timing belt – bent valves?

[Amit Shakya]

hi everyone,

2000 accord 2.3L MT

in the process of doing the timing belt , i got to the part where i had the covers off and had NOT yet removed the tension or the belt.

so heres the situation:

1) crank was at tdc but 360 degrees off (i.e. i set it at tdc before removing upper cover as per instruction).
2) cam’s up mark was pointing to the floor (therefore indicating that turning the crank 360 would make everything TDC)

while i was getting reading to leave the rest of the job for another day, i was already irritated and i got dumb for some reason and decided the loosen the cam sprocket bolt (to change the seal) under these conditions:

1) car in 1st gear (forgot to put it in neutral)
2) crankshaft damper and pulley bolt removed but the crankshaft (the gear) itself still in place.
3) spark plugs still in, timing belt and tension still in place.
4) crank and cam positions as stated above.

i basically just used a breaker bar on the cam sprocket without holding it in place with a screwdriver (as suggested by others) and i heard “clunk” sound like either a metal to metal contact or a mental spring getting really tightly compressed (like a “twangggg” sound).

did i bend my valves? or was that just the bolt breaking loose (as i could remove the cam bolt after another push on my breaker bar after that)?

i wasnt mindful enough to see if the cam or crank skipped a tooth.

i dont know how these honda engines work and am curious logically what doing this would entail.

i am about to do a compression test to check but dont want that to damage anything further if this surely caused a bent valve.

also if i did bend a valve, i can just remove the head and take it to a shop and not have to worry about doing anything to the cylinder block right?

Topic

[Louis]

You should report the conclusion of your compression test to close out this thread.

I recently had a situation with having took the timing belt off and cam was 180degree off on a 4 cylinder 2002 accord. I was concerned with valve interference if I turned one without the other, and didn’t have time to remove valve components. What I ended up doing is as follows:
– by hand, turn crank 1/4 turn (if any binding, stop and don’t force it)
– by hand, turn cam 1/8 turn. (Expect some valve spring back, but don’t force it if it binds)
Repeat above steps until you achieve a total of 1/2 turn of the cam.
After reassembly and compression test, my lowest reading was ~190psi, thus no valve damage with what I did.
Hope this helps.

[Amit Shakya]

I followed one of the guys said here and just put the timing belt and rotated the engine to cam + crank TDC. lined up perfect.

I did do the compression test for the 1st cylinder. it was cranking real slow and the numbers were low but i suspected the battery was low cause the car hadnt been drive in a month. i got impatient at that point and started the car. ran fine.

finally, a few weeks ago i got the job done (including valve adjustment). i was a little worried because, at warm engine after coming to back to idle (e.g. moving to neutral at stop sign), it started going down to 500 and picking up back to 700 (almost like engine dying or coughin). i did the idle relearn by letting the car idle until the fans started twice and adding 5 mins to idle time and the problem went away.

one thing that worries me is that at around 750 rpm, i have mild steering wheel vibration despite (i think) having the balancer belt aligned accompanied by some kind of pulsating that i can feel throughout the car (like if i have no hands on the steering wheel, i can feel slow but mild rhythmic pulsation through the pedals). i hear that could due to engine imbalance.

so maybe i did do some damage by loosening the cam with the timing belt on. the question really is what that sound was. sounded like a “twang”.

but the car drives just fine. i still have slight bucking at low gear/low speed acceleration and when i release the accelerator pedal at low speed/gears but this was present before the TB change as well.

thanks for everyone help here.

[Amit Shakya]

anyone have a tip here on how to loosen the camshaft bolt without damaging anything if you dont have power tools?

[Louis]

Regarding your new vibration at 750rpm, are you sure the balancing shafts were correctly oriented?
The service manual calls for a temporary bolt to be installed in the rear of the block to ensure shaft alignment while the little mark lines up. I found the bolt to be useless, but rather used a cheap horoscope to align the hole. Note…the tiny alignment mark on the outside AND the internal hole BOTH require alignment at the same time, in addition to the front balance shaft alignment.

[Louis]

[quote=”karmapacox” post=135920]anyone have a tip here on how to loosen the camshaft bolt without damaging anything if you dont have power tools?[/quote]

Buy an electric impact from harbor freight?

[Author]

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