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Discussion Starter · #1 ·
I have the chiltons auto book it tells you to
adjust valves 1,3,7,8,9,11 when both cams lobes
are pointing up. I thought you adjust the valves
when the #1 lobe points up. It then says to
adjust valves 2,4,5,6,10, and 12 when #1 lobe
points down. Also the books says, The clearance
should be .25 mm for intake valves 1,7,and 9, and
.30 mm for exhaust valves 1,7, and 9. What happen to valves 3,8, and 11? Which valves are
intake or exhaust valves. Can someone help me
out. Thanks for your help. Want to adjust valves
before the super bowl.
 

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Re: Ajusting Value lash(misprint in chiltons auto

this is for a 81 280ZX out of the Datsun service manual

this is what it says

set so that high point of No, 1 cam lobe points above

Valve Clearanve (HOT)

intake 3,8,11, : 0.25 mm (0.010 in)
exhaust 1,7,9, : 0.30 mm (0.012 in)

then on they other page it has

intake 2,5,10, : 0.25mm (0.010 in)
exhaust 4,6,12, : 0.30 mm (0.012 in)

does this help at all?

also Chiltons has the sparking order wrong hmmm is it that good of a book or just a name?

Jeff 280ZXT
 

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Discussion Starter · #3 ·
Re: Ajusting Value lash(misprint in chiltons auto

This is how the valves are arranged.

EIIEIEEIEIIE E=Exhaust, I=Intake

I adjusted mine starting from one side and working to the other. First all exhaust, then all intake valves. Just pointed the lobe of each one I was adjusting straight up. It probably takes a little more time this way, but I got pretty fast at it after a few times.

If this way is wrong, someone let me know.

> I have the chiltons auto book it tells you
> to
> adjust valves 1,3,7,8,9,11 when both cams
> lobes
> are pointing up. I thought you adjust the
> valves
> when the #1 lobe points up. It then says to
> adjust valves 2,4,5,6,10, and 12 when #1
> lobe
> points down. Also the books says, The
> clearance
> should be .25 mm for intake valves 1,7,and
> 9, and
> .30 mm for exhaust valves 1,7, and 9.
> What happen to valves 3,8, and 11? Which
> valves are
> intake or exhaust valves. Can someone help
> me
> out. Thanks for your help. Want to adjust
> valves
> before the super bowl.
 

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WAITONE MORE THING!

Sorry I typed it at 5:30am and missed one thing

Valve Clearanve (HOT)

set so that high point of No, 1 cam lobe points above

intake 3,8,11, : 0.25 mm (0.010 in)
exhaust 1,7,9, : 0.30 mm (0.012 in)

then on the other page it has

set so that the No,1 cam lobe points down

intake 2,5,10, : 0.25mm (0.010 in)
exhaust 4,6,12, : 0.30 mm (0.012 in)
 

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WAITONE MORE THING!

Sorry I typed it at 5:30am and missed one thing

Valve Clearanve (HOT)

set so that high point of No, 1 cam lobe points above

intake 3,8,11, : 0.25 mm (0.010 in)
exhaust 1,7,9, : 0.30 mm (0.012 in)

then on the other page it has

set so that the No,1 cam lobe points down

intake 2,5,10, : 0.25mm (0.010 in)
exhaust 4,6,12, : 0.30 mm (0.012 in)

does this help at all?

also Chiltons has the sparking order wrong hmmm is it that good of a book or just a name?

Jeff 280ZXT
 

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Discussion Starter · #6 ·
That still doesn't sound right!

> set so that high point of No, 1 cam lobe
> points above
> set so that the No,1 cam lobe points down

This implies that you point #1 cam lobe straight up and then adjust all intake valves without rotating the cam??? Don't you need to set the cam lobe of each and every valve that you are adjusting to point directly up? Not just #1 cam lobe? and then the same for exhaust lobes?

Sorry if I'm sounding stupid, but I am getting ready to adjust mine for the first time after a second rebuild in a row and want to get it right.

Thanks

Steve G
 

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Re: That still doesn't sound right!

> This implies that you point #1 cam lobe
> straight up and then adjust all intake
> valves without rotating the cam??? Don't you
> need to set the cam lobe of each and every
> valve that you are adjusting to point
> directly up? Not just #1 cam lobe? and then
> the same for exhaust lobes?

> Sorry if I'm sounding stupid, but I am
> getting ready to adjust mine for the first
> time after a second rebuild in a row and
> want to get it right.

> Thanks

> Steve G

I have never done it before Im just typing what I see in my service manual for 81 Datsun 280ZX

it sounds like you put the #1 Cam lobe up then adjust
intake 3,8,11
and Exhaust 1,7,9

then put the #1 cam lobe down and adjust
intake 2,5,10
Exhaust 4,6,12

Adjust intake to 0.25 mm (0.010 in)
Adjust Exhaust 0.30 mm (0.012 in)

remember I never did this its just what the service manual says

NOTE its a 81 280ZX manual so it might not be the same for the 83 but all 280ZXs have a L28 I don't know if Turbo maters or not it might be the same

Jeff 280ZXT
 

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Discussion Starter · #8 ·
Re: That still doesn't sound right!

> This implies that you point #1 cam lobe
> straight up and then adjust all intake
> valves without rotating the cam??? Don't you
> need to set the cam lobe of each and every
> valve that you are adjusting to point
> directly up? Not just #1 cam lobe? and then
> the same for exhaust lobes?

> Sorry if I'm sounding stupid, but I am
> getting ready to adjust mine for the first
> time after a second rebuild in a row and
> want to get it right.

> Thanks

> Steve G

I was not sure exactly what the Chilton is saying to do, so I did mine by rotating the cam for each valve I did to be sure it was right.

The book says to first point the lobes for #1 cyl straight up, both valves closed. This would mean, at least in my zxt, that niether of the lobes are straight up. Then for the 2nd set of adjustments, the high point of lobe #1 points down. Either way I think will work, but the first seems less confusing to me.
 

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Discussion Starter · #9 ·
Re: Ajusting Value lash(misprint in chiltons auto

> This is how the valves are arranged.

> EIIEIEEIEIIE E=Exhaust, I=Intake

> I adjusted mine starting from one side and
> working to the other. First all exhaust,
> then all intake valves. Just pointed the
> lobe of each one I was adjusting straight
> up. It probably takes a little more time
> this way, but I got pretty fast at it after
> a few times.

> If this way is wrong, someone let me know.
Leslie, I've been doing it your way for several years and I haven't messed anything up yet. Unless there's something different / unique about one car, you adjust all valves with their lobes pointing up (means you must move cam during adjustment), and all intake are the same (as each other)and all exhaust are the same (as each other)depending on hot or cold adjustment and on the cam (stock or aftermarket).
Bill
 

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Discussion Starter · #10 ·
Re: Ajusting Value lash(misprint in chiltons auto

> I have the chiltons auto book it tells you
> to
> adjust valves 1,3,7,8,9,11 when both cams
> lobes
> are pointing up. I thought you adjust the
> valves
> when the #1 lobe points up. It then says to
> adjust valves 2,4,5,6,10, and 12 when #1
> lobe
> points down. Also the books says, The
> clearance
> should be .25 mm for intake valves 1,7,and
> 9, and
> .30 mm for exhaust valves 1,7, and 9.
> What happen to valves 3,8, and 11? Which
> valves are
> intake or exhaust valves. Can someone help
> me
> out. Thanks for your help. Want to adjust
> valves
> before the super bowl.
The best way I have found to adjust the valves is to get a wire with two aligator clips on the ends and a momentary switch in the middle. Connect one lead to the + on the battery and the other to the silinoin switch on the starter. Then starting with the number 1 cylinder place the lobe strieght up by turning over the engine. ( Make sure you are in N and the coil is disconected.) The momentarhy switch acts as the ignition switch. Once you have adjusted the valve move on the next valve. Simply look accross the head to determin if it is a exhaust or intake valve. This is a very simple way to bump the engine over to get the lobe in the up position. By the way this techinque is on ZTherapys tune up video.
 
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