After valve adjustment stall issues.

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Bewy said:
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.
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You nailed it man,
I have had very good results with .013/.020. The low-rpm torque increase was very obvious, and significantly more than I had anticipated. Increasing the exhaust to .023 did not make as dramatic, an improvement, but it was noticeable.
I was after fuel-economy tho, lol. So cylinder pressure is what I was looking for. I think I got 5psi outta that deal, hard to remember cuz that was 1994.
 
AJ/FormS, and Bewy. Am I understanding this correctly? That you feel .010 intake lash, and .020 exhaust lash is too much?
 
Charrlie_S said:
AJ/FormS, and Bewy. Am I understanding this correctly? That you feel .010 intake lash, and .020 exhaust lash is too much?
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NO!
While .020 is enough on the exhaust, and is the factory specified clearance, for the factory engine ;
I feel that .010 is NOT enough on the intake. It will run on that probably just fine, But I have always had a "better fine" at .013. Don't even think to set the intakes at any less than .010.
I set mine on a warmed up engine. That is to say long enough to open the thermostat. Then plus whatever time it takes to get the plugs out and the cover off. I'm not in a hurry.
I take the plugs out to make it easier to turn the engine over with the fanblades. To find TDC compression, I screw in the hose of my compression tester after removing the schroeder. Then I stick the other end in my mouth. Then I turn the engine until the rising pressure blows my lips off, and continue until the falling piston sucks my tongue in. Then I back up a little. Hyup, that is exactly how I do it on the stocker. The lash setting window on the stock cam base circle, is huge and a couple of degrees in either direction of TDC has never been an issue for me.
A little extra lash is better than not enough; especially on the exhaust. I run this slanty pretty lean while cruising, to get some fuel economy out of her; I could care less about power at the top. Running lean usually burns up valves. So I give mine .023 (a '77 engine) on the exhaust. It seems to be working cuz the odo was just starting on the 5th time around; since I got her in 1994. I finally sold her last summer. The only things I did to her was 9.5Scr, a SuperSix intake, and a heck of an ignition tune.

Edit; but I think this odo reset at 80,000 kms , so that's like 200,000 miles that I put on that 225, after I rebuilt her in 1994..
 
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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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So have you dicked around and readjusted yet? Inquirin minds wanna know. lol
 
I have not yet installed it but I had a cam reground by Oregon Cams and the "cam card" sheet that came with it says to set valves at 0.012 on both I&E. seems too tight to me on exhaust.
Also every slant (but 1) that I have ever had to adjust the valves on they started out way loose. which is why the /6 has its distinctive tell tale lifter clatter/
Once adjusted to spec (0.010/0.020") they are quiet. so I'm sure that a few thou loose, won't hurt a thing.
 
:rofl:
Bewy said:
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.
Click to expand...
The spec. is & has been .010"/.020" hot Int./exh., for over 60yrs. on over a million stock Slantys worldwide with mechanical cams(which would be most of 'em), running fine that way off the showroom floors........but if I ever meet Weertman, Hagenbuch, or other engineer from the day, I'll be sure to ask Them how They managed to F-it all up.
 
Killer6 said:
:rofl:
The spec. is & has been .010"/.020" hot Int./exh., for over 60yrs. on over a million stock Slantys worldwide with mechanical cams(which would be most of 'em), running fine that way off the showroom floors........but if I ever meet Weertman, Hagenbuch, or other engineer from the day, I'll be sure to ask Them how They managed to F-it all up.
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the cam grind determines the lash , I also have Oregon cam that going in my cam, follow the instruction of cam . . make sure you don't have a intake manifold leak
 
67belevdere/225 said:
the cam grind determines the lash , I also have Oregon cam that going in my cam, follow the instruction of cam . . make sure you don't have a intake manifold leak
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Yeah, those are the questions I have, is this an OE cam,...is the PCV hose intact/secured,...same with vac adv to dizzy,..?
There is as much as 16deg and .050"lift of difference from an early Slanty to the early-mid '70's Slanty cams, (excluding the Hyperpak). Tweaking out that extra .003" may show a viable bump in the bottom of the later cam, not buyin' it on an earlier one.
 
The lash is based on the clearance ramps of the lobes. A lobe with 0.010" lash could be noisier in operation & have less effective duration than a lobe that requires 0.020" lash, all else being equal.
 
Bewy said:
The lash is based on the clearance ramps of the lobes. A lobe with 0.010" lash could be noisier in operation & have less effective duration than a lobe that requires 0.020" lash, all else being equal.
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Absolutely. But IF We're talking the variations in the OE cams(again excluding the Hyperpak), all spec'd for the identical lash, the ramps are not going to have that variation...not from Mopar. And even tho' We know a bit loose is infinitely better than too tight, this sounds way off per the OP's account, sometin' ain't right......& the OP hasn't reappeared since the initial post so.....
 
Killer,
The ramps can have any variation that the cam designer designs into the cam. With the 0.020" used by Mother on the slant cams may have been done to reduce the chance of burned exh valves from careless lash adjustment.
If you are referring in general terms when you say a bit loose [ lash ] is infinitely better, no it wouldn't be. While too tight & too loose can both have issues, too loose can have the lifter crashing into the flank of the lobe which is harsh on the valve train & causes stress.
 
Bewy said:
Killer,
The ramps can have any variation that the cam designer designs into the cam. With the 0.020" used by Mother on the slant cams may have been done to reduce the chance of burned exh valves from careless lash adjustment.
If you are referring in general terms when you say a bit loose [ lash ] is infinitely better, no it wouldn't be. While too tight & too loose can both have issues, too loose can have the lifter crashing into the flank of the lobe which is harsh on the valve train & causes stress.
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If You miss the lash wide by that much on the OE Slanty ramps to "crash" them, You'll hear the consequences, & ought to get some help. None of the OP's problems would be the result of the lash being set properly to .010"/.020". This thread exists to assist dogdish, not to argue/discuss irrelevant ramp speed variations & their effect/response to different lash's, lets stay focused here.
 
Thank you all for your suggestions and support. As many said the valves were tight. Set them cold as many suggested and it perked right up, sounds and runs way better. Sorry I didn’t get to you sorry we had gotten almost two feet of snow here (Virginia) and that’s rare in my area!

D0896ED4-367B-4EF1-8DD4-8F6FB6B757B8.jpeg
 
Dogdish95 said:
Thank you all for your suggestions and support. As many said the valves were tight. Set them cold as many suggested and it perked right up, sounds and runs way better. Sorry I didn’t get to you sorry we had gotten almost two feet of snow here (Virginia) and that’s rare in my area!

View attachment 1715851388
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Thanks for posting a follow-up/conclusion, there are a bunch of open ended threads out there. Sometimes the OP realizes a "Doh!!" moment & is too embarassed to cop to it. Lol!
We seem to get our crazy snow in Feb./Mar. in SW PA, snows a little every April, & June can give us sub-freezing lows to highs in the '90's!!!!
 
AJ/FormS said:
NO!
While .020 is enough on the exhaust, and is the factory specified clearance, for the factory engine ;
I feel that .010 is NOT enough on the intake. It will run on that probably just fine, But I have always had a "better fine" at .013. Don't even think to set the intakes at any less than .010.
I set mine on a warmed up engine. That is to say long enough to open the thermostat. Then plus whatever time it takes to get the plugs out and the cover off. I'm not in a hurry.
I take the plugs out to make it easier to turn the engine over with the fanblades. To find TDC compression, I screw in the hose of my compression tester after removing the schroeder. Then I stick the other end in my mouth. Then I turn the engine until the rising pressure blows my lips off, and continue until the falling piston sucks my tongue in. Then I back up a little. Hyup, that is exactly how I do it on the stocker. The lash setting window on the stock cam base circle, is huge and a couple of degrees in either direction of TDC has never been an issue for me.
A little extra lash is better than not enough; especially on the exhaust. I run this slanty pretty lean while cruising, to get some fuel economy out of her; I could care less about power at the top. Running lean usually burns up valves. So I give mine .023 (a '77 engine) on the exhaust. It seems to be working cuz the odo was just starting on the 5th time around; since I got her in 1994. I finally sold her last summer. The only things I did to her was 9.5Scr, a SuperSix intake, and a heck of an ignition tune.

Edit; but I think this odo reset at 80,000 kms , so that's like 200,000 miles that I put on that 225, after I rebuilt her in 1994..
Click to expand...
im running a 270 cam from Oregone cams , and they recommend .022 ! I put it .016 and .018 hot engine running. so in hopefully a month I can drive it and see /6 twin webers 700r4 trans 390 diff. 2500 stall torque
 
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