Rep Power: 381

Nobody was able to answer this last time. I want to deck the PNP head I'm almost finished with and need to know whats safe. I know Honda says they can't go beyond the little bumps on the bottom of the head (which I guess to be ten thousandths, but I'd like to go 15 thousandths. I know I'll need a adjustable cam gear and need to run 93 at least but the compression change is worth the shot. Any real techs on this site?

 
Rep Power: 298

Honda service book says maximum resurface .2mm which off the top of my head is something like .0078 in. I think. Also take the shoulder on the head bolt into consideration, Im not sure how much thread is left after the decking. I know its less than 10 thousandths but Honda likes to figure stuff right on the money so I dunno how much thread will be left after bolt stretch. Once ARP starts producing headstuds for us it wont matter anyway.

 
Rep Power: 298

Im a dope they have the info in inches. It says 8 thousandths max.

 
Rep Power: 381

Finally some info. You think the 8 thousands is purely a safety issue (mechanical timing get to a point where an adjustable cam gear is needed)? I'd like to go to 15 thou. use an adj. cam gear and run 93 octane. My only concern is pulling it off without a VAFCII and obviously the head bolt issue. Whats seems strange is that I've heard Honda will dech a head twice before replacing it. Usually thats 5 thou per deck. That would put it at 10 which is still higher than 8.

 
Rep Power: 609

damn, u wanna go 15 thou

i would go no more than 6 or 7

i forget the formula to figure out what you compression would be.

 
Rep Power: 813

Mine is milled 1mm and the stock head bolts went on fine. And I'm only running 89 octane. Should I go higher? I didn't think compression would go up that much.

 
Rep Power: 381

I bet that could be your rough idle issue. If not completely, it's got to be hurting your lack of mechanical timing without the cam gear.

 
Rep Power: 381

Yeah, I've gotta find that formula.

 
Rep Power: 813

Our cars run very rich in stock form. I bet I'm still running rich after the port work.

 
Rep Power: 381

Doesn't the VAFCII allow us to remap our fuel curve? Your new plugs might help that issue out as well.

 
Rep Power: 813

I think my engine is running hot. The iridiums can handle it and haven't fouled, but regular copper went out in almost a day. Would the higher gas really help? I'm paying alot as is. Yes, the vafcII can add or subtract fuel. Most people who had it dyno tuned ended up subtracting like 4-8% even with intake/header/exhaust mods.

 
Rep Power: 298

Yea gearbox only run the good stuff. 1 mm is alot more compression. You can get away with crappy gas but you dont always feel detonation when its happening. Also I bet you are right,rufus, with the whole cam timing thing. I was thinking about that last night a bit and maybe with the cam gear you can get way crazier with it.

 
Rep Power: 381

Definitely. You need to adjust mechanical timing. Here's a solution that I think would work. You spent a load to get the headwork done and still haven't gotten the result you wanted, and even bought the VAFC to tune it. I think a new cam with the VAFCII would produce a mojor change. The only issue is that nobody makes a cam for the D17, only regrinds. Obviously, if we can still run rich we don't need a higher lift on intake, nor do we need larger injectors, but for as much as we're opening exhaust, a slightly higher lift on exhaust could be perfect. Your head works the same still, but its designed to have the Piston at TDC for a reason as the vacuum of the cylinder will pull fuel into the cylinder. On the flip side if the timing is off one of two things are happening: 1) the piston is dropping early and your combustion is actually being used inefficently as the piston wasn't in place to have to most effect on pushing it back down, or 2) the piston is still slightly on the upstroke and the combustion is actually fighting the piston before it reaches TDC. The latter of the two will cause the most loss of HP and damage to the engine.

 
Rep Power: 813

Well I've been using the head for a few months now using regular 89 gas and no adjustments. I've always been worrying about what's happening. I'll try the better gas for sure, and hopefully get some tuning. Someone else with a different DH head said the cam gear didn't need to be adjusted. I've also seen cam dial-in kits at summit racing. I have no clue how to do that tho.

 
Rep Power: 381

My post sounds confusing after reading it. It's not a case of pulling in too much or not enough fuel. Your head works just as it did before. But it's now closer to the block and the timing is the only issue. Call Honda and ask them if they'd allow a head decked as much as yours to go back on the road. If they think timing would be too much of an issue they'll tell you, however, due to safety regulations they might tell you no anyway. We need a tech in here.

 
Rep Power: 298

Yeah a degree wheel would do you good if you can adapt it to our engines, shouldnt be too hard. You can get the kit with a video explaining how to use it. Its really not that difficult. As for cams, ours suck for hp. We need more lift or at least longer open durations.

 
Rep Power: 813

I looked at the degree wheel instructions and it seemed very complicated. I don't know if my timing is off, but the engine still runs smooth. Usually timing problems cause severe problems right away, unless it's only a few degrees either way.

 
Rep Power: 381

Well thats just it though. You bought the head and the VAFC for dialing in the car. You've got almost all the equipment but I'm sure you're unsatisfied and it's simply a tuning issue. A few degrees equals a few HP, ya know. I think I'll finish up the head, deck it about 6-8 thou to be safe and throw an adj. cam gear on. Since I'm not changing the cam itself, I don't need to remap the fuel curve and I'll make up for timing with the cam gear. I'll let you know if I start to foul plugs and that wil tell you right away if that would solve your issue. I think after I pickup the new cam I'll buy the VAFCII. Thats when I think I'll notice a big change, because when I know where the car pulls the hardest on it's own, I can change vtec engagement accordingly.