As to problems from the system- the same design actually came from the racing industry, known as gear drive. The idea that vibrations go through the gears into the injection pump and cause issues is as ignorant as can be. Ignorant as in someone is uneducated. The db2 pump used in gm before the ds4 is the same db2 pump used by the ford 6.9 & 7.3 with the exception they run a reversed rotation than us, and they have 3/8” fuel line going in where gm had it changed to a 5/16” line. The db2 in the Ford outlasts the one in the GM dramatically.
Stanandyne builds this same style db pump for countless diesel engines across all kinds of manufacturers. I remember a guy doing a search on how many engines and think he gave up after 35 engines, only 1- the 6.2/6.5 platform uses a chain instead of gear drive.
People try analyzing vibrations but seem to have no concept of “chain slap” that occurs every single time the engine starts, stops, or has hard acceleration.
There is a power penalty that is paid for gear drive, and the higher the rpm the greater the penalty is. If ons of dyno runs on different engines have been done testing them in different engines. High rpm is affected the most as is lower compression engines, especially when naturally aspirated… well that leaves us out as we never break 5,000 rpm, we have ridiculously high compression, and I don’t know anyone putting in gears that hasn’t added a turbo if they are still n/a.
On my race truck I did dynos with chain and with a gear set I had made at a local machine shop back in the 90’s before DSG came out with it. At that time I was running nitro-propane and my shift point was 4,300 rpm & obviously most the internals were custom. My power “loss” was about 7hp and 10 torque was our best estimate, but the chain couldn’t withstand 3 miles so the power loss meant not scattering the engine when the intake valves hit the pistons.
So people can theorize all they want. Some of us lived it.
There was a question in did Leroy get the timing marks in the correct position or not. That is as easy as lining up the gears with the chain system.
The pictures I saw of a 6.5 and of a p400 that had problems, I saw the timing mark off from where it should have been. I’ve heard people say there was some made wrong but still wait for evidence showing it.
There is speculation about a 4° advance of camshaft being built into the DSG and therefore copies by Leroy. If that is the demise of an engine, it would have failed at about 60,000 miles anyways because chain stretch is easy to track for guys running db2 and who use a timing light to time it, we have to advance the timing every 30,000 miles to keep it accurate when everything is stock.
I would not get really upset over not being able to have a gear drive and running a timing chain, the quality chains will last and ds4 will self adjust for the chain stretch. If you are really pushing a lot of power, a d poured a lot of money into a build and have to run a chain, I would just plan on running 120,000 miles, then open it up for a new chain, do front seal and water pump all at the same time.
