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chuck, I don't think it could cause that damage. If the engine is A-OK on the mechanical timing, all VTEC does is engage the more aggressive cam profile...you still have the requisite piston-valve clearance. AFAIK, the only way to get valve-piston contact and the associated bent valve or damaged piston skirt (due to the piston cocking off vertical in its cylinder bore) is to have a mis-timed engine.

OF
 

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Discussion Starter #3
Thanks, OF. After the front head replacement, the engine only ran with the crank and cams in time. I even verified the tooth positions in reference to the following post: http://www.odyclub.com/forums/24-19...-timing-belt-tooth-counts-some-questions.html

The intake valve damage must have happened before I ran the engine. When I set and bolted down the front head, the crank was at TDC (cyl 5 at the top of its stroke) and the front cam was about 60* off TDC. I did this so that there wouldn't be any fully-extended valves when I set the head - I was worried about hitting a valve during head install. The cyl 5 intake valve must have been slightly opened. I must have bent the cyl 5 intake valve when I set and bolted the head.

Thanks,

Chuck
 

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...The intake valve damage must have happened before I ran the engine. When I set and bolted down the front head, the crank was at TDC (cyl 5 at the top of its stroke) and the front cam was about 60* off TDC. I did this so that there wouldn't be any fully-extended valves when I set the head - I was worried about hitting a valve during head install. The cyl 5 intake valve must have been slightly opened. I must have bent the cyl 5 intake valve when I set and bolted the head.
chuck, I think that is where the problem occurred. The only sure way to install a cylinder head is with that top end in-time with the bottom end, unless it is a non-interference engine, like some chain-timed Datsun's and Toyota's I've worked on, back in the day. Yes, it's a PITA to turn any cam with the head off the engine to gain TDC, and the darn things don't want to stay at 0-deg TDC ... you bump into something while holding the "timed" head, and "clunk", the darn thing hops off TDC. I've had a few frustrating, teeth-gnashing moments that way with FIAT 128-series engines.

However, there's nothing like getting through all that and assembling an engine while forgetting the dowel pins that laterally locate the cylinder head. That's the first time I've ever seen bright green Prestone dribble out of an ANSA quad exhaust .... :frown:

OF
 

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chuck, I think that is where the problem occurred. The only sure way to install a cylinder head is with that top end in-time with the bottom end, unless it is a non-interference engine, like some chain-timed Datsun's and Toyota's I've worked on, back in the day. Yes, it's a PITA to turn any cam with the head off the engine to gain TDC, and the darn things don't want to stay at 0-deg TDC ... you bump into something while holding the "timed" head, and "clunk", the darn thing hops off TDC. I've had a few frustrating, teeth-gnashing moments that way with FIAT 128-series engines.

However, there's nothing like getting through all that and assembling an engine while forgetting the dowel pins that laterally locate the cylinder head. That's the first time I've ever seen bright green Prestone dribble out of an ANSA quad exhaust .... :frown:

OF
I can see it happening on a 12:1 compression race engine. I just can't see that happening on an odyssey where the interference is really close to the end of the valve lift.
 

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Next time we will just pull the cam. I helped Chuck and wish we could just press rewind and not have to pull the head again.
 

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...I just can't see that happening on an odyssey where the interference is really close to the end of the valve lift.
greg, the key here is in which direction you turn the cam after it has "jumped timing" to regain TDC. This assumes it wasn't timed, and you bolted it down, and then started cranking the cam pulley around to realign the pulley & cam tower reference mark...if you go "the long way around"....ouch.

OF
 

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Discussion Starter #8
Once I set the head and bolted it down, I then rotated the cam to the TDC alignment mark. I rotated it "the short way", about 60* or less.

Chuck
 

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idk.... maybe i'm wrong but it seems like you would have felt the valve contact the piston.... also seems like turning it by hand would have taken a lot of effort to bend the valve... are you sure the valves are sealing properly on that cylinder? I would think it would be easier to either break the cam bolt than bend a valve. but I could be wrong wouldn't be the first time
 

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Once I set the head and bolted it down, I then rotated the cam to the TDC alignment mark. I rotated it "the short way", about 60* or less.

Chuck
I'm with greg...I don't see such a small rotation causing a problem, but then again, I've been wrong before. jester may be on the right track on this one. It could just be some bad luck, and a bad valve. Man, I just hate it when hard work ends up like this.

OF
 
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