Bent valves? Leak down and compression results...
06-21-2006, 05:08 AM
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Bent valves? Leak down and compression results...
Hey my car (99 gsr) started throwing a code for random misfiring. So i replaced the obvious....plugs, wires, dist., and still had the problem. One day i did a compression test the numbers were 220, 110, 220, 220. So i decided to run a leak down test. on cyl #2 with the 110 compression. The air came rushing out my intake. I immediatly thought it was intake valves. I pulled my head yesterday and the valves look straight and the guides look good too (no visible cracks). I'm wondering if i should just take it to a machine shop hav it checked out and hav new guides put in for the hell of it...what do u guys think. i dont kno what else to do
06-21-2006, 09:33 AM
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Re: Bent valves? Leak down and compression results... (MassCivicMan987)
when you did the leakdown test did you have number 2 cylinder at tdc. That would have the up mark on the cam gears pointing at 3 oclock.
06-21-2006, 10:34 AM
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yes i did...i mean aside from significant amounts of carbon deposits on the seats and margins of the exhaust valves the intake looked relatively clean....i'm almost positive i bent valves becuase i miss-shifted...the thing is the cars runs fine and only misfires slightly at idle
06-21-2006, 11:09 AM
#4
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Re: (MassCivicMan987)
Put a bright light over the valve and look in the intake port (in a darkened room). I've spottted light leaks from bent valves that way, or just drop the valve and it will be obvious from the seating surface if it is bent.
06-21-2006, 12:46 PM
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all the valves are dropped and i cant see **** wrong with them...ive rolled them acroos the edge of the table on the stems and they all look straight....is it worth dropping the head off at a machine shop and hav them inspect it and toss sum new guides in? i hav new valves they are inspected low mileage bead blasted stock valves and i will be using the original springs and retainers
06-21-2006, 12:51 PM
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Re: (MassCivicMan987)
have you marked the exact position and cylinder they came from?
It sounds like you have bent valves, sometimes its just a little that you cant see, you would have to measure straightness with a dial and measure length
It sounds like you have bent valves, sometimes its just a little that you cant see, you would have to measure straightness with a dial and measure length
06-21-2006, 01:03 PM
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they are marked exactly where they came from...ive been trying to hit up a friend for the dial gauge and his micrometer but he hasnt goten back to me so ive been rolling the valves along the edge of the table and seen nuthin....i guess im just goin to lap in the new valves and pray that theres no more codes.
btw anyone know how much the oem valve oil seals and oem valve guides would go for at the dealer. and about how much am i looking at if i decided to hav guides put in at a machine shop
btw anyone know how much the oem valve oil seals and oem valve guides would go for at the dealer. and about how much am i looking at if i decided to hav guides put in at a machine shop
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06-21-2006, 03:38 PM
#8
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Re: (MassCivicMan987)
You still have compression, so it wont be obvious. If you install them back into the head a little solvent in the port will tell you if theyre bent.
06-21-2006, 03:56 PM
#10
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Re: (Chiovnidca)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca »</TD></TR><TR><TD CLASS="quote">You still have compression, so it wont be obvious. If you install them back into the head a little solvent in the port will tell you if theyre bent. </TD></TR></TABLE>
w3rd..
they're bent....just replace them and get a valve job...
w3rd..
they're bent....just replace them and get a valve job...
06-21-2006, 04:12 PM
#11
Mad Scientist
Re: (MassCivicMan987)
like alcohol-acetone- etc.
you can also add some color to it to make it easier for you to spot, like food coloring.
do yourself a favor and get a valve job, you already have everything out...taking chances is cool, but there is a line..
you can also add some color to it to make it easier for you to spot, like food coloring.
do yourself a favor and get a valve job, you already have everything out...taking chances is cool, but there is a line..
06-21-2006, 04:17 PM
#12
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Re: (MassCivicMan987)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MassCivicMan987 »</TD></TR><TR><TD CLASS="quote">what type of solvent are you talkin about</TD></TR></TABLE>
I usually use brake cleaner, just because it's handy. Or put it in the parts washer. What you use doesn't matter that much.
I usually use brake cleaner, just because it's handy. Or put it in the parts washer. What you use doesn't matter that much.
06-21-2006, 04:27 PM
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what do u mean by valve job...the only thing i feel uncomfortable doing is valve guides becuase they need to be pressed in. Everything else like lapping the new ones in is easy for me. i just want to know now if i shud hav the guides replaced
06-21-2006, 04:38 PM
#14
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Re: (MassCivicMan987)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MassCivicMan987 »</TD></TR><TR><TD CLASS="quote"> i just want to know now if i shud hav the guides replaced</TD></TR></TABLE>
Do the valves have exessive free play in the guides?
Do the valves have exessive free play in the guides?
06-21-2006, 04:51 PM
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i can "wiggle" them all about the same...if i were to meausre them i would need a ball gauge and micrometer right?... Btw i appreciate all the help i'm getting from you guys
06-23-2006, 01:31 PM
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Re: Bent valves? Leak down and compression results... (MassCivicMan987)
After i lapped the valves if i shine a light to the bottom of the valves should i be able to see light through the ports?
no right?
no right?
06-23-2006, 02:03 PM
#17
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Re: Bent valves? Leak down and compression results... (MassCivicMan987)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MassCivicMan987 »</TD></TR><TR><TD CLASS="quote">After i lapped the valves if i shine a light to the bottom of the valves should i be able to see light through the ports?
no right? </TD></TR></TABLE>
yes...
they will seat thoroughly after start up...
no right?
</TD></TR></TABLE>yes...
they will seat thoroughly after start up...
06-23-2006, 02:51 PM
#19
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Re: Bent valves? Leak down and compression results... (rmcdaniels)
i shined light on my portflow head ports right when i got it after a full valve job with new REV valves...
light came through....
it had perfect compression after i installed it..obviously..
light came through....
it had perfect compression after i installed it..obviously..
06-23-2006, 05:31 PM
#20
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Re: Bent valves? Leak down and compression results... (onepoint6i)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by onepoint6i »</TD></TR><TR><TD CLASS="quote">i shined light on my portflow head ports right when i got it after a full valve job with new REV valves...
light came through....
</TD></TR></TABLE>
It shouldn't.
light came through....
</TD></TR></TABLE>
It shouldn't.
06-24-2006, 12:25 PM
#21
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Re: Bent valves? Leak down and compression results... (Chiovnidca)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca »</TD></TR><TR><TD CLASS="quote">
It shouldn't.</TD></TR></TABLE>
well it did...and it was perfectly fine when i installed it...c'mon its portflow ..
It shouldn't.</TD></TR></TABLE>
well it did...and it was perfectly fine when i installed it...c'mon its portflow ..
06-24-2006, 12:49 PM
#22
Honda-Tech Member
Re: Bent valves? Leak down and compression results... (onepoint6i)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by onepoint6i »</TD></TR><TR><TD CLASS="quote">well it did...and it was perfectly fine when i installed it...c'mon its portflow ..</TD></TR></TABLE>
Next time you get one like that, bring it over and i'll show you how to lap in the valves. It may have worked but it was far from perfect.
Next time you get one like that, bring it over and i'll show you how to lap in the valves. It may have worked but it was far from perfect.
06-24-2006, 01:36 PM
#23
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Re: Bent valves? Leak down and compression results... (Chiovnidca)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca »</TD></TR><TR><TD CLASS="quote">
Next time you get one like that, bring it over and i'll show you how to lap in the valves. It may have worked but it was far from perfect.</TD></TR></TABLE>
hit up Tom Fujita..and show him ..lol
Next time you get one like that, bring it over and i'll show you how to lap in the valves. It may have worked but it was far from perfect.</TD></TR></TABLE>
hit up Tom Fujita..and show him ..lol
06-24-2006, 07:17 PM
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so i suck at lapping valves? although i didnt have spring pressure on the valves i was pushing hard by hand...i havnt gotten around to intalling the head becuase i am waiting on a few things...so i should see no light at all? so then i should re-lap all my valves?
06-24-2006, 09:20 PM
#25
Honda-Tech Member
Re: (MassCivicMan987)
If it were my head, I would just get the head freshened up..it''s apart now and you wouldn't want to do that twice...you don't have to do the guides if there not cracked or worn, but I would reface the valve, it's the true way of seeing if it is bent..you see it as soon as you spin the valve in the machine in most cases. I have seen many valves that look decent and have no marks but are tweaked enough not to seal. Valvejob and mill it, install some new seals and know you don't have to worry about it would be my plan.