355 runs .. but feels weak?
355 runs .. but feels weak? so i got the car fired up, and it sounds good. well i took it for a spin around the block and it seems a little weak. i mean, i duno. whats the break in procedure on the lt1.? how many miles should i drive it. when i first fired it up someone told me to keep it at 2k for 10 mins or so. to break it in. ( did that). .well, what im saying, since it brand new, i have to put some miles on it before everything "seats" right. ? . can it be the computer, since i have no tune?(factory)
current mods. __
355 --20 off the deck, and 20 off the heads...
portmatched the intake side andexhaust, (polished to mirrorfinished-exhaust)
lt4 hotcam, all new lifters, cc 1.6 rr with harden pushrods
march pulleys (both)
e-water pump
throttle body by-pass
160 thermo
k&n CAI
stock manifolds , through the stock y-pipe, with no catback system.
NGK-tr55--gaped at 50
there are no check engine lights on, .. -- i know i need to get that tune, i will later in the week, just trying to figure out all the other crap..
oh and my drive side t-top is stuck, if u move the lever, nothing happens, its like shaft is striped out, and yes its unlock. is there a way to get it off the car? without breaking anything> /?
current mods. __
355 --20 off the deck, and 20 off the heads...
portmatched the intake side andexhaust, (polished to mirrorfinished-exhaust)
lt4 hotcam, all new lifters, cc 1.6 rr with harden pushrods
march pulleys (both)
e-water pump
throttle body by-pass
160 thermo
k&n CAI
stock manifolds , through the stock y-pipe, with no catback system.
NGK-tr55--gaped at 50
there are no check engine lights on, .. -- i know i need to get that tune, i will later in the week, just trying to figure out all the other crap..
oh and my drive side t-top is stuck, if u move the lever, nothing happens, its like shaft is striped out, and yes its unlock. is there a way to get it off the car? without breaking anything> /?
TECH Enthusiast
iTrader: (5)
Joined: Feb 2006
Posts: 527
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From: king of prussia, pa (home) and williamsport, pa (school)
well, your problem is definetly a tune. **** dude u need a dyno tune real bad. that'll straighten it all up. ur prolly runnin rich as **** right now
Honestly with the amount of milling done depending on the pistons compression is likely high and it could be in low octane retard mode due to the factory timing being so far off from what you need.
Stock manifolds with high compression is another recipe for detonation.
The hold at 2K for 10-20 minutes is for flat tappets you should not have done that, consider ignoring advise from that person in the future.
Stock manifolds with high compression is another recipe for detonation.
The hold at 2K for 10-20 minutes is for flat tappets you should not have done that, consider ignoring advise from that person in the future.
Not necessarily for Flat Tappets. The little paper that came with my Hotcam, and it came straight from GM, said to hold at 2000 RPM for appx. 20 min. to allow for proper break in.
And I would get it tuned, sounds like it needs it.
And I would get it tuned, sounds like it needs it.
Originally Posted by the_merv
Not necessarily for Flat Tappets. The little paper that came with my Hotcam, and it came straight from GM, said to hold at 2000 RPM for appx. 20 min. to allow for proper break in.
And I would get it tuned, sounds like it needs it.
And I would get it tuned, sounds like it needs it.
As usual you don't know your *** from a hole in the ground. GM also has it in print that the thermostat housing needs 21ft.lbs of torque on the screws, dare you to try that.
2000rpms for 20 minutes its to get flat tappets to spin in their bores and mate to their lobes which is completely not applicable to a roller cam.
TECH Regular
Joined: Sep 2006
Posts: 474
Likes: 0
From: MI
do a search, I posted a great link in "whats the break in for a 383", basically, run it hard up to 5000 rpms, then engine break to idle. do that AS SOON AS POSSIBLE!!!! The whole reason for the 60* crosshatch is to act like a file and wear the rings so they seat. The break in used to be all about the flat tappets. now that they left, we can adress what really needs to be done on break in. run that bitch HARD. babying a new motor is asking for trouble.
I'm starting to see what you mean "caprice". I concer with what you say.
I predict "...so go eat a dick."
I'm starting to see what you mean "caprice". I concer with what you say.
I predict "...so go eat a dick."
