Timing mark alignment

Hello All, doing my first timing belt and finding that my timing marks aren't perfectly aligned. I posted some photos. Are these good enough or is this going to be a problem? I tried for a long time to get the cam marks to align but as far as I could tell there was no physical way to get them to align with the Aisin belt I'm using. I failed to get a pic of how they looked with the original belt so maybe this is how they've been all along. Thanks for any advice!

 

Welcome to the forum! Please post the information about your vehicle so others can chime in and help. Year, can type, drive type, engine etc. I’m assuming this is a 2000-2004 2UZ-FE 4.7l V8 based on the photos?

 

Rotate engine manually at the crank with breaker bar.

Those lines on the belt should match the marks on the cams/crank after some revolutions. I think its like 7 or 8 rotations. @shifty` would probably be able to find that info faster than me.

 

Helpful thread about timing belt changes

https://www.tundras.com/threads/timing-belt-master-thread-sticky.107240/

 

Yes, thanks this is a 2002 2UZ-FE. I'm aware that the belt marks only match up every so often. I'm actually talking about the marks on the cam pulleys themselves. I see people say they need to align perfectly with the marks on the housing and mine is off by about a 1/3 or a 1/2 a tooth length. Is that good enough?

 

Check out this video from a real Toyota mechanic

https://youtu.be/k7V-QrwiTqI?si=uL-gCBiw1qWyHlPw

At about 14:30 he talks about lining up with the T rather than the straight mark to the left. This is on a Lexus but should apply to our trucks also.

 

That puts the cams on the flat spots so they don’t rotate IIRC

 

Appropriate cam timing mark alignment when crank is set to 0° and timing belt marks are lined up on the individual pulley marks correctly.

 

Toyota 2UZ-FE Timing Belt Marks 4.7L | TOYO Headquarters

 

That's a great video (as usual from the Car Care Nut... he's fantastic) But at 25:11 in the video he shows a close up of the arrow on the belt aligned with mark on the crank pully. To me that looks super confusing. The arrow is on a "valley" on the belt, and the mark on the crank pulley is on a peak. To me that looks a half tooth off. But if you move it one tooth to the right it'll be a half tooth off the other way. How do you know which half-tooth-off is correct?

 

It looks like someone gouged up the ribs on the crankshaft pulley. Before you go any further i'd smooth them up with a file. If you don't, it could severely shorten the life of the fan belt.

 

Good catch. Someone broke the cardinal rule: Always grab at the hip/lip of the pulley, not the surface the belt rides on!

 

OK good to know, thanks. For some reason both of the fan belts I've bought for this truck are too short so when I finally find the right size one I'll do that.

 

I took the belt off again and gave it one more try but there was definitely nothing that was going to make the R side cam line up perfectly with the TDC, aside from stretching the belt. After much gnashing of teeth I put it back toghether and it is running fine. It must've always been like that. In retrospect I would have noted the original TDC alignment before I took the old one off to avoid a bunch of lost time.

 

Hello, I'm reviving this thread hoping to catch the attention of some timing gurus. As it turns out my truck isn't running totally fine. It has a rough idle. I've been reading a lot of threads on rough idle and have replaced my spark plugs, a bunch of my ignition coils, cleaned my throttle body and MAF sensor. I haven't replaced my vacuum piping yet but am going to do that next. I'm guessing it's my slightly off timing that is the problem though. I cracked open my timing belt covers to have another look and will post them here. As you can see my crank and Left Cam are pretty much perfectly aligned. My left cam is off by a few milimeters. This is as close as I could get it and don't see how I could have gotten it any closer. People have told me I must be off by a tooth but I don't see how that's possible. The timing belt wouldn't allow the R cam to rotate any more counter-clockwise. I had wrenches on them but reached the max tension I could reasonably get out of the belt. I'll do the belt again if I have to to get rid of the rough idle but I just don't see how to get it any better. Any advice would be greatly appreciated!

 

Need to line up the marks as well as the lines on the belt to be 100% on the timing. If the lines on the belt are off on one side, you could have some belt stretch and be off slightly. That being said, looks pretty good and can't be far off if any. Vacuum lines could account for rough idle. Assuming all the recent parts, coils and plugs are legit and OEM? not scamazon parts?

 

Did you do the timing belt or did someone else do it?
I would inspect cam and crank sensors and clean them up.
When I did my timing belt on my old T4R it cranked and then stalled and died unless I gave it gas. I checked the belt and timing multiple times with no luck. Finally I took everything back apart to find that a tooth on the gear ring behind the crank pulley had broken off and causing the crank sensor to miss and causing it to stall. Not saying that's your problem, but something small like that and easy to miss could be contributing. It might be worth fully inspecting the belt, pulleys, and sensors to make sure everything is in good shape and not contributing to your issue.

 

I'd read this on timing marks: https://www.toyoheadquarters.com/threads/toyota-2uz-fe-timing-belt-marks-4-7l.335/

To add to questions above:

• This is a new belt, are you doing tensioner and pulleys, or just the belt?

Beyond those:

• Are you throwing any codes that led to you replacing coils etc.?
• Have you checked all your vacuum hoses?
• After cleaning the TB, did you pull the neg batt cable for 10-15 minutes to force a re-learn?

 

I've never done the timing belt so just shooting here, but the link you posted says to line up the "T" and it looks like the OP lined up to the bar instead of the "T" IS that what's going on?

 

I haven't done it either on a 2UZ. But that post explains the alignment of everything, and the expectation. I think this snippet covers it. And I just realize I missed the "I'm doing a new belt" part. Need to edit my questions above.

Not only that, but I see OP's belt orientation looks to be all-wrong? And that page should help with getting it right again.

​

 

@shifty` - my understanding is that either set of marks will line up if the cams are properly timed. The “T” marks are best to use when replacing the belt as the cams are not on a lobe which’s lessens the chances of a cam moving out of time.

 

I'm sure you're right. I'm only trying to say, I'm of the impression if you're at the dot on the crank pulley, you'll rest at the T of each cam with L/R-CAM lines lined up every other rotation, within a few mm. If you're at the zero mark on the crank pulley, you'll be aligned with the marks to their left. But I may be misinterpreting. It's one of those things I'd play with out of curiosity while doing my own belt, but can't speak to personally. Actually, looking back it appears KNABORES confirmed that.

But beyond that, I'm pointing out something concerning. Look at OP's 1st two pics. I assume they're in the 'off' crank pulley rotation, if that's the L-CAM mark on the belt I'm seeing at the right cam, and the CR(ank) line at the left cam. It would totally make sense, the belt should be at roughly half-rotation. That caught me off-guard until I realized the left cam had the CR mark.

 

Yeah my belt lines were lined up with my cam marks just couldn't get the one cam to line up with the housing. All parts recent. Used the Aisin timing belt kit of AMZ but the blugs and coils are Denso from Rock Auto. I will definitley replace all the vacuum lines before anything though

 

Right, but did you get the kit with part number ending "-001" or "-021"? One includes the tensioner, the other doesn't. Just hoping to conirm you did the tensioner also, since it appears a weak tensioner or stretched belt may result in a few mm variance on marks.

 

I did the belt about a month ago. I think I watched every youtube video on 2UZ TB's at least several times out of sheer terror lol. I don't get why I couldn't line up both cams as it just seems to happen for everyone in all the videos. That crank sensor sprocket looked to be in fine condition when I put it back on but I will check the connections on the sensor it self.

 

yep I got -021 with the tensioner. Assuming the belt is the right length the only thin I could think was that the pulley on the water pump was too big and not allowing me to "space" the two cam wheels apart enough. But I checked against the original and it is the same. I even put the old belt back on and still wasn't able to get it lined up. That's when I concluded it had to have been that way originally (but stupidly didn't take before pics)

 

this is a new belt with new tensioner and pulleys. I just bought the truck with 190k with a radiator leak so decided it was a good time to do the belt, pump etc. A bunch of the coils looked terrible - cracked and with a lot of carbon deposits so I replaced the worst of them. I have checked the vacuum hoses and don't see anything but maybe there is a leak that I can't see. Am planning on just replacing them all this weekend. I did pull the neg cable for a good 1.5 hours too.

 

Remind me, was the truck running fine before the t belt?

 

my belt marks were originally lined up when I put it on. Those pics were taken after I had rotated the crank a bunch of times hoping that the alignment would get better.

 

yeah was running fine. I only had it for a couple of weeks but didn't notice any rough idle before doing the belt. The rough idle is pretty slight I will say. I don't notice anything when driving or even when I first start it cold with the initial high idle. It's only after it drops to 500 rpm or so that it's noticable. Kind of an irregular surge every 15 or 20 seconds or so