Honda V6 Timing Belt Screw Up

On my 2012 Honda Accord V6 I made a huge mistake. While trying to change the timing belt I turned the crank shaft with the key out that connects it to the timing belt pulley. Once I realized the cams were not turning I discovered my mistake and honestly I panicked. I continued to turn the crank around to where I could put they key back in (360 degrees) then I turned it another probably 45 degrees so that #1 cylinder is at TDC. After my heart stopped pounding and I caught my breath I realized that a) I might be screwed anyway or b) I’m at least out of phase because the crank shaft turns twice for every one turn of the cam shafts if I am understanding things correctly. I’ve gotten differing advise. One person said that I’m fine just turn the engine through to TDC again to see if there’s any resistance. My local mechanic said turn the crank backwards 360 degrees and cross my fingers. I know this is an interference engine and if I did get lucky and not tear anything up my cylinders are in a different place now so the 2nd idea sounds risky. So HELP! Anybody got any ideas?

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[Richard KirshyParticipant]

Hmmm…
Let me see if I have this correct.
I assume you had all the timing marks aligned … cams, crank when you had the new belt install.
Then proceeded to turn the crank bolt, realized your mistake then kept turning the crank (without the cams turning one full revolution ( 360*) so that you could get the key installed.
If I got that correct, that means your cams are still set at TDC but your crank rotated 360*.
If you did managed to turn the crank the 360* without any type of lock up ( a piston hitting a valve ) you are EXTREMELY lucky.
Though it would be harder to tell with the spark plugs installed fighting cylinder compression.
What you would need to do is:

First, remove all the spark plugs
At this point you could try looking down each cylinder with a bore scope and look for any contact marks on the tops of the pistons for contacting the valves.
If you decide not to …
Second, Slowly and very carefully bar the engine over (by hand)
Third, Triple check your timing marks and that #1 cylinder is @ TDC both valves and piston.

If by some act of god there was no contact between any valve and piston turning the crank forward 360* you should ok.
Remember the whole engine needs to rotate 720* for all cylinders to complete their 4 strokes.
The crank repeats its position every 360*
Reinstall your plugs then cross your fingers and try to start it.

• This reply was modified 2 years, 10 months ago by  Richard Kirshy.

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