Turbo Drain pipe - block machining

[gdouaire]

I have looked at several threads on this forum, never got to see what the oil drain return looks like on a OEM block. I did see however a oil return pipe someone pictured (to sell), and it looks like the end that goes back into the block is non-threaded. I also understood that there were different setups offered by Buick over the years. I have also read that there's a grommet involved, again no picture found here nor on google.

Does anyone have a photo of a OEM drain pipe return in the block?

I have NA block that I need to modify to accept an oil return drain, where do I have to drill and tap (I want to use a threaded return)?

And also: from what I see, a valley pan intake gasket would interfere with the oil return, am I not right?

See picture, yellow X marks the spot where it looks OK to have a oil drain return. Valley pan gasket shown but will likely not be used.

Comments (and pictures!) welcomed

 

[michael evans]

what year you modifying for ?

84-85 or 86-87 ?

 

[gdouaire]

For 1979-1983.

 

[michael evans]

Hot air non-intercooled ?

 

[gdouaire]

yep. The turbo setup I bought to adapt came with a rubber drain pipe (see below), not sure if this is OEM, but I don't really want to use rubber.

I'd re-use the flange but for a different setup.

 

[Turbo6inKY]

If it were me, I'd run the drain all the way to a bulkhead fitting in the oil pan, not drill the block.

 

[oddmonte]

On a draw through carb set up the drain tube goes into a grommet in the intake. 78-83.

 

[gdouaire]

Ah! Thanks a lot! Got it. The intake below is for a Riviera of that vintage, I circled the port. I have such port on my Holley intake, I'll use that.

My next question: does that mean that the oil will pour down on the intake pan?

 

[Turbo6inKY]

Ah! Thanks a lot! Got it. The intake below is for a Riviera of that vintage, I circled the port. I have such port on my Holley intake, I'll use that.

My next question: does that mean that the oil will pour down on the intake pan?

View attachment 315607

Yup.

 

[oddmonte]

Mine had valley gasket when I took the intake off. Post a picture of your intake. That has to be a rare piece.

 

[gdouaire]

The grommet / port shown above on the intake is used in certain Buick applications for PCV. I have seen normally aspirated intakes in my 1976 shop manual with the same exact port. Maybe they moved the PCV on the valve cover for Turbo applications, leaving the intake port for Turbo oil drain duties?

 

[oddmonte]

My intake has two holes. One for the drain and one for the psv. I can get a picture of it if you want? My block also has a threaded plug where you marked yours for a hole.

 

[gdouaire]

My intake has two holes. One for the drain and one for the psv. I can get a picture of it if you want? .

That would be awesome if not too much trouble.

 

[oddmonte]

Here you go.

Here is what I am doing to mine.

 

[gdouaire]

that manifold is crowded with ports

So with your current project, that's quite a change...!! what car is that in?

 

[oddmonte]

that manifold is crowded with ports

So with your current project, that's quite a change...!! what car is that in?

80 Monte Carlo Turbo. Converting to inercooled blow through

 

[oddmonte]

Here is what it looked like with all the crap on it!