SVTMike |
05-06-2014 01:47 AM |
Created a unusal problem with a homemade high compression head - F22b2
I doubt anyone has asked this question before. I replaced the head on my 380,000 mile accord (burned valve) with a low mileage head from a wreck. I followed a DIY head resurfacing video on YouTube to clean up my "new" head. I worked it until every low spot on the was removed.
When I compared the two heads I realized I took off considerably more aluminum than I expected. There was at least a drivers license thickness difference in the valve area. On top of that my old head was milled previously when I replaced the head gasket years ago. So all in all I would say at least .0045 was taken off, about a 1.5:1 increase in compression. Always down for an experiment I opted to put the head on the car (after checking piston to valve clearance. So all back together, valves adjusted ect. Now the fun starts.
I know milling heads throws off cam timing. Everything set perfectly as it would be stock the car can barely move. I moved the distributor full advance and I can get around but it stumbling like crazy below 3k and still missing 1 cylinder in the upper RPMs. So I move the timing belt 1 tooth Advanced, car starts fast. I drive around, from a stop it doesn't break up unless you get past 1/2 throttle. Floor it and it feels like I'm missing 1 cylinder until 3k when it wakes up and moves, it has much more power than it had in the past, I was very impressed. The stumble gets more sensitive to throttle input after fully warmed up (open loop?). I tried 2 teeth advanced and the stumble almost is completely gone when warm, except on a hard stab from a dead stop it will do it for a couple seconds and then go, but the power band is shifted too low and it can't turn fast enough for the automatic to shift to the next gear when I am wide open throttle. And it pinged terribly, still pinged even with 93 octane.
I switched it back to 1 tooth advanced and I am trying to think of tricks to eliminate this stumble below 3,000 rpms. I feel like additional timing will solve the problem but the distributor is giving me all it has, unless I can modify the bolt openings to get a little extra advance. :D Perhaps adjusting my valves a bit out of spec might correct this? My goal is to work this out without buying an adjustable cam gear.
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