Maybe the Dayco belt has one too many teeth.
Bent valves in a Honda CRV engine
- Thread starter berniedd
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Originally Posted By: Audi Junkie
Maybe the Dayco belt has one too many teeth.
It's not a Red Neck belt!
(J/K)
Maybe the Dayco belt has one too many teeth.
It's not a Red Neck belt!
Thanks for the inputs. The new timing belt (replaced little over a year earlier), new head gasket, replacement valve and guide are all original, genuine Honda parts. Car has always been maintained (before I bought it from my brother-in-law) at the Honda dealer and to my knowledge, has never had any work done to the crankshaft, camshaft, or deck.
I'll pay the shop a visit tomorrow and get a really good look at the valve springs and shims used. Methinks I'll get the timing belt off and compare it with another new one from the Honda store too. Valve timing is right on the money, I had a look for myself yesterday when the valve cover was off. I have a shop manual for this model and the timing marks aligned perfectly as the crankshaft was turned.
About the engine ingesting something, it's not likely. This is the second time I've had a bent valve on this thing, and both within 2 months of each other. First time it was an exhaust, this time it's an intake valve. I've got an almost new, good air filter on it, and there are no holes in it.
If everything checks out OK, it looks like andyd and I may be right about suspecting the valve metallurgy. I'd forgotten to mention it before, but many months ago, when I last adjusted the valves, I noticed cylinder #3 to have a missing intake valve "finger or actuator." It's the part that the camshaft lobe pushes against, and which in turn pushes on the valve head and causes it to open. It simply wasn't where it was supposed to be. Engine still worked fine because there are 2 intake valves per cylinder.
I found the missing actuator nearby along the row of exhaust valves. I returned it to its intended location by pushing the valve stem down with a lever, and inserted it into place. Once it was home, I kept jiggling the thing to try to get it out again, and also checked the valve clearance on it, but it didn't look any different from the other valves. There's absolutely no way it could've worked its way out UNLESS the valve it works with didn't close quickly enough, thus allowing that engine part to fly off its location. On hindsight, it is probably this same valve that I now have problems with. The machine shop that did my cylinder head job 2 months ago simply didn't return it to #3 cylinder but instead put in #4. So many months ago, that valve was already starting to bend. Now, I'm really convinced I'll have to change all the remaining 15 valves and their guides.
I'll pay the shop a visit tomorrow and get a really good look at the valve springs and shims used. Methinks I'll get the timing belt off and compare it with another new one from the Honda store too. Valve timing is right on the money, I had a look for myself yesterday when the valve cover was off. I have a shop manual for this model and the timing marks aligned perfectly as the crankshaft was turned.
About the engine ingesting something, it's not likely. This is the second time I've had a bent valve on this thing, and both within 2 months of each other. First time it was an exhaust, this time it's an intake valve. I've got an almost new, good air filter on it, and there are no holes in it.
If everything checks out OK, it looks like andyd and I may be right about suspecting the valve metallurgy. I'd forgotten to mention it before, but many months ago, when I last adjusted the valves, I noticed cylinder #3 to have a missing intake valve "finger or actuator." It's the part that the camshaft lobe pushes against, and which in turn pushes on the valve head and causes it to open. It simply wasn't where it was supposed to be. Engine still worked fine because there are 2 intake valves per cylinder.
I found the missing actuator nearby along the row of exhaust valves. I returned it to its intended location by pushing the valve stem down with a lever, and inserted it into place. Once it was home, I kept jiggling the thing to try to get it out again, and also checked the valve clearance on it, but it didn't look any different from the other valves. There's absolutely no way it could've worked its way out UNLESS the valve it works with didn't close quickly enough, thus allowing that engine part to fly off its location. On hindsight, it is probably this same valve that I now have problems with. The machine shop that did my cylinder head job 2 months ago simply didn't return it to #3 cylinder but instead put in #4. So many months ago, that valve was already starting to bend. Now, I'm really convinced I'll have to change all the remaining 15 valves and their guides.
Valves dont bend on their own. Even with [censored] metal. When they close they land flat in the seat. So they can't bend unless something was between the seat and valve when it closed.
Too tight guides and stems is a possibility. If the valve stuck open and a piston hit it we all know that will bend a valve.
So either it ate something or the guides and stems are too tight. If the timing belt was off it would bend either all the exhaust valves or all the intake valves. If the belt was off more than a couple of teeth it wouldn't run at all.
Too tight guides and stems is a possibility. If the valve stuck open and a piston hit it we all know that will bend a valve.
So either it ate something or the guides and stems are too tight. If the timing belt was off it would bend either all the exhaust valves or all the intake valves. If the belt was off more than a couple of teeth it wouldn't run at all.
Chris you're absolutely right that a valve can bend if something gets in between it and its seat. If so, then I'd expect the damaged valves to be all from the same cylinder. But the exhaust valve that bent 2 months ago was in #2 cylinder and the intake valve that is the current problem is in #4 (or came from #3 if my suspicion is correct - see my post above). Ingesting two foreign bodies at two different points in time to hurt valves from different cylinders is too far fetched to me.
I'll check the fit of all the valves in their guides tomorrow.
I'll check the fit of all the valves in their guides tomorrow.
Odd for the thing to run 50,000 miles then suddenly have the guids tighten up instead of wear larger. When you pull the valves out check for carbon on the stems and guides.
Originally Posted By: Chris142
Odd for the thing to run 50,000 miles then suddenly have the guids tighten up instead of wear larger. When you pull the valves out check for carbon on the stems and guides.
wholeheartedly on Chris's comments.
Q.
Odd for the thing to run 50,000 miles then suddenly have the guids tighten up instead of wear larger. When you pull the valves out check for carbon on the stems and guides.
wholeheartedly on Chris's comments.
Q.
Could something have gotten sucked into the engine?
Update, guys. Some valves were hard to remove from their guides. We stood all 8 intake valves on a flat glass pane, used a straight edge to align the valve faces, and looked at the ends ot the stems. Two valve tips were not aligning together with the other 6. We did the same to the 8 exhaust valves, and two were not aligning with the rest, either. We concluded that 2 intake and 2 exhaust valves were bent.
I bought a new set of valves. I inserted them into the valve guides and got a plesant surprise - none of them were tight and none would wobble in the guides, so I guess I wouldn't need new guides after all. I had the mechanic lap them in, and reassemble the head. Using the old head gasket, we torq
I bought a new set of valves. I inserted them into the valve guides and got a plesant surprise - none of them were tight and none would wobble in the guides, so I guess I wouldn't need new guides after all. I had the mechanic lap them in, and reassemble the head. Using the old head gasket, we torq
Originally Posted By: berniedd
I had the mechanic lap them in, and reassemble the head. Using the old head gasket, we torq
A quick word of advise: never re-use a head gasket (always replace with fresh new one) and check your head/deck for flatness before you re-install your head.
Otherwise, you'll be begging for more trouble down the road.
Q.
I had the mechanic lap them in, and reassemble the head. Using the old head gasket, we torq
A quick word of advise: never re-use a head gasket (always replace with fresh new one) and check your head/deck for flatness before you re-install your head.
Otherwise, you'll be begging for more trouble down the road.
Q.
Update, guys. Some valves were hard to remove from their guides. We stood all 8 intake valves on a flat glass pane, used a straight edge to align the valve faces, and looked at the ends of the stems. Two valve tips were not aligning together with the other 6. We did the same to the 8 exhaust valves, and two tips were not aligning with the rest, either. We concluded that 2 intake and 2 exhaust valves were bent. All 4 came from different cylinders. We also checked the heights of the valve springs; all the intake springs and all the exhaust springs were the same height. We didn't check valve spring tension - didn't have the correct tool for this.
I bought a new set of valves. I inserted them into the valve guides and got a plesant surprise - none of them were tight and none would wobble in the guides, so I guess I wouldn't need new guides after all. I had the mechanic lap them in and reassemble the head. I got some modeling clay and filled the valve pockets/recesses in the piston tops with it. I wanted to see if the valves would hit the pistons later on. Using the old head gasket, we torqued the head bolts to 45 ft-lbs and set the valve lash to .006" intake and .009" exhaust as per the service manual. After making sure we got the valve timing right, we installed the timing belt and turned the crankshaft a few revolutions, then removed the head. The modeling clay I'd put in were undisturbed, so now I'm definite my valve problems are not due to piston contact.
Looking back, I am now faced with 2 possibilities as to the cause of my bent valves: bad valve metallurgy or possibly bad engine oil that coked up on the valve stems and kept them from moving freely as the camshaft opened and closed them, allowing them to hit the pistons. (As far as I can see, there are no marks on the pistons that would suggest this happened.) I don't think it's the latter - I've changed the oil religiously, many times even before the recommended OCI of 5000 kms and on my last oil change used ENOC brand 15w40 engine oil rated SH (exactly what the car manual recommends).
Next week, I'm going to bring the old valves to Honda, ask them if they are original Honda parts.
I bought a new set of valves. I inserted them into the valve guides and got a plesant surprise - none of them were tight and none would wobble in the guides, so I guess I wouldn't need new guides after all. I had the mechanic lap them in and reassemble the head. I got some modeling clay and filled the valve pockets/recesses in the piston tops with it. I wanted to see if the valves would hit the pistons later on. Using the old head gasket, we torqued the head bolts to 45 ft-lbs and set the valve lash to .006" intake and .009" exhaust as per the service manual. After making sure we got the valve timing right, we installed the timing belt and turned the crankshaft a few revolutions, then removed the head. The modeling clay I'd put in were undisturbed, so now I'm definite my valve problems are not due to piston contact.
Looking back, I am now faced with 2 possibilities as to the cause of my bent valves: bad valve metallurgy or possibly bad engine oil that coked up on the valve stems and kept them from moving freely as the camshaft opened and closed them, allowing them to hit the pistons. (As far as I can see, there are no marks on the pistons that would suggest this happened.) I don't think it's the latter - I've changed the oil religiously, many times even before the recommended OCI of 5000 kms and on my last oil change used ENOC brand 15w40 engine oil rated SH (exactly what the car manual recommends).
Next week, I'm going to bring the old valves to Honda, ask them if they are original Honda parts.
Good work and thanks for passing along the info.
Originally Posted By: Quest
Originally Posted By: berniedd
I had the mechanic lap them in, and reassemble the head. Using the old head gasket, we torq
A quick word of advise: never re-use a head gasket (always replace with fresh new one) and check your head/deck for flatness before you re-install your head.
Otherwise, you'll be begging for more trouble down the road.
Q.
Sorry, I wasn't finished composing my post when I hit some button accidentally on the keyboard, and my unfinished post was uploaded to BITOG. See the full story above - the used gasket was only intended to test for piston to valve contact. I've bought a new gasket and that's what's going to get fitted to the engine later.
Originally Posted By: berniedd
I had the mechanic lap them in, and reassemble the head. Using the old head gasket, we torq
A quick word of advise: never re-use a head gasket (always replace with fresh new one) and check your head/deck for flatness before you re-install your head.
Otherwise, you'll be begging for more trouble down the road.
Q.
Sorry, I wasn't finished composing my post when I hit some button accidentally on the keyboard, and my unfinished post was uploaded to BITOG. See the full story above - the used gasket was only intended to test for piston to valve contact. I've bought a new gasket and that's what's going to get fitted to the engine later.
Originally Posted By: berniedd
I am now faced with 2 possibilities as to the cause of my bent valves: bad valve metallurgy or possibly bad engine oil that coked up on the valve stems and kept them from moving freely as the camshaft opened and closed them, allowing them to hit the pistons. (As far as I can see, there are no marks on the pistons that would suggest this happened.) I don't think it's the latter - I've changed the oil religiously, many times even before the recommended OCI of 5000 kms and on my last oil change used ENOC brand 15w40 engine oil rated SH (exactly what the car manual recommends).
If it is the lack of oil that cools the valve, you'd see varnish and probably sludge under the valve cover. I'd double check for the coolant passage in the head and make sure the head is not overheating. I've heard cylinder #3 is prone to overheating under extreme condition (i.e. boost).
I am now faced with 2 possibilities as to the cause of my bent valves: bad valve metallurgy or possibly bad engine oil that coked up on the valve stems and kept them from moving freely as the camshaft opened and closed them, allowing them to hit the pistons. (As far as I can see, there are no marks on the pistons that would suggest this happened.) I don't think it's the latter - I've changed the oil religiously, many times even before the recommended OCI of 5000 kms and on my last oil change used ENOC brand 15w40 engine oil rated SH (exactly what the car manual recommends).
If it is the lack of oil that cools the valve, you'd see varnish and probably sludge under the valve cover. I'd double check for the coolant passage in the head and make sure the head is not overheating. I've heard cylinder #3 is prone to overheating under extreme condition (i.e. boost).
to OP-
Would you be able to find something better than ENOC (API SL/SM grade/ILSAC GF-3/GF4(preferred)) in you area?
I've seen oil coking inside valve stems before (with older engines and infrequent/older API grades) and if there's some carbon deposits on the neck of either intake/exhaust valve stem part, these carbonaeous deposits may break free during operation which lead to jamming of the valve, causing bent valve(s) and/or valve sealing surface burnouts (a groove similar to a crude gas torch cut).
Q.
Would you be able to find something better than ENOC (API SL/SM grade/ILSAC GF-3/GF4(preferred)) in you area?
I've seen oil coking inside valve stems before (with older engines and infrequent/older API grades) and if there's some carbon deposits on the neck of either intake/exhaust valve stem part, these carbonaeous deposits may break free during operation which lead to jamming of the valve, causing bent valve(s) and/or valve sealing surface burnouts (a groove similar to a crude gas torch cut).
Q.
Thanks, PandaBear, the inside of the valve cover was very clean, no sludge.
Quest, I got the ENOC oil for a small cost, that's why I used it. It's all gone now, and I'm filling the engine with Shell Helix as soon as it's back together. I'll have a good look at the valves for carbon deposits and keep you posted.
Quest, I got the ENOC oil for a small cost, that's why I used it. It's all gone now, and I'm filling the engine with Shell Helix as soon as it's back together. I'll have a good look at the valves for carbon deposits and keep you posted.
The CRV is back on the road.I've looked at the valves closely, and there was no coking or sludging of the oil on the stems or the valve cover. What I noticed is some valves have nonsymmetrical and uneven shininess around the circumference of the stems. The condition affects many valves, both intake and exhaust, some at the upper stem, others at the the lower stem. The conclusion is these valve stems are not true and straight. Ok, brought the old valves to Honda, but they couldn't confirm if they Honda parts or not. Apparently Honda does not mark their valves to id them as theirs.
While I was there, I got to talk with a customer who was buying parts for his 1996 Civic. He says he filled up with E10 gas not too long ago and noticed his engine ran noisier. When he refilled with nonE10 gas, the noise returned to normal.The Honda parts guy looked it up in his computer, and found that my CRV and the guy's 1996 Civic are E10 compatible. Despite this, is it possibly the E10 I filled up with in February and March this year that's the cause of all this? Coincidentally it was in March I had hard starting issues, till I returned to nonE10 gas and the problem went away.
From now on, I'm going to stick to nonE10 gas and change oil with full synth. More and more gas stations are offering nothing but E10 in my area, and I'm wondering how long before all nonE10 gas is gone.
While I was there, I got to talk with a customer who was buying parts for his 1996 Civic. He says he filled up with E10 gas not too long ago and noticed his engine ran noisier. When he refilled with nonE10 gas, the noise returned to normal.The Honda parts guy looked it up in his computer, and found that my CRV and the guy's 1996 Civic are E10 compatible. Despite this, is it possibly the E10 I filled up with in February and March this year that's the cause of all this? Coincidentally it was in March I had hard starting issues, till I returned to nonE10 gas and the problem went away.
From now on, I'm going to stick to nonE10 gas and change oil with full synth. More and more gas stations are offering nothing but E10 in my area, and I'm wondering how long before all nonE10 gas is gone.
I used E85 in ours a few times.
All our cars (dad's 7th gen civic, my 07 fit and wifey's 04 camry) all been on E10 diet since day-1 (that's the only type of gas our region gets, no "ifs" or "buts" and no other options available.
Our region has been running E10 for over 2 decades, and it's been about 3 yrs ago that almost all gas stations in lower mainland are already on E10, no issues whatsoever.
E10 may run kinda weird to some engines/users but never has any issues at all. In fact: 2-T trimmers and even lawnmowers run E10 just fine w/o the need of readjustments and such.
I still lay blame on oil and inferior gasoline in the Philippines, esp. those ENOC oil for API SH is really, really "old" and out of date if you are to bring to my attention (here in motoring NA, SH was for cars in the mid-80s, for we are now all in at least SL, currently on SM grade).
My 2c's worth.
Q.
p.s. Unless you keep your eyes peeled every step of the way during the engine repair, otherwise, you may be easily fooled into buying counterfeit Honda parts. In fact: I have a report recently from a good friend who lives in mainland china and he came across counterfeit VW/Toyota parts like oil filters, ball joints, etc. So, who knows?
Our region has been running E10 for over 2 decades, and it's been about 3 yrs ago that almost all gas stations in lower mainland are already on E10, no issues whatsoever.
E10 may run kinda weird to some engines/users but never has any issues at all. In fact: 2-T trimmers and even lawnmowers run E10 just fine w/o the need of readjustments and such.
I still lay blame on oil and inferior gasoline in the Philippines, esp. those ENOC oil for API SH is really, really "old" and out of date if you are to bring to my attention (here in motoring NA, SH was for cars in the mid-80s, for we are now all in at least SL, currently on SM grade).
My 2c's worth.
Q.
p.s. Unless you keep your eyes peeled every step of the way during the engine repair, otherwise, you may be easily fooled into buying counterfeit Honda parts. In fact: I have a report recently from a good friend who lives in mainland china and he came across counterfeit VW/Toyota parts like oil filters, ball joints, etc. So, who knows?
I just listed our CRV in the For Sale Forum. $3000 in PA.
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