The great wall of 4200-4500 rpm

[YGspider]

So, I've done lots to my Turbo T and it runs and idles very well. With exception to the tap the car makes at hot idle... Anyway the point i'm getting at is the car will not go over 4500 rpm. The knock gauge will come on strong or it will buck back and even with out knock it wont get over 4200-4500. I'm planning on getting I rebuilt cam sensor as a first resort and if its not that i'm starting to wonder if a wiped cam lobe can cause this type of issue. What RPM should these cars shift at? 

[YGspider]

So, I've done lots to my Turbo T and it runs and idles very well. With exception to the tap the car makes at hot idle... Anyway the point i'm getting at is the car will not go over 4500 rpm. The knock gauge will come on strong or it will buck back and even with out knock it wont get over 4200-4500. I'm planning on getting I rebuilt cam sensor as a first resort and if its not that i'm starting to wonder if a wiped cam lobe can cause this type of issue. What RPM should these cars shift at?

I'll post some Powerlogs when I get a chance.

[Steve Wood]

Thought some one told you it needs valve Springs

[278CIKILLER]

Steve they don't listen.

[YGspider]

Thought some one told you it needs valve Springs

I've also said at least 3 or 4 times they where replaced during the rebuild...... I don't think a new set of valve springs is going to wear out that fast in 20 km?? All I'm asking is can a cam sensor cause big issues and can a whipped cam lobe make a car pretty gutless?

[stratman]

You never know what to believe when someone says they changed something and they really didnt. Mine doesnt go past that either but i get around to that next year and im glad because i would probably just go faster anyways and get in trouble.these guys know these cars inside out so if they say you need springs i would go buy springs no questions asked besides they wont break your bank  If you really wanted to you could buy me a set too so i get off my ass and replace mine too

[Steve Wood]

I thought you said they were claimed to have been changed, but, never mind...I am sorry for wasting your time.  Won't do it again

[YGspider]

You never know what to believe when someone says they changed something and they really didnt. Mine doesnt go past that either but i get around to that next year and im glad because i would probably just go faster anyways and get in trouble.these guys know these cars inside out so if they say you need springs i would go buy springs no questions asked besides they wont break your bank  If you really wanted to you could buy me a set too so i get off my ass and replace mine too

I've looked through the oil fill hole with a light and camera and the springs are changed I know what the stock ones look like. But hey what do I know? 

[YGspider]

I thought you said they were claimed to have been changed, but, never mind...I am sorry for wasting your time.  Won't do it again

I know the engine was rebuilt by a piece of shit that stole peoples money and turbo cranks and that the engines where built by a good shop that just followed the orders of a so called "TURBO Buick expert" sorry for just wanting to get back on track with a car that has never run right? From my inspections the valve springs are not the stock hardwear. I really don't know beyond the valve springs that's why I'm asking about symptoms of internals.
Also do you think weak valve springs could create a KR issue trying to get over 4200?

[motorhead]

Just because the valvesprings were changed doesn't mean they are correct for the car.  The camshaft if installed incorrectly could also be limiting your topend.  As for weak valve springs causing KR... I am unsure?  However anytime your valvetrain is out of sync you are going to have problems.

Disconnect your wastegate rod and wire the puck FULL open then go and see if the car will break 4200-4500rpm.  Takes boost out of the equation.

[PacecarTA]

are you running a catalytic converter?

[firebird_1252]

My non expert opinion is valve springs. Also why flog the shit out of it when you know there's a problem? You said there is a "tick" at idle? Might want to look into that.

Also how much knock on the scan tool?

[YGspider]

My non expert opinion is valve springs. Also why flog the shit out of it when you know there's a problem? You said there is a "tick" at idle? Might want to look into that.

Also how much knock on the scan tool?

Well all the "experts said to ignore the tick. And I'm not flogging the car I'm trying to get readings as soon as I see KR I back off. obviously I want to fix the tick. But you cant just fix a tick that will cost 3000 grand in new parts and maybe I will miss the part that is ticking all together.
 
Yes the car has a brand new magnaflow high flow cat and the boost is very quick to build.
 
I'm just trying to kill the small issues before I decide if I really should pull it apart and check internals this winter.

[278CIKILLER]

I have a motor sitting here built ARP studded form top to bottom fresh heads with new springs with a good port job new 208/214 cam with new lifters 10/10 turbo crank yours $3700.00 and keep your motor for a spare this motor was used for one summer never to the track, just have to add a few of your parts from your motor and away you go, then you can tear your motor down and find out whats wrong with it. then you will have a spare.   

[trashmechlv]

Im not a turbo Buick expert but I am a heavy truck mechanic for a living. Just because a part is new or low miles doesn't mean anything. I have seen many parts come out of the box defective or bad. What is the reputation of the engine builder? Pull off the valve covers and have a look in there. Turn the engine over by hand and watch the rockers. You could remove a set of valve springs and have them tested. A new set only costs $45 shipped to your door. Listen to Steve and the other guys on this website. I have learned tons of info and fixed many issues on my GN with their help. You will figure it out.