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Timing Marks vs Timing Belt Marks


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Hi all,

I have scoured the internet for a detailed and specific setting of the timing marks on a '94 LS400 and have only found how-to articles. Me and my brother are rebuilding his engine after almost a complete seal replacement therapy and have gotten to putting the belt back on. My question is how do I know for sure that we aligned the cam pulleys and crank pulley exactly to their marks when putting a new belt on?

We bought a new Mitsoboshi belt and I'm sure its the right size. We first tried aligning the marks on the pulleys to the respective marks on the belt but after 2 revolutions, the pulley marks aren't even close to the engine marks. So we then set all the pulleys to the marks and put the belt on, ignoring the printed marks on the belt. After a couple retries getting the marks as close as possible, I'm still not confident. I know its a non-interference engine, but I really really dont want to tear all this down again because we got the timing off by 1 tooth.

Any sure fire way to know the pulleys are timed perfect? After 2 revolutions, they just dont line up to the engine marks perfectly. What I mean is that the belt could advance/!Removed! one tooth on that pulley and the pulley mark would be the same distance from the engine mark, only now on the other side of the mark. Does that makes sense?

How many degrees off does setting it 1 tooth out of time make it?

TL:DR

How can I be absolutely sure the pulley timing marks are exactly where they're supposed to be?

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If the timing marks don't line up after two revolutions, the belt is not installed correctly.  Remove it and start again.  Don't run it with the engine out of time.  It will cause other issues, not just mechanical ones.

If you have the old belt, compare it to the new one.

This link may be helpful:

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/782468-1995-ls400-timing-belt-and-water-pump-how-to.html

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On 7/29/2022 at 9:29 AM, biodiesel_boi said:

Hi all,

I have scoured the internet for a detailed and specific setting of the timing marks on a '94 LS400 and have only found how-to articles. Me and my brother are rebuilding his engine after almost a complete seal replacement therapy and have gotten to putting the belt back on. My question is how do I know for sure that we aligned the cam pulleys and crank pulley exactly to their marks when putting a new belt on?

We bought a new Mitsoboshi belt and I'm sure its the right size. We first tried aligning the marks on the pulleys to the respective marks on the belt but after 2 revolutions, the pulley marks aren't even close to the engine marks. So we then set all the pulleys to the marks and put the belt on, ignoring the printed marks on the belt. After a couple retries getting the marks as close as possible, I'm still not confident. I know its a non-interference engine, but I really really dont want to tear all this down again because we got the timing off by 1 tooth.

Any sure fire way to know the pulleys are timed perfect? After 2 revolutions, they just dont line up to the engine marks perfectly. What I mean is that the belt could advance/!Removed! one tooth on that pulley and the pulley mark would be the same distance from the engine mark, only now on the other side of the mark. Does that makes sense?

How many degrees off does setting it 1 tooth out of time make it?

TL:DR

How can I be absolutely sure the pulley timing marks are exactly where they're supposed to be?

The marks on the belt are only supposed to line up with the marks on the pulleys when you first put it on. Once you turn the engine the marks will no longer line up and they are not supposed. You most likely had it installed correctly the first time. I say most likely because I don't know if you lined the engine up at 50º TDC (Top Dead Center) when you removed the belt and if the engine stayed in that position during your rebuild.

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