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What valve specs y'all like for adjusting


Jabronie

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Let me be the first to be controversial and I know this isn’t the question you asked:

I fundamentally disagree with doing them hot! Reason? Can you keep the engine temp constant at “hot” over the 30-60 mins it takes to do the job? But cold is not going to fluctuate. My personal experience has been that by the time I finish and go back to cyl 1 to double check, the clearances have changed! ;) So for a rookie like me, I like doing them cold.

Secondly, this web page I LOVE:

https://www.engine-specs.net/nissan/l28.html

I do mine a fraction tighter than spec but let me not elaborate with an essay as to why.

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Let me be the first to be controversial and I know this isn’t the question you asked:

I fundamentally disagree with doing them hot! Reason? Can you keep the engine temp constant at “hot” over the 30-60 mins it takes to do the job? But cold is not going to fluctuate. My personal experience has been that by the time I finish and go back to cyl 1 to double check, the clearances have changed! ;) So for a rookie like me, I like doing them cold.

Secondly, this web page I LOVE:

https://www.engine-specs.net/nissan/l28.html

I do mine a fraction tighter than spec but let me not elaborate with an essay as to why.
Thanks for the link. I just bookmarked it.
Your thoughts on adjusting hot makes sense. So would you recommend cold at
Intake 008inches
Exhaust 010 inches

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Thanks for the link. I just bookmarked it.
Your thoughts on adjusting hot makes sense. So would you recommend cold at
Intake 008inches
Exhaust 010 inches

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Most welcome.

What you quoted is the correct recommended factory standard (cold) and it’s good to go with that.

I set mine cold at:

Intake: 0.15 mm (0.006”)
Exhaust: 0.2 mm (0.008”)

It’s good practice to also check head bolts torque at the same time: the FSM quotes 51-61lbft or 7.0-8.5kgm. I recommend setting your torque wrench to the lower number to avoid over-tightening.
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16 hours ago, AK260 said:

Let me be the first to be controversial and I know this isn’t the question you asked:

I fundamentally disagree with doing them hot! Reason? Can you keep the engine temp constant at “hot” over the 30-60 mins it takes to do the job? But cold is not going to fluctuate. My personal experience has been that by the time I finish and go back to cyl 1 to double check, the clearances have changed! 😉 So for a rookie like me, I like doing them cold.

Secondly, this web page I LOVE:

https://www.engine-specs.net/nissan/l28.html

I do mine a fraction tighter than spec but let me not elaborate with an essay as to why.

I've said it before, I can get the valves checked and adjusted in 15 to 20 minutes. So I always do them hot.

Sure, when putting a fresh engine together, they need to be set cold, and the clearances need to be set accordingly.

I also set them a bit tighter than the manual calls for. For racing it is a way to "cheat" a bit more lift and duration out of the cam profile.

 

Edited by Racer X
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I've said it before, I can get the valves checked and adjusted in 15 to 20 minutes. So I always do them hot.
Sure, when putting a fresh engine together, they need to be set cold, and the clearances need to be set accordingly.
I also set them a bit tighter than the manual calls for. For racing it is a way to "cheat" a bit more lift and duration out of the cam profile.
 
If you know what you're doing, it's 15-20min to adjust valves?
Ok i wasn't sure if being a little tighter would be bad

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1 hour ago, Jabronie said:

If you know what you're doing, it's 15-20min to adjust valves?
Ok i wasn't sure if being a little tighter would be bad

Sent from my Pixel 2 XL using Tapatalk
 

Knowing the job, having the correct tools, and planning are the keys to a quick, hot valve check and adjustment.

As for running them a bit tighter to get that little extra bit of lift and duration, one mustn’t get them too tight, or the valves won’t close fully with the engine at full operating temperature.

 

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RacerX, this is how these valve lash adjustment threads always end up.  The guys that have done many and have practiced (that's the real key to speed - practice), and have calloused burnt finger tips,  say it's easy and everyone should do them hot.  "It's easy, don't be a weeny!".  They have forgotten that their first time probably took a couple of hours.

Logically, setting cold and checking hot has no flaws, except time spent.  In the big scheme of things, for a guy with an engine that's new to him, the time spent looking at the engine parts with no reason to hurry might be more valuable than actually adjusting the lash.  Plus, mistakes in lash settings can cost a lot of money.  One hanging valve and the head might have to come off.

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As I was thinking about this a bunch of memories passed through my head in voice over type thoughts.
"Is this one exhaust or this one?"
Do they just alternate from here?  Exhaust - intake - exhaust - intake...  No?  Crap.
The engine's tilted.  Up is not Up".
Is this still hot?  Should I start over?
It was perfect before I tightened the lock nut, now it's too tight.
Does it matter if it's hard to get the feeler gauge in?
Am I scratching the cam lobe with the feeler gauge?
Where's my small sledge, I don't want to bleed anymore.  
#1 is a B___h!
I should have wiped that oil off the edge before it dripped down the side of the engine.
Wow, I really wacked something when the nut came loose.  Hope nothing got bent.
I could have just taken my time setting them cold, then rechecked them when they're hot.
 
And that's just in the first hour.
 

LOLILOLOLOLOLOLOLOLOLOLOLOLOLOLOL!!

I’m amazed how you managed to list my exact thoughts!

Brilliant!
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  • 2 weeks later...

Hello,

 

I have a Datsun 240z 1973, when I bought the car I was informed the previous owner may have added a "hopped up cam". Since owning the car I have had issues with rough idle and pinging and I am curious if this some of this could be related to the valve timing. I have not checked the Valve timing but I am not sure that stock numbers will work if the cam was changed from Stock. Curious advice for a Zcar novice.

 

Thank you for your time,

 

Josh

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1 hour ago, paulreverex said:

Hello,

 

I have a Datsun 240z 1973, when I bought the car I was informed the previous owner may have added a "hopped up cam". Since owning the car I have had issues with rough idle and pinging and I am curious if this some of this could be related to the valve timing. I have not checked the Valve timing but I am not sure that stock numbers will work if the cam was changed from Stock. Curious advice for a Zcar novice.

 

Thank you for your time,

 

Josh

The cam should have come with a card showing the lobe profiles, lobe centerlines, lift, duration and recommend lash settings. If you didn’t get it with the car, see if you can get the cam manufacturer and cam type, then contact the manufacturer for the details.

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6 hours ago, Racer X said:

The cam should have come with a card showing the lobe profiles, lobe centerlines, lift, duration and recommend lash settings. If you didn’t get it with the car, see if you can get the cam manufacturer and cam type, then contact the manufacturer for the details.

Just posted mine in another thread, good timing!

20210928_152550.jpg

 

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  • 2 weeks later...

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