Cam Timing- How Far Out With Stock Cam Gears?

[unique1]

hey guys i have a built 26/30 with stock gtr cams, and the tensioner setup as per the pdf and an idler as well. Im interested to know how far out people have found the cam timing from the reccomended specs?

Mine is very very down on power and we did a check with the degree wheel and it was from memory spot on for the exhuast side and 4 degrees advanced on the inlet (might of been the other way round, it was a while ago).

I cant seem to find the missing power and its dying at around 5000rpm and not making anymore power. This is a 3076r 0.82 and ive changed the muffler thinking it was that and its on 19psi and makes that boost at 2900rpm but only managed 316rwhp before i swapped mufflers and now it seems a slight bit better but definately not in the 400hp range by a long shot.

Im thinkin try some cam gears and have a play with cam timing and see what happens but if its gonna do stuff all i dont really want to outlay for them when i cam buy something else.

The exhuast is 3' all the way to just before the diff and then 2 x 3.5' race series magnaflow mufflers, manifold is a steam pipe job which seems perfect for flow and i do experience some boost creep so it must flow alright. Other mentioned mods are a trust drag intercooler, 3' cooler piping, 50mm hks gate, autronic smc, stock coils, no porting and stock cams. Motor is fresh rebuilt with stock pistons and leakdown and comp tests are spot on too.

Im pretty tame on the ignition timing but dont want to push it with cast pistons for the sake of a few hp. We chucked a couple of degrees in it and it didnt make alot of difference and would up another couple of psi and same deal.

i had a similiar thread a fair while ago with a dyno sheet of the old tired motor and blamed the 300 000km engine but its all fresh and new now so im stuck for ideas and ready to sell the turbo and buy something bigger in the hope it will fix it.

[MBS206]

I'd be more looking at possibly the turbo restricting the setup...

3076R is a perfect turbo for a 2.5L... Touch small on the 3.0L isn't it?

[Swiper the Fox]

I'd be more looking at possibly the turbo restricting the setup...

3076R is a perfect turbo for a 2.5L... Touch small on the 3.0L isn't it?

ive got a T04Z here with a 1.0 rear housing which your 26/30 would love.

[bubba]

Pretty sure Brad already has a T04Z lying around

Doesn't Al(?) have the same turbo on his 30 with no restriction?

[unique1]

plenty of others are making over 400rwhp with this turbo and 3L setup. They also saying it pulls hard to redline, which mine doesnt. I personally think its way too small but thats because im used to t04z lag on a 2.7l and the hit that comes with it, this 3076r doesnt do it for me at all in its current state of tune.

I have a hks t04z lying around paul thats going on the other 26/30 in building as abit of fun, see how long it last for with stock internals, should be a great match for it. Then this 3076r will end up on that motor and ill be probably going low mount twins for this stagea engine, lookin at 2860 -10s as a possible option.

I have a feeling i did the cam timing measurements wrong and think its about time i double checked everything as its the only thing i can think of that could be restricting it.

Edited October 26, 2009 by unique1

[Guilt-Toy]

timing issues with twin cam 3 litres are a pain in the ass. keep trying. it took me months and months to fix my engine over a year ago...

I ended up doing the timing many times and found the engine made the best power with the cam gears set to 0, you can try to put 2 x cam gears on and setting everything to 0 and test to start this. after this then try and move them around for more power. First try and get it in stock position.

To give you an idea, i gained a extra 50 - 60kw at the wheels after fixing this cam timing issue, was a major head f**k but i was very happy when i finally managed to fix it.

From memory mine was allways out on both the inlet and exhaust side. it was only very minimal and did not look like it was far off but it did make a major difference in power!

[Swiper the Fox]

timing issues with twin cam 3 litres are a pain in the ass. keep trying. it took me months and months to fix my engine over a year ago...

I ended up doing the timing many times and found the engine made the best power with the cam gears set to 0, you can try to put 2 x cam gears on and setting everything to 0 and test to start this. after this then try and move them around for more power. First try and get it in stock position.

To give you an idea, i gained a extra 50 - 60kw at the wheels after fixing this cam timing issue, was a major head f**k but i was very happy when i finally managed to fix it.

From memory mine was allways out on both the inlet and exhaust side. it was only very minimal and did not look like it was far off but it did make a major difference in power!

properly degreeing them is the only way to go, didn't Pricey do this for you the slackass?

Edited October 26, 2009 by DiRTgarage

[unique1]

Hey thanks guilt toy i have a feeling its the problem due to the lack of top end power and theres a midrange dip in the curve too which is strange, not to mention the lack of power.

Paul what are you using to get an accurate reading off the bucket to do cam timing? i am struggling to get anything on the bucket without hitting the lobe as i spin the cam around which is throwing the readings off.

If i could find something to do this accurately then im sure i could get the cam timing spot on but until then i dont trust the readings i am getting. As someone said to me its impossible for one cam to be different to the other due to the timing belt joining them together, only both cams can be out the same measurement.

Guilt toy if you put your cam gears on zero then isnt that just the same as using stock gears? Or do u mean so that all the timing marks line up spot on?