valve train problems
06-12-2013, 04:39 PM
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valve train problems I have a loud tick (maybe intake backfire) coming from the engine at ~4800+ rpm, i would equate it to a small rifle as far as loudness. Also once the car starts doing it, it seems like i've run out of power... the car will keep running but the rpms don't clime much
Just put new valve springs because of same issue, car ran good for about 1000 miles. Then right after the valve spring swap i trashed a couple rockers. So after that I installed the stock rockers again while I waited for new rockers. One of them has a slight tick but i dont think that'd cause this noise.
stock rockers, springs in sig, stock length/size hardened pushrods
Just put new valve springs because of same issue, car ran good for about 1000 miles. Then right after the valve spring swap i trashed a couple rockers. So after that I installed the stock rockers again while I waited for new rockers. One of them has a slight tick but i dont think that'd cause this noise.
stock rockers, springs in sig, stock length/size hardened pushrods
06-12-2013, 09:00 PM
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06-12-2013, 09:15 PM
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Sounds like your floating a valve. Any bent valves, broken valve springs or are you hanging a valve do to misadjustment/lash.
Last edited by 93 LT1 Vette; 06-12-2013 at 09:24 PM.
06-12-2013, 09:30 PM
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ill check all the springs/pushrods and readjust all the rockers. how would i check for bent valves? I was thinking this was valve float, its just like hitting the limiter it just wont accelerate, the only reason it shifted the first time i went WOT was cause i let off a little
06-12-2013, 09:44 PM
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Physically seeing a bent valve with the heads mounted, springs, retainers and locks on, not much chance unless it is BENT bad. Leak down test would tell which valve isn't seating properly or compression test on each hole.
06-13-2013, 05:00 PM
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I would suspect the ignition sys, plugs or wires. Something physically wrong with the vavletrain would cause the problem to be present at all rpms especially at idle.
The rpm where peak torque occurs and higher (rpm) puts a real load on the ignition sys.
Hows it run overall? Does it pull OD at low rpm on the highway okay? or does it buck and stutter.
To see if its valve float and resultant lifter pump up try reducing your lifter preload and see if it gets better. How much lifter preload are you using? Overall curing high rpm valve float by reducing lifter preload is just a crutch for weak valve springs.
Did you have a old thread about these alex springs with broken dampers that chewed up the valve guide seals? or was it someone else.
The rpm where peak torque occurs and higher (rpm) puts a real load on the ignition sys.
Hows it run overall? Does it pull OD at low rpm on the highway okay? or does it buck and stutter.
To see if its valve float and resultant lifter pump up try reducing your lifter preload and see if it gets better. How much lifter preload are you using? Overall curing high rpm valve float by reducing lifter preload is just a crutch for weak valve springs.
Did you have a old thread about these alex springs with broken dampers that chewed up the valve guide seals? or was it someone else.
1/4 turn preload. yes that was me, the new springs I have dont have dampers in them. its just a single spring.
There is no reason these springs would be to weak for this cam. its so mild lol
I emailed the guy and he said the springs should be more then enough for this cam. He told me this spring has been used in a lot of CC503 applications which is considerably bigger then my cam.
The guy I emailed also suggested checking the cam lobes, but on a hydraulic roller cam i wouldnt imagine its wiping the lobes off...
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06-13-2013, 09:03 PM
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coil has been replaced within the last couple hundred miles, i still have the old one tho but its not in real great condition.
I'm at a loss as to what else to check... i just got back from a quick round the block test and its still doing it. I went threw the pushrods, springs, looked at the valves, adjusted all the rockers with 1/4 turn again. No noticeable issues in the valvetrain. I figured i'd try charging the battery since it is a tad weak, got the trickle charger on it
I'm at a loss as to what else to check... i just got back from a quick round the block test and its still doing it. I went threw the pushrods, springs, looked at the valves, adjusted all the rockers with 1/4 turn again. No noticeable issues in the valvetrain. I figured i'd try charging the battery since it is a tad weak, got the trickle charger on it
Last edited by englundjd; 06-13-2013 at 09:13 PM.
06-14-2013, 04:18 PM
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You say the car ran good for 1k miles after the spring swap. Is the way it's running in the vid the same as when it was running bad before? Yes this is the exact problem I had before the new springs were put in
Things break, could be a new problem. Maybe recheck the basics. Low fuel press at WOT will cause it to run lean. Fuel pressure is checkin out good according to my guage
Read a thread a while back of a guy chasing a high rpm miss for a LONG time, turned out the metal contact flew off his opti rotor and the sparks had to jump from the metal strip on the rotor to the cap contacts. Lower rpm everything was fine, at high rpm ran bad.
What kind of plug wires are you running? stock ACdelcos were put on about 30k miles ago, none are burned.
What was the rocker arm problem? SA rocker pop off the valve stem? You can check for bent pushrods by rolling them on some glass. Yes thats what happened, i went threw all the pushrods after that happened and checked them for straightness
Listened to the vid with headphones on, still hard to tell exactly what is going on. Your car sounds really nice BTW. The vid was taken with a galaxsy s3 .... shorty headers, 3" ORY, cat deleted and replaced with a 3" cutout, then into the stock catback
Things break, could be a new problem. Maybe recheck the basics. Low fuel press at WOT will cause it to run lean. Fuel pressure is checkin out good according to my guage
Read a thread a while back of a guy chasing a high rpm miss for a LONG time, turned out the metal contact flew off his opti rotor and the sparks had to jump from the metal strip on the rotor to the cap contacts. Lower rpm everything was fine, at high rpm ran bad.
What kind of plug wires are you running? stock ACdelcos were put on about 30k miles ago, none are burned.
What was the rocker arm problem? SA rocker pop off the valve stem? You can check for bent pushrods by rolling them on some glass. Yes thats what happened, i went threw all the pushrods after that happened and checked them for straightness
Listened to the vid with headphones on, still hard to tell exactly what is going on. Your car sounds really nice BTW. The vid was taken with a galaxsy s3 .... shorty headers, 3" ORY, cat deleted and replaced with a 3" cutout, then into the stock catback
would a lifter cause this? once in a blue moon if i haven't started the car for a while the lifters will make some noise immediately after start-up but it goes away quickly
Also any thoughts on a wiped cam lobe? this was the suggestion given to me by the guy I emailed that sold me the springs
Last edited by englundjd; 06-14-2013 at 04:30 PM.
06-14-2013, 09:50 PM
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Yes I am, running the same springs. I dont know about a spring pressure tester, i dont have one.
i'll look at the wires and make sure there not arcing.
And start checking things over for something I may have missed
I have adjusted and readjusted the rockers probably 8 times in the last couple months between the valve spring swap, the rocker failure, and this issue. lol
i'll look at the wires and make sure there not arcing.
And start checking things over for something I may have missed
I have adjusted and readjusted the rockers probably 8 times in the last couple months between the valve spring swap, the rocker failure, and this issue. lol
Last edited by englundjd; 06-16-2013 at 09:26 PM.
06-17-2013, 06:23 PM
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i went threw and tightened up the preload another 1/8th of a turn per a friends advice and what do ya know it got better, I'm going to go another 1/8th tho cause its not totally gone, but i think i have the problem solved. Thank you guys
06-19-2013, 09:19 AM
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Ok, update:
Last night I took it around the block and pissed off all my neighbors and brought it up to the 6300rpm limiter
I locked it in first gear and then rolled into the gas, all the way up it only popped once. it popped at around 5000 rpm.
I'm at a 1/2 turn preload, think i should add another 1/8th or more or just say the hell with it (im tired of adjusting rockers)? I want to figure this out so I know its nothing else before i swap my 1.6 rockers on it
06-20-2013, 04:46 PM
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i went to 5/8th preload and still had one pop, tried 3/4 preload and got a good clean pass then it popped once on the second try... im thinkin i should just leave it where its at.
anyone else got any ideas?
anyone else got any ideas?
06-21-2013, 01:25 PM
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so i put everything back together and took it out for a drive last night, halfway threw i turned a corner and smashed the go petal and i got a nice lively pop pop pop in quick succession (there was a lot more then 3 pops) I let off the gas as soon as i could react to it.
back to square one I guess. this is frustrating
think the lifter would be causing that kinda noise?
bad A/F ratio?
im lost as to what to do next.
back to square one I guess. this is frustrating
think the lifter would be causing that kinda noise?
bad A/F ratio?
im lost as to what to do next.
06-22-2013, 12:10 AM
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How did u adjust the lifters? By feel with roller the p-rod with your fingers or by noise? Because one method is error likely i have to ask before advising anything else.
Noise can also be from tiny exhaust leak(s) and can surprisingly sound like a lifter tick. But sorry to say i read like your noise problem is growing not diminishing. Thats how a wiped cam lobe(s) degenerate. And this even increases compression pressure if u can measure it.
A quick check that works if some lobes are badly worn is to just take a straight edge like a metal ruler and hold it parallel to to the vlv retainers. U can sometimes see either the intk or exh spring retainers depress to different compressed heights on different cylinders. Ive tried using a machinists pocket rule to measure the compressed heights vertically like the shop manual says but this never seemed to work for me.
cardo
Noise can also be from tiny exhaust leak(s) and can surprisingly sound like a lifter tick. But sorry to say i read like your noise problem is growing not diminishing. Thats how a wiped cam lobe(s) degenerate. And this even increases compression pressure if u can measure it.
A quick check that works if some lobes are badly worn is to just take a straight edge like a metal ruler and hold it parallel to to the vlv retainers. U can sometimes see either the intk or exh spring retainers depress to different compressed heights on different cylinders. Ive tried using a machinists pocket rule to measure the compressed heights vertically like the shop manual says but this never seemed to work for me.
cardo
06-24-2013, 01:21 PM
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spun the pushrod and turned the rocker nut till the pushrod had drag on it. Ive done both ways before and they both work good, i just find this way to be easier.
The problem itself is not getting worse its just also not getting any better when i adjust things, I've added almost a half turn preload since i starts (at the max recommended now)
Your not the first person to suggest the cam, but as you say it'd be getting worse, which it isnt. It's just staying constant.
I now believe the reason it seemed to get better on the short runs around the block were cause the engine wasnt totally up to operating temp, the problem is almost none existent when the engine is cold.
The problem itself is not getting worse its just also not getting any better when i adjust things, I've added almost a half turn preload since i starts (at the max recommended now)
Your not the first person to suggest the cam, but as you say it'd be getting worse, which it isnt. It's just staying constant.
I now believe the reason it seemed to get better on the short runs around the block were cause the engine wasnt totally up to operating temp, the problem is almost none existent when the engine is cold.
06-24-2013, 01:25 PM
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How did u adjust the lifters? By feel with roller the p-rod with your fingers or by noise? Because one method is error likely i have to ask before advising anything else.
Noise can also be from tiny exhaust leak(s) and can surprisingly sound like a lifter tick. listen to the video and see what you think. I'm pretty sure its not an exhaust leak
But sorry to say i read like your noise problem is growing not diminishing. Thats how a wiped cam lobe(s) degenerate. And this even increases compression pressure if u can measure it.
A quick check that works if some lobes are badly worn is to just take a straight edge like a metal ruler and hold it parallel to to the vlv retainers. U can sometimes see either the intk or exh spring retainers depress to different compressed heights on different cylinders. Ive tried using a machinists pocket rule to measure the compressed heights vertically like the shop manual says but this never seemed to work for me.
cardo
Noise can also be from tiny exhaust leak(s) and can surprisingly sound like a lifter tick. listen to the video and see what you think. I'm pretty sure its not an exhaust leak
But sorry to say i read like your noise problem is growing not diminishing. Thats how a wiped cam lobe(s) degenerate. And this even increases compression pressure if u can measure it.
A quick check that works if some lobes are badly worn is to just take a straight edge like a metal ruler and hold it parallel to to the vlv retainers. U can sometimes see either the intk or exh spring retainers depress to different compressed heights on different cylinders. Ive tried using a machinists pocket rule to measure the compressed heights vertically like the shop manual says but this never seemed to work for me.
cardo
On a side note, im strongly considering of putting in a different cam and having new springs installed for the new cam. I'll have the heads shaved off a little and thinner head gaskets put in, for a bump in compression also. At that point all the variables will be taken care of.
