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Discussion Starter · #1 ·
i am timing a 96 gt with pi heads.

ok get this. i did the procedure twice and the marks all lign up perfect and then once i rotate it 52 times they line up again so i know its right. but yet i hear noises, idk if its valves hitting pistons or what but i did not force it. also the passengers side timing chain gets loose and then tight and then loose and then tight and it slacks up the chain then tightens it again. the passenger side tensioner it half way out and the drivers side one is barely out with no slack.
 

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blackmustang09:

What kind of cams? Bigger cams in PI heads on an NPI block can indeed have PTV issues (duration is the problem, not lift). Lots of threads about this. The solution is to degree the cams. (This is not due to any problem with your work but it is due to the sloppy keyways in the cam gears. The slop results in cam timing being off +/-4 to 6 degrees (worst case). Even degreeing may not eliminate PTV because some durations require notched pistons. I am no expert on this subject (not by a long shot) but I have read many, many threads about aftermarket cams and have learned a little along the way.

The tensioners require oil pressure to maintain proper tension. Maybe the passenger tensioner ratchet is broken and not keeping things snug? Kind of a pain but you could take it off and check the ratchet mechanism. If you are degreeing the cams then taking the tensioner(s) off will not be a big deal.

Chris
 

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Discussion Starter · #3 ·
yea i have just pi cams so i didnt think it should happen. but no i took the tensioners off to bleed them w a c clamp then put em back on and i saw no problems. if there is ptv issues would i be able to turn it over by hand still and just bend valves or would it stop.

and if this helps i hear the tensioner release its pressure when the chain tightens on it.

i have pics of my pistons at tdc im gona look at that then look at the lobes of the cams and see if they match bc i have the heads torqued on already. i kno bad move.

i just wona be sure i dont mess up my brand new heads!!!!!!!!! ahhhhh!!! headache
 

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the slack issue is normal if you dont pull the stoppers out on the tensioners far enough.
 

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blackmustang09:

Worry not! If you've used the "assembly line method" of timing the PI cams in PI heads (or NPI heads for that matter) then you will not have PTV issues. It is the lumpy aftermarket cams where things can get dicey.

HTH,

Chris
 

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I had the same issue where the timing chain gets loose and then tight, etc, etc. If you watch the tensioner piston as you rotate the motor you'll see it goes up and down, which it shouldn't do. All I did was make sure the little ratchet in the tensioner was out as far as it could go. To do this I puched on it with a punch to get it to go to the next ratchet. It's possible this will be taken care of when you start the engine, as the oil pressure could force the ratchet out all the way, but I'm not sure. I felt better being able to do that with everything apart. Hope this helps.
 

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One more thing, the noises you're hearing could be the chain getting taut and slapping against the chain guide(s). I had this same thing when I swapped cams on my car.

Like nyuk98gt said, you shouldn't be having any PTV issues with the stock PI cams. As long as you lined up everything, like you mentioned in the first post, once the chain is taut you should be good.
 

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Discussion Starter · #8 ·
cool cool thanks alot guys i thought i did it right but i did push the little rachet out and its fine now. i do know the sloppy keyways is an issue. would you guys recommend new adjustable gears, there kinda pricey for some good ones just wondering if there tottaly nessesary because i have a few things left to do such as gears and injectors before i send it to more power or pauls high performance for a dyno tune.

thanks alot guys
 
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