SNAP!!! TDC Rear Cam moved to 2 o’clock

[Bryan]

Replacing Timing Belt on 4WD 2006 Honda Pilot J-series engine. 94k miles.

Followed Eric’s VManual exactly. Wrapped belt nicely over Crank, Idler, Front Cam and Water Pump. I felt good belt tension between Idler and Front Cam. I put the belt over the Rear Cam, but had way too much slack between Rear Cam/Water Pump/Front Cam.

Then I tried my best to catch an extra tooth on the Rear Cam to get that required tension. As I was tugging on the belt to get that extra tooth….SNAP!!!

I then noticed the Rear Cam moved from TDC to 2 o’clock. WHAT HAPPENED!? The sound has scared me to think that I just committed some engine damage. I think I accidentally pushed the Rear Cam counter-clockwise trying to put on the belt (engine spins clockwise) and then it sprung clockwise to 2 o’clock. Front Cam and Crank are still TDC.

1) What was that sound?
2) Which direction and how many times do I rotate the Rear Cam Pulley Bolt to get back to TDC?

Thanks in advance for your help!

Attached is an illustration of the Timing Belt setup from the Honda Service Manual.

Attachments:

• JSeriesTimingBelt.png

Topic

[college man]

Hopefully the sound was not a valve getting bent. Redue everything and hope for the best.
If the vehicle runs bad after start up the damage was done.

[Bryan]

What should I do as far as re-doing everything? I still have the belt off ready to get Rear Cam to TDC but don’t know the safest approach. Service Manual doesn’t cover this situation.

2a) Which direction should I turn the Rear Cam to get back to TDC? It sprung to 2 o’clock.
2b) Should I be turning the Rear Cam Pulley with my bare hands back to TDC or should I use a wrench on the Rear Cam Pulley Bolt?
2c) How much resistance should I feel when doing so?
2d) As I turn the Rear Cam Pulley, should I suspect the spring-action to happen again?

[college man]

[quote=”Bnavarre9″ post=158598]What should I do as far as re-doing everything? I still have the belt off ready to get Rear Cam to TDC but don’t know the safest approach. Service Manual doesn’t cover this situation.

2a) Which direction should I turn the Rear Cam to get back to TDC? It sprung to 2 o’clock.
2b) Should I be turning the Rear Cam Pulley with my bare hands back to TDC or should I use a wrench on the Rear Cam Pulley Bolt?
2c) How much resistance should I feel when doing so?
2d) As I turn the Rear Cam Pulley, should I suspect the spring-action to happen again?[/quote]

By redoing everything I meant remove the belt and put the cam back in time then put the belt back on.
I would turn the cam the way the engine rotates. Found this old thread. see if it helps.

http://www.ericthecarguy.com/kunena/8-Service-and-Repair-Questions-Answered-Here/51967-help-honda-j-type-engine-timing-belt-replacement

[Bryan]

I think it’s best to get multiple opinions on this.

Thanks for the link college man. Reading through that other thread, it actually looks like the poster was incorrect in turning the Rear Cam Pulley Bolt Clockwise on a J-series and bent a valve. Although the correct direction on the Crank with the timing belt completely on is Clockwise, I’m thinking I need to go Counter-Clockwise from 2 o’clock back to 12 o’clock TDC mark with the belt off on the Rear Cam Pulley Bolt.

I don’t think I incurred damage at this point based on Eric’s comment of this being a relatively common instance to spring to 2 o’clock on the Rear Cam. I just need to be 100% sure on how to fix this.

[Greg]

Do not roll the cam 360 degrees to set the trimming roll it back from 2:00 12:00
If it helps paint the entire tooth so you have a good visual of the timing marks. To get the tension on the belt roll cam back towards 2:00 a tooth so you can take up the slack roll it back to 12:00 and the slip the belt over the tensioner pulley.
Use a 17mm box end wrench while you a rotating the cam so you have control of the cam.

I have done this repair 100’s of times
and this how I do it. The noise you heard was the cam lobes slipping off of the valve springs. Because at TDC the cam lobes are right on the point of the cam and it only takes a slight bump for the spring pressure to spin the cam in wither direction.

[Greg]

One other thing that may he is if you use binder clips to hold the belt on the cam pulleys

[Jared]

Best thing to do, as this can happen very often, is like stated above, carefully roll the cam back to TDC then put the belt back on and continue with the belt replacement. (I’ve done a lot of these belt replacements, I work on Hondas all day every day).

[EricTheCarGuy]

This is quite common and I get comments on this all the time. The spring tension on the valve springs caused the cam to move on the rear cam. Remove the belt from the rear cam, use a 17mm wrench to put the rear cam back into position, and reinstall the belt. You might have to try a couple of times to get it right but that should solve the problem. Once you’ve got the belt in place, go back and make sure all the other timing marks have lined up before you close things up.

Keep us posted on your progress.

[Mike]

Aren’t there holes in the cam gears for locking pins, which keep the camshafts from rotating?

[Erin]

I would not think the cam rotating a little bit would cause a bent valve. It is possible a valve may have touched the top of a piston but not slammed together like when timing belt or chain breaks.
If you have not finished this repair already, maybe “engineer” a way to attach the other end of the wrench to the water pump pulley or whatever to keep the rear cam from rotating when you are trying to situate the belt. Of course try NOT to situate things where you cannot route the belt cause something is in the way.
Maybe even have an assistant hold the wrench in place as you wrap the belt over the rear cam.

[Bryan]

Thank you very much for everybody’s input! You all saved me a bunch of money for what could have been a bent valve.

Eric, is there anyway to add what appears to be a common situation to the vmanual? I would have incorrectly thought to bring the cam all the way back around given how much emphasis is put on the engine rotation direction of clockwise.

So I rolled the rear cam from 2 o’clock back to TDC and did not go 360 degrees back around. Before i got the rear cam to TDC, I overshot the mark and it actually went past 12 o’clock (TDC) and sprung to 10 o’clock. So i had to bring it back the other direction and it stayed put at TDC. The resistance to get it back to TDC was quite a bit, sort of felt like using the serpentine belt tool on the auto-tensioner drive belt pulley. Maybe that was because I had your average size 17mm wrench on the cam pulley bolt.

I did do the rear cam trick of being almost one tooth ahead, putting belt on, then rolling back to TDC. This trick makes it easier only if those timing belt guide prongs get in the way of putting the belt on. Got the tension I needed between the front and rear cams (felt like same tension between crank/idler/front cam).

Engine runs normal and sounds normal. Hardest part was making 100% sure I was dead-on TDC on the 3 pulleys. I decided to trust the 2 cam marks with the top plastic covers removed and the crank mark with the bottom plastic cover installed. I ignored the other possible marks due to getting mixed results (at one point the front cam looked a hair ahead while front cam plastic cover mark looked behind). The rear cam was the toughest to tell given the angles for a 2006 Honda Pilot. Nevertheless I rolled the engine over a few times to ensure all 3 marks were dead-on TDC.

One last note for readers on the Honda crank bolt. If you can’t get that bolt off with air tools, below is a picture of my setup. 3 cement blocks (couple rags on top for added height), 19mm impact socket, Honda crank bolt rental tool attached to a 2nd break bar using the ground to hold it in place. Be ready for a loud CRACK!

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• IMG_20160202_213155865.jpg

[Greg]

Glad you were able to get it running.
And yeah that crank bolt can be a bear sometimes.

[Author]

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