hi. im going to be really nice here. so please pay attention.



spring pressure is VERY important in valve control. to light of a pressure and it will lose control at higher rpms and the dreaded piston to valve contact happens. this is why stock lsj springs with over 30k miles on them do not like to be revved past 7400. they get weaker over time. as does everything that is constantly being used.

now, if the pressure is too high. it takes more power to turn the cam and more stress on the cam itself, the timing chain and everything associated with that. granted you can run higher rpms and sustain them longer, but you also wear out the cam lobes way too fast and it is over from then on out.

proper pressure choices on what you are doing with the motor will result in a beautiful act of power and rpm. meaning, the engine will be happy and will be able to turn 8k rpms without valve train issues.

you will spit a rocker arm out when a couple things happen. A. the base circle of the cam and the lash is way off, and there is too much wiggle room in there and it works free at higher rpms. which is why you really can't shim an lsj lifter and expect them to stay in place. another way to lose a rocker is if complete valve control is lost. bend a valve, everything comes loose and the devil reveals that you suck and should buy a new motor.

think of it like coil springs on your suspension. to stiff and it rides like hammered dog ass. to soft and you float down the highway. one must find the happy medium.

 

 

Hopefully you make it back alive to see your build........Oh man the army is worthless with these incentives. Thank god for Obama!

 

It's pretty obvious you don't know much about the valvetrain in the ecotec.

But, if you want to talk about lifters in pushrod engines, we could do that on another forum.

The total possible travel in the ecotec lash adjuster is 4mm/.157". However, these lash adjusters get unhappy very quickly when having to take up more than 1.5mm/.060" of lash. IF your valvetrain is setup in such a way that this amount of movement would allow the roller rocker to come off its pivot there are for more issues with your valvetrain than the lash adjusters.

 

You call them lash adjusters, most of the world calls them lifters. Lash adjusters can be adjusted, hydraulic lifters can't. Funny, we can't adjust our LIFTERS. It kind of sounds like you've never had a lifter collapse on you when you needed it the most.

See vid:

http://www.youtube.com/watch?v=stTit...e=channel_page

And if you're smart, you'll know I'm not talking ****, just stating facts. No 30R will make 600whp as pump gas car, I don't care what motor it's on. It just can't support the airflow.

 

meh....between Area and Shab all the answers are there....

 

the vid of a failed race? Lets not play dumb i saves all your funnies you claimed but be supercharged there . What happend to your 500 whp turbo build?

 

Good luck.

 

I know how the valvetrain functions. I'm not talking about the springs. I'm talking about the lack of strong enough lifters to keep the whole thing together. He's not gonna be happy when he spends all this money and all that wonderful spring pressure and high lift bleed out a lifter that can't recover fast enough because it's being overstressed and it sends a rocker bouncing around his head, destroying the poor cylinder that can't get it's exhaust gases out.

I think we've all been through enough motors and monies to know what works and what doesn't. And the stock lifters, when asked to take up a buttload of extra slack and another 2000rpm more than they're used to, don't.

 

As others have said go to atleast a 35r. Also i think its going to be harder than you think to make 600whp. Not saying it wont happen, Just saying i think its gonn abe harder than you think. I suggest you take all the advice area and others are willing to give

 

??? Bush is the one who signed for us to get out, not obama...

 

He don tknow what hes talking about, Like 80% of Americans... But id leave him be so this dont turn into a flame fest

 

they are lash adjusters. they adjust for lash differences as the cam wears on the roller follower.

stick a dry set of them in an lsj and fire it up. it will make noise for a bit. then it quiets down. what happened? it adjusted for it with the use of oil. lifter is just faster to type and say

 

x2.....subscribed incase this build goes through

 

for once, I'll totally agree.

also, note the fact that this IS NOT a "normal" 30, its even SMALLER.

he said 3065, so 30 series comp wheel and a 65mm turbine...christ!

most intelligent people run 28 series wheels on at least 71mm turbine, let alone 30 series.

the turbine will determine spool via shaft inertia and max shaft speed.

that shaft speed will determine the max speed of the compressor and thus the flow it can create.

this small wheel is going to kill what flow hes going to get from the wheel, and even that in a perfect world isnt near the 60lb/min mark.

the SMALLEST 30 series wheel that garrett sells is with a 71mm turbine...there is a REASON FOR THIS FOOL!

you must maintain pressure ratio across the turbo in order to have efficient operation and not just **** small amounts of vary hot air out the compressor.

the "-3" variant is the most favorable assembly combo as its trim is a best fit match. that turbo, at a high-ish 2.7PR only delivers 47-48lb/min, thus a max of about 480hp....at the crank son.

crank the boost to the moon, you wont gain flow. its just how a compressor operates.

 

between you and Shab all the answers are there....

 

Ok streamdreamz. Think about it this way, in a pushrod engine, a hydraulic lifter is directly affected by the amount of pressure from the valvespring. That is because it is between the camshaft and pushrod, directly in the line of movement from the cam to the valve. On the ecotec engine, this is not the case. The camshaft is running directly on the rollerfollower and the rollerfollower is riding directly on the valve. The lash adjuster provides the pivot point for this arrangement, but is least affected of the entire valvetrain by the spring pressure.

 

oh snapps

 

That wasn't a failed race in the least. Someone brought this up on another forum because of all the bickering:

Look at the little green markers on the side of the road. They count off every tenth of a mile. The video is only 18 seconds long and they claim to have started around 50mph. The first 5 seconds of the video is the cars staging and honking. By the time the video is almost over, they clear the span of two markers in about 2.5 seconds. 1/10 of a mile / 2.5 seconds = ~130. They claim to have gone to about 150 and it's clear the camera was shut off before the race was actually over, however it would only have taken about 3 more seconds to see 150. The fact that the vid goes from the 5 second mark at about 50mph to the 18 second mark at about 130 mph, means in 13 seconds they cleared 80mph from a high speed roll. That makes this a pretty legit race between two pretty powerful cars to me.

What happened to my 500whp turbo build? I bought this and started modding it instead of trying to cheat nature by having traction with a high powered FWD vehicle:

 

stock lash adjusters are just fine to 8192 rpms. i have ran them that hard for a lot of miles and have had zero problems. the only time i had a problem is when the base circle of the cam was too small and the lash adjuster destroyed itself trying to take up the extra lash caused by the cam.

the 272's i had did fine on stock lash adjusters
the gmr ones killed them
the stock cams are fine with the right air source to 8k rpms. it all comes down to valve train geometery

 

sub'd

 

LOL uh huh. we know the truth you coudnt do it now you spend your time lurking talking **** in other peoples build threads.

 

Couldn't do what? I have the same plans for the Sky, it's just a better platform to build on.

Again, I know how it works. I've dismantled and rebuilt plenty of them. When the lifter collapses, life ends. Plain and simple. I just won't chance it because you can "get away" with it.

 

Can someone remind me how many people are running engines that have entirely stock valvetrains other than the springs and retainers to 8200 RPMs and exactly how many failures they've had?

 

I would like to see an actualy full built cobalt to 600hp! Hope it dont fail!