Join Date: Nov 2004
Location: Sumner, WA & Clam Gulch AK
Feedback Score: 0 reviews
yeah, and depending on what engine (7.3 in particular) if you just slap on the bigger turbo without addressing the restrictions in the heads, you will have significantly reduced the efficiency of the design. You can end up with higher back pressure without getting significantly more air into the combustion chambers, which certainly leads to more "bang" for the buck alright- especially when you pump up the pressure and don't bother with heavier springs. Suddenly you have valves that blow open hitting pistons, blown head gaskets, failed PMR's, out of control EGT's, intake temps that you wouldn't believe as the air compresses in the "necks" before reaching the bowls, puked turbos, turbo lag, blown hoses and intake plenums, etc. Ignorance is bliss- right up until reality bites.
Porting my 7.3 heads helps tremendously- 100 degress lower temps and aprox 75 more hp, but it was so time consuming (100 hours) and such a filthy PITA that I'd never do another set of them. It's not cheap either- a die grinder with a compressor big enough to run it (or big heavy electric die grinder), numerous carbide burrs (some of which can kill you because of their length) , and about a million sanding cartridges are spendy, as well as very hard on the elbows, wrists, lungs and sinuses. I was offered $2,000 to do another pair and said NO. Mine are for sale for $2,000 if anyone is interested. New valves, seats, guides, hypermax springs, hardened pushrods, all with 10,000 gentle miles on them. Two bent valves (a very easy and inexensive fix) from an unrelated incident- a Cunningham connecting rod fatigue cracked and broke off. That was the last straw for me and I began the process of converting to a Cummins.
BTW, I documented the entire process on here a few years ago- don't know if that can still be accessed.
Porting is such a nasty job that I paid someone else to port my 5.9 cummins head.
clam the powerstroke grinch
2000 Excursion LTD 4x4
Slightly tweaked HPCR 5.9 Cummins
Allison 1000 5 speed auto