High Performance Diesel Engines

Bruce Mallinson
May 2016

The Louisville Truck Show is now over for another year and it was wonderful to meet all of our owner operator friends. I must say this show is like a family reunion, being we have been working the show for the past 25 years. The attendance was down slightly from 81,000 last year to 74,000 this year, and that might have been because the truck manufacturer and engine manufacturers decided to not participate this year. We stayed very busy and did NOT miss the OEM’s, besides, why would you purchase a new OEM built truck with all of the related problems. You can build a brand new truck with a 2002 trouble free engine with 650 to 700 horsepower that will run one million miles and get great fuel mileage properly driven. To me a glider kit is the most intelligent purchase you can make today.

After the Louisville show we were invited to tour the PACCAR Engine Plant in Columbus, Mississippi. Two of our engineers, Debbie and myself were impressed with what we saw, a spotlessly clean well organized facility with American workers who cared about what they built. It’s always nice to see people with a good work ethic, after-all isn’t that what built America? The 13-liter engine is what we focused on and we like the piston, connecting rod combination along with the configuration of the head. The intake and exhaust valves are offset so the exhaust doesn’t have to push past the valve in front of it and both intake valves will receive the same amount of fresh air. The block and head casting are made of compacted graphite iron which is lighter and stronger than cast iron so the engine is several hundred pounds lighter. Another beautiful item on the PACCAR engine is a Holset Turbocharger. Over the years I have had the privilege of working with several Holset engineers, and have the utmost respect for them and the fine product they produce. It was a brilliant decision for the PACCAR engineers to work with Holset and stay away from the turbocharger group in California. Who knows, we may be working on PACCAR Engines in the very near future.

60 Series Detroit Diesel Engines, 12.7 liter DD4 smoking problems. If you own a DD4 and the engine is a PK or GK, it will have 15.0 to 1 compression ratio pistons and if you rebuild it and stay with the OEM parts for that series of engine you are guaranteed to have horrendous white smoke upon start up until the coolant temperature reaches about 140 degrees. This has happened twice to us and a client of ours just had a Detroit Reman Engine installed in his new glider kit and he has the same problem. We have spent many thousands of dollars trying to fix this smoke problem and the only cure is to build the engine to a BK serial number. The compression ratio of the BK piston is 16.5 to 1 which requires a different camshaft, injectors and Jake Brake. Let’s go back to the 1980’s, the Big Cam 400 Cummins ran a 14.0 to 1 compression ratio piston, and yes we had some white smoke until 140 degrees, however it was just that, white smoke. The PK and GK Detroits have a raw fuel smell along with the white smoke. The raw fuel smell is bad, it will permeate your clothes and you’ll smell like an old diesel engine from back in the 1960’s. We love the DD3 and DD4 Detroits, however there is a problem with the OEM parts for PK and GK engine, so we WILL NOT build one, we will convert it to the BK series. Because of this problem, we have invested in the equipment to CC the combustion chamber and the head, and that took place today at our shop. The reason for this process is to find the effective compression ratio, which is the CC’s of the combustion chamber and the head. Keep in mind the valves in the 60 Series head are recessed and on a 4 valve head, that is most of the area of the circumference of the combustion chamber. So even though the piston is a 16.5 to 1 compression ratio, the effective compression ratio is much less. We know what it is and unfortunately I can’t tell you, there are too many other shops reading my articles and learning from us. We will figure out the smoke problem, we have purchased degree wheels and they arrived today, so at the CMC in Council Bluffs, Iowa or in next month’s article I will have more information for you about these two engines. Next week we will have a 15.0 to 1 piston from a PK or GK engine in a block and will CC that combustion chamber.

Balancing connecting rods and pistons, CCing the combustion chamber and head, degreeing the camshaft, and measuring the crankshaft and rod bearings in the connecting rod with a micrometer is called Blue Printing an engine, and that is how we have to build engines.

Please keep in mind that with an overhead cam engine there is a minimal amount of material that can be machined off the block, so we had .012” thicker head gaskets made for the 60 Series Detroit just in case you need to machine .010 or more metal off the block.

There is another reason to mic the crankshaft and bearing in the connecting rod. An owner-operator from Minnesota brought rod and main bearings for us to examine at the Louisville show, out of another DD4 Detroit and they were beat out in 120,000 miles. He had new bearings installed at a Detroit dealership, and now under a pull has a hammering sound coming from the oil pan. The bearings are going to fail again. We think his crankshaft is undersized for the standard bearings. As these engines get older, we have to go back to race car engine building techniques. Whenever we do an out of chassis rebuild on any engine the crankshaft is magnafluxed, straightened, and polished, and the block is lined bored. Both are measured with the micrometer so we do not have this problem with rod and main bearings.

We have had great success with the BK 60 Series, so please be careful if your rebuilding your 60 Series and make sure it’s a BK engine. You will have to call your Freightliner dealership or a Detroit Diesel engine dealership with your engine serial number to find out which 60 Series you have.

We will see many of you at the CMC. We will be building a BK 60 Series at the seminar and will show you how to CC the combustion chamber and the head, along with completely rebuilding the engine from the crankshaft up.

Written by; Bruce Mallinson, Pittsburgh Power Inc., 3600 South Noah Dr. Saxonburg, Pa. 16056. Phone 724-360-4080 Website: Pittsburghpower.com