Print

Email

CAT 3208 Cylinder Block Identification

The 3208 Caterpillar engine was the last of a long line of engines developed as a partnership between Caterpillar and Ford.

By Roy Berndt
The turbo block has two vents for the lifter chambers of the block that the non-turbo does not have. Figure 1 shows the rear lower extremity of the “V” of both blocks. The non-turbo block is plain and just follows suit with the rest of the casting. The counter bored and threaded hole (red circle) is where the camshaft thrust bolt is installed. The turbo block on the right has a cast and machined turbocharger mounting flange in the rear of the block at the bottom of the “V” with oil feed and drain back in between the mounting bolt holes. In the rear of the blocks you can see the last cam bearing bore and the main oil galley plug threaded bore just above it and you get a better view of the breadth of the mounting boss.

You also need to pay attention to the #1 main bearing housing bore register in the block. If it has a center bearing tab locator (Figure 2) you will use the three hole main bearing since that register also has a groove cut into it. If it has the offset bearing locator tab in the main bearing housing bore the block will have a plain single hole main bearing bore register.

Turbo blocks also have piston-cooling jets/nozzles that feed off of the main bearings (see Figure 3). You may find non-turbo blocks that have been machined for these nozzles but actually have plugs installed.

Early 3208 non-turbo blocks had a slightly steeper main bearing cap parting line angle. I was unable to determine a serial number break as to when that happened but if you’re salvaging main caps for block repairs you will want to be aware of it (see Figure 4). One worldly piece of advice on main caps: they need to be tight in the register in the main saddle. If you have a cap that is loose (one that slides in and out with little or no resistance), it has stretched and is out of round. If you have a main cap that is “kind of” loose but still measures in spec, you will probably have a premature main bearing failure at that location. If the caps are tight enough that you need to struggle to get them out of the register, preferably having to wiggle them back and forth, you will be perfect.

If you need to, reclaim the register area of the cap and mill the register face back to a dimension that will keep the cap good and tight in the block register. Then align bore the block, but remember that you have a stacked gear train with this engine, so you shouldn’t be moving centerlines if you want your gears to work.

I know that this information is a “feel” dimension and I have not given you a specific press fit but I am unaware that there ever was a published specification, I can only share a “school of hard knocks” lesson.