I posted in the performace section, but i havent gotten the response i really need and i thought that being here would help out. When i changed my timing belt, my head was warped to the point where 50 thousandth had to be removed to reinstall. Well now i have a hesitation problem that just not curable with bolt on parts. One response to my question said that my timing needs to be changed to compensate for the compression change and the missing 50 thousandths of an inch. When i reset the timing, how should the timing gears look? I need details in order to fix this problem. Secondly, what compression ratio am i looking at with this much taken off? Third, is this actually my problem? Thanks for your help

With .050 taken off the head, I would guess its at LEAST 1 point of increased compression. You will need to get some adjustable cam gears to compensate for this. Anytime you mill the head, you have to retard the cam gears. I cant remember exactly what it is, but for every x amount of thousands taken off, you retard 1 cam degree. I would start there and see what happens. Someone else may have more insight to this also.

I cant really get the adjustable gears right now, i just need to know how to position the cams once i redo/retard the timing. Thanks

Without cam gears, you will need to time the motor as stock. With adjustable gears, you would time it as stock, and adcance/retard the gears as needed (maybe a degree or two). You aren't near a half of a tooth, yet, so I wouldn't worry too much about cam timing.
-=B-=

Would the timing being off a degree or two cause any type of hesitation or problems starting in the morning?

My guess is you are probably in the range of 10.5:1 to 11:1 compression ratio, all other things being equal.

As for cam timing the only way you are going to bring it back to stock is with adjustable cam gears. Then you want to find TDC with the crank sprocket. Then adjust the gears so they line up as they would in relation to each other stock. I made a mark on the inner part of the cam gear so I could see where they were in relation to each other when doing these adjustments.

Yes cam timing being off can cause problems. And are you sure it was 50 thousanths and not 5 thousands? To need a mill of .050" you would have had to warp the ever loving piss out of that head.

What exactly does the car do?



15.9 @ 86.7mph

Smooth idle? We don't need no stinking smooth idle.

Mods List:
http://highlander.dsmpower.com/sig.htm

from what i understand my head was extremely warped and was milled 50 thousandths. I resently reset my ecu after fixing a leak in the fuel line and now from second gear to fifth gear i get extreme hesitation up to 4k rpms, then the car jumps and takes off as it would normally. Other than that i dont know what to tell you, it just feels like the car is misfiring like hell up to 4k rpms. Does this help?

My head is milled 40 thousandths and it is supposed to be 10.6:1 compression. It takes off fine except that it idles rough, no matter how I adjust the cam gears. It does seem to kind of jump, but after 2k rpms, it is just normal smooth acceleration. I don't think that cam gears could really smooth out my car any more because I tried a large number of settings. However, my head is also ported, so that might be the cause too. Maybe you need to try one heat range colder spark plugs since you are probably running around 10.8:1 compression (guessing). Try closing the gap on the spark plugs closer also. Mine are set around 0.030" (around the range of a turbo car's spark plug gap) because it runs worse with a larger gap.

Do either of you have an S-AFC to adjust fuel? What do your EGT's and A-F ratio look like? It may be a tuning issue...



15.9 @ 86.7mph

Smooth idle? We don't need no stinking smooth idle.

Mods List:
http://highlander.dsmpower.com/sig.htm

all i have is an air fuel gauge and its showing that im running lean. I'll go one bar into rich and full into lean while driving down the road. I have the one range hotter plugs and they are gapped to .050. Im thinking this could be the culprit. Any more info?

edit, i gapped the plugs to .035, ran the car and the hesitation was still there. It wasnt as bad as before but it was still there. I came back and gapped the plugs to .030 and i can see a difference in the air/fuel ratio. The gauge seems to read a bit richer now. I still have this hesitation and im really starting to get irritated with it. I have alot of driving to do in the next weeks and i really need to get this under control. Im going to give the ecu another day to learn and i'll get back to you. After a few days the car seems to work itself out. We'll see. The crank angle sensor is the last sensor on the motor that needs to be replaced, could this be the culprit? The car just doesnt have any pick up until 4k rpms and it seems like a misfire but who knows. Any help?

You seriously need to get adjustable cam gears. If your head is cut .50 then you cams are probably around 8 cam degrees off. WAY TOO MUCH!! You need to degree your camshafts.

well, when its cooler outside the car runs much better. The hesitation goes away alot longer than when its pretty hot outside. What could this mean? Also, when i start the car in the mornings it sounds like its going to cut off, then idles normally.