timing woes

[bentvalves]

Hey guys,

Having an issue where I cant seem to establish 15 btdc with the CAS roughly in the middle of its range. In order to get 15deg, the CAS has to be fully advanced.

I double triple checked my mechanical timing, and that **** is spot on. Although many of you have said to never count the teeth, I think Im going to resort to that method and check a 5th time today. When I got my motor back together, 15 btdc was established with the CAS more to the retarded side (clockwise). I then proceded to rattle my timing belt tensioner loose while street tuning, and skipped 1 tooth on the exhaust cam. I got that squared away, and now my CAS is giving me ****.

Tried a different CAS, same thing.

heeeeeelp!

p.s. I do remember someone on this board talking about advancing or retarding I think the exhaust cam 1 tooth for a dyno proven 15 fpt or something along those lines?

I think he was from club turbokillers or something.....A guy from Poland I believe. Anyone ever try this out?

Greg

[r34 gtr]

Well, it can only really be mechanical timing then, since you have tried another CAS and found you get the same problem. Sometimes it can be a tricky little bastid, and you can overlook that skipped tooth. You sure the whole thing isnt out by one tooth on the crank gear or something? Ive had my mech. timing off by a tooth or so many a time and gotten the exact results you describe, but I dont think it has ever been such a pain to fix, visually.

[bentvalves]

yea man i had an extra set of hands and eyes helping out to advance/retard the intake exhaust cam in order to get everything to line up kosher.

Its SPOT on, please god allow me to establish 15 dbtdc with my CAS in a reasonable location.

where are most of you establishing 15 degrees with the cam angle sensor in relation to the timing cover.....more advanced (counter) or more on the retarded sided (clockwise)?

Greg

[r34 gtr]

Well, I no longer use a CAS, but for me it was usually somewhere near the middle. Something has to be out if its that far over. Can you actually establish 15 dbtdc?

Just out of curiosity, how does the pin on the end of the camshaft look? If its chewed up that could probably cause it. I have an extra set of camshafts if you decide you need them.

[bentvalves]

nah the keyway is fine, they are new tomei cams.

wtf wtf wtf wtf wtf wtf

this shyet

is starting

to drive

me crazy

I LOVE my baby, but she better start putting out or I might start chasing her younger, sluttier sister sr20.

[mbmbmb23]

You arent using the pre-indexed Pon Cams are you?

[bentvalves]

yes, yes as a matter of fact I am.

256's 8.8 lift I believe.

What makes you ask this question.

The car makes full boost before 4k rpm, is very responsive partial throttle cruise, light load.

but when I mash my foot into it from 4k-65k it doesnt rev out fast enough and just feels flat. Something is out, I have adjustable cam gears that have also been double, triple checked and are positivley zero'd out.

have you had issues with tomei cams in the past?

[mbmbmb23]

If the Poncams are already indexed (adjusted for timing in relation to one another as a pair) then doesnt zeroing out the adjustable cam gears actually change TOMEI's intended preset indexing/timing? If it were me I'd try the OEM gears just to make sure. Also, is it possible your timing is off 180 deg?

-m

[bentvalves]

When I say zero'd, I mean to stock specs. I lined them up perfectly with the stock cam gears.

At this point Im going to start messing with these gears in 2 degree increments. Normally, you'd start by advancing the intake 2 degrees and seeing if the engine liked it or not. But because im having issues with the CAS being all the way advanced to see 15deg, im thinking of retarding the exhaust cam 2 degrees and going from there.

Or just tossing these tomei cams on the bench and putting the stockers back in.....Im at the end of my rope, not sure what to do!

[r34 gtr]

You neglected to mention you had aftermarket cams AND cam gears. Why not play with the cam timing using the gears until you have the CAS within reasonable limits? I would also suggest the stock cam gears.

The timing cannot be out 180 degrees because when you re-time it you make whatever stroke its on the compression stroke. You just reset the thing to TDC and go from there. Now if you were dumb and used the #2 cyl at TDC you could have some problems.