Maybe a silly idea but ... if it's crank/rod/bushing issue, would there be high copper/metal content in the oil? For $25, you may want to send the oil into a lab for analysis?

Exactly what I thought, and the oil filter contents were quite clean - frankly the insides of this engine are clean enough to eat from.

An idea that was just offered in an email thread is broken valve spring. I'm going to check that next - I didn't even think to check that when I was going over the rockers and head studs.

A broken or lose head-stud is supposed to be a higher pitched "bird chipping" like sound, right?

What if more than one head-stud on a cylinder worked it way off or lose and is allowing a larger than normal air leak?

Could it be an intake leak? Just thinking it's not loud enough nor low enough in frequency to be an exhaust leak.

Head studs, and head/cylinder joints, have already been checked. Intake leak is possible but the sound seems wrong.

Head studs.............both top and bottom?

I'm not expert, and I know it's not a guessing game. So I'll just watch this one, a very interesting problem.

hi,
could be cracked exhaust flange on one of the cylinders.
hope this helps.
Anthony.

I may have missed it... did you do the stethoscope or long screwdriver thing?

When I re-listened to it, it sounded like air to me too.

So an update!

The long screwdriver trick revealed a rattle in the #4 cylinder head. Absolutely no rattle from the bottom end. This was difficult to check while the engine was running and spewing oil everywhere out of the exhaust....that was 30 minutes of hazmat cleanup. Yuck.

Anyway, I pulled the motor and tore it down over the weekend. All the valve guides are shot; #4 had one that was so bad that the vibration broke off part of the guide. That was the same head that was producing the sound.

Haven't gotten all the pistons and cylinders off yet, but so far they are in perfect condition. Nikasil cylinders. No broken rings. Rods feel 'right'.

Not sure what I'm going to do with this motor yet, but a twin-plug 3.4 or 3.5 is sounding pretty attractive.

I didn't expect that. Pretty much sucks, but good to know you know now.

I don't recall you mentioning the oil flow out of the exhaust. That sucks too.

Keep us posted on your progress and/or mods. Where are you planning to get the heads reworked?

Shawn

Well, it was honestly the best possible news of all the scenarios requiring teardown. I was thinking broken rings, foreign object, rod bearing, etc.

The exhaust was full of oil - when I brought the car home, I was thinking it was just suffering from an over-fill (Hey I can dream, right??) due to all the smoke - it was otherwise running fine after putting in some fresh plugs. Wonder if the cat is ruined?

Heads - not sure yet. I got my last set of heads done at EBS Racing and was really happy with the work. I may use Black Forest Racing this time around; they are semi-local (down in Charlotte). I'll still have to call EBS Racing for the JE pistons, Wrightwood gasket set, and other tasty bits for building the 3.4.

And there's me thinking its just a few exhaust studs broken!:eek:
Anyway, glad to hear that you have now sussed the problem, and apart from the heads needing re-working, its not as bad as it could have been, still bad enough on the wallet though.
hope you get it sorted soon.:)
Anthony.