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I recently discovered low compression in one cylinder due to bad exhaust valves. I removed the head and had it serviced by a machine shop. After re installation, I now have perfect compression across the board. However, it hasn't run QUITE perfectly ever since.
Symptoms:
Slightly lumpy acceleration (occasionally)
I have had to advance spark timing more than normal (about 20 degrees BTDC) anything lower and it runs even worse, not sure if this is just because I am at elevation.
Anyways, I would like to confirm that I have the timing correct, please take a look at the following pictures and let me know what you think.
Did you turn the crank by hand a few revolutions to insure the timing still lined up?
Yes I turned the crank after I removed the valve/timing cover to line up the marks, not only that but I have put about 500 miles on it since I originally took the head off.
Just trying to diagnose why it isn't running perfect... it's close, but not perfect.
Yeah it is, he needs to rotate it to verify tdc at cams and crank. If he did it wouldn't look so loose, also don' try to rotate it counter-clockwise if you miss your mark.
line up the crank pulley to TDC (just like you have it in one of the pics).
loosen up the belt tensioner
use a 12mm socket wrench/box wrench and slightly rotate the cam gear bolt (CW)
tighten belt tensioner
Follow up: You guys were right, opened her up and found a mightly loose belt. I had not even considered, when I had the head machined, they said they milled it a tiny bit, which no doubt resulted in a looser belt. Thanks to the great people here, the belt is now tight like a tiger and she is humming along nicely!
Just wanted to say thanks to all of you who took a look at my post, I love Honda Tech, one of the main reasons I have been able to keep this beauty running strong for nearly 14 years now, you guys are the best!!!
Great news! I wonder if this could benefit from adjustable cam gears, to correct for the milling.
If the the cam gears are still lined up and at TDC there's no need for adjusting cam timing, if you do that you should know your PTV clearances and set ignition timing and have a aftermarket tuning ems to properly time and tune the fuel maps. Using the stock ems is fine as long as cam timing is not adjusted.