Adjust valve lash on unknown cam

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hotrod swinger

hotrod swinger

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Slant six engine with unknown cam. It seems to perform like a stock engine, by no means a lopey or choppy idle.

How do I adjust the valve lash without knowing the specs of the cam? Should I assume stock and just go with 10 intake and 20 exhaust?

Thanks!

IMG_4532.jpeg
 
Yes. Opinions vary, but I prefer adjusting cold. I add .002" to the spec and adjust cold and not running. The book says adjust hot and running, but I've always thought that was asking to get burned of hit by a flying wrench. It's worked well for me for a very long time.
 
^^Or do a combo of the above^^ The first time you set them, do them cold, as above, then warm it up and I mean FULL warmed, and recheck hot and see "what you have." THEN you will KNOW

I hope I don't have to tell you that "a little looser" is better than too tight, but you don't want it so sloppy as to beat the valve gear to death, either
 
I would use 0.010" int/0.012" cold. These numbers will ensure the valves have clearance.
Without knowing the original specs, going over 020, could put you past the clearance ramps & onto the opening/closing flanks of the lobe which is hard on the valve train & could break parts.
The worst that could happen by keeping lash tight on a cam that has large lash setting is that you roughen the idle & reduce vacuum, but you will not damage anything.
 
RustyRatRod said:
Yes. Opinions vary, but I prefer adjusting cold. I add .002" to the spec and adjust cold and not running. The book says adjust hot and running, but I've always thought that was asking to get burned of hit by a flying wrench. It's worked well for me for a very long time.
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When adjusting while the engine is running just use a swivel socket on an extension. Assuming friction adjuster with no lock nut.

Solid Ajusting Tools 1.JPG
 
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I've run them all. .008/.018- .010/.020- .012/.024 None made the car run any different.
Any above will be fine.

The only Slant cam I ever had was a Clifford that had a 548 lift and cam card stated .030/.030.
That Clifford cam I experimented with .022/.026- .024/.028- .026/.030 again no difference in the performance.
Your 66 just looks outstanding ! That color pops.
 
Hot is one thing. Adjusting (solids) them running is just silly. I wish we could put that to bed.
 
66fs said:
When adjusting while the engine is running just use a swivel socket on an extension. Assuming friction adjuster with no lock nut.
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Yeah, I've tried it every way under the sun. I don't like it. lol
 
I’d be willing to try it while running for the experience but I’m thinking it will be difficult me to get a good reading with a feeler gauge with the rocker arms moving up and down.
 
hotrod swinger said:
I’d be willing to try it while running for the experience but I’m thinking it will be difficult me to get a good reading with a feeler gauge with the rocker arms moving up and down.
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Use a go, no go combination. .010 and a .011 then .020 and a .021. Not really that hard, you just have to get in there and do it.
 
66fs said:
I don't know any better, I started with a 64 Barracuda running a 273 and a 4 speed. Jim at Racer Brown laughs at me because I run solids in everything from a /6 to a Desoto Hemi.
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I love a good solid cam. At least you're not held hostage to "whatever" preload a hydraulic lifter feels like giving you at any time.
 
RustyRatRod said:
I love a good solid cam. At least you're not held hostage to "whatever" preload a hydraulic lifter feels like giving you at any time.
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I like to think that brief gap gives a shot of oil that a hydraulic lifter never gets. I have a 273 with a solid cam past 300,000 miles on it still purrs like a kitten.
 
66fs said:
All depends on how well you want your engine to run. Pretty stinking easy once you know how.
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No, its' pretty stinkin easy to adjust valves HOT (or cold) with the engine STOPPED EOIC

Not necessary, at all, to throw hot oil all over the fender aprons and exhaust system.
 
67Dart273 said:
No, its' pretty stinkin easy to adjust valves HOT (or cold) with the engine STOPPED EOIC

Not necessary, at all, to throw hot oil all over the fender aprons and exhaust system.
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Vixen's motor idles at 70 PSI hot so it will do JUST THAT. lol
 
67Dart273 said:
No, its' pretty stinkiny easy to adjust valves HOT (or cold) with the engine STOPPED EOIC
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Do that, then adjust it running. You will find out that your lash is off. That base circle is not as constant as people think... If you won't adjust them running, turn the crank by hand and adjust them every 20-30 degrees. That is what I do before start up plus .002 for cold see post #2. Then hot and running after 100 miles.
 
Adjusting hot and running ain't that hard at all...and you can usually turn a /6 idle way down...... Long enough to do the valves. Less oil throw that way. But they don't fling it as far and wide as some who have never done it think it will.....
 
volaredon said:
Adjusting hot and running ain't that hard at all...and you can usually turn a /6 idle way down...... Long enough to do the valves. Less oil throw that way. But they don't fling it as far and wide as some who have never done it think it will.....
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Makes sense with low oil pressure at idle
 
I adjust ONE at a time cold with the engine not running. That way I can get each one DEAD on the base circle. It works for ME.
 
I gave it a shot adjusting the valves with the engine running. It’s difficult to get a reading on the feeler gauge.
 
I should add that although it was difficult I did make some adjustments and the engine is running a bit smoother. I’ll probably take another stab at it soon. Do some finer tuning.
 
66fs said:
Do that, then adjust it running. You will find out that your lash is off. That base circle is not as constant as people think... If you won't adjust them running, turn the crank by hand and adjust them every 20-30 degrees. That is what I do before start up plus .002 for cold see post #2. Then hot and running after 100 miles.
Click to expand...

When Pro Stock sets their valves with the engine running I’ll give it a shot.
 
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