Valvetrain noise after cam swap

[3400-95-Modified]

Ok, parts in run for a little while, noise quieter, but still there slightly. He's gonna drive it for a while to see if it goes away.

Now question is... Idle Vac

1357 cam Adv Dur:284/290 LSA:112 IC:108 Lift:515/515 He said he's getting around 6-7in's of vac...

My cam
278/289 adv dur .517/.568 lift 112LSA I get about 13in's

so why is his vac so low? would you guys think intake leak somewhere? or does that sound right for that cam?

[SappySE107]

Spark advance?

[3400-95-Modified]

I think his table is stock... Not sure on that one.

[gectek]

yah id up the spark maybe more...but that is low for that cam...the adv dur doesnt have as much of an impact as the .006 and .050 .006 is when port velocity becomes significant enough to measure and the dur at .050 will show mostly the ramp of the cam...that has more to do with vacuum than just flat out adv dur. you can have a cam with adv dur of 280 and .006 at 270 and .050 at .260 and itll run alot worse than one with 280...240...210, diff lobe diff ramp diff characteristics

[3400-95-Modified]

ok then,

His is a 230/236 at .050

Mine is a 216/240

[gectek]

yah that makes alot of diff, not so much the exhaust dur as the intake...thats what is killing him...u may still check for leaks, but on his GA itll idle VERY high if there is a significant leak. like above 1k...if he wants more vacuum idle, he will have to mess with the idle speed and raise it up...thatll help

he must see quite a bit of overlap...

any audio of his idle right now???

[3400-95-Modified]

No, he is currently at the dentist, and when I heard it a while ago when I was helping him it was pretty agressive, I cant say it was worse than mine but definately had a unique sound.

[gectek]

ok, just wanna hear it, kinda makes me wanna go more aggressive with my cam now...dang im such a waffler

[3400-95-Modified]

There is a vid way back in the begining of this thread, like page 9... but that was with a high idle.

[gectek]

i can wait until a new one magically appears...lol

[bszopi]

There is a vid way back in the begining of this thread, like page 9... but that was with a high idle.

Lol, at the beginning of the thread - page 9 - I am currently on page 9 with my settings (30 posts per page).

[geldartb]

nice guys ill get a vid for you guys next friday. tomorrows kinda shot with my grandmothers birthday and well sunday i dont do shit on sunday.

but it def does have a unique sound at idle. sounds pretty good and the noise is still there but its getting quieter, FWIW when i first got it back together with the new lifters you could hear the noise over the exhaust while standing behind the car outside, now its still there but getting quieter.

runs and drives pretty good i just gotta fix the idle it dips down kinda low sometimes, and i also forgot about the rust that accumulated on the rotors wow took a few for that to burn off car didnt want to stop.

just noticed it today but im getting a little black smoke out the rear. never was there before and you can def smell its running rich. im gonna swap out the o2 sensor with a new ac delco one cause whats in there is a few years old anyway.

i didnt go rippin around with it just a spin around the block, but it seemed to run good and sounds good too, forgot what old betsy sounded like while driving.
once i get things set ill start takin it to work for the break in process about 200 miles a week to work so it should be good.

oh yeah i got a scan i gotta pull off the laptop so ill edit this when i do which will be in a few mintues.

my scan from today
oh yeah im running the 30lb injectors from the series 1 3800 at like 45psi or 43 cant remember and the correct ifr table in the bin

[SappySE107]

Your idle fuel is horrible. injector ms is way too high and the fuel trims are trying to fix it but yeah...tuning there and that will fix your vacuum too. Also, why does your TPS show .39% in there from time to time at 0%?

[geldartb]

i dont know about the .39%, if the rest was at 0% it was prob when i was decelerating which still wouldnt explain the 0.39. prob the thing tweaking out on itself.

270.52 is the ifr i got with the series 1 injectors from the flow rate from witchhunters site

http://www.witchhunter.com/flowdatapix/b0280150934.jpg

ive recalculated the flow rate for 28lbs which is what these are and that gives me 283.5 for a injector flow rate so ill try that one which should make it run better and not blow raw fuel out the pipe

my o2's are wicked low too, i know there suppose to bounce around but there kinda hanging around the high 20's.
ive got a brand new ac delco sensor im swapping in to replace the old one in there.

[gectek]

because of the overlap from your higher dur you should expect some unburned fuel out the ext. and also it may be a bad TPS...sometimes when the wiper contacts a bad spot on the resistors, like an open or corroded spot, it will momentarily go haywire, then when you go past it itll be ok...i would swap that TPS out...also it dips low because you havent adjusted the idle right...it sees a higher pressure in the manifold so it thinks its revving too high and will try to kill the rpms..then when it sees its trying to dye itll bring it back up, and up and down and up and down...its a vicious cycle