Valvetrain noise after cam swap

[geldartb]

ok so i bought the cam and the pushrods and spring the whole nine yards, tore into the engine replaced the old parts with the new ones i had put it back together and it sounds like i swapped a duramax diesel in there instead.

heres what went in
99 3400 chain and sprockets.
1357 grind with pushrods from the store here
comp cams springs from the store here

now it made the noise the first time when we started it up, yeah ok its been sitting for three months the oil drained out of the lifter. you figure a couple of minutes it would go away nope it didnt still sounded like i swapped a duramax in there.


fast forward 2 weeks later i started by taking the valve covers off to see if anything was hitting or looked wrong. the only thing that was looked off was one of the spring ate away a little peice of metal from the head where it wasnt ground down from the factory.

later that day my helper Jon showed up and looked over checked a few things couldnt find anything out of the ordinary so we took the lim off checked the lifters found a few that hadnt oiled up yet. ok so the only thing i had with me was the cordless impact so we hooked up some extentions so we could check oil flow, did that and had good oil presure while doing so and all the lifters filled up so you would think problem solved nope after putting it back together still ounded like a duramax diesel.

the cordless impact spins freeload at 1650 and impact and 2600 so it should have been putting out near full idle oil pressure which it was doing a pretty good job at.

im at a loss here on what the problem could be. i mean the lifters are getting oil and the engine has oil pressure about 40-50 at 1200rpm.

any suggestions would be helpful. next are to replace all the lifters with new ones and if that doesnt work it gets pushed out back and burnt.

fyi the engine and lifters only have about 7300 miles on them and this thing ran fine before taking it apart. i find it kinda funny that the lifters failed or whatever while the engine wasnt running and out of the car.

sorry about the long novel

[powerdoctor]

Have you checked your lifter pre load? or clearances?

What kind of rockers?

You may have to take some off your rocker pedistals.

Turn the engine over till you lifter is bottomed out or on the back side of the cam.
Is the rocker loose at this point?

What clearence if any do you have?

Are you sure the cam is timed right ?, just asking here.

I usually like about .004/ .006 preload on the lifters.
Some say .006/ .008

This is valvetrain noise and not spark knock right?

[geldartb]

checked all the lifters they all seemed fine and filled up with oil when we test primed the engine. it definately had good oil pressure.

they are stock rockers.

cam is timed right i used the printout from the all data subscription i have and did everything the way the picture was.

its definately coming from the middle of the engine. it stays with the rpm's as the engine rev's.

3400-95-Modified was the other guy there with me, he was mostly monitoring the engine with me.

the pushrods are the one that ben makes with the cam from the store here so they were all custom measured by him.

[IsaacHayes]

Yeah the only thing other than lifters I can think of is if the push rods are way too short and there is no load on the rocker/etc when the valve is closed but a lot of space for the push rod to bounce up and down.

Are the pushrods in the right places? :P

Did you use the pre 99 chain guide too? You can't use the new guide on the old chain/sprockets.

[Superdave]

you did put assembly lube on the cam for the install right?

pushrods are all in the right spots?

the 99 lower chain sprocket is a press fit, are you sure it's installed all the way in?

oh yah, and you CAN use the new guide with the old chain but you'd have to shave off about 1/8" of the rubber. Smells great

[powerdoctor]

If everthing, lifters rockers ect... is good, you will have to take some off the pedistals.

Why not use the old 2.8 aluminum head valve guides and use the new big block chevy 10mm to 3/8" threaded rocker studs and go fully adjustable with roller rockers?

I loathe non adjustable valvetrians.....

[geldartb]

all pre 99 stuff for the chain sprockets and guide.

bottom sprocket is on all the way.

we checked it with the pushrods mounted and the rockers tightened down and there wasnt any movement so the pushrods are the right length.
one of the valves on the front head was mostly open and it had no excessive movement.

pushrods are in the right place. the first time before i put the egnine back in the car i made sure it rotated freely and it did before i put it back in the car.

burning rubber hmm cant say i miss that smell everyday use to work in a rubber factory they make shoe soles

[SappySE107]

Don't touch the pedestals. You want .020 to .040 prelease, .006 is no where near enough. Those pushrods aren't designed for valve guides either.

How does it run? Do a compression test on the cylinders and see what that turns up.

[geldartb]

it runs fine aside from the sounding like a diesel. i havent touched the idle from stock yet, so it lopes down to like 4in vacuum. had to reflash that when we first started it cause i had it turned down before it was idling stock before the cam at like 1200.

the only thing ive done to the pcm was flash it for the different injectors.

[powerdoctor]

Just because "those" pushrods won't work with an adjustable valvetrain does not make it a bad idea though.

I was wondering if the new cam is leaning out his mixture too much and he is getting "ping" or spark knock.

Your reflash may need reflashing...

[geldartb]

i didnt get to turn the fuel pressure down so its still 55 psi so the injectors are prob hitting 36lbs instead of the 30lbs which they will become.

they are the series 1 supercharged 3.8 30lb injectors.

in the pcm they are set up to flow the 30lb rate, just havent had it running long enough to change the fuel pressure.

[SappySE107]

Very well could be the tune. Thats not a small cam you have in there now. If the fueling is off, it will run like you describe as well. If it has compression on all cylinders, the pushrods are fine. No point in going adjustable if you don't need it. That is what the custom pushrods were for I would go with the crane gold race rockers if anything, but that isn't cost effective for everyone.

[geldartb]

the only part of the fueling thats off right now is the pressure at the rail. might go give that a shot tomorrow its suppose to be warm. other than that its setup in the pcm to run the 30lb injectors.

the tune is not really a tune its basically the tune i did when the engine was stock, so its basically just 1 run into a ve tune so not really much done to that.

the check engine light flashes while the cars running but it doesnt give me a code when i read it. so i cant really tell what thats all about cause its not giving me any info/

ill try anything before i rip into it again. so any ideas are welcome.

ill try changing the fuel pressure and snap a quick vid if i can. it actually idles all by itself without stalling comes pretty close but it stays alive.

the crane gold race ones are nice but it brings me back to not justifying the cost for the same ratio if you guys dont remember the thread i made and i beleive posted in another.

[powerdoctor]

Your right to a point.

The added benifit is not in the ratio, it's in the roller tip , valve stem wear, and adjustability plus a more ..... how should I say this... "stable" high RPM opperating potential over the stock rockers.

[gpse3400]

These engines make valvetrain noise when you put a cam in with your kind of grind. Its normal. You are moving the the valvetrain pretty hard it is going to make a bunch of noise.