Rod bearing question

[MattratfTSI]

I just got done doing my first rebuild of an engine. The first start up was great, idled perfect, no ticks, or knocks. Then the other night I took it up the road for the first time, not pushing it hard at all, and when I pulled back in the driveway she was knocking. Im going to pull the pan tomorrow and looks at my rod bearings which got me thinking... is there any way that on assembly I could have gotten a main and rod bearing mixed up? Im saying can a main bearing be accidently put in the rod cap or will it not fit?

 

[Jeff99GS]

No the main bearing wont fit in the rod cap. Here are some questions you need to answer.


1. Did you check your clearances with Platsigauge at least?

2. Was the crank within spec?

3. Was the crank polished?

4. Did you put the bearing caps on the same rod they came off of?

5. Did you put the Bearing Locks in the right direction?

6. Did you torque everything properly?

 

[8urwrx]

Pull off you oil filter and cut it open. See if there is any metal shavings in it.

 

[MattratfTSI]

No the main bearing wont fit in the rod cap. Here are some questions you need to answer.


1. Did you check your clearances with Platsigauge at least?

2. Was the crank within spec?

3. Was the crank polished?

4. Did you put the bearing caps on the same rod they came off of?

5. Did you put the Bearing Locks in the right direction?

6. Did you torque everything properly?

Thanks for the list of questions I need to ask myself. Nothing was sent to a machine shop because I was on a very tight budget. I guess I learned my lesson. I guess ill try to answer these questions.

1. Yes, but I only remember doing it on the main journals. Not rods.
2. Crank was from a 6 bolt automatic. My old one was shot.
3. Very clean...
4.Yes
5.Yes
6.Yes

Ill pull the oil pan tomorrow and let you know what I find. I hope its not what I found last time... metal.

 

[donniekak]

If your engine spun a bearing and you just replaced the crank without resizing the rods, cleaning all the oil passages, and oil cooler, it will continue to spin bearings.

 

[rush2252]

If your engine spun a bearing and you just replaced the crank without resizing the rods, cleaning all the oil passages, and oil cooler, it will continue to spin bearings.

+1 rods stretch and need to be replaced or resized if you spun a rod previously. Also note that if you didnt give it a good flushing with brake clean or some sort of solvent your going to have metal in the engine still.

And 3rd the caps have to go back in the correct order and make sure you didnt flip them 180 they are mated to their corresponding rod and if you mixed any of them up this could be bad news.

Kolby

 

[MattratfTSI]

thanks alot. I thought that some oil/metal could have been still in the block. whats the best way to "flush" it all out? and does a 91 tsi have an external oil cooler?

 

[rush2252]

thanks alot. I thought that some oil/metal could have been still in the block. whats the best way to "flush" it all out? and does a 91 tsi have an external oil cooler?

Ive always used solvent or brake clean. If your taking the motor out and going that route its easier. If you doing it in the car its going to be nearly impossible to flush it all out. IF it has the Engine Oil Cooler Id replace it. I wouldnt risk leaving any metal shavings behind. first time DIY builds are always a gamble and you dont want metal floating around hurting the chances of it working out well.


*chuckles Ill never forget my first rebuild on a DSM. Bought a 99GS with a bad knock. I decided to throw in new berings w out resizing the rods. Well it purred like a kitty and one day running 10mph a rod cap fell off and rod went throught the block behind the A/C compressor. Lesson Learned.

Kolby

 

[dsm'sROCK]

hey the same thing happed to me... i got my crank micro polished and i used the same size new bearings... when the coating wears of in the red bearing it makes a bigger clearence

but you didnt spin a bearing.. all you gutta do is ether : turn the crank a size under or get a bearing thats .005 thicker or so... i

i did that and shes running nice and strong

 

[Jeff99GS]

hey the same thing happed to me... i got my crank micro polished and i used the same size new bearings... when the coating wears of in the red bearing it makes a bigger clearence

but you didnt spin a bearing.. all you gutta do is ether : turn the crank a size under or get a bearing thats .005 thicker or so... i

i did that and shes running nice and strong

The Mitsubishi Service manual states that our Crank is NOT servicable. Its NOT a great idea to have the crank ground if you're trying to make more than stock Horse power.

Polishing is fine
But I would never use a Ground crank and undersized bearings. Just My 2 cents.

 

[rush2252]

first off they dont make .05 bearings. Or Ive never ran across them in my many years selling parts. They usually make .010 and .025 and they are OVERSIZED not Under. MITSU states they arent serviceable because they dont offer to turn cranks at the dealers. If its done correctly you can safely run a crank machined to .010

When you start running .025 + thats when you need to be concerned. Other suggestions find a 95-99 Neon/Plymouth Breeze with the 2.0 SOHC they rock the same bottom end you have to relocate the knock sensor. And Depdending if its 2ga or 2gb youll have to use your cranksensor coil and CAM sensor as they 2ga and 2gb use different style plugs

-Kolby

 

[Jeff99GS]

they are OVERSIZED not Under. MITSU states they arent serviceable because they dont offer to turn cranks at the dealers. If its done correctly you can safely run a crank machined to .010



-Kolby

NO the Correct term Is UNDERSIZED bearings look it up. The OPENING of the bearing is NOW smaller in diameter. Hence the term UNDER sized.

Mitsu DOES NOT reccomend servicing the crank cause that will remove some of the NITRIDE coating on the crank journals.

 

[tsiAWD91x]

i got lucky on my first rebuild.. but i leaned out racing a lexus gs500 and smoked the whole engine within a month after the rebuild ..lession learned i now have 1000X the knowladge since 2 1/2 years ago... gota start somewhere . i now have a side work building dsm motors etc etc.