Timing Off???

so now that I did my timing belt I'm paranoid about my timing being off. Before I took the old belt off I made sure the motor was TDC. When I was putting it all back on I noticed the notch on the crank pulley wasn't lined up with the 0 anymore but the marks on the cams were still lined up.

The truck idles fine. The only thing that MIGHT be different is very slightly less power. That could be my imagination so what would the symptoms of my timing being off and is there any way to know for sure? Thanks.

 

anyone?

 

The ECM controls timing. If you are that worried about it, then go back in and make it correct. Only option.

 

Thank you for the reply. I guess I was looking for other sypmtoms of the timing being off. Idle is smooth, rpm's are where they were before the job, and power seems OK when I get it on the freeway.

Would being off just slightly show itself in any other ways?

Just trying to save myself from going back in there.

 

Your valve timing is controlled by the belt/timing gear alignment. Ignition timing controlled by ECM. You would probably get
a check engine light if you didn't get your valve timing marks right. I've seen them run (not well) being off by 3 teeth, don't
recall which side of TDC.

 

Ok, so no CEL and a smooth running engine make me feel like I got it correct.

I do have a large crack all the way around my exhaust pipe, just before the first hanger coming off the manifolds. Maybe that could be an issue (lack of back pressure) making me think things are wrong.

In other words, if timing was off just a smidge, would the symptoms be extremely subtle or would they be obvious something is wrong?

 

I think you have it correct. There's a pretty simple way to check. Remove the upper valve gear covers & roll c-s up on TDC &
I think you can see.

 

I'd get that manifold fixed. The computer thinks it's running lean and putting more fuel into the engine

 

As long as everything lined up perfectly when you set the timing belt to the 3 marks, youre golden. the crank is bigger than the 2 cams, or vise versa. so it will never line up again until once every 60 or 120ish RPMs

whats the crank to cam ratio? 2:1?

 

Now I feel a little better. I'll have a look at the 3 timing marks later this week when I put my new fan bracket on. Can I leave the t belt on when I rotate the engine by turning the crank to make sure it's all TDC?

 

well..... yeah, but remember, those lines only line up every 60, 120, or even 240 RPMs. you may be doing a lot of cranking to see. youre better off resetting the belt honestly

 

Gotcha. I'll take it all apart again and snap some pics. Since I am not touching the water pump I am sure there are a few steps I can skip to make this not such an ordeal.

 

I've been wondering this about mine as well. Because once I did my kit, she ran like brand new for a week or so. Little more power and awesome throttle response and perfect idle. Thought my timing may have been a hair off before the kit. But after that week or so(at least it seemed that long) it went back to being kinda sluggish and not so much throttle response. So subbed for further details. Because I really don't wanna tear mine apart again either. Ha.

 

there has to be a way to find out. im sure you can turn the crank a certain degree from TDC, where a set of valves should be closed but would be open if the timing was too advanced or retarded, and get ultra low compression from the valve being open.

 

looks like you can google valve timing diagram 4 stroke petrol engine for some good info on that.

 

Since I have to replace the fan bracket I might as well just reset it all to tdc.

 

The c s turns 2 turns to the cam/gears 1turn,,2:1. The timing marks should line up perfectly at tdc every 2nd turn of the c s...the writing on the timing belt floats all over the place.

 

Thinking back I believe it all lined up UNTIL I put the crank pulley back on. The little notch on the pulley wasnt lined up with the 0 on the smaller plastic timing cover (not the larger cover on top).

 

The critical part of lining things up is matching the belt marks to the pulley marks.
Starting with the cam and crank pulleys lined up to their marks on the engine. Then set the belt marks starting at the pass side cam followed by the driver side. Now you get down to the crank pulley and it looks like the belt is too short like the pic below. It's not to short and nothing is wrong, the belt is just new and has not yet seated to the pulleys. As long as the belt marks match the pulley marks you are good to go.

The pic below is how things frequently end up, just can't quite get the belt mark to match the crank pulley. The solution is to rotate the crank pulley slightly (yellow arrow) to get the belt mark to line up with the pulley mark. One the engine has run for a few minutes the belt will seat and the timing marks (pulley to engine) should line up every 2 crank revolutions.

 

OK! After MUCH stressing I talked to a 30+ year mechanic and a long time lexus tech who has been all over these motors inside and out, told me if I am not getting a CEL and the truck idles and runs like it did before, 99.9% chance I got it right.

Sometimes I guess we doubt ourselves when tackling something we have never done. I'm going to replace the noise fan bracket and call it done.

Another thing I noticed is my MPG has dropped off slightly. I also pulled and cleaned the MAF sensor and left the battery undone so the ECM and relearn stuff. I expect the slight drop in MPG is due to the computer relearning. The slight sluggishness that's probably in my head I'm chalking up to the huge crack in my exhaust pipe that goes the full 360 degrees. Fixing that today.

Thank you for all who replied. I HOPE I'm good on this job.