Precups and headgasket

[BorJansson]

I shall replace my cracked head with a pair of used heads.
They are witout cracks and looks good to me, but how can I figure out if they are resurfaced and I need thicker gasket ?
In the new heads there are Turbo precups ( one dot + T).
In the old heads I have economy style ( two dots).
My engine is a non-turbo - 94.
Is there any reason, despite economy, to change cups ?
Will T-cups add more particles and other stuff to the emission gases ?
I have no intention, so far, to change fuel pump settings.

1989 Buick LeSabre Estate Wagon
1994 6,5l GM diesel
1988 THM 700r4

[Robyn]

The "T Cup heads will work fine.

The fuel injection as is will work fine with these.

If the heads are flat and in good shape, your good to go. The thicker gasket is used when the block has been decked.

Be sure that the cups are not below the surface of the head. The rule is from flush to .002" above the head surface.

If they look good dont fool with the cups, just use the heads as they are.

Missy

[6.5TDTahoe]

Since they're off the engine IMO a mag crack test would be prudent use of money. Just think if ,the cracks are there & are leakers the total cost will more than double to fix.JMO.

[Robyn]

The only sure fire method for testing a 6.2/6.5 head is to pressure test it.

The shop should be able to bolt a plate on the head with a rubber gasket that seals around all but the area where the valves and such are.

The cap off the water passages at both ends and then put air pressure on the water passage area of the head to about 150 PSI.

They usually soap the combustion area well and look for any bubbles.

Almost any and all used heads will show cracks between the valves, with most of them being harmless.

Magnafluxing is always good but can miss a tiny leak.

I have also seen Pin hole leaks in these too.

Missy