Well earlier this year I found myself a core IP and resealed it. While I was at it I did a few things internal to gain more fueling/power. One of these things was to gain more dynamic timing.

To do this I had 2mm milled of the retarded side of the timing piston. From another thread someone had determined that this gains you I believe about 4-5deg of additional advance.

So the main purpose of my posting this is to give my findings. When I originally installed I advanced the pump gear one tooth, but still with the pump rotated to the head I still didn't fell like I had enough timing. So I jumped the gear ONE more tooth, for a total of 2 teeth advanced from stock. So now I finally can get more advance than needed, with the pump to the head it sounded like a gm 6.2. haha

So I backed it off some. But now what I really need to do is get the timing gauge and really set it right. Hopefully in a month or so.

So seat of the pants, this thing pulls to 3500rpms with no sign of power drop off, this is also with a pretty good haze of greyish smoke trail. So i'd say the additional timing really helps the high rpm power. Maybe someday i'll run it on the dyno, but who knows.

So anyways, if you have your IP apart i'd really recommend doing this, and go ahead and jump your gear TWO teeth.

Aaron

 

Man, mine was NOT happy with much more than "to the head" with the stock timing. It would surge awful under a light load. I'm only about 1/16" past "to the head" right now.

Which side of the piston did you shorten?

 

I took 2mm off the retarded side, so it gave me less base timing. So by jumping the gear advance gave me the same base timing, but more usable dynamic timing.

I lost the diodes in my alternator so once I get that fixed i'll be able to drive it more with 2 teeth advanced.

Aaron

 

OK, that's what I figured you'd done. My truck ran strong at full power, but just cruising along at highway speed it would buck until I backed the timing down a little. YMMV.

 

Yeah haven't gotten on the highway with it yet, soon as I get the alt on i'll give it a test.

But until I jumped 2 teeth I couldn't get enough timing to make it rattle, and even with 2 jumped teeth it wouldn't rattle until the pump was turned to the head. So I have plenty of room to back it off. Man I really need that timing tool.

Aaron