on my car particularly, it makes quite a bit of noise at idle. to me it sounds more like piston slap. Not a deep rod knock,. I work on a lot of volvo and hear the same noise exact noise. No one ever complains about it so I've never attempted to really nail down the cause or fix it. I've yet to do or check the valve lash.

I heard about these hushers and at $3 a pop, I guess it worth a try, something to do and learn. and if it all quiets the engine It'll be worth it.

 

I've never heard of "valve hushers"; sounds bogus to me. How are they supposed to work? If you're talking about something that comes in a can, well, I personally have never believed in chemical cures for mechanical problems - certain stop-leaks and injector cleaners being the exception.

You failed to mention what kind of car we're talking about, which is always helpful information, but I'm assuming by where you're posting that we're talking about some variation of B230 redblock. These cars have solid lifters and shims, not tappets, so in most cases it's easiest to take it to the appropriate Volvo shop and get the valves adjusted to eliminate valve lash as a possibility.

Noise is not the main reason for keeping your clearances in spec; you're trying to avoid burnt valves and performance loss.

Turbos with the short piston skirt are prone to piston slap, but they will run forever in that condition, so most of us just live with it until rebuild time.

 

I have a 88 740 turbo

Absorber (Husher) B230XX

it's a seal/grommet that fits over the end of the valve steam. it doesn't show it so well here. I seen another pic somewhere that should it better.


I recall somebody mentioning the piston skirts, but I don't how that matters. piston slap is the result of excessive clearance between the bore and piston. what does the skirt matter??

 

Engine:Mechanical

 

The valve hushers look like tiny top hats that go over the end of the valve stems...all ohc red blocks had 'em from the factory.

So...ya want to grasp what piston skirts have to do with slap? The 85-89 permutation of the B230F, the so-called low friction motor had a number of features. The design included block steered pistons rather than crank steered pistons. That basically means the piston slides laterally on the crank to go where the piston needs to go according to the bore. As well, connecting rods were reduced in cross section from 13mm to 9mm AND the piston skirt height was reduced substantially. All this was done to reduce the weight of the rotating assembly in an effort to increase gas mileage. The shorter piston skirt combined with the cylinder bore dictating the piston's path is tailor-made for wear and resultant slap.

 

hmmmm, so husher probably aren't going to make any significant change to the noise my engines making.

 

Well, worn hushers produce a mild clicking or tapping sound. Pretty hard to mistake piston slap for worn/nonexistent hushers.