GM techs and Vortec truck owners, Rod Bearing knock?

[sweetk30]

also a big point thats over looked is the newer ones call for 5-30 oil. i ran 10-30 in mine and it was o.k. then switched to 5-30 speced oil and got 10 lbs more pressure and seemed to start better. thay are designed diffrent now and run the thinner oil to help get stuff to the places needed faster and the clearences are set for that weight oil.

 

[sled_dog]

I have never run anything but 5-30 in it.

 

[89GMCSuburban]

I was talking to the owner of an engine shop about putting a serpentine belt setup on my old 400 and he advised against it.
He has a newer chevy p/u an went over to it, started it up, and pointed out the slight knock on startup.
His theory was the extra grip the serpentine belt provided, caused the crank to move untill it got oil pressure at the bearing. He said the engines are still quite tough, they all do it, and GM wont do anything for it. But he would not recommend putting the serp. setup on my motor.
Now that is his viewpoint, but he has much more knowledge than me in this area, so I'm thinking of taking his advise and sticking with V-belts

That don't make sense...like V-belts don't cause any tension on the bearing either? Sounds tarded to me.

 

[sled_dog]

I was talking to the owner of an engine shop about putting a serpentine belt setup on my old 400 and he advised against it.
He has a newer chevy p/u an went over to it, started it up, and pointed out the slight knock on startup.
His theory was the extra grip the serpentine belt provided, caused the crank to move untill it got oil pressure at the bearing. He said the engines are still quite tough, they all do it, and GM wont do anything for it. But he would not recommend putting the serp. setup on my motor.
Now that is his viewpoint, but he has much more knowledge than me in this area, so I'm thinking of taking his advise and sticking with V-belts

imo, he doesn't know his ass from a hole in the ground and just made something up that sounded decent. The noise in newer Chevy's is piston slap, plain and simple. They don't do anything about it because even when they pull the engine and install a new one, it does the samething. its just a normal operating condition for them.

Sidenote: ex-GM tech I work with thinks it is just piston slap... don't know that I agree but I'll ignore it for now, ha.

 

[89GMCSuburban]

Meh, as long as there ain't metal in the pan/oil, you're in good shape. You'd see a bearing going bad when you change your oil.

 

[beater_k20]

Sidenote: ex-GM tech I work with thinks it is just piston slap... don't know that I agree but I'll ignore it for now, ha.

the Gen I engines didnt have forged pistons, and that's where the piston slap comes from. its probably the lower end, without proper oil pressure. causes a slight rod bearing knock. most people cant hear mine, but i hear every single cycle in the engine, because i know exactly what it should sound like. i havent had a pre-86 engine do it, so it may be a redesigned oil passage, or oil pump issue, as a result of the change to the 1pc RMS.