Issue link: https://read.dmtmag.com/i/680184
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 cool- ant 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 dol- lars trying to fix this smoke problem and the only cure is to build the engine to a BK serial number. The compres- sion 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 Cum- mins 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 ef- fective 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 pis- tons, 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 mini- mal 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 con- necting rod. An owner-operator from Minnesota brought rod and main bear- ings for us to examine at the Louisville show, out of another DD4 Detroit and 24 www.bigrigowner.com J U N E 2 0 1 6 HPD