your clearance will probably be off, and your rod big end may be out of round. Not to mention the journal will more than likely be scored up.

Good luck
Later/joe

 

[Old Mitsu Tech]

A couple of thoughts. I'm not going to step on your toes, but the truth is the truth. First of all I need to know the profile of your car. I have nothing to go on. Secondly, if you are planning to ditch the car then if you polish and plastigage the bearing and crank you can buy some time. This means it works or it doesn't and can fail again at any time. Usually in the worst place and time. OK? Depends on the amount of damage incurred during the "spin" Now, If you want it done right you need to bite the bullet and pull the engine. Have a reputable machine shop go completely through it. Another option is to find a good used engine and just replace it. It all depends on what you want from the car and is it worth it to you. Personally on my driver I found a good low mile used engine and stuck it in. Spent 600 for the engine and several years later I'm still driving on it. It's cheaper than a car payment. Good Luck

 

[bullettdsm]

Ok, I know what the "official" answer to this is (you've already got that) BUT, yes you can in very limited situations. I'm fully aware that there will be people who want to smoke me on this and, to be honest, their position has merit. But, IF you want to buy some time and IF you did not spin the bearing too badly and IF you haven't banged out the rod end and IF your rod journal cleans up OK and IF you feel you can clean up the particles good enough and IF... I think you get my point.

I have done this before and, oddly enough, I JUST did this on my 97 RS. I actually thought about doing this as a tech article but I felt it would mislead too many. I had a situation of a wife who used my car a lot but never checked the oil (yeah, my bad). So I hopped in and brought it to my usual 8k and heard it pop. I brought the car home and parked it. When I checked the oil I knew what happened. I haven't gotten around to putting together my replacemant engine yet, so I decided do the rod bearings. I popped the pan and did the bearings from underneath. Polish out the journals and use plastigauge. Mine were within spec because I just caught it (this was with 138k on it). Took me all of 1 1/2 hour. I''ll enclose a pic of the bearings for those that want to "read" them. Feel free to PM me if you have any questions. THIS IS FOR VERY LIMITED SITUATIONS!

Oh yeah, PartsDinosaur.com for all your OEM parts. Great service ,great response.
MB

 

[XtReMeToYz]

Well, the last time my friend just "replace a bearing" with the engine in the car to get by it lasted 3 days. He had it towed 10 seconds after the sound appeared. I would say just pull the engine. I know how you feel, I just pulled my built motor back out and back in over the weekend.

 

[Spidey]

I had a bearing get chewed up for an undetermined reason in my 6-bolt with less than 10,000 miles, but it did not spin. I DID however buy a new set of bearings, put them in and used plastigauge, with the motor in the car still, and it has been fine for around 1500 miles now. I was advised that had it spun, not to re-use the rod it spun on, as it causes a lot of heat and fatigues the rod.

 

[osswalam]

I can personally say I have done this and it lasted quite a while (3,000 miles and still going). I got very lucky though. My bearing spun so bad it took material out of the rod and I had to use half a standard size and half the first oversized bearing for it to come out right on plastigauge. I got the crank cleaned while still in the car and did the backyard mechanic slap it back together after quickly plastigauging it and somehow got lucky. You have to step back and look at your personal situation. I have a engine on a stand being built right now and didn't care how much longer the current motor in the car lasted and if anything in the current motor got hurt or destroyed. There really is no correct answer for if it works or not, it all boils down to luck.

 

[Catbox_95]

I've done it in a small block Chevy, along with a piston, in about 3 hours in my driveway, and it lasted dozens of thousands of miles.

Granted it may not be as easy as an old school Chevy, and granted it is just chance on weather or not it will last, but I say go for it. What've you got to lose? Just don't drive it hard.

 

[defrag010]

What I've done before as a side-of-the-hiway fix to an old ford 300 straight 6...

drop the pan, and take the piston and rod out from the bottom.
unplug the injector on that cylinder.

drive.


I had to do that in our work truck this summer when it ran low on oil and spun #1 rod. It got us halfway across the state of oklahoma running on 5 cylinders, and we even ran it like that for a few months after we got back just cause we didnt feel like fixing it.

 

[Defiant]

What I've done before as a side-of-the-hiway fix to an old ford 300 straight 6...

drop the pan, and take the piston and rod out from the bottom.

DSM (and, most motors) have pistons that are wider than the space between the crank bearing webs. They won't come out the bottom.