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1G Rear balance shaft bearing came loose

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
I’ll try to keep this short. Built short block with about 1k with balance shafts and new bearings. Break in oil looked normal and nothing seems off. Been adjusting oil pressure by shimming the oil pressure relief valve nut (the big one). Finally got it close all the way through the rpm band. I haven’t gone wot until this was fixed. So did several wot pulls and everything was fine. Last one I did, the oil pressure was only at 50psi at about 6k so I let off and drive it home. Next morning I start the car and there’s a clack every 10-15 seconds. Turned the car off and looked around and didn’t see anything. Started the car again to figure out where it was coming from and the clack changed to a constant rattle. Pulled the motor and found the rear balance shaft bearing came out.

Checked a rod bearing and it looks fine so I assume the mains should be alright.
Oil pump gears and front case looks fine also but going to double check that.
Balance shaft journal in the block looks fine.
Balance shaft is slightly scored and barely feel grooves.

What do think caused this?
Could the bearing have been installed backwards? Not sure if that
Is it possible to install a new bearing at home?
Is the balance shaft toast?

Again, sorry for the long post.

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Since that bearing doesn’t have an oil port, I assume it gets oil from the crank spinning. If that’s the case, could the girdle prevent oil from getting to that bearing? It sits right behind the girdle. @kiggly

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pauleyman

DSM Wiseman
7,280
2,199
Nov 19, 2011
oklahoma city, Oklahoma
Since that bearing doesn’t have an oil port, I assume it gets oil from the crank spinning. If that’s the case, could the girdle prevent oil from getting to that bearing? It sits right behind the girdle. @kiggly

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No. It's oiled through the shaft.
No way would I try a bearing again. This is one of the only time I would say a bs elimation is required. I don't think I could trust the block to retain a bearing.
 

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
No. It's oiled through the shaft.
No way would I try a bearing again. This is one of the only time I would say a bs elimation is required. I don't think I could trust the block to retain a bearing.
You’re right! That’s the last option and I may have to go that route. Just check oil pump clearance and we’re good. .003 on the driven gear and .004 on the drive gear.

BSE will increase oil pressure, correct? And I can leave oil squirters in?
 

pauleyman

DSM Wiseman
7,280
2,199
Nov 19, 2011
oklahoma city, Oklahoma
I'm sure you're aware it's common practice to port the oil filter housing to alleviate high oil pressure
 

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
I'm sure you're aware it's common practice to port the oil filter housing to alleviate high oil pressure
Yes. It’s slightly ported now but I’ll have to port it a little more.
For the front balance shaft, can I knock out those bearings and reuse those? They’re brand new.
 

pauleyman

DSM Wiseman
7,280
2,199
Nov 19, 2011
oklahoma city, Oklahoma
Yes. It’s slightly ported now but I’ll have to port it a little more.
For the front balance shaft, can I knock out those bearings and reuse those? They’re brand new.
For a shaft I would say no but for a bs delete yes that's what I would do. Flip em and reuse them.
 

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
For a shaft I would say no but for a bs delete yes that's what I would do. Flip em and reuse them.
Yup. I don’t have the oem tool so planning on finding a socket to do this. Is that how you get them in and out?
 

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
I use the oem tool or flip the shaft and use it.
Socket may work as you not real concerned about the edge
So the inside bearing is smaller than the outside bearing (closest to front case)?
 

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
A 32mm socket works. For the deeper bearing, I taped half the bearing onto the socket and drove it half way in then removed the tape. Not too much damage but definitely don’t use this method when using balance shafts. New gaskets and bse kit is less than $100 so not too bad. Just hope I can deal with the vibration. Thanks guys!!

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Dericsh

Supporting Member
895
274
Nov 25, 2002
Pearl River, Louisiana
I think you made the right decisions for the BSE here. Any history of that block spinning that bearing out before this?
Let us know your opinion of the vibration, hopefully not too bad!
 

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
I think you made the right decisions for the BSE here. Any history of that block spinning that bearing out before this?
Let us know your opinion of the vibration, hopefully not too bad!
No prior issues. It has 130k and all the old bearing (including main & rod) were all mint so I have no clue why it popped out. Yeah me too but I’ve read some people regretting doing it so we’ll see.

Going to order parts now. So the only things I need are the stub shaft and the cover for the front bs, correct? And the gaskets involved.

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1990TSIAWDTALON

Moderator
8,593
4,498
Nov 14, 2013
Independence, Kansas
Are you reusing the bearings, just rotating them 90* to block the oil holes?
Stub shaft with oil groove and the rubber stopper plug for the front balance shaft hole in the front cover is all I can think of.
You can take it apart from the front, but I take the oil pump apart from the back and install the stub shaft so I don't have to remove the castle plug and oil pump pulley.
 

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
Are you reusing the bearings, just rotating them 90* to block the oil holes?
Stub shaft with oil groove and the rubber stopper plug for the front balance shaft hole in the front cover is all I can think of.
You can take it apart from the front, but I take the oil pump apart from the back and install the stub shaft so I don't have to remove the castle plug and oil pump pulley.
I rotated the bearings already, just the fronts. No bearing for the rear. Yeah I’m not touching the castle plug.
 

DSMPT

DSM Wiseman
1,750
1,310
Jun 12, 2014
Japan / Mexico, Arizona
Tony, Isn't the shaft sleeve on pump gear cover oval? or doesn't have too much play where the stub shaft goes? Just in case, you should inspect it. Because the balance shaft bearing pops out easily when the shaft contacts the bearing for some reason besides improper installation of bearing or the block side bore is enlarged/damaged.
So the inside bearing is smaller than the outside bearing (closest to front case)?
Correct, like 1mm different.
 

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
Tony, Isn't the shaft sleeve on pump gear cover oval? or doesn't have too much play where the stub shaft goes? Just in case, you should inspect it. Because the balance shaft bearing pops out easily when the shaft contacts the bearing for some reason besides improper installation of bearing or the block side bore is enlarged/damaged.

Correct, like 1mm different.
I just measured it with calipers as I don’t have a telescopic gauge that small. I’m getting .05mm difference 90* apart. There is very minimal play when I put the shaft in.

If I put the drive gear in the front cover by itself, it slopes around quite a bit. Is that normal?
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talon77

Proven Member
230
81
Sep 12, 2004
annapolis, Maryland
A 32mm socket works. For the deeper bearing, I taped half the bearing onto the socket and drove it half way in then removed the tape. Not too much damage but definitely don’t use this method when using balance shafts. New gaskets and bse kit is less than $100 so not too bad. Just hope I can deal with the vibration. Thanks guys!!

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Is it just me, or is a small piece of that bearing missing at the seam? No idea if it's ok to run like that, but just figured I'd point that out to you in case you missed it.
 

TK's9d2TSi

Supporting Member
5,777
2,897
Sep 11, 2017
Cincinnati, Ohio
Do you have a pic or video?
There’s a video in post 21


Is it just me, or is a small piece of that bearing missing at the seam? No idea if it's ok to run like that, but just figured I'd point that out to you in case you missed it.
It spread a little when I was installing it. It’s the seam where it’s joined and won’t be an issue since I’m not running balance shafts.
 

talon77

Proven Member
230
81
Sep 12, 2004
annapolis, Maryland
Ok, glad you are aware and that it won't be a problem. I will be in a similar boat as you with oil pressure with the BSE in my build, except my NT block doesn't have oil squirters so I will have to keep an eye on oil pressure as well. I pre-emptively ported my 1990 oil filter housing as much as I felt comfortable with... I'm hoping that my oil pressure stays reasonable. Good luck!
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