Koenig928

Ok, finally completed the leakdown test on the Koenig engine. Results look pretty straight forward to me, I'm guessing there are no major issues with these numbers? The leakdown tester was dialed up to 100psi for simplicity, read the difference between the 2 gauges on the unit. Engine was run to operating temp prior to performing the test. These pressure numbers were taken with the piston at TDC.

Passenger side:
Cylinders #1, 2, 3, and 4 - all read 2% leakdown

Driver side:
#5 - 2% leakdown
#6 - 4% "
#7 - 5% "
#8 - 4% "

These numbers tell me that the rings are holding pressure... however this car has alway been known to smoke a bit. I became concerned that something was not quite right after having the car on the dyno last month. After the engine was coming off redline RPM, I witnessed large amounts of white smoke belching out the exhaust. No smoke under acceleration to redline, but lots of smoke as you take your foot off the gas pedal. I couldn't tell if it was oil smoke or coolant. Never really noticed this driving the car, but was quite a show as I stood behind it as it screamed on the dyno.

Things I know are wrong still:
1. The oil breather system is not correct (pretty sure of this)
2. Mixture is too rich / and reliable fuel delivery under boost is erratic.
3. Coolant level is slowly decreasing every time I drive it hard.
4. It eats oil at a constant rate 'normal' for a GTS engine (5.4L) - (which is not a problem)

Anyone have any ideas?

AO

White smoke is indicative of coolant loss through the heads. So my guess is head gasket? I don't know what's acceptable on a LD test, but 6,7,8 all seem a bit high. I think you might be able to pull the heads with the engine in place, but don't quote me on that. But given that your breather system isn't right, I'd fix that first, then look at other sources.

shaaark89

definitely not a good sign. also could be due to cracked head or block though there would likely be other symptoms with those. leakdown numbers actually look pretty good.

Lagavulin

The numbers look good.

Is there a thread on this? If so, please provide a link; if not, what were your numbers?

Are you sure concerning the color of the smoke? If not, then more than likely it is oil-smoke. On deceleration, especially starting from high RPM, there's a lot of vacuum, and that vacuum may be pulling oil in past the valve seals and into the combustion chamber.

Hmm, I didn't see this until now. Can you tell whether or not you're blowing it out through the overflow tank? To check for this, rig up a simple catch-can, run it hard, and check for coolant. If you are getting coolant in the catch-can, first get a new coolant reservoir cap and try again.

If you're still getting coolant in the catch-can, then it would appear that pressure-ization of the coolant system is occurring which implies either a bruised head-gasket, or, a cracked head, none of which may necessarily be revealed by a low-pressure leak-down test.

Koenig928

No thread, since my scanner isn't working I tried a digital picture of it below.

I agree. I'm no expert here, but I would think that if the head gasket was leaking or a crack developed somewhere that there the passenger side cylinders would leak more pressure than they did. I plan to do a compresson test tomorrow just to see what that does. Actually, I was thinking that perhaps corrosion in the coolant system has started to eat away at one of the cylinders or head mating surfaces and cause a slow leak that way (I could be way off). Can't help remembering when Tony and I dissasembled his extra 'fire-burnt' engine he bought, one of those heads had evidence of corrosion eating away at the head and top of one cylinder. That seal looked still good (did a leakdown on it prior), but you could tell wouldn't take too much more before it started leaking.
I'm toying with the idea of removing the passenger side head just to see what's going on. Though I'm afraid I'll find something and I'll need to pull the engine anyway. Well if it comes to that, I might as well rebuild the darn thing (with a 6.0L crank... )
Yup, it was white, to white-ish gray. I tried to give it a good sniff, but excitment at the time probably kept me from identifying it accurately.
Agree there's a lot of vacuum on deceleration, its got to be either oil getting past the rings, or like Tom said, a crack somewhere.
I did notice (when doing the leakdown) more of an audible 'hiss' coming out the oil filler neck opening on the passenger side cylinders, which tells me piston rings. Definetly wasn't coming out the intake or exhaust.
Another thing I noticed too was that each cylinder had, what seemed to me, lots of oily, sooty, crud on top of the pistons. Used a wooden dowel stuck down the cylinder to tell me when to stop rotating the engine - that stuff was sticking all over the tip. All the spark plugs looked a bit more dirty than my S4 does, lots of buildup on them.

Not really, but I try the can thing when I put it back together. Its got a new cap on there though.

Koenig928

Good news - I found the coolant leak, its the resevior tank and cap. I rigged up a pressure test with my compressor. (thanks for the spare tank, Tony!) As far as I can tell, its not the head gasket leaking (which I was worried about). With the cooling system pressurized, I listened to each cylinder with a stethascope down each spark plug hole. Also went fishing for coolant with a Q-tip on a flexable tool retreiver, to see if it was pooling anywhere in the cylinder. (its not scientific, I know, but it worked...) Couldn't find anything. I left it pressurized for about 1 hour.

So that white smoke out the exhaust on the dyno tells me I'm getting oil blow-by past the piston rings - or at least excess oil getting sucked into the cylinder on deceleration (with alot of vacuum).

I did a compression test also. Since I'm at an altitude of 2,858' MSL here in Vegas, not sure how much it affects true compression value compared to sea level. Here's the numbers:
Passenger side:
#1 - 169
#2 - 161 (retested leakdown also - its 4% loss)
#3 - 163
#4 - 170

Driver side:
#5 - 165
#6 - 165
#7 - 155
#8 - 170

From what I can tell, leakdown and compression number indicate that the pistons rings are just wearing out.

Anyone else have an opinion??

Blown Beast

Bill,
Your numbers are fine as far as I can see but you need to drive the car more!!!!!! Not kidding this will help.
Most boosted cars are ALLOT cleaner in the engine....if yours is not, you are sucking oil/blow by into the intake = not good as you know.
How is your breather set up installed? Does it vent back to the intake in any way?
Does your exhaust pipe have oil-soot in it? When you wash your car is the back end have a oil mist on it?
White smoke is water not oil. Just my .02
Rob

Gretch

My S/C install uses a seperator, and the ventilation system is not plumbed into the intake, at all........I loose no oil, and more importantly The car ingests no oil......It is a simple modification, if your Koenig still has the PCV system. Contact Quick Carl at 928 motorsports for the kit.

Koenig928

Tony and I were looking at the oil separator/breather setup the other day. We both agree this NEEDS to be routed differently. Yes, the breather lines all vent back into the intake. I know this is NOT good. The supercharger is literally caked with oil residue / crud, tiny spots of oil pooling in the intake tube, and I know this will kill the MAF eventually. Its all gonna get replummbed to dump into the exhaust.

The exhaust is very much sooty - it will 'spit' soot (and moisture) out the exhaust when its warming up, but goes away when reaching operating temp. There's no true oil residue on the back side of the car, but I do get soot deposits there which has a tiny bit of oil in it I'm sure. I was thinking that the soot deposits are due to the car running too rich. I'll know for certain here shortly, just ordered the LM-1 with AuxBox kit. I'll get the car completely wired up like Tony has, then I'll know more what's going on exactly. Adding adjustable fuel pressure regulators will be next to tune the mixture.

Gretch

Tony knows his stuff, you are in good hands. What injectors are you running, do you know? Without a RRFPR the car would have to run very rich at idle and low speed to be capable of avoiding a lean condition at WOT.....I would think. Sounds like there is a LOT of low hanging fruit for you to collect as regards your SC install. have fun!!!

Koenig928

I agree, there's lots of power in this engine just beggin to come out!

From what I can tell, it looks like the stock injectors are in there. I say this because they look identical to the S4 injectors in my 87. Extra fuel delivery is accomplished by an additional fuel injector added just beyond the throttle valve. They cut and welded a port for it, sandwiched between the upper and lower intake housings. Its controlled by an on/off switch device that detects intake boost at a certain level. Pretty crude, I know, but thats the way Koenig did it ~12 years ago. I very much question if ALL cylinders are getting the appropriate amount of fuel needed under boost. I'll take this thing out completely when I add the adjustable fuel regulators.

The only question I will have is possibly adding larger fuel injectors at that point.

Lagavulin

I do not agree with your assessment.

Firstly, your leakdown numbers are very good, and secondly, your compression numbers are all consistent with the slight exception of #7.

Continuing, based upon your camshaft-pitting post, it appears that you do not have S4 cams whose early closing intake valve causes high cylinder pressure in the 180's and 190's range. Likewise, the GT and 85/86 cams have a much later closing intake, which means the piston keeps rising up in the bore without compressing anything since the intake is open and bleeding off the charge through the open valve, all the while decreasing available volume above the piston once the intake finally closes.

To sum up, your lower compression numbers combined with your pitted-cam pics point to non-S4 cams. And finally, your engine appears to be in good shape!

Tony

What are the part numbers on the heads?

Koenig928

The head numbers for both sides are:

928.104.413.1 R