Delete the balance shaft on the Liberty 3.7 engine

[KJlibertyBR]

Good afternoon, I’m rebuilding the entire engine of my Liberty 3.7. The balance shaft is worn out, and so are its bushings. Is it possible to assemble the engine without the balance shaft, just plugging the oil gallery holes? Has anyone ever done this?

 

[u2slow]

I wouldn't try it. It's not hard to find good used shortblock. It the heads that cook off usually.

 

[Shankster]

That would be a bad idea in my opinion. I bet you'd have massive vibration leading to failure of multiple parts. When I rebuilt my engine the balance shaft was bent so I bought a used one from somewhere (I forget where). Replacing the rear bushing looked tricky so I had the machine shop that worked on the block install it. I don't remember having any issues replacing the front bushing myself.

 

[Shankster]

That would be a bad idea in my opinion. I bet you'd have massive vibration leading to failure of multiple parts. When I rebuilt my engine the balance shaft was bent so I bought a used one from somewhere (I forget where). Replacing the rear bushing looked tricky so I had the machine shop that worked on the block install it. I don't remember having any issues replacing the front bushing myself.

I just saw where you revived Pricebill's old post - sounds like he successfully took his balance shaft out of commission. Maybe it's not such a bad idea and hopefully he reports back and proves us naysayers wrong.

I wouldn't try it. It's not hard to find good used shortblock. It the heads that cook off usually.

Agreed, and you can find rebuilt shortblocks for not a lot more money - I got one from flengines4less.com and the cost ($850ish) was comparable (or cheaper) than rebuilding my original motor. Those guys specialize in these engines and seem to know their stuff (the machine shop I used on my earlier rebuild screwed up my crankshaft resulting in catastrophic failure at about 3000 miles). I wouldn't do it any other way now.

 

[KJowner]

When they designed the engine they will have put that nice expensive component in there for a reason. I really wouldn't suggest removing it, it will be there to prevent it from shaking itself to bits!
The bushings and shaft could probably be sorted out by a machine shop if you can't get hold of a good second hand one.

 

[KJlibertyBR]

When they designed the engine they will have put that nice expensive component in there for a reason. I really wouldn't suggest removing it, it will be there to prevent it from shaking itself to bits!
The bushings and shaft could probably be sorted out by a machine shop if you can't get hold of a good second hand one.

Good afternoon,





I’ve completed the full rebuild of my 3.7 KJ engine. I replaced the rod and main bearings, bought new connecting rods since the piston pins had wear, and also installed new pistons. The cylinder heads were serviced, and both the oil pump and water pump were replaced.





As I had asked you before about removing the balance shaft, I removed it completely and blocked the two oil passages that come from its bushings. The engine is running 100% — I didn’t notice any practical difference, no unusual noise or excessive vibration.





The oil pressure at idle at 95°C is 1 kg/cm², which I consider excellent.

 

[Shankster]

Interesting - thanks for following up. Apparently just one more useless hunk of steel Jeep put on the Liberty (in addition to the rear diff counterweight and the rear sway bar).

 

[KJowner]

I'd be surprised if they spent that much time and money on balance shaft, it probably stops the crank doing something nasty ~ like the infamous land rover v6 diesel.
Hopefully you will get away with it.