361 Woes

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MOPARJ

MOPARJ

What can I upgrade now?
Joined
Nov 3, 2006
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Location
Thousand Oaks, Ca
I know its not an Abody, but its a Pentastar and you guys have always come through with good tech opinions and advise for me to compare my diagnosis' with.

I have a 66 Charger with a 361 that I acquired for my father. The car sat motionless for 17 years, but started fine and ran on all 8 cylinders with no smoke, until today. I have had it for 5 months and it has not been driven, just fired up and ran once a week for 25 minutes or so at varied rpms.

I went to fire it up today, and I noticed a slight misfire, almost like a dead cylinder or loss of compression. The real issue is the extensive and contant blue oil smoke puffing out of the rigth cylinder banks tailpipe. I am at a loss. How the hell could this happen so suddenly? It was running fine, with no smoke for 45 minutes yesterday. I checked the right banks plugs and they had some oil on them, but not a large amount to signify the problem has been present for a long time. Nothing was severly fouled.

Does this seem too sudden for a ring land or ring itself to fall apart at startup and cause this problem, or possibly a valve seal? I wouldnt think a valve seal would cause consistant smoking and a misfire. The smoking gets worse with rpm it seems. I replaced the pcv to no avail. Am I overlooking something?

I have yet to run a compression test. The oil has a slight fuelish scent, but not like pure fuel. This is due to the slightly maladjusted carb. I wouldnt think that a ring would wash out that quickly. The oil had no milk in it, or other signs that would hint at a cracked head or head gasket.

Any advise or opinions are appreciated.
 
Sounds to me like the ring end gaps on one cylinder have lined up. Try putting some miles on the car at freeway speed with some Marvel Mystery Oil in the crankcase. If the smoking hasn't cleared up in 20-30 miles, plan on rings and a hone job, possibly new pistons. If you have a fuel smell in your oil, you are not running the engine long enough to evaporate the extra fuel from starting and warmup and having a rich carb doesn't help. If you don't put some miles under load on the engine to clean out the extra fuel, the ring lands fill up with varnish. 10 minutes under load is worth an hour of idling. Hope this helps.
 
MOPARJ,

If had to hazzard a guess (which is all we can really do over the net :-s) I would say that a ring has frozen in the land. It could be due to the flucuating temps this time of year (your location isn't posted) combined with condensation and extended idling time.

A valve seal would leak at idle and clear out on acceleration as vacuum will drop. Do a compression test, or better yet a leakdown test and post your results.
 
If the smoke smells like gas and not oil, the carb may have developed issues. You could have a bad float. I assume the carb is a Carter 2bbl. Also you may have weak spark from old plug wires.

My suggestion would be to remove the plugs after running the engine at normal operating temp and disconnect one lead to the balast resistor and do a compression test on all 8 cylinders wot. Then at least clean the plugs and reinstall the plugs. Fire off the engine and note the condition of the plugs again.
 
I dont mean to bring this thread back to life, but I have one more question. I have changed the oil out and am running a little marvel mystery oil too. No chance to drive yet, just parked and holding the throttle open to about 2,500 rpm for 20 minutes at a time. No change, still smoking. The weird thing is that the smoke, even with clean oil has a slight fuel smell too. I still have a heard time thinking that the ring just fell apart or moved itself overnight and a valve seal shouldnt smoke like that all the time, even if completely shot. The other aspect is that at different rpms, the revs vary a little and the engine surges, not a consistant miss, plus I hear a little pop now and then through the crappy glasspacks. the real issue besides the miss that is throwing me offf is the smoke. Then I thought about it.

Could it be that the intake gasket is shot somewhere, or do they usually not fall apart like that? The weird misfiring has me wondering. Any other ideas? It was running good the night before it started doing it with no smoke.
 
Yes it could be valve seals. Not just one but many. I know you say it ran fine and no smoke but that doesn't mean that the valve seals didn't start to disentegrate after setting for 17 years. Once you started running it and the seals started to warm up and move a little it is very possible that one or more could begin to break apart or crack losing there ability to hold a seal. I had a winter beater that I bought from a old guy that had been sitting for who know how long and at it started right up and after I drove it for a few days it started smoking so bad that I couldn't stand it. When I started checking things out I could see the valve seals inside the springs were broken and cracked. As for the gas smell I would definetly check out the carb. Good chance of a needle and seat leaking or a power valve if that carb has one. The two items I mentioned would be the easiest and cheapest to fix. It's what I would try first if it was mine.
 
416stroker said:
Yes it could be valve seals. Not just one but many. I know you say it ran fine and no smoke but that doesn't mean that the valve seals didn't start to disentegrate after setting for 17 years. Once you started running it and the seals started to warm up and move a little it is very possible that one or more could begin to break apart or crack losing there ability to hold a seal. I had a winter beater that I bought from a old guy that had been sitting for who know how long and at it started right up and after I drove it for a few days it started smoking so bad that I couldn't stand it. When I started checking things out I could see the valve seals inside the springs were broken and cracked. As for the gas smell I would definetly check out the carb. Good chance of a needle and seat leaking or a power valve if that carb has one. The two items I mentioned would be the easiest and cheapest to fix. It's what I would try first if it was mine.
Click to expand...

Could be I guess....leaking so bad that its fouling some plugs and causing the miss. Even though its missing and smoking now, its still revs easily. Thats why I dont think its the rings.
 
I`m amazed the car has run this long without a lot more issues. Did you clean the fuel tank before starting the car? I would have cleaned the fuel tank and sending unit screen, run some lacquer thinner through the fuel line ,change the fuel filter, and installed new gaskets/or rebuild the carburetor. You should replace all vacuum lines, belts, and hoses. The engine could probably use valve stem seals, they`re most likely hard and cracked and particles of them are probably in the pan now, getting pulled into the oil pick-up. I`d take a look at them if nothing else. A can of Rislone or a similar additive would help out with sticking rings. New plugs and points will also help.
 
After the oil change, no change in condition. Gets worse as it sits and idles. Go figure.

Just dont think its the rings, shouldnt fall apart or get stuck overnight like that.

I am no thinking about trying to source out a set of used heads that I can give a shot at. Being that this is a 9:0:1 compression 2 bbl B motor, can I use any 383 or 400 heads, or can I use 440 heads as well?

I already have a low deck 4 bbl intake.
 
Unless I am mistaken, the heads on a '66 361 will have closed chambers, meaning if you were to swap later model open chamber heads on to it - you will loose compression ratio by probably close to 1 point - ie 9:1 to 8:1.

Try a compression or leak down test yet ??

Why not pull the valve covers and inspect them to see if the stem seals are still there. Just a thought. If they are gone then consider changing the seals.

It can be done without pulling the heads, backyard mechanic style. Ive seen a lever type tool sold that uses the rocker shaft as a fulcrum to pop the spring retainer apart. You would either need to pressurize one cylinder at a time with compressed air to hold the valve shut - or Ive heard of stuffing cotton clothesline into the cylinder one at a time at BDC thru the plug hole, and then rotate the crank as far as possible to TDC for the cylinder in question, which would also shut the valves.

Good luck with it.
 
416stroker said:
Yes it could be valve seals. Not just one but many. I know you say it ran fine and no smoke but that doesn't mean that the valve seals didn't start to disentegrate after setting for 17 years. Once you started running it and the seals started to warm up and move a little it is very possible that one or more could begin to break apart or crack losing there ability to hold a seal. I had a winter beater that I bought from a old guy that had been sitting for who know how long and at it started right up and after I drove it for a few days it started smoking so bad that I couldn't stand it. When I started checking things out I could see the valve seals inside the springs were broken and cracked. As for the gas smell I would definetly check out the carb. Good chance of a needle and seat leaking or a power valve if that carb has one. The two items I mentioned would be the easiest and cheapest to fix. It's what I would try first if it was mine.
Click to expand...

I would think that valve seals would be a potential problem, but not many all at once. Literally, I S%^t you all not, was running perfect the day before with no smoke, no misfires, then the next morning, fired it up and it was smoking and running like crap,with a clear cut misfire and it has been the sam esince. When revving, the revs surge a bit, not consistant miss. No backfiring.

I would have checked compression already, but my damn tool has gone missing.:wack:
 
It sounds more like the va. seals...When they are worn the sign is it smokes on fire-up due to the oil running down the valve stem passed the worn seal. I'm picturing the seals to be cracked and brittle/non-existant, so I can see it running like crap sitting over-night. I could also see, of course squinting real hard, that as long as this engine has been sitting that now you have an oil fouled cylinder that is now allowing oil to be sucked up into the intake and is making its way into the intake and effecting other cylinders. As easy/cheap as it is to change out the va. seals I'd do that and hope for the best...but then again these heads probably don't have hardened seats, so it may be better to bite the built.
 
Your valve stem seals may have gone from complete and intact to crumbling bits in the oil pan after the initial run of the engine. It would only take a few minutes to check it out. If they have crumbled and found their way to the pan they may be in the pick up which they could potentially completely clog. I`d err on the side of caution and pull the valve covers.
 
Well, I dove into her yesterday and heres what I found:

Check compression on all cylinders. All were good except for #4, which showed no compression. Big red flag came up immediately. Definately not a ring. Sounded to me like some kind of valvetrain failure.

I proceeded to take the manifold off and once its off, its clear what is wrong; number 4's intake valve has a severely pretzeled push rod. Damn. It gave me no signs that it was that, no backfiring through the carb, no knocking, nothing!! I pulled the lifter and checked it. It was not able to be freely pushed in, so I pulled it apart, drained the oil and put it back together. The lifter was able to be collapsed after that. I am thinking some crap in the oil got into the oiling hole of the lifter and prevented it from collapsing. I am search of a new pushrod to put back in a try to see if it will run well again. I am thinking it will, as the cam lobes look find and the motor looked very clean interior wise.

There was no sign of broken valve seals anywhere, no debris...clean...

If it runs well again, I am thinking I will replace all lifters and pushrods, as I have a four barrel intake to put on.

I am guessing that the smoke was coming as a result of that intake valve being held shut. I wondered why it smelt more like fuel than oil.

I think it will run ok again and the smoking will disappear when I put a new pushrod in....
 
I'd guess the intake valve might be stuck for some reason. Before doing any more work, I'd check to see if that's not the reason. Assemble the valve train and turn the motor over by hand watching the valve in question for "free" movement when its supposed to open.

Valves get stuck, or can get stuck shortly after being started when engines sit for years and years.

If the valve is stuck, I'd pull the heads and do a basic clean up and overhaul. You may have another valve getting ready to pull the same stunt. I encourage you to replace all the exhaust studs if you pull the heads, regardless of their appearance, they get old and then snap when you reinstall them.
 
A friend of mine had a similar fate with his car and bent two pushrods after a bleed down of the lifters. At least you`ve got a starting point now and something to go by. Let us know how things progress.
 
I installed the new pushrod, rechecked the old lifter to see if it would still collapse, added some oil to the top of the valvetrain, put her back together and turned the key. Fired right up and has good oil pressure (45-50 lbs at idle cold to warm and 60 lbs above 1,500 rpm) no knocking and was running on all eight cylinders. There was no smoking, with the exception of the fuel/oil remmnants in the exhaust, but that burned out. Revved cleanly, no backfiring. Seems to have solved the problem. I have cleaned the fuel tank(obviously the previous owner lied about cleaning the tank) and changed the 17 year old oil. That should help keep the crud out of the oil holes in the lifters. Otherwise, the top of the motor looked clean, no valve seal remains anywhere. The carb is due to be replaced with our new holley and four barrel intake, as it seems a bit rich and out of adjustment from sitting so long.

The sole fact that a motor could sit so long without running, then be started back up after 17 years without any prep by the previous unwise and dishonest owner and run decent is awesome.

Tough, these mopars are.

Now, to get the insurance on and see if this thing is driveable. It needs to be driven hard under load to clean it out more.
 
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