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Cam Timing

950 views 16 replies 8 participants last post by  GTS_Ed 
#1 ·
Well yesterday I took off my valve cover to check the cam timing that I suspected to be off. Sure enough it looks like it was. Here are the pics:

By chain marks:


By setting the crank to TDC:

^^ these marks should be offset. The exhaust cam mark should be up a notch. I think the dealer set it in a straight line b/c thats the way it looks in the service manual, its confusing.

If you look at the chain marks it looks advanced by 2 notches, but when you look at the TDC marks, it looks off by 1 notch since the marks are even.

I'm not going to attempt to fix this myself, but was wondering if anyone has any insight why this is.


.. this is a 2003 GTS btw.
 
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#4 ·
GTS_Ed said:
Well yesterday I took off my valve cover to check the cam timing that I suspected to be off. Sure enough it looks like it was. Here are the pics:

By chain marks:


By setting the crank to TDC:

^^ these marks should be offset. The exhaust cam mark should be up a notch. I think the dealer set it in a straight line b/c thats the way it looks in the service manual, its confusing.

If you look at the chain marks it looks advanced by 2 notches, but when you look at the TDC marks, it looks off by 1 notch since the marks are even.

I'm not going to attempt to fix this myself, but was wondering if anyone has any insight why this is.


.. this is a 2003 GTS btw.

The same sprocket is used for both 1ZZ and 2ZZ exhaust so there are extra marks on it. It also used to be used for 1ZZ intake back in the day before VVTi. And yes your exhaust cam is advanced a tooth. Lots of techs make that mistake.
 
#7 ·
I never go off the markings on a cam chain to verify cam timing. Always go by TDC and the markings on the cam gears. What if someone installed the cams without using the markings on the chain? It would "appear" to be off, but it really isn't because he used the markings from the crank/cam gears only and not the chain paint.

Just something to think about.

Why is this such a common mistake? I don't get it. I guess it's a "take an extra 5 minutes to do it right" thing. They just don't do it.

Anyway, my .02
 
#13 ·
Originally posted by bagodoosh
boosted roxor. :D
werd thanks boosted

Originally posted by Red01GTS
I never go off the markings on a cam chain to verify cam timing. Always go by TDC and the markings on the cam gears. What if someone installed the cams without using the markings on the chain? It would "appear" to be off, but it really isn't because he used the markings from the crank/cam gears only and not the chain paint.

Just something to think about.

Why is this such a common mistake? I don't get it. I guess it's a "take an extra 5 minutes to do it right" thing. They just don't do it.

Anyway, my .02
Well shouldn't the markings on the gears be the same distance from markings on the chain anyway? I mean, I could see that if they took out a link it would make things different.

The Toyota service manual actually has come confusing pictures in it. I have it on my other comp, but I think it doesn't have the 2ZZ-GE mark on it like the lift bolt TSB does.
 
#15 ·
Originally posted by bagodoosh
well, i think the chain marks show the intake/exhaust timing relation. TDC method would show the absolute timing. they would have to both match, ya? ya.
They would have to match, if you aligned the markings on the chain to the markings on the gears during assembly. If that didn't happen, for whatever reason, then they would never line up. If you read the TSB for Lift Bolt Replacement, it doesn't say anything about lining up the painted marks on the chain, it only says to align the marks on the timing gears while a true TDC. This takes the guess work out of the painted chain.

Here are the words from the TSB, just to verify things...and to think, all I did was state not to trust the painted marks on a chain!


Set No. 1 cylinder to
TDC/compression.

A. Turn the crankshaft pulley, and
align its groove with timing mark
 
#16 ·
Red01GTS said:
Why is this such a common mistake? I don't get it. I guess it's a "take an extra 5 minutes to do it right" thing. They just don't do it.
Because every other Toyota engine you line the dots up with eachother or with fixed marks on the backing plate behind the cams. The 2ZZ is unique (in a lot of ways really).

Also in a case like this the paint marks are a great way to verify that the cams are out of time - as they make it abundantly obvious.

Anyways - heres timing a 2ZZ made simple:

1 - put the crank at TDC (dot lines up with 0)
2 - Lay a flat object (knife, feeler gauge, whatever) on the timing chain cover pointing at the left side of the intake cam sprocket.
3 - when the intake cam is in the correct position the dot will be JUST BELOW the knife orfeeler gauge
4 - Set the exhaust cam dot 1.5 teeth up (CCW) from the dot on the intake cam.

Presto - in time every time

Theres also a trick for adjusting the timing without removing the chain tensioner, but I'm not sharing that one - its too easy to do wrong and break stuff if you don't know what you're doing.
 
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