my new motor has solid lifters.
when i start it the lifters are very quiet
as the motor gets hotter the lifters get noisier.
as the parts of the motor are getting hotter and they expand so shouldnt the lifters still be quiet.
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my new motor has solid lifters.
when i start it the lifters are very quiet
as the motor gets hotter the lifters get noisier.
as the parts of the motor are getting hotter and they expand so shouldnt the lifters still be quiet.
when i start it the lifters are very quiet
as the motor gets hotter the lifters get noisier.
as the parts of the motor are getting hotter and they expand so shouldnt the lifters still be quiet.
Bob....If you have steel push rods, they will not expand as rapidly or as much as the aluminum units the VW factory used....Your valve lash increases as the motor heats up and hence the noise.......Most people I know, with C B Perf. motors run "Zero" valve lash.....
When the valves are adjusted, the screw is tightened until the push rod rotates freely, but has no end play....And you always double check after you tighten the lock nut.....Even at this setting, things get noisy as the engine warms up...
Stick a magnet to a push rod ......If it sticks, call the engine builder and verify the valve settings....Hope this helps...
When the valves are adjusted, the screw is tightened until the push rod rotates freely, but has no end play....And you always double check after you tighten the lock nut.....Even at this setting, things get noisy as the engine warms up...
Stick a magnet to a push rod ......If it sticks, call the engine builder and verify the valve settings....Hope this helps...
Bob your motor has chromoly pushrods and the valve lash should be set at zero when cold Roland
Listen to Roland - he probably built your engine and should know. You should also have his email address and have him on "speed dial" on your iPhone.
Regardless, let's look at thermodynamics for a moment...(there's nothing like learning the basics for a new guy):
As your motor warms up to operating temperature, it "grows". Just look at the thing, all horizontal and everything.... There's a lot of distance between the right and left valve covers and a lot of it is made of Aluminum, which gets bigger as it warms up.
Well, ok.......the reality here is that as it warms up, it increases the distance between the camshaft, in the middle and the valve rocker arms way out at the ends of the motor. No mystery here, it's just simple thermodynamics (with a little metallurgy thrown in). This growth can be as much as 1/4" end-to-end (no kidding).
As this happens, the gap between the lifters (which are, indeed, solid steel), the pushrods and their associated rocker arms increases, too. Normally, that would mean that, as the gap increased there would be a bit more noise as the push rod slammed against the rocker arm cup instead of simply tapping it.
But! Those pesky German Engineers thought about this in advance! They were crafty little buggers, and they thought: "What if we put in a pushrod that expanded at about the same rate as that of the case, cylinders and heads? And what if we could predict the expansion rate and maybe even compensate for it?"
Eureka! So they spec'd push rods of a specific grade of aluminum that would expand precisely to provide a constant (more-or-less) gap of the pushrod to the rocker arm under all operating temperatures.
Pretty clever, eh?
Trouble is, when us "tough guys" with our big displacement and big horsepower, aircooled engines look at the valve train and add REALLY BIG AND STRONG valve springs, those wimpy aluminum push rods tend to bend a bit under the strain and go all flaky, so we went to pushrods made of really strong steel (chromoly - that means it's wicked strong, but attracts a magnet, which the wimpy aluminum ones do not). Trouble is, the steel pushrods don't expand at the same rate as the rest of the motor, so we set them at zero clearance when cold, and allow the engine to "grow" such that they have the proper clearance when hot.
That's pretty clever, too, no?
So....What the hell is this guy sayin?????
Well....as your engine warms up, it actually gets wider and the gap between pushrods and valve rocker arms gets bigger and THAT makes more noise. Happens to all of us. Either take it to someone who knows how to set your valves for the pushrods you've got (and show you how to do it properly so you can do it later on) or live with the noise.
The Speedstah Guy from Beaufort
Regardless, let's look at thermodynamics for a moment...(there's nothing like learning the basics for a new guy):
As your motor warms up to operating temperature, it "grows". Just look at the thing, all horizontal and everything.... There's a lot of distance between the right and left valve covers and a lot of it is made of Aluminum, which gets bigger as it warms up.
Well, ok.......the reality here is that as it warms up, it increases the distance between the camshaft, in the middle and the valve rocker arms way out at the ends of the motor. No mystery here, it's just simple thermodynamics (with a little metallurgy thrown in). This growth can be as much as 1/4" end-to-end (no kidding).
As this happens, the gap between the lifters (which are, indeed, solid steel), the pushrods and their associated rocker arms increases, too. Normally, that would mean that, as the gap increased there would be a bit more noise as the push rod slammed against the rocker arm cup instead of simply tapping it.
But! Those pesky German Engineers thought about this in advance! They were crafty little buggers, and they thought: "What if we put in a pushrod that expanded at about the same rate as that of the case, cylinders and heads? And what if we could predict the expansion rate and maybe even compensate for it?"
Eureka! So they spec'd push rods of a specific grade of aluminum that would expand precisely to provide a constant (more-or-less) gap of the pushrod to the rocker arm under all operating temperatures.
Pretty clever, eh?
Trouble is, when us "tough guys" with our big displacement and big horsepower, aircooled engines look at the valve train and add REALLY BIG AND STRONG valve springs, those wimpy aluminum push rods tend to bend a bit under the strain and go all flaky, so we went to pushrods made of really strong steel (chromoly - that means it's wicked strong, but attracts a magnet, which the wimpy aluminum ones do not). Trouble is, the steel pushrods don't expand at the same rate as the rest of the motor, so we set them at zero clearance when cold, and allow the engine to "grow" such that they have the proper clearance when hot.
That's pretty clever, too, no?
So....What the hell is this guy sayin?????
Well....as your engine warms up, it actually gets wider and the gap between pushrods and valve rocker arms gets bigger and THAT makes more noise. Happens to all of us. Either take it to someone who knows how to set your valves for the pushrods you've got (and show you how to do it properly so you can do it later on) or live with the noise.
The Speedstah Guy from Beaufort