Timing Belt - PLEASE HELP!
01-09-10, 07:52 PM
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Timing Belt - PLEASE HELP!
I was in the middle of completing the timing belt service on my 99 gs300 - had the old belt off and all the timing marks lined up when I turned around and a buddy of mine was turning the cam gear! I dont know how many times he turned it, but it is no doubt out of sync. I know that for every two rotations of the crank it equates to 1 rotation of the cams, but how do I check to the cams are at TDC when the crank is? Is there a way to visually check the valves when the crank is positioned at TDC to be sure they are on the correct timing? Thanks for your help.
01-10-10, 08:06 AM
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he turned it by hand so I very much doubt that he would bent any valves. He said he didnt feel any thing bottom out. The reason why I am concerned is I was reading about compression and exhaust stroke and how it must be in sync with the crank - maybe this only applies to v8's? As long as the marks line up after two crank cycles it should be okay, right? Im worried about being 180deg off on the crank-cam timing.
Thanks
Thanks
01-10-10, 08:11 AM
#4
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The sprocket is turning but the cam is not turn haha you are good BrO.
Just make sure everything is line up and install the new belt back on.
Yes after 2 crank cycles if it's lines up your are good.
Just make sure everything is line up and install the new belt back on.
Yes after 2 crank cycles if it's lines up your are good.
01-10-10, 08:15 AM
#5
he turned it by hand so I very much doubt that he would bent any valves. He said he didnt feel any thing bottom out. The reason why I am concerned is I was reading about compression and exhaust stroke and how it must be in sync with the crank - maybe this only applies to v8's? As long as the marks line up after two crank cycles it should be okay, right? Im worried about being 180deg off on the crank-cam timing.
Thanks
Thanks
So, I'm in the middle of a timing belt/water pump replacement, and I think I've messed up. I got to the point where I aligned the cam pulleys and crankshafter pulley, and removed the timing belt. And now it's time to remove the damn crankshaft pulley bolt, which I can't seem to get. But that's not the main problem, the problem is that while I've been trying to get it off, I turned the crank full 360 several times, and then I realized something - even if I align it with the 0 mark again, it may not necessary be aligned with cams, since it only aligns every other turn. How can I determine if the alignment is correct?
If you mean your problem about having turned the crank several times without moving the cams, don't worry about it.
If you line up the notch on the timing belt drive pulley, with the dot on the oil pump housing, then you're fine, as long as the marks on the cam drive sprockets are lined up with the corresponding fixed marks on the brackets behind them.
Think about it, if #1 cylinder is at TDC, the piston/rod/crankshaft doesn't know if it's TDC on the compression stroke or exhaust stroke. It's the position of the valves that determine that. So as long as you keep the cam sprockets lined up on their marks, you can turn the crank 360 degrees, 720 degrees, etc. and it's OK. Just make sure when you're finished, that you line up that notch with the dot on the oil pump. See the photo below for what I'm talking about.
If you line up the notch on the timing belt drive pulley, with the dot on the oil pump housing, then you're fine, as long as the marks on the cam drive sprockets are lined up with the corresponding fixed marks on the brackets behind them.
Think about it, if #1 cylinder is at TDC, the piston/rod/crankshaft doesn't know if it's TDC on the compression stroke or exhaust stroke. It's the position of the valves that determine that. So as long as you keep the cam sprockets lined up on their marks, you can turn the crank 360 degrees, 720 degrees, etc. and it's OK. Just make sure when you're finished, that you line up that notch with the dot on the oil pump. See the photo below for what I'm talking about.
01-10-10, 08:59 AM
#6
GS300 engine is interference.
Here are some videos I made to do a timing belt job on a 2JZ. The video has a 2JZ-GTE VVTi, but the timing belt alignment procedure is the same. I never finished making the videos but I think I explained how to do timing on a 2JZ VVTi motor in one of these vids.
Servicing a 2JZ
Part 1: YouTube - Jeff's Garage: Servicing a 2JZ Part 1
Part 2: YouTube - Jeff's Garage: Servicing a 2JZ Part 2
Part 3: YouTube - Jeff's Garage: Servicing a 2JZ Part 3
Part 4: YouTube - Jeff's Garage: Servicing a 2JZ Part 4
Part 5: YouTube - Jeff's Garage: Servicing a 2JZ Part 5
Here are some videos I made to do a timing belt job on a 2JZ. The video has a 2JZ-GTE VVTi, but the timing belt alignment procedure is the same. I never finished making the videos but I think I explained how to do timing on a 2JZ VVTi motor in one of these vids.
Servicing a 2JZ
Part 1: YouTube - Jeff's Garage: Servicing a 2JZ Part 1
Part 2: YouTube - Jeff's Garage: Servicing a 2JZ Part 2
Part 3: YouTube - Jeff's Garage: Servicing a 2JZ Part 3
Part 4: YouTube - Jeff's Garage: Servicing a 2JZ Part 4
Part 5: YouTube - Jeff's Garage: Servicing a 2JZ Part 5
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01-10-10, 10:01 AM
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When did I ever say that the cam wasnt turning??? Of course the cam turns when the sprocket does, I meant that the valves did not come in contact with the pistons, hence no resistance.
01-10-10, 10:13 AM
#12
which cam did he turn? intake or exhaust? If it was the VVTi cam gear it is going to have some play in it...
Jeff is correct. Very interference engine, but I also agree with you doubt anyone could turn the cam and bend valves by hand. Unless he was doing it with a wrench?.....
Watch Jeff's videos they are pretty comprehensive!
A good test to see if the you've clocked it 180 out or not, would be to line up the marks, install the belt, remove #1 spark plug and turn the motor and make sure that you are building compression every other crank revolution. You should feel air pushing out of the plug hole....
Jeff is correct. Very interference engine, but I also agree with you doubt anyone could turn the cam and bend valves by hand. Unless he was doing it with a wrench?.....
Watch Jeff's videos they are pretty comprehensive!
A good test to see if the you've clocked it 180 out or not, would be to line up the marks, install the belt, remove #1 spark plug and turn the motor and make sure that you are building compression every other crank revolution. You should feel air pushing out of the plug hole....
01-10-10, 11:02 AM
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No, thankfully he turned it by hand. Unfortunately, it wasnt the VVT-i one so it was turning. He couldnt remember how many times he turned. Lesson - keep drunk friends away from the garage.
