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sand_man 04-26-2007 06:44 AM

turbo scavenge pump - NOISY?
So Ive clocked about 10,000 miles on the new engine. But I've got a "ticking" sound coming from what I think to be the driver's side cylinder bank.

I thought it might be an exhaust leak, so I tightened up all of my nuts...still have a "tick".

I have a new custom Borla exhaust (I'll take pictures soon) which has quieted things down over the zork/straight pipe that was on before, so I'm able to hear the actual engine better.

I've adjusted all of the valves twice at various case some tolerances changed during engine break-in. I've adjusted literally hundreds of valves over the years so I'm confident in my technique, but will check them again this weekend.

While I was under the car, it dawned on me that the scavenge pump that runs on the driver's side cam might be the cause of the noise! When I rebuilt the engine, I replaced it's seals but did nothing to check it's oil pump gears and such. For those that are unfamiliar with these things, it's a pretty straight forward pump with an extremely basic drive mechanism off of the cam.

I've tried to use a stethoscope, but these engines are pretty noisy so it's hard for me to get a feel. Plus it's not so bad at idle...more audible when a load is on the engine.

So what say the experts? If I find that my valves are fine, has anyone run into a noisy scavenge pump? If it is, I'll probably go with the oil line that connects the turbo drain to the engine sump/drain plug, and just ditch the pump.

sand_man 04-26-2007 07:01 AM

Here's a picture of what I might try if my pump is the cause of the noise:

I've heard that the stock scavenge pump is really quite bullet proof, so I might be digging...

WERK I 04-26-2007 09:16 AM

Re: turbo scavenge pump - NOISY?

Originally posted by sand_man

I've tried to use a stethoscope, but these engines are pretty noisy so it's hard for me to get a feel. Plus it's not so bad at idle...more audible when a load is on the engine.

My vote goes to an exhaust leak. The tick, if it were something in the scavenge pump area, would be the same regardless of load. Exhaust gas temps and velocity rises when the engine is under load. Are your EGR ports plugged up adequately? Are the header flanges/gaskets sealing properly? I almost flipped out when I looked at the header flange gaskets B&B sent me with their headers. They looked like they had been cut out by a torch! There was no way these POS were going to properly seal the flanges. I used the factory exhaust gaskets instead.
How about when the engine is cold versus warm? Is there any difference then?

sand_man 04-26-2007 10:02 AM

Thnaks for the response, David.

As for the EGR ports, I'm using the proper threaded "plugs" to close the holes.

As much as I hate to do it, I guess I need to pull the headers and have a close look at the flanges if I find that my valves are still in adjustment. I didn't use the B&B gaskets...I had the metal gaskets that came in my gasket/seal kit.

turboteener 04-26-2007 08:08 PM

Agreed sounds like a header leak. Take a file and lightly skim the flanges when you get them off, to make sure they are true.

You might have a head leak (heaven forbid), maybe a little imperfection in the cylinder sealing surface or head surface. Try a leak down on the cylinders on teh affected side of the engine, just to be sure.

mb911 04-27-2007 05:25 AM

broken head stud??

sand_man 04-27-2007 05:56 AM


Originally posted by mb911
broken head stud??
I know it's still possible, but they are ARP. I'm confident it's not a headstud or head sealing issue.

sand_man 04-27-2007 07:06 AM

Regardless of what I find when I get ready to dig into this thing (I have ordered new exhaust hardware and gaskets from our host), can anyone tell me if the scavenge pump runs quiet as a mouse...or is some noise expected?

WERK I 04-27-2007 07:15 AM

Relatively speaking, pretty damn quiet. Well, when compared to the valve train and headers, you can't tell it's there.

turboteener 04-27-2007 11:22 AM

You should be able to take a stethoscope and with the engine running put it on the pump and hear any weirdness. It should be making a slight whirring noise when you touch it with the probe, anything else you should probably be concerned.

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