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cam timing question

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210 dsm

15+ Year Contributor
268
24
Dec 6, 2007
san antonio, Texas
ok recently i changed a bunch of things on the front of my motor. balance removal, timing belt, auto tensioner, oil pump gasket, blah blah blah. anyway as i put everything back together the exhaust cam gear was off one tooth. i turned it over by hand just to make sure before starting it and it was all good. today i timed them perfect and now my question is "why am i feeling a slight power loss?"... now im not to sure on what "retarded" and "advance" means when it comes to cam timing ,but the exhaust timing mark was one tooth above the spec. mark. so in other words "counter-clockwise".
should that slight timing difference really effect the power like i felt?
AND
is it bad to have the exhaust cam off like that?,i thought the intake was the one that would make a power difference?
thanks.
 
Yeah man, you should try and get that gear back in true time. Having either gear off a tooth means that you are not fully seating the valves in the compression stroke. If you’re interested in really dialing in a cam you need to get an adjustable cam gear instead of putting off time one tooth. In all honesty I'm not sure why your motor isn't knocking/ticking with is one tooth off time. To answer your question about the timing terms, retard is to pull or reduce your timing, advance is to increase. I wouldn't really advice you to modify the base timing. You can help control some predetonation like that, but the adjust is through the entire timing curve, not just the point in which you are experiencing the predetonation.
 
I think what he was saying, is that he FIXED the timing and he now feels a power "loss."

It's hard to say when all we have to go off of is that you were off a tooth...you could have been advanced or retarded. If you advanced your exhaust, your exhaust valves would open quicker...retarded...they open slower.

But if I had to guess, I'd say you were advanced a degree (for the sole fact that you said you had more "power")...just leave the timing stock though. You don't really have to worry about messing with your timing unless you start modding internally.
 
thatblondechick knows what im talking about.
its not like i dont know which way it was set . the exhaust mark was one tooth ABOVE. not below.
and with that said, also understand that our motors rotate clockwise. and my cam was one tooth counter-clockwise. thanks for the response :thumb:
 
well since it was driving out of time, it might have a slightly bent valve. do a compression test to check. and if its for some reason still out of time, recheck your timing becuase it has to be almost perfect or else it wont run correctly. To "thatblondechik" being advanced or retarded dosn't mean opening quicker or slower, it means opening too soon (advanced) or too late(retarded), it being off time isnt going to effect the valve speed.
 
well since it was driving out of time, it might have a slightly bent valve. do a compression test to check. and if its for some reason still out of time, recheck your timing becuase it has to be almost perfect or else it wont run correctly. To "thatblondechik" being advanced or retarded dosn't mean opening quicker or slower, it means opening too soon (advanced) or too late(retarded), it being off time isnt going to effect the valve speed.

i have perfect compression. but having good compression dosent fix timing issues so i dont see how that matters.
it takes more than one tooth to hit a valve. trust me. and if that were true about not running correctly while not timed, then i dont see why they would sell adjustable cam gears as they would make everyones car run like crap. but what you say about the definition of retarded and advance sounds like its right. so i guess i can say that my cam WAS one tooth retarded.
a friend of mine told me that because the exhaust was opening later then its suppose to that i was building boost quicker since it takes longer to let out the compression through the exhaust valves. hence the increased power i was talking about.
 
Your right, but it is a perfect explanation for a loss of power, maybe not the case here, but valid. The adj. cam gears are for when you have altered the factory lift and duration of the cam. The maximum point of valve depression will benefit from an adjustment in the cam gear position. I'm running BC 280's with no adj. gear and don't have any problems. The adjustment you would make is also very minor, certainly less than the equivalent of a full tooth.

Another theory on your temporary increase of power could be that the exhaust cam is opening at a later point in the exhaust stroke, and could possibly be providing a more time for combustion. It would have been interesting to observe the EGT's and WBO2 readings in a situation like that. I would suspect that you were lean and hotter than normal which is a good combination for adiabatic efficiency.
 
It's still early and the coffee isn't working yet.

Since the cam was one tooth counter-clockwise and the engine rotates clockwise, the cam was retarded from it's normal timing. This would cause the exhaust valve to open later and close later compared to stock. The closing later would also increase the overlap during which both the exhaust and intake valves are open and that might have added a little power but I assume this was all measured with the butt dyno which is notorious for inaccurate results.
 
i have perfect compression. but having good compression dosent fix timing issues so i dont see how that matters.
it takes more than one tooth to hit a valve. trust me. and if that were true about not running correctly while not timed, then i dont see why they would sell adjustable cam gears as they would make everyones car run like crap. but what you say about the definition of retarded and advance sounds like its right. so i guess i can say that my cam WAS one tooth retarded.
a friend of mine told me that because the exhaust was opening later then its suppose to that i was building boost quicker since it takes longer to let out the compression through the exhaust valves. hence the increased power i was talking about.

actually i "alluded" it in this previous post. reputation points! reputation points! LOL
ROFL
 
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