Vehicle in question is a 2004 Honda Odyssey EX with 138k miles. Purchased this in January of this year; days later, I found recent service records where the PO had problems with the engine overheating, and temp gauge going into the red. PO took the vehicle to three different shops, each of which just threw parts at the problem. None of their guesses fixed the problem, and the owner ultimately sunk about $2,000 chasing this down. No wonder they gave up and traded it in.
I narrowed down the problem to a bad head gasket (likely started out as something small or insignificant, but repeated overheats probably lead to a HG failure and subsequent warping of the cyl. head) on the front cylinder bank. After removing the heads, it was clear that the front HG had failed.
A $410 valve job and resurfacing of both heads, and lots of my time later, I have the van back up and running. I had the engine out of the van, and replaced every seal, belt, plugs, etc; pretty much all maintenance items have been replaced.
For some reason the van doesn't feel like it has all the power it used to. Compression is outstanding (200-210 PSI on all cylinders), the whole upper end is practically new, thus there's not many things to point a finger at.
I did have a heck of a time getting the cams & crank aligned right when I put the new timing belt on. I probably took the belt on & off about thirty times making sure it was 100% accurate. The problem was, it seemed that the cam alignment mark was always 1/2 tooth off. If I tried moving the cam one tooth to correct it, it would go one half tooth off in the other direction. When I had the belt on as close as I could get it, it would go a whole tooth off (advanced, IIRC) when I pulled the pin on the tensioner and turned the engine by hand. What I later discovered, is that if you install the belt with the cams one full tooth retarded (in other words, you're sort of installing the belt wrong), once the tensioner is let go (pin pulled), all the marks line up after turning the engine a couple times. This is where I left it, and I'm fairly confident it is right-- while I can't be 100% certain there's a loss in power (I haven't driven the van in 3 months) it does feel noticeably more sluggish, whereas I would expect an increase in power due to the valve job & HG swap. I'm used to having timing marks on the belt itself, which practically eliminates any chance for error, but the belts on these engines are absent of any markings. I did mark the old belt, however, where the camshaft was, so I'm 100% sure there's the correct number of teeth between the cams.
Is this worth digging into and investigating, or am I just being paranoid? Is it correct to have the markings fall into place *after* the tensioner is released, instead of before? Because I can see two ways of installing the belt: You're either correct (timing marks line up) before tensioner is released, but it moves one tooth off when tensioner is applied... *OR* you install it "wrong," being one tooth off, and then once the tensioner is released and engine spun, then the lines match up nicely.
What sort of symptoms will an engine exhibit when a belt is only one tooth off? I ask this because the engine is 100% smooth as silk, quiet, basically runs like a dream with no driveability issues whatsoever. Only thing I've observed is what I believe to be a slight loss of power, perhaps on the order of 5-10%. I haven't tracked fuel economy as I've been doing a lot of idling, thus gas mileage will certainly be lower than I'm used to.
I am only getting one OBD-II code, which is for the knock sensor. The sensor broke when I was working in the "V" of the engine, the plastic broke off the metal housing. I attempted to repair it by soldering the wires back onto the piezo(?) element, and then using RTV to fasten the plastic back onto the metal housing. This appears to be a common occurrence, as I attempted to pull a sensor from a junkyard vehicle (to replace mine), and the same thing had happened to theirs, even before I used a wrench to remove it.
VTEC is not engaging, presumably because of the knock sensor code, but I experience the slight loss in power at lower RPMs where VTEC would not be active anyways.
Is there anyway short of removing timing covers and physically checking the belt to ensure that the valve timing is correct? Or has anyone had similar trouble setting timing as I have? Or is it imperative to set timing to the marks before tension is applied? If I knew what type of problems manifest themselves with valve timing off one tooth, I might be able to eliminate that as a possibility-- for example if being off one tooth causes horrible performance, misfires, codes to be set, etc. I could safely say that is not the problem here, because I'm not experiencing anything significant-- just a slight, but noticeable decrease in performance.
Any info, suggestions, tips, advise on the subject would sure be appreciated. I've done timing belts before, but I've always had marks on the belt to go by-- without it, I simply had the marks on the pulleys and backing plate which seems sort of crude to me. Thanks in advance for any help.
I narrowed down the problem to a bad head gasket (likely started out as something small or insignificant, but repeated overheats probably lead to a HG failure and subsequent warping of the cyl. head) on the front cylinder bank. After removing the heads, it was clear that the front HG had failed.
A $410 valve job and resurfacing of both heads, and lots of my time later, I have the van back up and running. I had the engine out of the van, and replaced every seal, belt, plugs, etc; pretty much all maintenance items have been replaced.
For some reason the van doesn't feel like it has all the power it used to. Compression is outstanding (200-210 PSI on all cylinders), the whole upper end is practically new, thus there's not many things to point a finger at.
I did have a heck of a time getting the cams & crank aligned right when I put the new timing belt on. I probably took the belt on & off about thirty times making sure it was 100% accurate. The problem was, it seemed that the cam alignment mark was always 1/2 tooth off. If I tried moving the cam one tooth to correct it, it would go one half tooth off in the other direction. When I had the belt on as close as I could get it, it would go a whole tooth off (advanced, IIRC) when I pulled the pin on the tensioner and turned the engine by hand. What I later discovered, is that if you install the belt with the cams one full tooth retarded (in other words, you're sort of installing the belt wrong), once the tensioner is let go (pin pulled), all the marks line up after turning the engine a couple times. This is where I left it, and I'm fairly confident it is right-- while I can't be 100% certain there's a loss in power (I haven't driven the van in 3 months) it does feel noticeably more sluggish, whereas I would expect an increase in power due to the valve job & HG swap. I'm used to having timing marks on the belt itself, which practically eliminates any chance for error, but the belts on these engines are absent of any markings. I did mark the old belt, however, where the camshaft was, so I'm 100% sure there's the correct number of teeth between the cams.
Is this worth digging into and investigating, or am I just being paranoid? Is it correct to have the markings fall into place *after* the tensioner is released, instead of before? Because I can see two ways of installing the belt: You're either correct (timing marks line up) before tensioner is released, but it moves one tooth off when tensioner is applied... *OR* you install it "wrong," being one tooth off, and then once the tensioner is released and engine spun, then the lines match up nicely.
What sort of symptoms will an engine exhibit when a belt is only one tooth off? I ask this because the engine is 100% smooth as silk, quiet, basically runs like a dream with no driveability issues whatsoever. Only thing I've observed is what I believe to be a slight loss of power, perhaps on the order of 5-10%. I haven't tracked fuel economy as I've been doing a lot of idling, thus gas mileage will certainly be lower than I'm used to.
I am only getting one OBD-II code, which is for the knock sensor. The sensor broke when I was working in the "V" of the engine, the plastic broke off the metal housing. I attempted to repair it by soldering the wires back onto the piezo(?) element, and then using RTV to fasten the plastic back onto the metal housing. This appears to be a common occurrence, as I attempted to pull a sensor from a junkyard vehicle (to replace mine), and the same thing had happened to theirs, even before I used a wrench to remove it.
VTEC is not engaging, presumably because of the knock sensor code, but I experience the slight loss in power at lower RPMs where VTEC would not be active anyways.
Is there anyway short of removing timing covers and physically checking the belt to ensure that the valve timing is correct? Or has anyone had similar trouble setting timing as I have? Or is it imperative to set timing to the marks before tension is applied? If I knew what type of problems manifest themselves with valve timing off one tooth, I might be able to eliminate that as a possibility-- for example if being off one tooth causes horrible performance, misfires, codes to be set, etc. I could safely say that is not the problem here, because I'm not experiencing anything significant-- just a slight, but noticeable decrease in performance.
Any info, suggestions, tips, advise on the subject would sure be appreciated. I've done timing belts before, but I've always had marks on the belt to go by-- without it, I simply had the marks on the pulleys and backing plate which seems sort of crude to me. Thanks in advance for any help.
