After valve adjustment stall issues.

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Dogdish95

Dogdish95

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So I dicked around and messed with the valves on my 225 slant when they were okay. Checked them 3-4 times after engine was hot and adjusted them to .020 exhaust and .010 intake as per several suggestions. Timing is good. I am getting an immediate stall when it’s in gear and I drive then stop. Adjusted the carb idle and same issue. When I accelerate it feels almost as if the engine is under load (like pulling a trailer). The exhaust sound is deeper as well. Any ideas? Ran prefect before valves messed with..
 
One more reason to adjust cold and not running. I don't care what any book or expert says. Why on earth would someone risk burning themselves on a hot engine or causing injury with flying tools a running engine throws at you? Never made any sense to me.

Just adjust them cold and not running. Make sure you get each lobe on the base circle and make your adjustment. You can add .002" to the cold adjustment to make up for parts expansion if you want to, but it really doesn't make a whole lot of difference.
 
RustyRatRod said:
One more reason to adjust cold and not running. I don't care what any book or expert says. Why on earth would someone risk burning themselves on a hot engine or causing injury with flying tools a running engine throws at you? Never made any sense to me.

Just adjust them cold and not running. Make sure you get each lobe on the base circle and make your adjustment. You can add .002" to the cold adjustment to make up for parts expansion if you want to, but it really doesn't make a whole lot of difference.
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Agreed! My 273 get's the same treatment.
 
..........Or adjust them hot and not running...........

EOIC.......Do you know what that means?

Bump the engine until the EXHAUST just begins to OPEN, and adjust that intake
Rotate engine until the intake is clear open and bump until the INTAKE is almost CLOSED and adjust that exhaust

ESPECIALLY where you have a low performance engine which 'may' have somewhat weaker valve springs, it can be "easy" to adjust them too tight and since the engine is RUNNING (when you adjusted them) it is easy for the valve action to "make it seem" that the feeler is "loose."
ADJUST THEM ENGINE STOPPED
 
Dogdish95 said:
So I dicked around and messed with the valves on my 225 slant when they were okay. Checked them 3-4 times after engine was hot and adjusted them to .020 exhaust and .010 intake as per several suggestions. Timing is good. I am getting an immediate stall when it’s in gear and I drive then stop. Adjusted the carb idle and same issue. When I accelerate it feels almost as if the engine is under load (like pulling a trailer). The exhaust sound is deeper as well. Any ideas? Ran prefect before valves messed with..
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As suggested above, adjust them back immediately. Too much lash will cause the valves to not seat properly so you are not only losing compression but you might also burn your valves.
 
Ive always done these hot and running.... not as big of a deal as people try and make about it....
 
That change could have gone either way louder or quieter. didn't say which way he adjusted them, tighter or looser
I bought a 69 D100 some years ago that had no power. I mean you could get rolling in 1st and 2nd but shift to 3rd and it absolutely would not pull itself. 2 young brothers had bought it out of state, dying to get home as their parents were split and they came back to the area because they couldn't do without the kids they grew up with.
They made it home but sold it out of desperation because they couldn't make it run right.
They'd changed (or maybe had someone else change) the clutch thinking it wasn't grabbing good enough to pull in 3rd, changed from column to floor shift, tuned it up, and still couldn't get any power out of it. I got the truck and 1st thought was that this engine was shot. I did a compression test and 3 cylinders showed NONE.
Come to find out they had adjusted the valves so tight that a couple wouldn't close. I did a valve adjustment and it was a whole different truck.
Another one I should have kept
 
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volaredon said:
Ive always done these hot and running.... not as big of a deal as people try and make about it....
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There isn’t one single reason to adjust valves with the engine running. Not one. If there were, every drag racer from pro stock on down would do it and they don’t.

Lash the valves cold, with the engine off and then verify what it is hot and adjust your cold lash from there.
 
How I learned to adjust the valves and have just always done it that way.always worked for me.

Even on my 360 Magnum in my Durango, on which I put aftermarket roller rockers on, I had to adjust them running and then add 1/2 a turn. I tried EOIC on that and all were WAY too tight, had to back them off to get it to start. Set them running and all was great.
I'm somewhat old school though.
 
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everyones assuming a valve is to tight & thats probably exactly whats wrong....
But a quick test to make sure would be to connect a vacuum gauge & see what it does... A tight valve will cause the needle to flutter rapidly... If thats not the case you could have something else causing the problem & it's just a coincidence that it happened at the same time as your valve adjustment..
 
If it helps any, this is what I do:

Engine warmed up, shut off. Valve cover off, 3/8 + feeler gauges + flathead screwdriver.

Using the screwdriver, I slowly bump the engine over bit by bit (from the starter relay) until I have a piston JUST STARTING it's intake stroke. IE, the intake valve for that cylinder is JUST starting to open. And I mean JUST.

When that happens, I know the mirror piston of that one is on full compression stroke, so then I adjust the mirrored piston.

Sound confusing? Example:

Bump engine until cylinder #2 is JUST starting to open its intake valve. When it's at that point, I stop, and adjust cylinder 5 (the mirror piston to #2).

Then I'll bump it over until I see #3 just start to open the intake valve. Stop. Adjust cylinder #4.

Basically, don't try to watch the cylinder you want to adjust, watch it's mirror. It will be a lot easier to determine TDC compression stroke that way.

As a note: you want your feeler guage to feel resistance between the rocker and the top of the valve. You still want to be able to slide it in/out, but it shouldn't just glide around either. It'ss hard to describe without actually demonstrating it.
 
.013/ 023 on a warmed up engine, I don't care what the specs are; I never had a slant that ran at .010/.020; mind you I've only had lemmee think ................... five, lol.....
I set them at TDC compression, one atta time. All except one were stock cams.
 
AJ/FormS said:
.013/ 023 on a warmed up engine, I don't care what the specs are; I never had a slant that ran at .010/.020; mind you I've only had lemmee think ................... five, lol.....
I set them at TDC compression, one atta time. All except one were stock cams.
Click to expand...

Wow, thats crazy. Mine takes kind to 10/20 when hot. I run one of the old three-core-plug forged crank jobs. I guess gapping them a little larger might be worth a try given the differential expansion of the metals.
 
Dogdish95 said:
Timing is good. I am getting an immediate stall when it’s in gear and I drive then stop. Adjusted the carb idle and same issue. When I accelerate it feels almost as if the engine is under load (like pulling a trailer).
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Saying the timing is Good, only means something to you.
Some to all of your symptoms could easily be caused by retarded timing.
You do know that your engine has at least THREE timing requirements, right?
It has one for WOT Power,
One for part-throttle acceleration and power NOT at WOT,
and one for Part-Throttle cruising.
The Idle-timing is relatively meaningless and for the most part is just a fall-out from the other requirements.
For example;
>At full power after 3600up, she might like 32 to 36 *
>At stall rpm, she might like 20*
>At hiway cruise she might like more than 48*
IDK; I'm just guessing.
>At idle, your slanty will idle smoother the more you give her, up to around 24*. And will have more power as well. But it s unlikely you can set her there and not have other issues like, detonating at WOT, under say 3000.

The very first thing I would look to is the float level. and the second is the transfers slot exposure underneath the throttle(s); which should be obviously taller than wide, and return the Idle mixture screws to 2.5Turns out.. and the third thing is checking the PCV system for full and proper operation. Ok wait, since the PCV is the easiest, I'd do that first.
 
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I'm with AJ/FormS
I always leave mine on the loose side.

Did you make sure you adjusted those inner ones correctly? The center has an intake next to an intake?
 
You're not going to make it stall out "just" adjusting .010 and .020. That ain't what did it. You have some too tight because you accidentally adjusted some off the base circle. I have mine adjusted at .008 and .010 and it runs fine. It's a custom grind Oregon cam though so it's a kinda apples and oranges thing. The specs for it were .020/.020, but after consulting Ken Heard, who ground the cam, he said it could tight lash with no problem. I did that to help lower cylinder pressure just a tic fighting detonation. I can most likely adjust it back loose, as other mods I did got rid of the detonation.....but I probably won't, because it runs strong as hell.

The way I've always adjusted valves is one at a time. I get the valve all the way closed and turn the crank about 10 more degrees. That puts the cam slam in the middle of the base circle every time. I don't use the EIOC, or ABC, or LGBTQ or whatever the hell it is, because it's too much for my mind to keep up with, so I do them one at a time. Been doing them that way over forty years and it works for me.
 
In decades of engine building, I haver never seen a 0.010" spread [ 0.010 int, 0.020 exh ] in valve lash for a street engine. Usually 0.004" at most. If the correct lash is actually 0.020" [ likely ] for the intake, then your comment about the feeling of extra load on the engine makes sense. The tighter lash increases duration, & at low rpms [ lugging ] that often reduces torque, making the engine feel sluggish.
 
Intake is o.010 exhaust is 0.020. you didn't reverse them did you?
 
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