Valvetrain/Valve Lash Adjustment

Rooster34

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Hey Guys, so I have been playing around with my 318 Poly getting the carb and all that tuned and such, however I have also been.playing around with my valvetrain. So a little info on that the engine has a 264 .450 solid lifter cam, heads are milled to achieve 10:1 compression, I reused the original pushrods, rocker arms, rocker shaft and springs. The cam card from the manufacturer list the lash cold at .015 for exhaust and intake. I had them adjusted at .018 cold and she didn't seem to mind it but definitely a little loud, idled nice in drive and reverse. When I shrunk the lash down it seems to like it a lot more when driving. In idle whether in reverse or drive and the engine isn't quite up to temp if I even tap the gas she will quit or wants to, this isn't a problem when warm however. I'm wondering if I should split the baby and run at .016 cold lash....last thing I want is to hang a valve open and burn it. Also is there any other way to tell if your lash is too tight or loose?

P.S Also the method I used was EOIC method of the lash adjustment
 
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Hey Guys, so I have been playing around with my 318 Poly getting the carb and all that tuned and such, however I have also been.playing around with my valvetrain. So a little info on that the engine has a 264 .450 solid lifter cam, heads are milled to achieve 10:1 compression, I reused the original pushrods, rocker arms, rocker shaft and springs. The cam card from the manufacturer list the lash cold at .015 for exhaust and intake. I had them adjusted at .018 cold and she didn't seem to mind it but definitely a little loud, idled nice in drive and reverse. When I shrunk the lash down it seems to like it a lot more when driving. In idle whether in reverse or drive and the engine isn't quite up to temp if I even tap the gas she will quit or wants to, this isn't a problem when warm however. I'm wondering if I should split the baby and run at .016 cold lash....last thing I want is to hang a valve open and burn it. Also is there any other way to tell if your lash is too tight or loose?

P.S Also the method I used was EOIC method of the lash adjustment

Milling the heads to go from a 9.0-1 to a 10-1 comp ratio has moved the valve gear closer to the pistons and you are also running a higher lift cam than the engine came with. I trust you checked the valve clearance with the reduced head thickness. Set the valve lash per the manufacturer's specs and run a compression check to verify proper compression on each cylinder. Setting the valve lash too wide reduces the duration that the valves are open and closed and this can tend to reduce the fuel load to the cylinders as well keeping more exhaust gasses in the cylinders. Setting the lash to specs should improve performance. The factory ran .013 intake lash and.021 exhaust lash on the poly engines If the engine is running poorly cold, that would usually indicate an over lean condition, you may need to fatten up the mixture at idle or make a choke adjustment.

Dave
 
Milling the heads to go from a 9.0-1 to a 10-1 comp ratio has moved the valve gear closer to the pistons and you are also running a higher lift cam than the engine came with. I trust you checked the valve clearance with the reduced head thickness. Set the valve lash per the manufacturer's specs and run a compression check to verify proper compression on each cylinder. Setting the valve lash too wide reduces the duration that the valves are open and closed and this can tend to reduce the fuel load to the cylinders as well keeping more exhaust gasses in the cylinders. Setting the lash to specs should improve performance. The factory ran .013 intake lash and.021 exhaust lash on the poly engines If the engine is running poorly cold, that would usually indicate an over lean condition, you may need to fatten up the mixture at idle or make a choke adjustment.

Dave
Thanks Dave! I'll do compression checks hopefully this weekend. I'll double check mixture adjustment and curb idle too. I know solids make a bit of noise but how much noise I guess is the question
 
A flat tappet will always be a bit noisier than a hydrualic will. Just as a roller chain has a bit of noise at idle, if you listen for it.

The reason the factory did the split clearances between the intake and exhaust was to compensate for heavy load situations which would heat the exhaust valves more, so a bit more clearance on that side of things. Start with the cam-makers' recommendations (cold) on intake and exhaust. Then you can increase the clearance very slightly on the exhaust side of things and see if that impacts your compressioin test pressures, with the engine good and up to temp. If not, you might keep the exhaust at the cam-makers' specs and not worry about it.

As noted, the cold clearance ultimately affects the total duration of the cam. I'm suspecting that the cam card specs are taking that detail into consideration?

So, play around with it a bit, over time, and see how things work out.

Enjoy!
CBODY67
 
A flat lifter will be louder than a hydaulic? What if the hydraulic lifter is flat?
I think you meant a SOLID lifter is louder than hydraulic, no?
 
A flat tappet will always be a bit noisier than a hydrualic will. Just as a roller chain has a bit of noise at idle, if you listen for it.

The reason the factory did the split clearances between the intake and exhaust was to compensate for heavy load situations which would heat the exhaust valves more, so a bit more clearance on that side of things. Start with the cam-makers' recommendations (cold) on intake and exhaust. Then you can increase the clearance very slightly on the exhaust side of things and see if that impacts your compressioin test pressures, with the engine good and up to temp. If not, you might keep the exhaust at the cam-makers' specs and not worry about it.

As noted, the cold clearance ultimately affects the total duration of the cam. I'm suspecting that the cam card specs are taking that detail into consideration?

So, play around with it a bit, over time, and see how things work out.

Enjoy!
CBODY67
Yes, so my cam manufacture says the lash at cold should be .015 exhaust and intake. I have an iron block with iron heads and from what I've gather the expansion when warm is .002 so once warm and at temp the lash should be .013 I may set exhaust at .016 cold as the exhaust valves get hotter. I'm going to do a compression test to also make sure my rings have seated and vales aren't hanging open.
 
Funny
Hydraulic and solid cams are flat tappet cams, meaning non roller. Same for the lifters. Kim
Funny...both my Dakota and Taurus have hydraulic rollers from the factory. My brother's 64 389 Goat had solid rollers.
And lifters of any kind aren't tappets. The tapping is at the rocker/valve stem. If your lifters tap you have a serious problem.
Lifters of flat or roller variety can be either hydraulic or solid.
 
Lifters ARE also known as "tappets", not because they make a tapping sound, but because that's their name.

From Wikipedia: "A tappet is most commonly a component in an internal combustion engine which converts the rotating motion of the camshaft into linear motion of the valves, either directly or indirectly."
 
Funny

Funny...both my Dakota and Taurus have hydraulic rollers from the factory. My brother's 64 389 Goat had solid rollers.
And lifters of any kind aren't tappets. The tapping is at the rocker/valve stem. If your lifters tap you have a serious problem.
Lifters of flat or roller variety can be either hydraulic or solid.

'64-67 389 GTO had a flat tappet cam. The 389 engine was noted for serious valve train problems. Some genius at GM decided to save a few bucks and used pressed in rocker studs. The pressed in studs worked loose over time and detached from the head.

Dave
 
Uh...it had an Isky cam with roller lifters he installed but they were solid lifters. I never said or implied they were factory.
But, you can have solid or hydraulic lifters of either flat or roller variety.
And they aren't tappets. They don't tap anything.
Case in point- why do people say "flat tappet" but "roller lifter"? Their function is the same. The common nomenclature of "tappet" is a misnomer.
You don't adjust the lifters, you adjust the clearance between the rocker arm and valve stem where the "tapping" is. A tappy valve is a happy valve.
What would you call the lifter on a Japanese moorsickle engine with overhead cams?
And, kimmer, your attempt at humor failed but you succeeded in being a smart ***!:thankyou:
 
And they aren't tappets. They don't tap anything.

BULLSHIT! My now deceased 110 year old Dad always called them "TAPPETS", all the mechanics that he did business with also called them TAPPETS! Maybe it's a old school thing where the people that used the term are all dead now! So don't go telling people **** and make them believe that you're always right and everybody else is always wrong!
You won't win this argument, here, learn something about your so called misnomer!!!
What are Tappets?
Definition of TAPPET
Definition of tappet | Dictionary.com
tappet
 
You don't adjust the lifters, you adjust the clearance between the rocker arm and valve stem where the "tapping" is. A tappy valve is a happy valve.
Who ever says they "adjust the lifters"? People usually say they "adjust the valves". But that doesn't make sense either. Usually the adjustment is on the rockers, but nobody says they're going to "adjust the rockers". They really mean "adjust the valve lash".

Just because "tappet" has the word "tap" in it doesn't mean that has to be the thing that makes a tapping noise. :p On that note, since there is slack in the valvetrain on a system with mechanical lifters/tappets, YOU can't say for certain where that slack is! It is between the valve tip and the rocker when you adjust it specifically, since you put a feeler gauge in there to take-up the slack! However, during operation the slack could be anywhere between the valve and rocker, rocker and pushrod, pushrod and lifter/tappet, and lifter/tappet and cam lobe when the cam lobe is on its base circle. On engines with stamped-steel rockers, some of the slack could be between the rocker body and the shaft as well.

As the cam lobe comes around off the base circle, everything else in the valvetrain gets pushed first, so all the other clearances close-up. But nothing is pushing back so they don't make much noise. At that point all the remaining clearance is between the rocker and valve, and that's what makes the tapping noise you actually hear.

What would you call the lifter on a Japanese moorsickle engine with overhead cams?
Finger follower or cam follower.
 
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Overhead camshaft engines have "cam followers", with an adjustment mechanism that is either a hydraulic lash adjuster or a select-fit "bucket"/shim that goes on top of the individual valve stems. FWIW.

Have fun,
CBODY67
 
i always understood tappets to be pre-lifters. like in a flathead ford or side valve engine.
64-23956.jpg

i thought that the old timers just carried the name over to the new fangled lifters.
 
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