jensenracing77

I am not sure I can ask this question correct but here it goes. Would oil pressure react different between a oil port and a rotating shaft in a bearing compared to the same but the shaft not rotating?

What I am doing is deleting the counterbalance shafts on a Toyota 2.4 engine. The "proper" way is to remove the shafts and drill and tap the oil feed hole and plug it off. With this, I can never add the shafts later if desired. What I want to do it leave the shafts in place but without the gear that spins them. This would still allow oil to feed the bearings but the shafts are not spinning. I personally can't see a problem with this but I am also not an engineer.

66_Jetstar

You will lose a lot of oil pressure like that. The shaft has to to rotate to get the oil film. The oil film takes up the clearance and keeps the shaft centered in the bearings. Without rotation the shaft will be pushed up by the oil psi against the far side of the bearing and oil will **** out between the bearing and shaft. It'll bleed off a lot of pressure off.

BillK

Why could you not just remove the plugs and put the shafts back in if you wanted to later ?

Is this the engine with the balance shaft assembly hanging off the bottom ?

jensenracing77

I likely could but the port has to be drilled a little larger and threaded and thread locker used. I don't think the larger hole would affect anything because the port in the lower cradle would still be the correct size. My luck is that I would not be able to get the plug out later. Yes, these bolt to the bottom.

jensenracing77

That was my concern at first but talked myself out of that being a problem. Then I figured I would ask people that know this stuff better than I

66_Jetstar

I'm not the authority on the subject, but 20ish years ago I worked at machine shop that did mostly dealer work. This was back when there was a near steady stream warped aluminum heads from the big three and some imports trickling in daily as well. Anyway there was some hotrod Japanese motor, a Mitsubishi I think, that had balance shaft issues.. the oem deemed removing the shaft a suitable fix. Many techs saw a flat rate gold mine by doing what you suggested, and they all lost their shirts trying that once. I think most started removing the bearings and reinstalling them clocked so the feed was blocked. That probably still seaped oil pressure but not nearly as bad.