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Grenadiers · Last edited by Grenadiers on Fri Dec 14, 2012 10:46 am; edited 1 time in total

In previous posts, I mentioned that the CGT car has an excessive smoking problem. I quit smoking cigars in '09, marriage thing and all, and I'm looking for answers for the poor car!

I thought initially, that the turbo seals were bad, and the head gasket too. However, after replacing both, with the engine in the car, turns out they were not the problem. Nice to know the turbo doesn't need a rebuild, small victory there. I still have clouds of blue smoke out back, on a short test run today, turbo pulls real well, and car sounds great.

The car has EFI and since the fuel rail interferred with the breather port on the head, I closed that off. I now understand how important that upgrade is for the 931~! As a test, I connected a silicone hose to the upper plastic AOS breather port, and Teed it into the hose I have running from the port under the intake manifold to the recirculating valve. WOW, what a difference that made. Still have a puff or two of blue smoke, but hope it's just residual oil from before.

Is this an OK method? I can make it permanent, and it's EASY. I bought an oil catch-can which I attached to the A/C compressor bracket. It sits right below the factory AOS. I'd use a spare plastic 'Y' that usually is used for the brake booster setup. I believe one end has a smaller venturi opening. I could connect that end to the open catch-can nipple. I'd rather have the vacuum come from the valve cover as the engine doesn't run as well with it sucking up CC fumes. I think the rings are healthy as I had almost zero blow-by. Thanks, Dave.
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Fifty50Plus · Posted: Wed Dec 12, 2012 4:27 am Post subject:

Dave,
Crank case and valve cover vacuum is the same. Remember the oil drains from the head back into the crank case via holes in the head and block. As long as there is vacuum there instead of positive pressure, the rings are good.
Chuck
_________________
1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA

flosho · Posted: Wed Dec 12, 2012 6:20 am Post subject:

The thought is that the oil is not draining quick enough from the turbo and is backing up into the turbo and being pushed past the seals into the exhaust.

Dave, perhaps, run a hose from the breather port on the cylinder head to a catch can or breather filter.

You said it interferes with the fuel rail, and mine did too but I just massaged the stock piece with a hammer a bit to clear the fuel rail..

If you're looking for good hi-temp hose, you can get the clear/braided dishwasher supply line in 3/8" or 1/2" and it will withstand engine temps.
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[This Space For Rent]

Grenadiers · Posted: Wed Dec 12, 2012 7:36 am Post subject:

I like how you think, application crossover!

Here's another one:

I took the rubber PCV grommet off my Jeep 4.0L engine valve cover. It fits perfectly in the 924 oil filler cap hole. (NAPA part BK 6301410) Covers the slots too. I broke the PCV breather on the Jeep, old plastic, and will pick up another one of those tomorrow! May need the jeep, getting 8" of snow on thursday.

Anyway, I had purchased a cheap aftermarket push-in valve cover breather with a hose connection. This fit nice and snug, if I used a new grommet, maybe a tad tighter. I connected that up to a hose to the AOS system, still smoked. Then, I connected those two hoses to a 'T' and then to the intake manifold, still smoked. All and all, it didn't smoke as much as before, but this isn't the answer.

I'm waiting for wife to return to do a compression test. Have an old-fashion Sears/Allstate compression-vacuum-timing light kit. And need her to press the starter button! Technical stuff!
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Grenadiers · Posted: Wed Dec 12, 2012 7:39 am Post subject:

'I just massaged the stock piece with a hammer a bit to clear the fuel rail.. '

I massaged the firewall a 'bit' to remove the cylinder head. Hammers are handy!
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Grenadiers · Posted: Wed Dec 12, 2012 10:56 am Post subject:

Well, in the not so good news department, the compression numbers are 91-95 each on all four cylinders. So, guess I'll stop dinking around with the breather issues! Probably just garage it till the return trip to Wisconsin this spring. Still have the incredibly reliable 911 that starts, runs stops, and repeats!
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

flosho · Posted: Wed Dec 12, 2012 11:12 am Post subject:

Did you do the test at WOT?

I know there are a couple different methods floating around here as to the procedure.

If all 4 cylinders are within 5% that is good news isn't it?
_________________
[This Space For Rent]

Grenadiers · Posted: Wed Dec 12, 2012 1:40 pm Post subject:

I did the test twice, not sure if my old test equipment is up to the task, the instructions said to keep throttle closed.
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Current conventional wisdom is to do it at WOT.

Also keep in mind that the turbo motors don't have a ton of compression anyway, so i wouldnt expect numbers much higher than that. The fact that they are so close together in spec is more important than the peak numbers.

Try WOT. The numbers should be a little higher. If they are still too low, maybe squirt a little oil in the cylinder and retest. If the oil causes the numbers to jump the you've got ring issues. If not the it may be in the valve train.
_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

Grenadiers · Posted: Wed Dec 12, 2012 11:36 pm Post subject:

Mind reader! I plan on testing it again with oil, and WOT, and then do a valve adjustment. Quietest motor I've ever had though.
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Fifty50Plus · Posted: Thu Dec 13, 2012 2:26 am Post subject:

Dave,
Easy ring test is with the engine idling. Put your finger or hand over the breather hose, Is there vacuum in the crankcase or do you feel some positive pressure? If there is vacuum at the hose, the rings are good. If there is slight pressure blowing out, that's worn rings.
BOL
Chuck
_________________
1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA

Grenadiers · Posted: Thu Dec 13, 2012 3:23 am Post subject:

Slight pressure as I recall at idle to almost none. No vacuum though.

Checking the valves, 5 out of 8 are really tight. The number one intake valve require 3 turns out before the feeler gauge slips in. Using a concave mirror and flashlight, I see plenty of threads in the follower on the other end. Good news, it's a number 3 adjuster. I have about 15 assorted adjusters back home, but luckily have three of the number 2 adjusters here!

Off comes the cam, btw, is that bolt holding the cam gear right-hand or left-hand threaded? Haynes has no answer.
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Grenadiers · Posted: Thu Dec 13, 2012 9:28 am Post subject:

Well, after figuring out that .004 can actually equal .009, with .005 on the backside! Sheeeesh. The aforementioned valves were still tight, even with the flimsy .004 gauge. Took three removals of the cam with swapping adjusters back and forth.

Wow, what a difference it made, the once quiet cam (they're quiet when things are a bit tight), now sounds 'normal'. Wife wasn't home so didn't do a follow-up compression test, had nothing to lose really. So, reinstalled the top mounted intercooler, and fired it up. Nice, no smoke at idle cold or warm. The road trip was pretty good too.

Went downhill first for a couple of miles, no smoke, then turned around. Honked it back up the hill the car shot thru the air, hardly touching the ground!! Ok, not quite, but, the turbo gauge did shoot past 10psi, and I hadn't floored it. Some smoke, then a little bit more, but not BLUE!!!! Was more a smoky grey, could be the Neon SRT4 too big injectors I currently have installed. Had some blue smoke, all is not perfect. But still, I'm pretty pleased.

I have a mr. gasket breather on the valve cover, I should have put the oil cap back on. I do have air/oil coming out of that cap (has a nipple on it), when I boost the engine. I reckon if the oem cap is on, the oil would purge out the AOS into the catch can. Hmmmm, will have to try that.

Unfortunately, not enough dry days left till the PCA track day this saturday in Phoenix. Getting 10-12 inches of snow starting tomorrow. But, taking out the Jeep with 33" tires is a bit fun too! Oh well, can now concentrate on reacquainting myself with my wife!
_________________
'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Raceboy · Joined: 01 Mar 2004 Posts: 2327 Location: Estonia, Europe

Sorry for the ingorance but how there supposed to be vacuum in the sump on 924 engine?
There is always some blowby and the only engine type I know that really creates vacuum during operation is GT3 RSR/Cup one and that has special high-capacity dry sump oil pump, special breather setup and special crankshaft seals.
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold

'84 924, turbocharged, sold.
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Ozzie · Posted: Fri Dec 14, 2012 7:24 am Post subject:

The sump breather is connected to the air intake, either before the air flap (US models) or after (UK, AU and others) on NA models.

not sure of the setup on turbo.

This provides the vacuum.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
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