Quite Valves
#1
#2
#3
Join Date: Mar 2007
Location: Woodstock, Ont , Can
Posts: 3,706
Likes: 0
Received 6 Likes
on
5 Posts
RE: Quite Valves
This is an area where lots of people screw up. Solids won't work on a Harley and be quiet. The only purpose they have is to eliminatevalve float cause from a hydraulic overpump. That's another story. Lash increases with heat and with that comes lots of noise.This is the purpose of hydraulic lifters. It keeps thevalve train in zero lash. For a hydraulic lifter to work silently it needs to be in good shape. The leak down rate must be within spec. The unit needs a slight deflection (.010-.020 compression)when cold which is controlled through pushrod length or adjustable pushrods.This allows it to be in a working zone even when the heads are hot. Grind a valve seat without attention to lifter preload you may have noise .Oil viscosity plays a huge part in leak down rates, as thinner oil will be noisy due to more hydraulic deflection from leak down. A cam with longer duration will expose the lifter unit to more time for leak down with less time for pump up. Different lifter is required for silent operation in this case. Any of these not being correct, the unit will not stay in zero lash and what you hear is the sound of the piston in the hydraulic unit compressing the air and hitting a wall of oil. It sounds like a crack or snap. It sounds like it's from the tappets in the head, but being hollow in there the head amplifies it. With zero lash , there is no air and no running start, with more of a solid effect. As the unit is exposed to the cam lobe and valve spring pressures it will lose a very slight amount of oil. It must replentish this oil in between pushes or noise will occur. Oil pump pressures have a large bearing on this fuction. Hydraulic lifters need a specific amount of oil pressure to keep them full. Too little they become noisey, too much and they can over pump at high rpms and make the engine miss. That's called valve foat.
The only thing you should hear in a well set up valve train on your Harley is the valves hitting the seats. It's constant and fairly quiet. This sound doesn't jump out at you.
Ron
The only thing you should hear in a well set up valve train on your Harley is the valves hitting the seats. It's constant and fairly quiet. This sound doesn't jump out at you.
Ron
#4
RE: Quite Valves
I my experiance the larger the parts are the more noise they can make.
I bought my 05 new and it clattered abit, all HD do.
I belive there are two kinds of HD engine noise, good and bad.
In good or normal noise and slight tick or engine growl is normal. and a running rattle at 2800 to 3500 rpm is noticalble on every bike ive ridden. esp. ones with windshields!
the Bad, is banging, loud ticking that may cause a engine misfire, like when adjustable pushrods are loose and backing out. or a lifter that has collapsted.
My bike made a little noise new and more noise after bigger cams gear drives and heavy valve springs.
but it is nothing that I have not seen before in a domestic V8s that have been hopped up.
If you think there is a problem with your bike, get a second opinion from a dealer or an Indy mech.
and see what they think.
or trade it for somthing that you can tollerate!
I bought my 05 new and it clattered abit, all HD do.
I belive there are two kinds of HD engine noise, good and bad.
In good or normal noise and slight tick or engine growl is normal. and a running rattle at 2800 to 3500 rpm is noticalble on every bike ive ridden. esp. ones with windshields!
the Bad, is banging, loud ticking that may cause a engine misfire, like when adjustable pushrods are loose and backing out. or a lifter that has collapsted.
My bike made a little noise new and more noise after bigger cams gear drives and heavy valve springs.
but it is nothing that I have not seen before in a domestic V8s that have been hopped up.
If you think there is a problem with your bike, get a second opinion from a dealer or an Indy mech.
and see what they think.
or trade it for somthing that you can tollerate!
Thread
Thread Starter
Forum
Replies
Last Post