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Engine still smoking after valve seal replacement!!!!
https://www.slantsix.org/forum/viewtopic.php?t=24407		 Page 1 of 3
Author:  A. Lewis [ Fri Aug 10, 2007 12:17 am ]
Post subject:  Engine still smoking after valve seal replacement!!!!
Hi everyone,

This is my first post on ANY forum and sorry it might be too long, but...
I have a 1972 dart swinger w/225 that I bought off of one of my buddies about a year ago with 50K miles (now 67K miles on it, i think it has gone around once). Since I've had it, it has smoked whenever I let off the throttle on the freeway from going about 65 - 50MPH . This was a constant thing for a while with it being that sometimes it smoked and sometimes it didn't ,every other week or so. I change the oil and filter on a regular basis.Tune up done last week with cap,rotor, spark plugs, wires. I've changed the PCV valve also. I've been meticulously searching through the posts on this forum about ways to help it last longer until I can really put some time into rebuilding it.
i've talked to a couple of machine shops and engine builders and they all said it it was my valve seals. I also searched on google and all the forums dedicated to slants and found the same info about my problem. So, I got the seals, a valve cover, spark plugs, a helping hand, and the instructions on how to do it with head on from SlantSixDan's post and went to work today(now yesterday). Well... the procedure went perfect and I followed SlantSixDan's instructions word for word. Adjusted valves correctly with the engine HOT!(...I've adjusted valves before). NOW...the Engine is smoking EVEN WORST at idle and letting off the throttle from highway speeds. I need help!!! I'm stuck scratching my head Asking myself..."what did I do wrong?"
ANy help will be greatly appreciated.
-Angelo
Author:  Eric W [ Fri Aug 10, 2007 2:00 am ]
Post subject: 
Just a thought, but have you done a compression check yet? Could be your rings are shot. Do a test and record the numbers. If they are low (like below 100psi), put some oil down the plug holes. If readings go up, you may have found your problem.

Hey, I used to live in Vacaville while stationed at Travis in the early '90's. In some appartments off Alamo Dr. Are there still wrecking yards off Peabody?
Author:  LUCKY13 [ Fri Aug 10, 2007 2:02 am ]
Post subject: 
This is something hard to diagnose over the internet. But I guess there is a few things that could be going on. First off, if it has gone around ones on the odometer, then changes are that the engine really needs a overhaul before you can do it any good.

You wander what you did wrong, but you may have done nothing wrong. You could have done everything right & it still smoke worse than it was. I am going to guess and say the valve guides are warn out, and new seals are just not going to help it any. And the reason it is smoking worse is everything is cleaner up in the head now so more oil can get around the valve guide than before. Plus you ajusted the valves which is good but, it probably is opening the valves farther now, which is going to let the engine suck on the valves harder. Plus if the Valve guides are warn out, it is going to let even more oil threw because the valve is being pushed open farther.

You may even have piston ring problems, and now the valves are opening father & putting more pressure on the the rings because it is getting more fuel & air in the cylinder.


I would run a conpression check on the engine. If it holds goood compression then you could remove the head and have it worked. The problem with though, if the piston rings are giving problems, you could even make it smoke worse than now. With this many miles on the engine, the only way out may be a complete overhaul.

A nother thing to think about. Who knows if this is the origanal engine. It could have been replaced at one time & have even more miles on it than you think.


Does the engine get good gas milage, and have good power. These two thinks would be a good indication of what kinda shape the engine is really in. But it could do good on both, and still have warn valve guides & piston oil rings. But if it eats gas & is low on power chances are you need to rebuild it.


If money is a problem, I would get the head rebuilt & give it a shot if you plan to keep the car. Then if it doesnt fix it you could rebuild the bottom end latter. Its pretty easy to remove & replace the head so its really not that much extra work. And it would allow you to rebuild in stages so you dont have to spend all the money at one time.


Are you sure the smoke is coming out of the exhaust. It could be leaking somewhere and the smoke be getting blown back under the car . Also if you have not run the car much sense your repair you might want to give it a couple days because oil could built up in the exhaust so bad & take awail to burn out. A good long highway drive (20 miles) should take care of that if so. If you try it, be sure it is full of oil & you have extra to refill the engine if it gets low on you while driving. You should also check the PCV valve & system, make sure it has vacume on the valve & that the valve cover is not stoped up where it connects.


Jess
Author:  dakight [ Fri Aug 10, 2007 4:15 am ]
Post subject: 
My observations have been that a smoke at startup is usually related to valve guides/seals. Smoke when running, especially when lifting the throttle often means a ring sealing problem. You may have some stuck rings. There were a couple of methods posted recently to free stcuk rings, but more than likely you're looking at an overhaul in the near future.
Author:  slantzilla [ Fri Aug 10, 2007 6:43 am ]
Post subject: 
Quote:
My observations have been that a smake at startup is usually related to valve guides/seals. Smoke when running, especially when lifting the throttle often means a ring sealing problem. You may have some stuck rings. There were a couple of methods posted recently to free stcuk rings, but more than likely you're looking at an overhaul in the near future.
Yep, smoke when lifting is usually a ring/piston issue.
Author:  SlantSixDan [ Fri Aug 10, 2007 6:57 am ]
Post subject: 
Yup, Slantzilla and Dakight are right: it's probably a ring-seal issue, not valve guides or seals.

If the car is actually a low-miles unit, then it's possible the rings are merely stuck, not worn out. You can try carefully cleaning out the engine, which will sometimes unstick the rings and restore oil control.

If the rings are worn or broken, though, the only fix is disassembly and rebuild (or swapping in another engine).
Author:  440_Magnum [ Fri Aug 10, 2007 11:10 am ]
Post subject: 
The rule of thumb that has always served me well is:

If it smokes on deceleration, its rings. If it smokes when you take off from idle, its valve stems.

The reason is that coasting creates very high vacuum against the rings, and will pull oil past them. Only the intake valve gets exposed to high vacuum, so on decelration its not likely to increase its oil leakage much, and the exhaust valve won't at all. At idle, the rings don't see high vacuum, but the intake valve does and so its the dominant "leaker" in the system, but the oill tends to pool until you step on the gas to drive away.

As for "making it last," worn or even cracked rings aren't a fatal thing, and as long as you KEEP THE OIL REPLENISHED, you can pretty much drive it indefinitely. The smoking is an annoyance, but its not particularly harmful. Switching to a synthetic or semi-synthetic oil will drastically reduce the amount of visible smoke, but the oil will still get burned so don't let it get low! And of course you'll want to consider whether its worth spending extray $$ for synthetic just to suppress the smoke. Also, you could consider running a heavier grade, say 20w50, but that can sometimes be counter-productive since heavier oil doesn't get circulated as readily in an engine. Whatever you decide, just take care of it (meaning don't let it get low on oil, and continue to change the oil regularly) and it'll survive until you can fix it right.
Author:  slantfin [ Fri Aug 10, 2007 12:20 pm ]
Post subject:  sounds familiar
I went through the same thing, smoking on startup. First I changed the seals, then rebuilt the top end. That bought a year, but the smoke came back. Now I replaced the engine with a low mileage /6, along with some mods suggested on this forum. No more smoke. 8)
Author:  A. Lewis [ Sun Aug 12, 2007 1:19 am ]
Post subject:  updates on what's going on...
Thanks for all the replies back guys!
OK...yesterday I drove the car. I woke up, got dressed, and started it right up after letting it sit all night. NO SMOKE! Not even a PUFF! so, I drive it around town for a few minutes just to warm things up and checking behind me through my mirrors and window for smoke. NONE!!! So, about 4-5 minutes go by and I stop at a light; temp gauge is now reading just at operating temperature. Now I SEE Smoke! It's weird how it didn't smoke until the car got warm. :?
Author:  A. Lewis [ Sun Aug 12, 2007 1:28 am ]
Post subject:  add-on to above...
Also,

I did a compression check when I got the car and after I did the seal replacement and got the almost the same numbers I did the first time.

first time:
#1= 138
#2= 140
#3= 145
#4= 143
#5=150 (best cylinder)
#6= 142

second time:
#1= 139
#2= 142
#3= 143
#4= 145
#5= 151
#6= 143

Thanks!

-Angelo
Author:  slantzilla [ Sun Aug 12, 2007 5:42 am ]
Post subject: 
How much have you driven it since the seal replacement? It is an outside possibility that there is just oil residue left in the exhaust that is burning out. It should burn out in about an hour of driving though.

Compression numbers aren't bad, but just from past experience I would say your #1 cylinder is worn. :shock:
Author:  Sam Powell [ Sun Aug 12, 2007 6:00 am ]
Post subject: 
It is normal for #1 to wear more because it is the coldest bore. That is not bad enough to be of concern, in my experience. I would try Dan's suggested engine cleaning. If the rings are sticky, that will clear the varnish out. As a cheap and fairly effective additive, you might try adding a single quart of automatic transmissin fluid to the engine oil right before your next oil change. It has a strong detergent that will clean your rings some, and has a seal softener to keep the seals soft and pliable.

The thing that you should feel really good about is that your engine apparently has the induction hardened valve seats. It is my understanding tht this was started mid year in 1972 fo accomodate unleaded oil. Dan wil set us straight on that one if my years are wrong. Anyway,if you had the older softer steal valve seats, your compression would more than likely be very bad by now. As Jess implied, this might not be the original engine. It could be older or newer, but my intuition tells me it is the original. Does it look like the original engine? Do the colors match? Is the paint on it smooth and uniform,and do the bolts look like they have not been turned on alot? Or, is the engine all scarred up as if it has been on a hoist and dragged across the bed of a pickup or flatbed?

Sam
Author:  Davey [ Sun Aug 12, 2007 6:25 am ]
Post subject: 
Did the fellow you bought it from drive it much? I bought my slant from a guy who let it sit a lot, and it smoked a bunch every time I started it. It also used a fair amount of oil. I started driving it every day, and the smoking stopped...just about completely. Took about five months of steady use. Oil consumption has also improved steadily, but it hasn't stopped like the smoking did. If a rebuild isn't in your plans any time soon, keep oil in it and drive it. It might get a LOT better with regular use. Mine sure did. Davey
Author:  SlantSixDan [ Sun Aug 12, 2007 9:07 am ]
Post subject: 
Quote:
The thing that you should feel really good about is that your engine apparently has the induction hardened valve seats. It is my understanding tht this was started mid year in 1972 fo accomodate unleaded oil. Dan wil set us straight on that one if my years are wrong. Anyway,if you had the older softer steal valve seats, your compression would more than likely be very bad by now.
Officially, the V8s got induction-hardened seats for '72, slant-6s for '73. It's likely the announcement was for '73 and there were some '72 heads produced with zap-hardened seats.

But even if not, the older slant-6s with unhardened exhaust seats tend to run just fine for a long time even on unleaded fuel. The small valve size and excellent valve seat cooling built into the head make it so.
Author:  Aggressive Ted [ Sun Aug 12, 2007 10:15 am ]
Post subject: 
Lewis,

I used to work in a junk yard and we would get old cars with SL6's still running good but smoking as you have described. They were mainly suffering from allot of slow speed driving and lack of use. I would do the transmission fluid treatment or Rislone and after a few months the rings would clean up inside. Several cars I purchased for $50. became real good runners after 4 or 5 months of hard use.

You can try a quart of Rislone with each oil change, and a quart of transmission fluid as a flush just before you change the oil. The years of varnish will slowly dissolve and free up the rings.
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