[BuckeyeTheDog]

2004 Honda Pilot and I’m changing my first timing belt.
I did a bunch of research and carefully aligned everything top dead center to the best of my ability.
But I couldn’t get the engine to start.
Now when I try to align the camshaft (closest to the cabin/ furthest from the radiator, it wants to “spring” past top dead center. I can almost set it, but it rapidly lunges forward- or backward.
I fear that I have ruined the engine somehow. Fingers crossed.
.
I took the video below- it’s hard to see what I’m talking about, but you should be able to get the idea.
Help? Thoughts? Mechanics prayers (ha)?

Trouble doing timing

I am doing a timing belt on a 2004 Honda Pilot.I set up the timing belt - all on top dead center, but then could not start the car.I notice the overhead pull...

youtube.com

 

[Tacoma'03Pilot]

There are Real Mechanics here who will respond, but here's some basics to get you going again:

1. As long as things still turn easily, you probably haven't damaged anything.
2. The cams won't always cooperate with you. You can turn them backwards to re-align if you need to. Just don't force anything. A fixed breaker bar may be a better tool for the job than a ratchet. Make sure the plugs are at least loose, so you're not pushing against compression.
3. You have to spin the cranks around at least twice to be sure that your cams are aligned. The marks should be perfect every time they come back around.
4. A Pilot will run with a cam that's slightly out of time (like one or two teeth). Unless you suspect you made a massive error, your diagnostic time may be better spent looking for another problem, vs. fussing with the belt. Check the basics: spark, fuel, air, and work from there.
5. When you feel anxious or upset about a mistake while working on a car, stop, step away and relax. The odds of doing real damage accidentally are far lower than for something you might do if you're not thinking clearly and act rashly.

 

[BuckeyeTheDog]

Good idea to loosen or remove the spark plugs.

by the way, the last time I did a test start, it seemed that my cams jumped forward a piston from when i started it.

maybe maybe I missed it before I started it.
Good advice on stepping back. I was cursing a bad streak on n the midst of it.

 

[sparkydave]

I'm confused. Even further confused watching your video. You aligned it, but you couldn't get the engine to start? Did you try to start it after you replaced the belt? In your video, you're turning the cam, but it looks like the belt is still attached. You should never try to turn the cams to turn the engine, only turn the engine from the crankshaft. If you tried to start it with the belt not connected, then yes, you've probably damaged some valves.

If the belt is still attached, turn the crankshaft ONLY, and only turn it clockwise looking at the crankshaft. Line up the marks on the crank, make sure the #1 is lined up on the cams, and if not, turn the crank one more turn and line up the marks.

 

[BuckeyeTheDog]

In the video, the belt is not attached to the cam and is totally off the crankshaft. I was trying to align the cam with top dead center by making small movements, but then the cam would snap thrust forward right around top dead center.

I never did run the engine without the timing belt on.

What is the springy thrust on the cam telling you?

 

[Tacoma'03Pilot]

What is the springy thrust on the cam telling you?

That's the valve lifter pressing on the cam lobe as the lobe passes the high point. It's normal.

Unless I'm missing something, your goal is to get all three marks (crank and two cams) to align with their partners. Unless you've gotten one of the cams wildly out of time by turning it manually, they should be within 90 degrees or so of alignment.

Get the cams aligned. Get the belt back on and tensioned. Turn the engine over at least 4 rotations by hand to make sure everything turns smoothly and stays aligned. If not, you'll have to re-pin the tensioner and do the belt again.

Once that's done, you can start looking for reasons why it won't start, because you'll know that the cams and crank are in time with each other and the motor can spin without wrecking itself.

 

[royalbiggster]

When you replaced the belt, you aligned cams and crank TDC, then removed the belt, and installed the belt starting at the crank, and routing it counter clockwise tight between the crank and cams with the slack all at the tensioner. You also ensured you have no slack anywhere except at the tensioner pulley, and pulled the pin on the tensioner so there was no slack anywhere. Looked to make sure you didn't lose any tension. Once you were assured you had good tension and everything was aligned, you turned the engine over at the crank a coupe times making sure your marks were still all at tdc. You also aligned the crank by the triangle, and not the circle at the crank. Once you ensured that everything turned without making contact, you attempted to start the car. Once you attempted to start the car you decided to loosen the belt? That is where I am lost. Assuming you did everything I mention above.

 

[royalbiggster]

Get a breaker bar, or wrench and turn the crank. Don't use a ratchet. It will be difficult to get it just right. There is a sweet spot you have to hit, and with a ratchet it is almost impossible, since you lose it after it hits the sweet spot. A wrench or breaker bar will not allow it to spin freely. You will have complete control of it.

 

[royalbiggster]

The crank rotates 2 times for every 1 rotation of the cams. You could be off a full rotation now.

 

[BuckeyeTheDog]

The crank rotates 2 times for every 1 rotation of the cams. You could be off a full rotation now.

Yes, I did everything that you mentioned above. Great point on everything- including using a breaker bar and not a ratchet.

Interesting on possibly being off a full rotation. I did not know that and yes, that could be. I even seemed to remember rotating the very cam that was “springy” a full rotation (believing at the time that I would damage things if I went backwards. If I had to guess, the crankshaft and the radiator-side cam are synced- but the springy cam is not.

How would I get ensure that the cams and the crankshaft are in the correct sync?

If I get the timing all synced, after doing a timing belt and an oil pump, what might be likely causes of having a difficult time starting (when I did not have that problem previously)?

 

[royalbiggster]

Cams are 1 rotation, crank is 2. Only Crank can be off.
You pulled the pin on the tensioner to put tension on the timing belt?

 

[royalbiggster]

Do this. Remove the tensioner pulley. Remove the timing belt. Start by routing the timing belt around the crank work it behind the pulley and up around the front cam. Except this time take a breaker bar or wrench on the bolt and turn it clockwise a little. Once the belt is around it, put tension on the belt by turning the front cam counter-clockwise. Pull it tight, but not tight enough to move the crank. Look at your marks, and make sure they are aligned. If the belt is tight, and the crank and front cam are aligned, route the belt under the water pump and do the same clockwise to counter-clockwise on the rear cam. Turn the rear cam tight, but not tight enough to move the crank or front cam. Once you see both are tight and everything is lined up, install your tensioner pulley and double, triple check everything is tight, nothing is binding, all of your marks are aligned, and everything is routed properly. On the rear cam on the back side, the timing belt slips into place. You should be able to let go of the belt without tensioner tension and everything holds on its own without slipping.
Now that everything is correct, pull the pin on the tensioner. Make sure to turn the engine by hand at the crank clockwise at least 3 rotations going slow, making sure it doesn't bind to a stop. There will be resistance from the valve springs, but you shouldn't hear metal hitting, or parts where it is real hard to turn it.
Check your timing marks one last time before you try to start it.

 

[royalbiggster]

The engine is cranking?

 

[BuckeyeTheDog]

Great! Thanks so much. I am out of town during the week and will try this on Saturday.

I can’t wait to get this thing going again!

 

[royalbiggster]

You can verify the crank is TDC with cylinder #1 by taking out the spark plug and putting something thin and long enough to stick out of the spark plug tube. You want it to hit the piston head. Has to be skinny enough to clear the spark plug threads, but also straight so it doesn't get jammed when the piston raises and causes it to raise. So no grooves or steps on it. Watch it move up when you hit TDC on the crank. If it is not fully extended, you are not on TDC, and need to go back around. If you have a compression tester you can remove the pressure gauge, and put a balloon on the end of it, and watch the balloon expand. This is more accurate. This shows it is on the compression stroke. Make sure you do this to the #1 cylinder and not any of the others. Once you know the crank is TDC, the cams are only 1 way, so there is no need to double guess if they are TDC as long as they are at their marks.

 

[BuckeyeTheDog]

Great. Thanks so much. Time go go tackle this!

If I read correctly, cylinder #1 is the rear left (as seen from standing in front of the Pilot),

Also, when I have the timing belt on and I’m ready to start the car, I’m not planning on re-attaching the drive belts until I know it can start and run. Is there any problem with that?

 

[BuckeyeTheDog]

Btw, does anyone have tips on removing and attaching the hydraulic tensioner? It is always way too hard for me and I’m missing something.
To attach… top bolt first or second? How do I get the pulley out of way to get the tensioner head in there? Do I reach the rachet on from the top or the bottom? Anything else?

Same question from removing the tensioner.

Thanks!

(I notice that I am trying to install the pinned hydraulic tensioner AFTER putting the belt on.
Man, am I a rookie. Is that my problem?)

 

[BuckeyeTheDog]

So I soldiered up the belt. I was dead on center when I started. But when I turn it, it gets off a bit.

I can start it and it runs very rough and dies on idle.

Here are photos of how it lines up when the front cam is dead on.

Front cam

Rear cam

Crank. (From my eye, it short of top dead center.

So is started but ran rough. So close. So far away.

Any ideas what I am doing wrong?

 

[royalbiggster]

The tensioner still have the grenade pin in it? If not, it needs to be compressed and the pin put back in to install it. If your timing is off, you need to redo it, until it is aligned. One of the reasons you rotate the engine so the slack on the belt is let out, and you can see if you need to adjust your belt.
If your timing was off, and you tried to crank your engine a lot, you could have bent a valve or more.
Your rough idle could be from either timing off a few teeth or bent valves not allowing compression.
When you re-did the timing belt was it off? If it was way off and you were cranking did you hear the pistons hitting the valves?

 

[Tacoma'03Pilot]

I agree that it doesn't look right from the pictures.

One of the best tips I got (probably here, maybe the Eric the Car Guy video) was to buy an extendable mirror so that you can see the marks straight on, up close.

As soon as you get off-axis (like the front cam pic) you really can't tell anything.

Pull that tensioner again and follow @royalbiggster 's advice.