Oversized head gaskets may not be something you would normally think about when repairing or rebuilding a Caterpillar engine.

As the 3114, 3116 and 3126 (2-valve) engines age you may encounter engines that have or will require thicker (oversized) head gaskets. IPD does not offer these oversized head gaskets at the time of this publication, but our intent in our tech bulletins is to help inform you of issues within the engine ranges that we do offer products for.

Items that could cause issues include the block deck surface to crankshaft center line measurements decreasing due to machining of the deck or the line bore of bearing journals. Be aware that the last machine shop may not have stamped the block so you may need to do your own inspection to tell which head gasket is correct for the engine you have. There are a number of ways to determine whether a standard or oversized (thick) head

gasket is correct.

• Measure the block height. Cylinder block deck to crankshaft centerline.

• Measure the thickness of the existing head gasket.

 - Standard gaskets have an assembled thickness of approx 1.5mm (.060”)

 - Thicker oversized gaskets have an assembled thickness of approx. 1.75mm (.070”)

• You may be able to identify the old gasket by a remaining part number or by the gaskets profile. Standard gasket have a straight edge, whereas the thicker oversized gasket should have a series of notches cut in the area shown below.

• Look for previous machine shop stamping to indicate block height. According to OE publications, if the block has been remanufactured by them there will be a “TG” stamped on the remanufacture tag located on the upper rear corner of the block or on the center tab on the top surface of the block.

3126B – 3 valve engines are not addressed in this bulletin and to date the OE has not released oversized gaskets for those applications.