i searched but couldn't find anything that said exactly what i'm looking for. when i installed my HP4 i didn't change the IP timing. my question is should i change the timing or do a TDC offset or just leave it be? i've got access to a tech II(its sitting next to me at the computer now as i type this). just want to know what to do before i either put the tech II away or give it a shot. thanks all.

checked TDC offset and its at 0.88 degrees. Ian from heath said it should be at -1.94 degrees. i'm guessing for best performance. thats over a 2 degree difference. is that bad?

IIRC it's the "optimal" and suggested (as you found out) timing for the HP4.

but will it lower my mileage? turbine doc said -1.5 is a good spot in his book. since i've got access to the tech II i may try and mess with it next class. wonder what i'll need for tools to adjust everything? the papers i have say a special wrench is needed to loosen the hold down bolts. looks like a tight fit in there so i may be working on it for a while. :rolleyes:

-1.94 is optimal for power, -1.50 is best for power and fuel economy.

currently my truck IP timing is at 0.88. i'll have to adjust it next class. whats the easiest way to do it? do i need special tools to loosen the hold down bolts on the IP so i can turn it and adjust the timing?

currently my truck IP timing is at 0.88. i'll have to adjust it next class. whats the easiest way to do it? do i need special tools to loosen the hold down bolts on the IP so i can turn it and adjust the timing?
Dave, I had a cheap 15mm combination wrench that I put about a 40* bend in edge wise approx. 1 1/2" from the box end. Most repair manuals show pics. of the special tools. Leo