hey what are the affects of a worn lobe on a cam? and how could i tell if that is what it is for sure? could it keep causing a lifter to fail or tick, or even a rocker to come aloose?
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hey what are the affects of a worn lobe on a cam? and how could i tell if that is what it is for sure? could it keep causing a lifter to fail or tick, or even a rocker to come aloose?
u could have a misfire code..running rough..a pushrod off of rocker..Do a compression test....take the valve covers off and have a look...I had 1 lobe gone on my '79 454 & it ran like poop...
I'd wip the valve covers off and check the valve lash if you think its worn a lobe off, why do you suspect this problem? Its not usually the first point of call.
i had a tick. kinda drove it like that for a year because there were no performance problems i could tell since it was ticking wen i bought it. then recently i changed the rockers the arms and also intake. and it still ticks!. and It sounds like something is going to come aloose now.Quote:
Originally Posted by mick08
I would think you would have metal contamination in the oil if it was slowly wearing a lobe away, do you do your own oil changes? If so check both the oil and oil filter, i cut mine open and fan out the media to see exactly whats going on, or you could send a sample out for an oil analysis, that will tell you for sure what is in the oil, what type of metal and where in the engine its coming from.
A small exhaust leak will often times sound like a "tick".
Reading your first post again, a worn lobe obviously increases the clearance at the rocker tip and valve top, this could very well be the tick and if left unchecked will flog out the pushrod seat in the rocker, could wear the top of the valve with the constant jackhammering from increased clearance and i have had a pushrod come adrift from the rocker and smacked up against the inside of the valve cover making a horrible noise, luckily i shut it down quick,that engine was a straight six but when i had a rocker break on my 400SBC the rotating cam lobe flicked the lifter out of its bore, this could have been real bad if that lifter had made it down one of the drain back holes and 'interfered' with the crank. You won't always notice 1 cylinder down in a V8 caus the others compensate, i only knew something was up when i came to a stop and the idle was a bit fluffy, a 4cylinder with a dropped cylinder shows up much more dramatic.
Piston slap usually sounds kinda like a tick
A lifter going out sounds like a tick
Like PAJeff said, exhaust leak sounds like tick
Valve train can sound like a tick (Sewing machine)
Worn cam lopes are very uncommon in the LS1 motors. They use roller lifters which don't wear on the cam as much as older motors. I would not suspect that first. Rockers are known for losing the needle bearings, thats probably not the noise but I would suspect almost everything before a worn cam lope. Just my .02 :shrug:
I actually found evidence of worn lobes I have 2 bad 1s on my original cam that has 130000k on it ill try n post pics up.
In my 6 years on this site, you are the first person I have seen say that :shrug:Quote:
Originally Posted by RedHot99T/A
I'm being 100%honest to lobes are noticably ruined....ever since I bought the car it had a noticable skip in the power band,when I get home and on my comp ill take a pic of the lobes,maybe there not ruined but they are deff worn looking compared to the rest.
Not calling you a liar, just saying its a first for me here.Quote:
Originally Posted by RedHot99T/A
Does it have aftermarket springs, rockers, or lifters in it? Your post said that you changed the rockers, but not with what.
yes all aftermarket new top end except for the valves and cam and heads. Comp Cams ultra gold rockers
decked bbk intake. 98 ss port and polished heads. custom cam. manley valves. but these were not replacedQuote:
Originally Posted by nativetalon
i think I'm going to have to tear it down soon to find out.
Got the pictures to show you all the cam,but my computer isn't working right now,ill sure start a thread about it when its up n running to see what all of you think could cause this.
Quote:
Originally Posted by nativetalon
Did you convert to an adjustable valvetrain??Quote:
Originally Posted by nativetalon
If not, it could be an improper length set of pushrods creating too much lash.
I have a regrind I got off Ebay laying in the garage for my ls1...after running it for less than a year it had VERY bad grooves worn into it
I'm not sure what you mean, and if so, how do i fix it?Quote:
Originally Posted by Firebirdjones
These engines don't have adjustable valvetrains from the factory,,,meaning the rocker arms are torqued to spec and that's it. The lifter preload and valvetrain geometry is set by the pushrod length.Quote:
Originally Posted by nativetalon
You mentioned you installed new rockers, but didn't mention if you converted to adjustable or not. There are many kits out there that allow adjustability so you can set preload to a desired amount.
I don't remember if you mentioned replacing push rods either. The standard length seems to be in the 7.4" area, but I've been hearing that alot of shops are going just a tad longer now on the "NON" adjustable setups to quiet the lifter noise down a bit.
Not to mention also,,,,larger camshafts generally are ground with a smaller base circle (that's how the lift is obtained) which in most cases requires a longer pushrod anyway to get valvetrain geometry back in check,,,and also set proper preload on the lifters if your valvetrain is "NON" adjustable.
how would i know the difference? and i bought comp cams ultra gold rockers and also 7.4 pushrods. how will i know if i need longer pushrods, and how do i measure to assure proper lenght?
and also, cam lift is 601/612
Hmmm, I'm looking at the comp cam website. There is no mention of whether or not the the ultra gold rockers for the LS engines are adjustable or not. They only say they are stud mounted. So I can only guess.Quote:
Originally Posted by nativetalon
I run stud mounted Crane roller rockers and they are fully adjustable. There are others out there that stud mount,,,but are not adjustable and basically mount onto a stud that is bevelled. Much like a conventional pontiac engine similar to what your 79 firebird in your picture would have.
I'm taking it that you didn't install the parts? You would have either simply torqued the rockers down to spec and let it be, as preload is set by pushrod length. Or you would have had to adjust lifter preload with each individual rocker. Setting lash just as you would on an older GEN 1 SBC.
no i paid Larry Turner's Performance $850 to do the work with $4000 in parts and the 1st time i got it home it sounded ok when i left the garage about 30 miles away. but it was ticking by the time i got home. and finally started to sound like a rocker was coming aloose so he then come bak amd got it. then again when i drove it home it started the same ticking and it has been parked since last march. o haven't had the cash to find out what it is until now. so this time I'm going to try to do the work myself. what do you suggest? different rockers?