I'm considering leaving the balance shaft out of my 231 as the motor is getting balanced. Has anyone done this or heard of anyone running the motor without it vibrating apart? To me it just seems like extra weight the motor has to turn.
Are you referring to a GN engine having a balance shaft? If so, I don't think there is one, or at least I have not seen a balance shaft in a 87 engine.
I'm in Australia and we use the 231 in our GM Holden Commodore(we call it the 3.8 v6 efi)
The service manual does say the balance shaft is used to reduce the vibration and improve idle quality. I have the motor in pieces and would like to find out what the consequences of removing the balance shaft would be.
If there is one in your engine, I would keep it. At any rate why don't you talk to your local balance shop. My race engine was done by The House of Balance in Baltimore. That engine is so smooth. I am running my stock engine at the present and I can really tell the difference just riding down the highway at cruze speed.
Curious as to what model year the motor in question is.
I have read articles on balance removal in the interest of rotating weight removal on other make motors (MoPar, Mitsubishi, etc.) and have never known it to be a problem. I suppose you do need to insure that critical oil passages would not be left exposed, possibly causing loss of pressure.
There were some pictures of a teardown of a supercharged Series II 3800 motor ('96-present) at http://www.thrasher-ep.com/ but it looks like their site is being redesigned at the moment. These pictures showed the balance shaft arrangement. They may be a good source to ask about this.
Our 'sister' group for the supercharged 3800 cars (http://www.gnttype.org/sc3800/) maintains a mailing list that might be a good forum to discus this.
Strange if you have any pics could you send them or send them to scott maybe he will post them, I also would like to see what eng config this is. But back to the important part, Scott hit the nail on the head if this shaft isoil fed similar to a cam you would have major problems or more like a adache oil pressure problem...like none! unless the passages were taped and blocked off with pipe plugs or similar method of block off. So no matter what your decision look at the big picture, because yes that is extra drag on a eng but I highly doubt it is enough to notice performance wise...good luck
GNs don't have balance shafts. The 3800 in my '89 Riviera has one. I wouldn't remove it even if the engine were balanced perfectly. It also cancels vibration from the natural imbalance that exists in these engines.
The 3.8 was first used in 1988 and is still being used in the current Commodores. It replaced a very smooth 3Lt Nissan motor(RB30)and GM have since been trying to make the v6 smoother by changing the efi, manifolds, cam etc.It is a cast iron motor(heads as well)and looks the same as the 3800 supercharged motor you have in the US.
IS this motor what you call the odd-fire or the even-fire Buick 231?
I'll send some pics of the 3.8 we have here.
Actually, the Holden motor and the US motor are pretty much the same thing. The 3.8 (231) RWD motor pretty much bowed out in 1987 with the last of the G Bodies.
The first 3800 was available in the US in 1988 and from there it has gone through several upgrades ... Series I, Series I Supercharged, Series II, and Series II Supercharged.
They have a balance shaft ...