flashgordon

if your talking about the on next to the timing cover, i just used a standers box wrench on slight angle.

jrussell

Hi Dave,

Ok, I bumped the timing just a hair more so there is now 1/8" between the marks (it sure didn't take much to get it there). I noticed a difference in the sound as soon as I started to drive off. It definitely got a little louder (not straight pipe loud or anything) and a little more "throaty" sounding. Seemed to make a little difference in max EGT's, as I was only able to hit 1300* after an extended run and it is about 95* here today. My last tests were performed with temps in the 80* range and they say 1* in outside air temps = 3* in EGT's. That would mean the hotter temps today = about 45* in higher EGT's. This would put me about 50-55* lower than my previous tests when you compensate for the outside air temps, so the timing seems to have helped.

Now my only question is, should it have gotten a little louder or does that mean I am too advanced? When you normally bump it up 1/8" over stock do you notice any change in sound?

EDIT: I also lost about 1-2psi of max boost (like you said), but that could also be the 15* higher outside temps helping today.

jrussell

I don't know how you do it. Mine has a fuel or air hard-line blocking any and all access to it. I had to use the old hammer & chisel method to get it undone and tightened again. That chewed up the bolt a little, but I think you could still get a socket on it if you had to. I don't have enough extensions to reach it from the back though. If I tighten the other 2 real tight can I get away with a 1/4 turn less on that top-inside bolt?

G1625S

I use 1/4'' drive. 13mm coupled to a universal (wobbler universal works WAYYY better, but the u-joint style is fine) then just a 6'' 1/4'' extention with a 1/4'' to 3/8'' adapter and a 3/8'' rachet for leverage, though a 1/4'' breaker bar will do the trick. With the universal, you can bring the extention up in front of the AFC top and it works pretty slick till the pump is jammed right up to the head, which is usually more than a 1/8'' bump. Try to get all the nuts tightened evenly if you'd rather not see oil pee down your timing case....

flashgordon

i say yes on the the bolts but isn't there 3 that bolt to the timing cover and one that is a brace in the back of the pump!!!!

jrussell

Oop...I have no idea!

I loosened the 2 on top (into the case) and another on the bottom that I couldn't even see. Definitely didn't loosen a 4th one though. It seemed to move just the hair I needed and I just held it in position with one hand and did up the bolts with another. Think that would cause any problems?

wannadiesel

It's normal to hear more clatter with additional advance. If it starts sounding like an old 6.5 liter GM you've gone too far.

I'm surprised you got any movement without loosening the 10 mm bolt at the back. Check that and make sure it's tight, you can crack the timing case if the pump is just hanging by the 3 front bolts.

jrussell

Can you describe the "bad" sound another way. Unfortunately, I have no idea what an old 6.5 GM sounds like.

I wasn't able to move it much, but then didn't need to go very far either. Maybe I'll go back in there today and loosen all 4 bolts this time and bump it up another 1/32" or 1/16" and see how it sounds. Are there any other signs of being too advanced, other than the sound (ie. temp gauge reads higher, EGT's go up, etc)?

flashgordon

I thing that you can get a little more timing out of the intercooled pumps cus thay didn't have as much from the factory but i only advance mine and 1/16 (non intercooled).....and thats all i wanted to go but it responded a lot like you described earlyer.

jrussell

Went back in there to bump it a hair more and find that elusive 4th bolt. Turns out my truck is missing that bolt on the back bracket all together!

So this time I went a little too far and now I know the tinny sound everyone talks about. I also lost bottom end power, but EGT's were a lot slower to climb from 1100 to 1250. Guess I'll back it off some and see if the tinny sound goes away and my bottom end comes back. Also, I didnt' lose any max boost this time even though I moved it further than the first time. I think the first spot I had it was the sweet spot.