Timing a tooth out. Updated

[TRD_ZERO]

Ok so I had an issue with my cam belt turning into a 3 piece one. I replaced it and I swear I sat checking the timing over and over again. But when I started it over but I was getting an aweful tapping noise in the head and didn't really want to idle(doesn't have cold tune sorted anyway). I checked the timing today and when the cams are set at tdc the crank sprocket is one tooth off the mark on the oil pump. The sound in the head makes me think I've just busted my valves up. It's a blacktop head with 8.9 comp pistons. I do know it's an interference motor regardless of pistons.

This might be tough to answer but what are the chances of my valves be bent and which valves are likely to be bent? The mark in the crank gear is one tooth too far to the right. I just want to know will one tooth out on the crank gear be enough to hit?

I've pushed an inspection cam down to see if u could see anything on the top of the pistons but not much. If anything I saw a mark by the exhaust valve. I pulled the spark plugs out and turned it over by hand and had a mate listen for any bumping odd hitting noises but nothing.

I'm going to reset the timing and turn it over and see what happens but in the back of my head I'm already thinking it's too late for hope.

Any ideas on what I can check or do before I just pull the head off. Thanks

[Grrrrrrr!]

Pull cams out or rotate so all valves in closed position, pressurise cylinder via sparkplug hole. If pressure drops instantly, valves = more bent that Bieber

[matt dunn]

This might be tough to answer but what are the chances of my valves be bent and which valves are likely to be bent?

Will bend the exhaust valves and the centre inlet valves.

my old engine did 12 of the 20 valves when it slipped the cam drive sprocket,
that was a ST 20V head with the 8.9 pistons.

Any ideas on what I can check or do before I just pull the head off. Thanks

Check valve clearances and see how they are ??

[evil_si]

Wouldnt think the valves would make contact at only a tooth out,

Did your belt split length ways or break?

[Bling]

I might be missing something (i'm green when it comes to engine internals), but could the damage not have occurred when the belt went three piece spec? Rather than it being due to the timing since replacing the belt.

The above may be exactly what you're thinking and i'm just reading the post wrong.

[matt dunn]

Wouldnt think the valves would make contact at only a tooth out,

Probably not but may have happened when it broke originally

[TRD_ZERO]

Wouldnt think the valves would make contact at only a tooth out,

Did your belt split length ways or break?

It split length ways, the car was still idling when I peeled the cam gear cover back check as there was a flapping belt noise. The came belt tensioner nut and washer fell off and started shaving the cam belt. The belt hadn't snapped and I didn't have an issue with idling or the head noise on idle when I found the ripped belt.

How much pressure do I apply to the cylinder when valves are closed? How tightly sealed are combustion chambers/cylinder? Could I blow up a balloon and put it on the spark plug tube? Would that sort of pressure work as a test or do I need to get a compressor?

So is one tooth on the crank enough to bend them Matt?

[rollaholic]

leak down test or compression test

[TRD_ZERO]

So I pulled the spark plugs out of 3 and 4 to check the top of the pistons. I pushed the leads back in the spark plug tubes and when I was turning it over by hand. When doing so the leads popped out. That gave me hope in the sence that the cylinders were holding pressure. I moved the crank back a tooth and put it all back together. Started it up and it ran like it should no missing or tapping noise in the head.

Now when I was putting the hydraulic tensioner back on I noticed it had about a millimeter play in the little shaft when fully extended and when it pushes the tensioner wheel i can move it a mil or so which creates abit of slack.

When I reved the motor I could see the belt moves alot like vibrates as if it isn't tensioned enough.

Replace the tensioner that is only 200kms old? but I have taken it off a fair few times.

[loudstealthGT-Four]

Did you set the tensioner correctly?

[TRD_ZERO]

Did you set the tensioner correctly?

Correctly? The actual hydraulic cylinder? Or the wheel and arm/bracket?
I just bolted the cylinder on with the shaft in, pushed the wheel into place pulled the pin out and the shaft pushed the bracket tensioning the belt.
Is that not correct?

[rollaholic]

there will be some specs somewhere for max extension, or how much is supposed to stick out once its all tensioned up.

[loudstealthGT-Four]

Did you set the tensioner correctly?

Correctly? The actual hydraulic cylinder? Or the wheel and arm/bracket?
I just bolted the cylinder on with the shaft in, pushed the wheel into place pulled the pin out and the shaft pushed the bracket tensioning the belt.
Is that not correct?

Sorry, ignore that. The hydraulic tensioner on a 4AGE doesn't need to be set like on a 3S.

[Bazda]

But why was the timing out in the first place.

Are you using the right crank sprocket?
20v BT and 20v ST have the markings in a diff location on the sprocket as both oil pumps on those models have the dot in a diff place.

[xsspeed]

quite easy to drop a tooth one way or the other when you have the belt around the crank sprocket and not around the cam gears if you dont wedge a rag in and leave it - possibly the issue - slack would have been on no tensioner side then, and could have ended up a tooth out.

[jacobrjett]

when you reset the hydraulic tensioner, i believe its quite easy to damage the internals if you press it too fast.

get a new tensioner they are like 30 bucks?

my tensioner was rock hard when i tried to reset it the second time when i did my cam belt, there was absolutely no way you could reset it without a vice, and i was told if you do it too fast in the vice they spill their guts

otherwise i can imagine user error when pulling the pin out and putting then putting the tension back on the belt. i had to pull tension upward with my hand from the crank pulley to the exhaust pulley, then all the way around, to try and get it to sit on the gears right, and it was quite hard because the gears arent all 100% lined up when you are about to do it, and it could have jumped the belt on the wrong tooth on one of the gears

[rollaholic]

did you turn the engine over by hand a couple of times before starting?

[matt dunn]

when you reset the hydraulic tensioner, i believe its quite easy to damage the internals if you press it too fast.

From my experience too they are real easy to stuff them by pressing them back in,
Read somwhere they need to do done slowly and vertically,
so need to be done in a press not a vice which lays them horizontaly.

I converted a stuffed one to become mechanical with a thread right through the centre.

[TRD_ZERO]

But why was the timing out in the first place.

Are you using the right crank sprocket?
20v BT and 20v ST have the markings in a diff location on the sprocket as both oil pumps on those models have the dot in a diff place.

Timing was out because when replacing it i set it wrong. Yes im sure the crank pulley is the correct one its been on this motor for awhile.
I dont know how i got it wrong after all that checking.

quite easy to drop a tooth one way or the other when you have the belt around the crank sprocket and not around the cam gears if you dont wedge a rag in and leave it - possibly the issue - slack would have been on no tensioner side then, and could have ended up a tooth out.

Yeah must have been something like that.

when you reset the hydraulic tensioner, i believe its quite easy to damage the internals if you press it too fast.

Yup its farked. I put it in and out 4 or 5 times not really taking any care in what speed they were getting pushed in at.
Didnt spill its guts though, no obvious oil leaks.

did you turn the engine over by hand a couple of times before starting?

Yeah i did and checked it each time and changed it each time.
What i probably should of done was check the crank pulley slot with the timing cover right at the end before starting but didnt cross my mind until after starting.