this really sucks. sometimes it makes me want to part the car put it back to stock and sell it but i dont want to. i want to burn out y brand new nittos dammit!

i just hope its something small and i can fix it asap. i have owned the car for about 7 months and only had it in my possesion and using it for 2 months. it was parked for about 4 months. and about 2 weeks at the mechanics. and now its been 2 weeks at the current mechanics. this really sucks.

so is it safe to say that we have narrowed it down to

cam
roller rockers
cam
timing
computer?

 

Cam: Was the cam degreed when it was installed? if it's off, that could make a HUGE difference. The timing would be all wacked out.

Roller Rockers: Doubtful. You'd know it because more than likely you'd hear it too. I don't think rockers would cause the car to not rev over xxxx rpm.

Timing: See Cam

Computer: Who knows?!?! If it ran on the stock computer like it ran on the tuned computer, probably not.

 

to be honest with you. i dont know what degree the cam was put in. the mechanic did it and i dont know what he put it in. but im gonna take it back to him to see what he says. i am just wondering so i know more or less whats wrong with it so maybe i can save some money. even tho if its their fault, i am not paying for anything. i hope this is settled soon.

i was thinking computer, cam/timing.

the new mechanic said maybe the lobes were rounded off?

 

Ok, someone correct me if I'm wrong here, but the LT4 Hotcam is set up for a 4* advance. If the cam isn't degreed in when installed, you could have a way more advanced or retarded timing, right?

 

lets say the cam was not degreed correctly.

does that mean the cam is messed up? or can they just fix it and reinstall it?

 

I don't know jack, but if the cam is a 4 deg advanced cam and it is installed straight up or according to marks, then it should ok.

If you didn't change out the old lifters (if indeed they were really worn) then it probably would have been a good idea to have done so.

I guess I will just have to respond as some others have and simply say that " something was not installed correctly"

I would go by the numbers (process of elimination beginning with the simplest/most obvious problems.

Spark, fuel, timing etc.

 

Second that...check for proper lash and correct timing chain install.....the hotcam will run fairly well on stock program.

 

good. so we are narrowing it down to the valves? cus i recall the mechanic said something bout the valves. and i did have a new stock timing chain installed.

 

It has 4* of advance built into it. Just put the crank gear dot at 12 oclock and the cam gear dot at 6 oclock with #1 piston at TDC....with the chain installed rotate the assembly till the crank gear and cam gear are both at 12 oclock and install the opti.

 

when i did mine a couple of months ago... i did it by myself and it was a pita, but to get to the point im still on stock tuning and ran the car at the track with stock 1.5 rockers and hit 13.22@108 Keep in mind the car weighed 3750lbs... the car had 160000 miles when i istalled the cam, and now has 167000 miles and running pretty strong....then i installed the 1.6rr's and the car picked up a little more pep but still on stock tuning..

Btw i hope you get that thing fixed... youll really like it with that cam...

 

i would to have it working so i can expierence a modded lt1!! but its not working riht and it really makes me mad i hope its fixed soon

 

There is no cam degreeing involved with LT1s, as long as the dots are lined up, there is only one way it can go on there and it is timed up correctly. now if the shop took off the crank hub and didnt put it back on correctly at 1 tdc or didnt line up the dots on the crank and timing gear, that could F it up pretty bad, but since the car got worse even after the stuff was installed i would rule that out. take your valve covers off and see if the rockers are tight but with some lash, and make sure you cant push the springs down with your fingers.

 

how? the timing wouldnt be screwed up... the hub just wouldnt be accurate measure of TDC.

if i were you i would go back to the shop and ask him if he advanced the cam any but trick him and say because you heard you were supposed to advance it maybe 2 degrees or something... of course this is a lie! mechanics like to tell you what you want to hear so to make sure he isnt screwing you id mislead him a little. like everyone said you are supposed to install the cam with straight up or with no advance/retard because the computer takes care of all that.

 

Don't be so quick to make that statement. Ask anyone whose ever gone ahead and degree'd a cam while installing in an LT1, and more often than not, you're going to find that there's some adjustment needed. While it is true that you can get away without checking, even cams straight from GM (I.E. GM847) can be way off. Ask an experienced mechanic, and 99% of the time you'll probably be told to degree the cam, if anything, just to be sure.

 

Check the valve lash. You'll probably find that it's way off. You should also double check the valve springs to ensure that they can handle the additional lift of the hot cam.
Kevin