head gasket fixed on 68 Dart, now oil burning - thoughts??

[Dart270]

Slant 6 boost sages,

Well, I got the '68 Dart bolted back together after my head gasket blow at Bristol, and I have some unsettling results - major oil smoke and rough running at low RPM. I am looking for ideas/advice on this problem before I do something rash like sending the turbo back or pulling the head again.

Here are symptoms and observations:

1) With head off, there was no evidence of piston or cyl wall damage. I drove this car 130 mi home from Bristol with #4 and #5 injectors disconnected and valves slightly open all the time, and on disassembly the plugs and piston tops were a bit wet with oil (I assume) since any residue was not being burned up on the way.
2) When cranking, sometimes it kicks back hard against the starter, quite violently. Tomorrow, I'll reinstall plugs in an alternating sequence and crank it to see if I can tell which cylinder(s) might be causing this kickback.
3) It still sounds like it's missing on 1-2 cylinders, but is smooth above 2000 RPM.
4) It burns a bunch of oil when under load, and even a little at idle
5) AF ratio is leaner at idle than I feel it should be given the tuneup. Could be oil is screwing up WB O2 reading?
6) Compression test showed pretty good numbers on all cylinders, although the range was broad - 130-165 psi. Medium warm engine (160 F?). The range of psi across the cylinders could be valve adjustment variation? I only did a rough (cold) valve adjustment, thinking I'd warm it up and reset them.
7) All plug tips were dry of oil when pulled, but a bit sooty, likely from the rich cold weather tuneup.
8 ) There was a crackling sound (boiling oil) and oil smoke coming out where the downpipe hooks to the turbine housing, after a drive around the block. I pulled the exhaust downpipe and there is oil just visible down behind the turbine blades, and on the bottom edge/floor of the pipe and turbine housing. This could come from oil exiting the cyilnders, or from the turbo shaft seal.
9) I pulled oil drain line and cranked motor to see flow out of the turbo. It looked higher than when I did this in MN on first startup. Out-the-drain flow was something like 1/2 qt in 10-20 seconds after the oil pressure came up. Drain flow liquid column was just over 1/4" in diameter.
10) I had made and installed a new oil drainback line. I just blew into the disconnected drain line and confirmed no restriction.
11) Upon reinstall, I twisted the oil input nipple on the turbo, which seemed to be epoxied in place. I will pull that tomorrow to check inside. Increased the flow somehow??
12) I pulled the intake tube from the turbo to throttle body and no oil inside the compressor housing or tubing.
13) The head gasket was blown (about 3/8" section) between #4 and #5 cylinders, and a bit heat spotted in a few other fire ring spots, but was otherwise not damaged. I found no debris in any cylinder.

Thoughts:

1) Blown rings on 1-2 cylinders? It's hard to see how there could be 1-2 cylinders with horrible rings if the comp reads 130+ psi across the board. If somehow just the oil rings got stomped but comp rings are OK, why would this cause kickback against the starter??
2) Blown turbo shaft seal? That would have shown up as smoke clouds on the way back from Bristol, and there were none. This would not cause rough running, but would cause smoke. Given that the oil smoke started with a pretty cold engine and before loading the turbo, it seems doubtful it is the turbo shaft seal, since that oil would not burn inside the turbo housing when cold.
3) Valve adjustments are off causing rough running at idle? Wouldn't make oil smoke, but would cause rough idle.
4) Did I leave something in a cylinder and then it is in the chamber and poked a hole in a piston? I can't recall that could have happened. Also, then one plug at least would be oily, and that cyl would have ~ 0 psi pressure. #1 cylinder was the only one with even a little oil on it, and that seems to have come from the aluminum drool tube and futzing when I pulled it. Also, #1 had 165 psi cyl pressure (the highest). This could explain starter kickback, though there are no crunching or pinging sounds with engine running for >20 min.
5) This kickback against the starter is really creeping me out.

So, there's the data. Anyone have ideas about WTF is going on?

Thanks so much for reading, if you made it this far...

Lou

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Return of the 64 Dart. Hang on...

[Rick Covalt]

Wow, that is some issue! It would not seem to be a compression issue, even if all the cylinders had 165#. That is not that high. It shouldn't be kicking back unless it is firing way to soon should it?

No answers here Lou, just thinking out loud. Keep us posted. I'm sure you'll get it all worked out.

Rick

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2 Mopars come with Spark plug tubes. One is a highly refined, record setting, world class, racing machine. The other is a 426 CI. boat anchor!
]

[madmax/6]

Great Lou,now I will thinking about this till you figure it out.If I think of anything I will post,till then I will scratch my head and bee thinking WTF could cause this,weird.Guzzi Mark

[Charrlie_S]

How about a leakdown test? Did the engine get into detonation? if that is waht caused the head gasket problem, it might also have damaged piston(s). Maybe collapsed ring lands, or skirts.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Cuda 170 nitrous
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

[Joshua Skinner]

When the FWD turbo Dodge guys break a piston and it's not a catastrophic, hole in the block kind of failure it usually shows up as an idle speed miss. So my money is on a broken piston.

About the only thing that causes starter kickback I'm aware of is ignition timing or crossfire/cross tracking in the distributor. This car still has a distributor correct?

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Joshua Skinner
car nut, telecom tech, tool using mammal
'72 Dart Swinger

[Dart270]

Thanks Josh and Charlie for your thoughts.

Yes, crossover in dist was one thought, which I'll check tomorrow, but why just at this moment? I thought maybe I reversed two plug wires, but checked that (will check again). I wonder if something about driving on 4cyl could track up the dist inside?

There was no evidence of detonation (speckling) on the plugs or piston tops when I first pulled at the track, but it is possible. I guess that would make sense that the car would NOT smoke on the way back from Bristol (on 4cyls) but would smoke now.

Can the compression psi test really read 130 psi on a cylinder with fried rings or a busted/distorted piston??

I won't be too sad if there's a piston problem, since this is a 150k mile motor rebuilt in 1989 that has a LOT of hard beat miles on it.

BTW, Rick, 165 psi is about right or even a bit high for this combo (8.7:1 static comp, 244 MP cam).

More soon and thanks again...

Lou

_________________
Return of the 64 Dart. Hang on...

[Dart270]

More data and thoughts...

I am thinking (with some of your help) that maybe 1 or 2 pistons have distorted ring lands and a ring or two are sticking intermittently. This could cause those cylinders to misfire and burn oil, and might even cause the kickback if unburned fuel built up on cranking and then fired several cycles worth at once.

1) I remembered that there were erratic periods where the idle would jump up and be very smooth for 2-5 seconds at a time. Intermittently stuck ring?
2) I did a cold comp test this morning, and all cylinders were between 148-172 psi. 4, 5, and 6 were 148-152, and 1, 2, 3 were 160-172. Yesterday, one of the cylinders (3 or 4, but probably 4) read ZERO compression on a couple of tests, but I blew this off as being a flaky comp tester, or that it was not all the way screwed into the head (leaking around o-ring). It might have been real... That was a warm motor, and nothing like this happened this morning with a cold motor.
3) I installed plugs and plugged in a single injector on 4 different cylinders (one at a time), then tried to fire the engine. #4 did seem to have a different rhythm than the others, and might have kicked back once or twice. Not a huge difference, but hard to say with the cold motor.
4) I pulled the dist cap and there was indeed quite a bit of carbon spotting in there. Some crossover could be happening. Why this would happen now, I don't know, but I suppose the kickback on cranking could be a coincidence...

I will likely fire up the engine again and see if I can isolate the kicking back cylinder better. I am still puzzled by the high comp readings, and may try a leakdown test.

I think I'm getting over my denial that I'll have to pull the motor.

I feel really good about this engine's service. It was the first one I ever rebuilt (stock replacement parts - 1989) and it has endured severe test mule service for 22 yrs and 150k miles with someting like 100 different configurations of heads, induction, exhaust, cams, EFI, you name it... Best 1/4 times in the high 14s, best mileage 25 MPG hwy.

Lou

_________________
Return of the 64 Dart. Hang on...

[slantzilla]

Lou, how long have you run it since you got it back together? Driving it with dead cylinders may have filled the exhaust up with oil and it takes time for it to burn out. That wouldn't explain the miss/kickback though.

Kickback is most always timing related. Do you have any boost retard functions that could be off?

A leakdown test will be the only way to really judge the condition of the motor. Trust me, a broken piston is not always visible from the top.

The first one I wicked really good fell in two when Mike took the rings off. Neither of us even noticed any cracks.

If you need a leakdown tester I have one I can send you next weekend. It's down at the shop.

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Proud supporter of Mike Jeffrey Racing Engines since 1999.

[Dart270]

Thanks, Zilla! If you have a good leakdown tester you could send, that would be cool. Maybe they are cheap enough I should buy one? Quality differences?

I am convinced that the oil is freshly coming out of a new source, not built up in the exhaust. Kickback could be timing related I suppose, but I checked timing with it running and it was spot on and stable. I rotated dist some and it made no difference in kickback I noticed.

I am actually getting excited about building a new engine, or trying a different combo with this car. I have a brand new aluminum short block and Jeffrey head to do a NA combo, and I can then put together a strong turbo motor shortblock and work on intercooler mounting and such in the meantime. I do have a stock long block I could bolt in too, and run that boosted for a while...

My new '64 Valiant driver (from Thropar) is almost done with mods at Charlie Schmid's, and I'll go down and pick that up, so I'll have Slanted transport soon enough. The Slantkota is happily serving its new owner in Waynesboro, PA as of last Saturday... I have one running Slant vehicle (Project V), but it's not street legal!

Lou

_________________
Return of the 64 Dart. Hang on...

[slantzilla]

Lou, a leakdown tester is mainly a couple air gauges and a couple valves, not really much to one. I can't remember what I paid for mine, but it is a middle of the line one, probably $100 or less.

One other thing that could cause kickback is fluid puddling in a cylinder. (Fuel, oil, coolant) Pull the plugs out and let it sit overnight, then turn it over with a remote button and watch for spray out a plug hole. Make sure the ignition is dead, lest a stray spark ignite the plume.

I'll be back down at the shop next weekend for sure. If you need it I can get it out to you then.

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Proud supporter of Mike Jeffrey Racing Engines since 1999.

[Rick Covalt]

[sixinthehead]

Two cents more.
Sticking intake valve(s)? If you have a sticky guide/weak valve spring, you could have intermittent kickback maybe?
I agree on likely piston damage, especially with stock rebuilder style pistons seeing boost. However, that type of damage doesn't usually 'come and go', so you are also chasing a legitimate misfire, either ignition or valve related (sounds like you have eliminated fuel causes in your testing).

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You're not entirely committed to sanity, are you?

[emsvitil]

Leakdown tester from harbor freight.

http://www.harborfreight.com/cylinder-leak-down-tester-94190.html


$35

I have one and it seems to work fine.

The only thing is that you set input pressure to 1 bar, not 100psi.....


You could probably use the 20% coupons you find in magazines too......

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

[Dart270]

Slant 6 community,

The 68 Turbo Dart is back in action, and apparently completely fine! Big thanks to Josh and Dennis for providing the two key points: (1) Dist cap spark crossover AND (2) oil built up in the exhaust causing the smoke.

I pulled the dist cap and there was some speckling of carbon around the inside and worn terminals. Didn't look awful, BUT after installing a new cap and rotor it fired right up and the idle was glass smooth and no kickback on subsequent starting. Sucker had at least 50k miles on it, and may have caused some misfiring before, and then worse with the weather change??

After fixing the ignition we went for a ride to check for smoke. It was smoking when we started off, and we saw big clouds after 3-4 moderate pulls, but kept decreasing. After a 10 min hwy run with a few mid boost pulls, the smoke was totally GONE! Hit full boost a few times briefly, but I need to reset the timing before really leaning on it.

So, in contrast to most things, there were TWO problems at work at the same time. Actually, there were THREE because the throttle position sensor (TPS) also crapped out while sitting and I fixed that last weekend after first starting it. What a weird confluence...

Matt Pyrek from Blacksburg (red79 on this site) came over to help and hang out, and told me another story about a buddy with a WRX with an oil smoke problem after reassembly that supported this idea too. Great to meet him for the 2nd time in person and make contact with a local Slanter and Mopar nut.

THANKS AGAIN to everyone who weighed in, and MAN am I glad I don't have to pull this thing all apart. Happily indulging boost addiction again...

Boost on,

Lou

_________________
Return of the 64 Dart. Hang on...

[1974duster kev]

Sweet, I love it when a plan comes together. Thats great you got it figured it out it was a pretty big downer when i first got my turbo setup and motor running and had to pull the dam thing back out in the first month because I broke the trans and had a leaking rear seal and blown manifold/header gasket, oh and had to send the turbo back because shaft play lol.

Good times
Kev

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