ok..... first of all ive got to tell ya'll that there's not a dyno available for 70 miles....
my problem is that i have a .05 milled head... and adjustable aem cam gears now.... what is the timming adjustment for this....??? satin gave me mixed answers... i mean has anyone else done this? or am i screw'd and have to drive to a dyno??
#52077, "RE: Ive got a hard one........" In response to Reply # 0
You want to get the timing back to stock first and then tune from there. Make additional timing marks on the inner ring of the cam gears. Set the crank to TDC, then adjust the cam gear, setting the inner timing marks to each other, just like you match them up stock.
Then with the increased compression I would increase the amo0unt of overlap on the cams by adjusting the intake cam gear, leave the exhaust cam alone. If you retard the intake cam this should increase overlap. Play with and you can get a feel for it. But the best results would be to go to the dyno and have concrete numbers to work from.
#52098, "RE: Ive got a hard one........" In response to Reply # 3
It is better to have the adjustable cam gears so the ECU doesn't get confused by the crank and cam position sensors not agreeing. There should be room for playthough. How far off was the timing when you did, my guess is you were probably very close. But you can get more power with the gears.
#52140, "RE: Ive got a hard one........" In response to Reply # 5
Yeah, I mean I get em all the time but you don't hear me brag about it
Seriously though, a dyno will let you tune for power - there's nothing special about a dyno as far as revealing where the 0 mark should be.
One way to be more precise would be to measure/set the valve movement in relation to the crank.
An easier method, but possibly accurate enough, would be to start the 0 mark the milled distance from the normal zero mark. They start out straight across from each other right, something like this --. Well if you shaved .05" from the head, since the belts go nearly straight down towards - you could estimate that the exhaust 0 mark is about .05" lower than -- and that the intake mark is about .05" above --. The marks should be about .1" away from each other on a .05" milled head.
#52141, "RE: Ive got a hard one........" In response to Reply # 5
Oh shit! *LOL* I didnt even think about that!! *L* (topic) Ok thanks guys... imma start from scratch... doing everything TDC(and pray i dont bend a valve) Ill let you know how it goes
#52144, "RE: Ive got a hard one........" In response to Reply # 7
Hold the phone, I'm looking at a diagram of the belts, and they definately don't go straight down. The exhaust side(coming up from the idler pulley) looks pretty steep - somewhere around 20 degrees not 90. It's the exhaust side pulley thats important for this, as it'll "take up" some more belt as it gets closer to the idler pulley because the idler pulley doesn't move. The "slack" is taken up by the tensioner on the intake side, so that angle doesn't really matter in calculating this. Both pulleys will still move the same distance from --. So how much less? With a 20 degree angle, Pythagoras says .02"
So the marks should be around .02" from -- or .04" inches from each other to bring them back to zero degree timing. Sorry about the false start on this, I should have looked closer at the belt angles first.
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