Head Gaskets & More

Back in the 1980s, the Cummins Engine Company made a .013 thicker head gasket for engine blocks that were resurfaced. It was an ingenious idea, because as the block is resurfaced, the compression ratio of the piston is increased because it’s now closer to the top surface of the block. As the compression ratio increases, the volumetric efficiency decreases and the horsepower decreases. Volumetric efficiency is the engine’s ability to ingest air. A turbocharged engine with a lower compression piston will ingest more air than a high compression piston. So, when the block is resurfaced, the compression ratio is raised.

The thicker head gasket for the Big Cam Cummins engine was an ingenious idea, and now, with all of the diesel engines being overhead camshafts, the problem that it fixed back then is an even larger problem now. As the decrease in deck height moves the camshaft and cam gear closer to the idler gear, it rotates the camshaft. This is a particular problem with the 12.7-liter 60 Series Detroit. Think about this: when the head is resurfaced, it also moves the camshaft closer to the idler gear. So, resurfacing both the block and the head, compounds this problem. But, this is a necessary evil, as blocks and heads must be resurfaced, from time to time, in order to maintain a good seal of the head gasket.

Here at Pittsburgh Power, we discovered this problem with the 12.7 Detroit while building several engines for our clients. There was not enough material to resurface the block and maintain the proper piston to deck height. At this time, we were not thinking about the rotation of the camshaft, we were more concerned with the compression ratio going too high and losing performance. The valves can also hit the piston during a hard pull if the piston to deck height is too high. We are always looking for cures for the engines we work with and, since knowing that the Cummins .013-inch gasket for the Big Cam solved this problem once before, we wanted to make a head gasket for the 60 Series Detroit that would restore the piston to deck height and fix the problem on this engine, too.

It took one year to design and have manufactured a .012-inch thicker head gasket for the 60 Series, but now the first one is in service. On the dyno, we gained 27 horsepower to the rear wheels without changing anything other than the head gasket, and, on top of that, the gear train on the front of the engine got a lot quieter, as well. Other changes we noticed were that the engine ran smoother, quieter and smoked less, even when the engine was cool. If you are in the process of having your 60 Series rebuilt, please have your mechanic check the piston to deck height with a dial indicator, and if it’s at or near the minimum spec, you just might want to install a Pittsburgh Power .012-inch thicker head gasket.

The new programs we have been developing for the 2008 and newer ISX Cummins continue to impress us. With all of the stock emissions still intact, the horsepower to the rear wheels is 600 (which is 705 flywheel horsepower), and the torque is 2,150 pound feet. This engine is completely compliant – you can take your truck to any truck or engine dealership and it will pass the emissions tests. We currently have four of the ISX engines running with this tune and, so far, the emission-related problems have diminished. We feel that we will need to do an emissions tune-up about every 250,000 miles, but we expect these engines to run in excess of one million miles – with EGR, DPF and DEF – and to run perfectly.

For the past 39 years, we have always looked for ways to improve the Cummins engine, and we feel that we have hit a HOME RUN for owner operators with the 2008 and newer ISX Cummins – while still keeping the engine completely legal. You can now have horsepower, torque and fuel mileage, and run in and out of California, and be completely legal and smoke free.

The 2016 Owner Operator Snowmobile Conference is now over, and a wonderful time was had by all who attended. We had a total of 27 people (six of them were women), and we met at the Togwotee Mountain Lodge in Wyoming. The riding on Friday was good, Saturday it snowed most of the day but we still rode, and Sunday we had great riding. Saturday night we watched the movie Convoy and, like last year, as we watched Smokey and the Bandit, the amusing and enlightening comments heard from all of the owner operators in attendance was very entertaining.

This was our eleventh year riding together, and many of the owner operators talked about wanting to get together twice next year. If you have never participated in a motorized sport with a group of owner operators, you are missing out on a great time. We talk trucks, motorcycles and snowmobiles, and ride hard on the mountains. We really need to get together to do a motorcycle trip someday, as well. I want to say thank you to Michelle Buzalsky of Riverton, WY for being our tour guide and avalanche patrol. She is the president of the snowmobile club in Riverton and a trained avalanche instructor. Her husband, Keith, is an owner operator and mechanic, and we really enjoyed their company.

Next year, we will have two Owner Operator Snowmobile Conferences – the first one will be at the end of January, and the second one will be the end of February. I know most of you will not be able to attend both of them, however several of you will, because it was your idea to get together twice a year to enjoy each other’s company and ride snowmobiles together. Stay tuned for more details about these events as the dates get closer.

In the meantime, we are packing up and getting ready for the big Mid-America Trucking Show in Louisville, KY. We will be in the West Wing in booth #69212 – we hope to see you there. And, as always, if you have any comments or questions, I can be reached at Pittsburgh Power in Saxonburg, PA at (724) 360-4080.

About Bruce C. Mallinson

Bruce Mallinson has been a pioneer in the high performance diesel industry for over 30 years. Bruce is also the owner and founder of Pittsburgh Power Incorporated, a company based in Saxonburg, PA that specializes in high performance diesel engines and parts. Bruce has been writing informative articles for 10-4 Magazine’s “gear head” readers since February of 2002.