[Cammer-6]

without a lot of fuss you could try using plastigage to see if its centered

[sdbob]

I think we ve all done things when we were learning we look back and say how did I do that. I myself wouldn't be condescending. I remember putting that 389 in my 55 with a slant pan hydro. Everything bolted up fairly easy. Fired the new 389 right up. Oil POURING out of the front of the hydro. I thought seal ,nope . The 389 has a slight bump on the rear flange that the 287 didn't. Flywheel wobbled, Took the front pump out of
the trans. Now what? I happened to have a B&M catalog ,yep they have special machined flywheel for this very thing. Irony I had 2 flywheels when assembling 389 to hydro. One was cleaner so I used that one. The dirtier one was machined to fit the 389 in parts I had bought. Ugh. Live and fall down get back up fall down again! That's the way I learned mistakes then asking questions.

[NeighborsComplaint]

Originally Posted by sdbob

I think we ve all done things when we were learning we look back and say how did I do that. I myself wouldn't be condescending.

We're not talking obscure parts interchangeability issues, this is fundamental machine parts assembly and plain common sense.

We all have Smartphones these days and accepted methods of disassembly and reassembly (even if generalized) are right in the palm of your hand. Google "How do you seat a main bearing cap on a Pontiac V8?" and here is what you get:

"Seat the main bearing caps by carefully aligning, lightly tapping, and snugging them before torqueing in sequence, ensuring proper clearance and thrust bearing endplay."

Before Smartphones, you bought a Chilton's Manual to consult.

[hurryinhoosier62]

Originally Posted by NeighborsComplaint

We're not talking obscure parts interchangeability issues, this is fundamental machine parts assembly and plain common sense.

We all have Smartphones these days and accepted methods of disassembly and reassembly (even if generalized) are right in the palm of your hand. Google "How do you seat a main bearing cap on a Pontiac V8?" and here is what you get:

"Seat the main bearing caps by carefully aligning, lightly tapping, and snugging them before torqueing in sequence, ensuring proper clearance and thrust bearing endplay."

Before Smartphones, you bought a Chilton's Manual to consult.

How many times have you personally replaced the main cap on a block, then align bored it? Me? Couple of thousand times. There are ALWAYS fitment issues; that is why I kept around 150-200 main caps set for the most common blocks we machined. On average, I was able to match a replacement main cap after 8-10 tries. Keep in mind this was a cap that fit close enough to cut the cap( usually .006-.010) so the carbide of the align bore machine was taking the majority of the material out of the cap instead of the block. Then, you have to resize the rear main seal area to prevent fitment issues. Here is my advice to everyone opining here( with the except of Mike G): if you have never performed this operation on an engine block leave it to the professionals who perform these matching operations every day.

[NeighborsComplaint]

Originally Posted by hurryinhoosier62

How many times have you personally replaced the main cap on a block, then align bored it? Me? Couple of thousand times. There are ALWAYS fitment issues; that is why I kept around 150-200 main caps set for the most common blocks we machined. On average, I was able to match a replacement main cap after 8-10 tries. Keep in mind this was a cap that fit close enough to cut the cap( usually .006-.010) so the carbide of the align bore machine was taking the majority of the material out of the cap instead of the block. Then, you have to resize the rear main seal area to prevent fitment issues. Here is my advice to everyone opining here( with the except of Mike G): if you have never performed this operation on an engine block leave it to the professionals who perform these matching operations every day.

Hey good for you. I'm surprised your big head fit through the forum door.

In a perfect world, with motor out and at the machine shop, of course you would have the motor align-bored or align-honed depending on the severity of the misalignment of the replacement cap. The cost and effort is insignificant vs the potential for main bearing failure..

The OP is looking for an option short of pulling the motor out, disassembling and hauling it to the machine shop, but you obviously missed the drift because you know it all.

He is willing to risk the consequences of a short-lived rear main bearing if the "fast-pass" doesn't work out. The inspection procedure I suggested, removes as many variables as possible for a successful outcome in light of the circumstances and his desire to avoid a full teardown.

[NeighborsComplaint]

Originally Posted by Cammer-6

without a lot of fuss you could try using plastigage to see if its centered

damn .... you got me there.

[NeighborsComplaint]

I thought about the plastigage a while and don't know how this would measure runout or eccentricity unless you rotated the crank and checked it every 90 degrees of rotation.

[sdbob]

My mother worked for a very good gynecologist. My father and I worked at their home many times remodeling.the wife said Phil,the Dr. cant even hang a picture. What I'm saying some need time to learn fundamentals. Its maybe easy for a mechanical inclined person. I'm just trying encourage understanding and patience. We need everyone in this Pontiac hobby.