how to realign timming marks after timming belt breaks.. nothing lined up at list point..

Asked by Mar 25, 2016 at 03:52 PM about the 1990 Lexus LS 400

Question type: Maintenance & Repair

how to make sure all timing marks are correct after
timming belt was taken off before finding top dead
center...was located..(kids)

9 Answers

37,975

What size is the engine?

37,975

Ok, was just looking on you-tube, they have all kinds of videos on this. So check out you-tube.

Best Answer

thank you but they all show them marking the belt before demo,..that did not happen so i need to start from scratch with no old belt to mark from...just straight from scratch..cam marks and crank marks..does it need to be on exust stroke or intake stroke TDC for marks on belt to line up

37,975

I will search some more, but I need to know what size is the engine? And what I do know is the number 1 piston needs to be on TDC. Also do not be cranking on it with the starter as from what I see some of the Lexus motors are a interference engine, meaning you could bend the valves.

37,975

I had found this.

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https://youtu.be/vd5y9teII9E..........The timing marks are actually not straight up and down on the cam gears as this picture shows. I am finding all kinds of stuff on you tube on where to set the timing marks.

thank you rowefast im getting closer ....i appreciate your help...

37,975

Thanks.

10

I just did my timing. Didn't mark the belts before taking them off. Doesn't matter how the belt goes on as long as the timing marks line up after the belt is on. Make sure you get the crank pulley to top dead center (TDC). There are markings on the both the cam shaft wheels that have to line up with marks on the engine. The spots that need to line up are probably marked with paint, if not, don't worry there are small grooves on the cam pulleys themselves that line up with a small ridge on the engine behind the wheels. Once you get those lined up, you should probably figure out a way to keep the wheels from turning while you put the belt on. It isn't easy to get it on without them turning. You can try zip ties around the belt on the inside of the cam pulley or a pin or something to hold them in place. I'm assuming you bought a new tensioner. When you pull the pin on it to tension the belt, if you are not extremely lucky, the cams will turn if they aren't held in place. I know because this happened to me when I did it. My cams advanced so I had to advance the timing on the crank pulley to make up for it and pull the belt back on to the crank. Once you get the belt on with the tensioner pin pulled and tension on the belt, turn the crank pulley by hand and all of your timing marks should line up perfectly every other rotation. Don't try to start the car if the marks don't line up. I rotated my crank pulley by hand a total of 6 complete rotations to make sure they all lined up every other full rotation. If they don't line up, you have to get them lined up. Most importantly, assuming you took the rotors off, make sure you put them on right. There is a tab on the back of the rotor. Look at the back side of the rotor and you'll see by looking where they go on how it goes on. If you put them on wrong, your rotors will be off by 180 degrees, you'll put everything back together your car won't start and you'll have no idea why since the timing marks line up. I know because it happened to me. I was following online instruction with pics and the pics of the rotors had them 180 degrees off. Once I finally figured out what was wrong, had to take it all apart again down to the rotors. Not fun and not a good feeling to do all that work and finally finish, turn the key and nothing happens. If your timing marks line up and you make sure you match the tab on the rotor with the slot on the cam pulley, it will start right up once it's all back together. This is not an easy job but you'll be able to get it done and you'll be a much more confident mechanic when you do.

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