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Getting Your Cam Timing Wrong Can Do This To Your Power Levels

Guilt-Toy

By Guilt-Toy,
in Engines & Forced Induction

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Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted

We dyno'd my car back in may and got 487rwhp, since then the boost only went up when i was game enough to use it on the street (not very often)

Ended up with a oil leak and had to change my timing belt (soaked in oil) and some cam seals to fix the issue and when it went back together the cam timing was out one and a half teeth.....

& This is what it did to the dyno results, a loss of 60hp at the wheels on the same boost.

Cant wait to get it back to where it was before put this Nismo clutch in and go down the track! I want some high mph and a 1.7 60 ft :( (yeah its nice to dream)

Anyway has anyone seen this kinda drop in power? the car still feels really good off boost its just lower power & torque... its running .80 lambda all the way through.

Il post a video of the dyno run later

post-1240-1196135858_thumb.jpg

RB30-POWER Mentor

RB30-POWER

Posted
Posted

thats normal to have a loss of that much power when your talking the power your car makes.

you should know more then anyone to turn the crank over twice (one engine cycle) and re-check the timing marks on the timing gears :yes:

however on a side note these are the typical gains that can be had if you have a set of cams that require dialing in with adjustable cam gears, even if you put the cams to factory spec/timing marks you don't make the power you can if you dial them in properly to the engine as per specs supplied by cam manufacturer.

poncams seem to make best power when setup to standard specs however from all reports.

  • 4 years later...
R33 Eddy Proficient

R33 Eddy

Posted
Posted

I know its a old thread but i think i may have the same problem but could be something else as turbo and cams where also fiddled with at the same time.

exhaust mani gasket was changed and cam caps where undone as i was going to remove the head but in the end i didn't so all was put back together, timing checked several times (dots lined up with backing plate mark and crank keyway was straight up)

I get a major flat spot from 3500~ to about 5000~ rpm it just hardly moves up the rev range but still makes 14psi as it did before changing timing belt..

CAN having the timing out a few teeth that when VCT kicks in its choking up?? as it comes sort of good after 5-6000rpm and feels ok good under 3000rpm..

could i have got something else wrong other than timing that would chock it up but still make same boost?

urtwhistle Proficient

urtwhistle

Posted
Posted

Are you still running the RB25? because I would imagine 99% of Guil-toys's problems would have been due to running a Rb3025 like me. which means that unlike a RB25 you most often are required to run 2 tensioners instead of 1 tensioner and a idler. IE on a 25/26 you only have 1 side to cause you greif. Unlike the 30 where you gotta try and balance tightening the timing belt with 2 tensioners while keeping the cams in the correct position in relation to the crank. Well that was my issue with my rb30 any way.

If you do have a 25, I would say your probly right about either the cam timing being out or even the CAS sensor being done incorrectly. like the 1st time I did my motor. I some how managed to time the motor off the wrong wire going to the coils instead of going straight at the #1 coil and the motor was about 10-15 degree's out and drove like an absolute dog.

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