I am getting lifter noise at low idle but not on a regular basis. Dealer says this is normal and that it is the supercharger spooling up. Any other opinions?

I am getting lifter noise at low idle but not on a regular basis. Dealer says this is normal and that it is the supercharger spooling up. Any other opinions?

Superchargers don't spool up, turbochargers do. (To be more specific, the Eaton type supercharger on the V does not spool up, some superchargers are belt driven turbocharger designs and have a characteristic far closer to that of a turbo compared to a supercharger. A true supercharger provides compressed air at a rate pretty well exactly matched to the rpm of the engine (i.e. the demand), a turbo doesn't).

I have no experience of 'normal' noise in a V XLR, but my supercharged experience has been that valve noise is the same as if not supercharged, and it has been nil.

How do you know you have lifter noise, is it piston slap?

By far the most usual cause of valve lifter noise (after a few seconds of running) is low oil pressure, generally caused by low oil levels. Indeed, it is so typical it acts as a useful warning of low oil levels.

Valve lifter noise in the first few seconds of running could be considered normal, though it is probably indicative of a minor fault in the hydraulic lifter assembly (internal oil return valve stuck open). The cost of fixing it usually exceeds any disadvantage of living with it, unless very bad.

The only characteristic noise of an Eaton supercharger is that supercharger whine, caused by using straight cut gears to link the two shafts. This is a deliberate sound, helical cut gears would be much quieter, but then quiet isn't what supercharging is about is it?

At low speeds the supercharger should be silent.

A defect in superchargers is the use of a poor quality coupler in the drive design. The belt driven pulley connects (internally) to a 'plastic' drive unit with a number (three often) of pins in matching holes. A similar set of three pins sits on the front of the supercharger and presses into this same plastic unit. Over time and heavy loads, those holes go oval shaped and at idle the supercharger develops a bad rattle. It sounds like severe piston slap or maybe you could describe it as very bad valve train noise.

The fix is to take the front (snout) off the supercharger and replace that plastic unit (the coupler) (they run about $30). The special oil will pour everywhere, so first extract as much as possible with a syringe. This might not be listed as a service job, but if it is the same as other Eaton superchargers, it really isn't difficult.

The simple test is to take the drive belt off and feel for rotational slack in the pulley. It should be zero.

I'll see if I can find a link to a site that show how to change the coupler.

Youtube:
http://www.youtube.com/watch?v=pSsSctYvOoI

zzperformance (3.800 s/c coupler replacement (supposed better materials than OEM)):
http://www.zzperformance.com/grand_prix/products1.php?id=155&catid=106

More instructions:
http://www3.sympatico.ca/aepa/blowerinstall.html

Superchargers don't spool up, turbochargers do. (To be more specific, the Eaton type supercharger on the V does not spool up, some superchargers are belt driven turbocharger designs and have a characteristic far closer to that of a turbo compared to a supercharger. A true supercharger provides compressed air at a rate pretty well exactly matched to the rpm of the engine (i.e. the demand), a turbo doesn't).

I have no experience of 'normal' noise in a V XLR, but my supercharged experience has been that valve noise is the same as if not supercharged, and it has been nil.

How do you know you have lifter noise, is it piston slap?

By far the most usual cause of valve lifter noise (after a few seconds of running) is low oil pressure, generally caused by low oil levels. Indeed, it is so typical it acts as a useful warning of low oil levels.

Valve lifter noise in the first few seconds of running could be considered normal, though it is probably indicative of a minor fault in the hydraulic lifter assembly (internal oil return valve stuck open). The cost of fixing it usually exceeds any disadvantage of living with it, unless very bad.

The only characteristic noise of an Eaton supercharger is that supercharger whine, caused by using straight cut gears to link the two shafts. This is a deliberate sound, helical cut gears would be much quieter, but then quiet isn't what supercharging is about is it?

At low speeds the supercharger should be silent.

A defect in superchargers is the use of a poor quality coupler in the drive design. The belt driven pulley connects (internally) to a 'plastic' drive unit with a number (three often) of pins in matching holes. A similar set of three pins sits on the front of the supercharger and presses into this same plastic unit. Over time and heavy loads, those holes go oval shaped and at idle the supercharger develops a bad rattle. It sounds like severe piston slap or maybe you could describe it as very bad valve train noise.

The fix is to take the front (snout) off the supercharger and replace that plastic unit (the coupler) (they run about $30). The special oil will pour everywhere, so first extract as much as possible with a syringe. This might not be listed as a service job, but if it is the same as other Eaton superchargers, it really isn't difficult.

The simple test is to take the drive belt off and feel for rotational slack in the pulley. It should be zero.

I'll see if I can find a link to a site that show how to change the coupler.

Youtube:
http://www.youtube.com/watch?v=pSsSctYvOoI

zzperformance (3.800 s/c coupler replacement (supposed better materials than OEM)):
http://www.zzperformance.com/grand_prix/products1.php?id=155&catid=106

More instructions:
http://www3.sympatico.ca/aepa/blowerinstall.html
XLRlist01:
You are correct not that you didn't know it but in my 2008 "V" there is no lifter noise whatsoever. My suggestion, change the oil with fresh Mobil1 and see if it doesn't go away naturally. There may be some "dirt" in the lifter that will disolve or move on with fresh oil as an aid.

Supercharger whine-- Yea "It's a habit forming really neat sound"???

If my "V" wasn't under the factory warranty I would do this change. I'll wait to see it it needs to be done if I still have the car post warranty.

Thanks very much for the information!!!

BTW: Is the eaton supercharget the same one that many Corvette owners are installing on their LS motors??

Regards

Jerry

My answer isn't that technical. I had a similar noise on my 08' V. Have you changed the exhaust? Check the studs where the y pipe meets the manifold. Mine got loose and the Y pipe rattled. It sounded just like a lifter knock. Drove me nuts! Sorry not as technical, but did solve the problem.

D

XLRlist01:
BTW: Is the Eaton supercharger the same one that many Corvette owners are installing on their LS motors?

In terms of the exact model I am not sure. The V has intercoolers as I understand it, not sure about the 'Vette.

If the question is a more general one, then yes it is an Eaton type supercharger. The Eaton s/c is an improved Roots air pump, developed in the mid 19th century to pump air for various industrial processes. The Eaton variant is more efficient (uses less power) and because the latest version has four blades (compared to two in the Roots design), causes less pulsation in the air pressure.

The overpressure generated by the s/c is controlled by the diameter of the pulley. It is the ratio of the diameter of the crank pulley to the s/c pulley that matches the s/c to the exact application. Eaton s/cs come in a modest range of sizes (about four or five) and this is how they are tuned to the exact use. Getting more power is a simple matter of fitting a smaller pulley. At modest levels the ECU will probably cope. If the pulley is too small the belt will slip, but also the ECU will probably start to detect a fault.

I should make it clear that I am not advising anyone to try this, I have no experience of it myself on a V. Also, you would need to discuss such a mod with your insurance company.

I,ve had a noise in mine since I've had it. About 25000 miles. It is not a V. Very slight, Only at Idle, and can only be heard from the drivers seat. I had a couple good mechanice I trust listen to it and both said It is common on GM's. Both said dont worry about and It will never cause a problem and it hasn't. I dont know if it is the same but it has never caused a problem.

I,ve had a noise in mine since I've had it. About 25000 miles. It is not a V. Very slight, Only at Idle, and can only be heard from the drivers seat. I had a couple good mechanice I trust listen to it and both said It is common on GM's. Both said dont worry about and It will never cause a problem and it hasn't. I dont know if it is the same but it has never caused a problem.

I have the same thing on my '06 (also not a V) and was told by my mechanic that it comes from the VVT on these engines. Also no problem - just the slight noise at idle.

Also, you would need to discuss such a mod with your insurance company.

Yea right I'll give them a call....NOT!! :lol :lol

Thanks for the detailed informaton. That's what I was looking for.

NO it isn't for a XLR or a replacement for a "V" supercharger.

I am just starting another "project" and was doing some initial research when I ran across your post.

I am getting lifter noise at low idle but not on a regular basis. Dealer says this is normal and that it is the supercharger spooling up. Any other opinions?

I had a problem that sounded like valve clicking but it only occurred under load (acceleration)... turned out it was a cracked exhaust manifold gasket. It may not be the problem you're having but could be helpful as you search for the solution to your problem.