Discrepancy between FSM and the forum's common guidance - Valve lash

[ilikefunkymusic]

I've noticed that the valve lash procedure info that is commonly supplied here on the forum differs from what my 1986 FSM says.

Looking to understand why, before I go and do this.

 

Forum says: example 1, example 2

Cyl 1 at TDC set 1, 2, 4, 6

Cyl 4 at TDC set 3, 5, 7, 8

 

 

 

My understanding of the cylinder to valve relationship:

||     Cyl 1         ||      Cyl 2        ||     Cyl 3         ||      Cyl 4       ||

intake exhaust exhaust intake intake exhaust exhaust intake

|| 1    |      2      ||     3    |   4     ||   5   |     6      ||     7     |     8  ||

 

 

 

1986 FSM says:

Cyl 1 at TDC set 1, 2, 3, 5

Cyl 4 at TDC set 4, 6, 7, 8

 

 

Edited September 17, 2021 by ilikefunkymusic
Multiple sources for forum based procedure instead of just a single source

[Charlie69]

The book shows the way to do multiple valve adjustments with 2 settings on the top dead center.  This might help the dealership mechanics stay wthin flat rate.

[datzenmike]

 I always say both valves on #1, Intake on #2 and Exhaust on #3. Turn engine ONE turn. Exhaust on #2, Intake on #3 and both on #4. This works for L and Z series engines even though the intake and exhausts are absolutely opposite in each cylinder.

[ilikefunkymusic]

On 9/17/2021 at 1:26 PM, datzenmike said:

 I always say both valves on #1, Intake on #2 and Exhaust on #3. Turn engine ONE turn. Exhaust on #2, Intake on #3 and both on #4. This works for L and Z series engines even though the intake and exhausts are absolutely opposite in each cylinder.

 

I actually called out one of your threads as example one in my post. What you promote is not in alignment with the FSM...

 FSM disagrees and says both on #1, exhaust on #2, intake on #3 then progress

 

So where did you get your procedure?

[Charlie69]

This is why I do individual valves.

[datzenmike]

1 hour ago, ilikefunkymusic said:

 

I actually called out one of your threads as example one in my post. What you promote is not in alignment with the FSM...

 FSM disagrees and says both on #1, exhaust on #2, intake on #3 then progress

 

So where did you get your procedure?

 

For the Z24 in the '84 FSM and I stand by this.

 

On 9/17/2021 at 8:30 AM, ilikefunkymusic said:

I've noticed that the valve lash procedure info that is commonly supplied here on the forum differs from what my 1986 FSM says.

Looking to understand why, before I go and do this.

 

Forum says: example 1, example 2

Cyl 1 at TDC set 1, 2, 4, 6

Cyl 4 at TDC set 3, 5, 7, 8

 

 

 

My understanding of the cylinder to valve relationship:

||     Cyl 1         ||      Cyl 2        ||     Cyl 3         ||      Cyl 4       ||

intake exhaust exhaust intake intake exhaust exhaust intake

|| 1    |      2      ||     3    |   4     ||   5   |     6      ||     7     |     8  ||

 

 

 

1986 FSM says:

Cyl 1 at TDC set 1, 2, 3, 5

Cyl 4 at TDC set 4, 6, 7, 8

 

 

 

Page MA-34 is for the Nissan Diesel engine SD25. Look at the picture of the valve numbering ET549/ET551 and valves being adjusted SMA795, you can see they are all on the same side of the head unlike the Z series valve locations.

[thisismatt]

1 hour ago, ilikefunkymusic said:

 

I actually called out one of your threads as example one in my post. What you promote is not in alignment with the FSM...

 FSM disagrees and says both on #1, exhaust on #2, intake on #3 then progress

 

So where did you get your procedure?

Not saying this is the case, but as long as the cam lobes are oriented so that they aren't pushing on the rocker and don't interfere with your feeler gauge, then it really doesn't matter.

[datzenmike]

Matt, that's the procedure for the SD25. Z24 lash is 0.012". The diesel is 0.014"

[thisismatt]

I'm just saying in general

[ilikefunkymusic]

3 hours ago, datzenmike said:

 

For the Z24 in the '84 FSM and I stand by this.

 

 

Page MA-34 is for the Nissan Diesel engine SD25. Look at the picture of the valve numbering ET549/ET551 and valves being adjusted SMA795, you can see they are all on the same side of the head unlike the Z series valve locations.

 

Holy shit you guys.

Sorry for the colossal waste of time here. Wanted to admit my fault before deleting this thread. Was indeed looking at the diesel engine info... Stupid mistake

[datzenmike]

 

[ilikefunkymusic]

With that out of the way, what is the best way to rotate the crank?

 

[datzenmike]

Socket and bar on the crank shaft pulley bolt. The engine turns clockwise and the bolt is 100-120 ft lbs tight. You won't disturb anything.

[ilikefunkymusic]

Awesome.

So, with a socket extension down the spark plug hole... TDC occurs after the intake valve has opened and shut, and the piston tops out right?

suck, squeeze, bang, blow

[datzenmike]

Check that both valves are close on the #1 cylinder. Turn crankshaft till the notch on the pulley is on the zero on the timing scale. This is TDC.

[Charlie69]

Be careful what things you stick in what holes!!!  LOL

[captain720]

4 hours ago, Charlie69 said:

Be careful what things you stick in what holes!!!  LOL

I always check the piston location carefully with a screwdriver in the spark plug hole but never turn it at the same time

[datzenmike]

 

6 hours ago, ilikefunkymusic said:

Awesome.

So, with a socket extension down the spark plug hole... TDC occurs after the intake valve has opened and shut, and the piston tops out right?

suck, squeeze, bang, blow

 

Use the timing mark and the timing scale for setting TDC. That's what it's there for. Not too often are these marks unusable. Don't be sticking anything down the spark plug hole. It does not have to be perfectly at TDC. Close enough is close enough for setting the valve lash. 

[Charlie69]

You can also put your thumb/finger over the #1 plug hole and feel the compression as you turn the crank.

Like Mike said this is what the timing mark and the timing scale are for setting TDC and also setting timing with a timing light.

[datzenmike]

#1 valves are both closed and will be for a long time before and after TDC. The middle cylinders in turn will have an intake closed during the exhaust stroke and an exhaust closed during the intake stroke long before during and after TDC. You can look at the #1 cam lobes and if both pointing downward at 4 and 8 o'clock as viewed from the front, close enough for setting the valve lash.