Timing belt help - Toyota 4Runner Forum

jreask · 06-06-2024, 07:37 AM

After removing the belt on my 2008 V8, the LH cam jumped about 40 degrees. Not sure which way it jumped, clockwise or counterclockwise. I was able to turn the left cam back to the mark but it wasn’t easy. It seems like this engine is hard to turn with a ratchet anyway. I’m 66 years old and it was tough to turn to TDC. Was it ok to turn the LH cam counterclockwise back to the mark? After I installed the WP, timing belt, etc I rotated to TDC and the cams both line up with the original marks now, not the T marks. The belt is in the correct position on the crank sprocket. Any harm turning the LH cam back to the mark? Just want to be sure before I start it up.

rdruss · 06-06-2024, 08:52 AM

Quote:

Originally Posted by jreask

After removing the belt on my 2008 V8, the LH cam jumped about 40 degrees. Not sure which way it jumped, clockwise or counterclockwise. I was able to turn the left cam back to the mark but it wasn’t easy. It seems like this engine is hard to turn with a ratchet anyway. I’m 66 years old and it was tough to turn to TDC. Was it ok to turn the LH cam counterclockwise back to the mark? After I installed the WP, timing belt, etc I rotated to TDC and the cams both line up with the original marks now, not the T marks. The belt is in the correct position on the crank sprocket. Any harm turning the LH cam back to the mark? Just want to be sure before I start it up.

You really have no choice, the sprockets have to be in the correct positions when the timing belt is installed and it sounds like you did it correctly. It's normal for a cam to jump position after the belt is removed and I think that's why it's suggested to turn the engine so the cam sprocket marks align with the "T" position on the cover before removing the belt. I haven't done the timing belt on my 4Runner, but did my V6 Highlander and very similar. Someone with the V8 experience will chime in I'm sure.

jreask · 06-06-2024, 09:35 AM

Quote:

Originally Posted by rdruss

You really have no choice, the sprockets have to be in the correct positions when the timing belt is installed and it sounds like you did it correctly. It's normal for a cam to jump position after the belt is removed and I think that's why it's suggested to turn the engine so the cam sprocket marks align with the "T" position on the cover before removing the belt. I haven't done the timing belt on my 4Runner, but did my V6 Highlander and very similar. Someone with the V8 experience will chime in I'm sure.

This engine was really hard to rotate even with the old belt on. The LH cam was hard to move back. Just concerned that it’s ok to start.

jreask · 06-06-2024, 10:06 AM

Just wondering if it is possible to turn the sprocket without the cam turning?

I want to be 100% before I start it. Everything lines up on the marks and the crankshaft correctly. It seemed like the cam was hard to turn, almost impossible and then suddenly it was moveable. I am confused.

Thanks for your help.

JR

jreask · 06-06-2024, 12:53 PM

Anyone? I don’t know which way the LH can spun. Could it possibly spin counterclockwise 300 degrees?

rdruss · 06-06-2024, 07:36 PM

Quote:

Originally Posted by jreask

This engine was really hard to rotate even with the old belt on. The LH cam was hard to move back. Just concerned that it’s ok to start.

Hard to turn because your turning against valve spring pressure and That's why it jumped, one cam lobe right near it's peak open and it tends to spring back. If you rotate the engine by hand through a few complete revolutions now that you have the timing belt on and are comfortable all marks are lined up you should be good. My Highlander did the same thing, and I did the same as you, and when I went to start it, it started immediately and ran perfect.

jreask · 06-06-2024, 08:50 PM

I turned the engine without the plugs in and it was fairly easy to turn. There were some inconsistencies but it never got “hard” to turn. All marks are lined up perfectly. Is there any way to absolutely tell if the timing is correct?

AuSeeker · 06-06-2024, 11:32 PM

Quote:

Originally Posted by jreask

I turned the engine without the plugs in and it was fairly easy to turn. There were some inconsistencies but it never got “hard” to turn. All marks are lined up perfectly. Is there any way to absolutely tell if the timing is correct?

The cam that moved will be right as long as you got it back on the timing mark, the cam and the sprocket move together, not separately i.e. as one, so that means if you get the sprocket back on the timing mark then the cam will also be in the correct position.

jreask · 06-06-2024, 11:59 PM

Quote:

Originally Posted by AuSeeker

The cam that moved will be right as long as you got it back on the timing mark, the cam and the sprocket move together, not separately i.e. as one, so that means if you get the sprocket back on the timing mark then the cam will also be in the correct position.

I guess I was overthinking it. One revolution is one revolution whether clockwise or counterclockwise? As long as the cam timing mark is correct I don’t have a problem. Thanks everyone.

rdruss · 06-07-2024, 08:24 AM

Quote:

Originally Posted by jreask

I turned the engine without the plugs in and it was fairly easy to turn. There were some inconsistencies but it never got “hard” to turn. All marks are lined up perfectly. Is there any way to absolutely tell if the timing is correct?

The cam would not spin 300 degrees once timing belt removed.
One way to check if everything is correct involves removing the valve covers and going through the valve clearance sequence.
The cylinders are numbered 1-3-5-7 front to rear on driver side and 2-4-6-8 front to rear on passenger side.
If you remove the covers you should be able to check #1 both intake and exhaust, then rotate the engine 360 degrees and should be able to check #6 and #3 intake and exhaust. If that checks out, you are in time on both banks.
Checking the clearance on these cylinders means a feeler gauge of .002" will slide under these cam lobes and between the valve spring cap beneath the lobe.

jreask · 06-07-2024, 10:14 AM

Quote:

Originally Posted by rdruss

The cam would not spin 300 degrees once timing belt removed.
One way to check if everything is correct involves removing the valve covers and going through the valve clearance sequence.
The cylinders are numbered 1-3-5-7 front to rear on driver side and 2-4-6-8 front to rear on passenger side.
If you remove the covers you should be able to check #1 both intake and exhaust, then rotate the engine 360 degrees and should be able to check #6 and #3 intake and exhaust. If that checks out, you are in time on both banks.
Checking the clearance on these cylinders means a feeler gauge of .002" will slide under these cam lobes and between the valve spring cap beneath the lobe.

Thanks for that. I think it’s ok now. The engine turns freely with the plugs out. Everything lines up perfectly. The notch on the crank is on the dot and the cams are on the mark. Am I missing anything? Thanks again.

jreask · 06-07-2024, 02:00 PM

I just wanted to say a big thank you to everyone who has helped me with this project. I love to work on my 4Runner V8. Sometimes I need some help and T4R is always there to help. It’s a great forum. Thanks again everybody!!

rdruss · 06-07-2024, 08:42 PM

Quote:

Originally Posted by jreask

Thanks for that. I think it’s ok now. The engine turns freely with the plugs out. Everything lines up perfectly. The notch on the crank is on the dot and the cams are on the mark. Am I missing anything? Thanks again.

I think you're good, start her up!

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