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Engine smoking and lower power higher rpm
https://slantsix.org/forum/viewtopic.php?t=52775		 Page 1 of 1
Author:  crater [ Wed Jul 17, 2013 7:29 pm ]
Post subject:  Engine smoking and lower power higher rpm
Okay So as I discussed in my purchase thread the 72 Dart I have acquired was described as it would smoke a bit (Edit: When on the gas, idle no smoke) and be low on power, more towards the high end. The previous owner said someone told him it was a compression issue.

I just checked the compression via pulling all the plugs and giving each cylinder a few cranks. readings from front to firewall were:

130, 120, 110, 110, 120, 120. Engine was warm/cold and not hot as I got interrupted after I pulled the plugs. But it seems like compression is good. Where else should I start looking for issues? Maybe the Valves? I haven't removed the valve cover yet. My research here and other places seems to indicate it could be the valve seals.
Author:  crater [ Wed Jul 17, 2013 9:25 pm ]
Post subject: 
I've got a Tach and Vacuum gauge on the way so I'll be able to a bit more troubleshooting.
Author:  ceej [ Wed Jul 17, 2013 9:58 pm ]
Post subject: 
It'll be important to know at what RPM the engine noses over. Once you get your tach installed, let us know. It isn't uncommon for these engines to loose power above 4000 rpm.

Your easy check:

Remove the Spark plugs. Pull the cap off the distributor, and rotate the engine by hand. use the fan and belt to rotate the engine. Be careful not to pinch your fingers! :shock:

Rotate in the direction the engine normally rotates, clockwise. Once you see the rotor move in the distributor, mark the balancer with a piece of chalk or something at the 0 mark. Rotate the engine the other way, counter clockwise, while watching the rotor. When it moves, note how many degrees the crank moved before the rotor moved. If it's more than a couple degrees, the timing set is shot. This retards the cam, so the timing isn't right.
Let us know how the test comes out.

Your compression figures aren't that bad, but they could be better. With the hot cold situation, they may have been skewed a bit. You were cranking at Wide Open Throttle, (WOT) correct?

CJ
Author:  crater [ Wed Jul 17, 2013 10:10 pm ]
Post subject: 
I was not wide open actually, didn't know there was a difference. Still learning all of this. Will wide open read lower or higher?
Author:  ceej [ Wed Jul 17, 2013 10:16 pm ]
Post subject: 
Considerably higher! :D

Your smoke problem may be fairly inexpensive.

Let me re-read your signature. Could be a simple as a bad PCV valve.

Positive Crankcase Ventilation Valve.

Most of these cars have a few miles on them. That you aren't seeing smoke at idle is good. When you give it a throttle jab, do you see a puff? Could be the valve seals are gone. Likely in fact, as most of our engines are getting a bit old!

Hang in there, the engine might be in OK shape! These engines will run a long way with proper oiling and cooling!

CJ
Author:  DusterIdiot [ Wed Jul 17, 2013 10:20 pm ]
Post subject:  Lol...
PM me your address and I'll send you a bag of new stem seals (I got several laying around doing nothin'), you'll have to get a valve spring compressor to put them on though...

:wink:
Author:  ceej [ Wed Jul 17, 2013 10:22 pm ]
Post subject: 
OK, 72 Dart.

Yes. Your PCV might be part of the problem. Recheck at WOT. Don't pump the throttle! Gasoline will wash the cylinders down. You don't want that. Set the throttle at Wide Open with the ignition disabled. Test all cylinders and report. Hot, cold, doesn't matter. Just tell us which.

See you tomorrow. I gotta get up and be a productive member of society and such!

:lol:

CJ
Author:  crater [ Wed Jul 17, 2013 10:26 pm ]
Post subject:  Re: Lol...
Quote:
PM me your address and I'll send you a bag of new stem seals (I got several laying around doing nothin'), you'll have to get a valve spring compressor to put them on though...

:wink:
Thank you! Was just reading about how to do this. Seems simple enough. Just gotta decide air vs a long string to shove in there to avoid loosing the valve. :-)
Author:  crater [ Wed Jul 17, 2013 10:31 pm ]
Post subject: 
Quote:
OK, 72 Dart.

Yes. Your PCV might be part of the problem. Recheck at WOT. Don't pump the throttle! Gasoline will wash the cylinders down. You don't want that. Set the throttle at Wide Open with the ignition disabled. Test all cylinders and report. Hot, cold, doesn't matter. Just tell us which.

See you tomorrow. I gotta get up and be a productive member of society and such!

:lol:

CJ
I have to do the same so I'll report back after work tomorrow. Should have my tach then too, vacuum gauge Friday according to amazon.
Author:  Fopar [ Wed Jul 17, 2013 10:36 pm ]
Post subject: 
Use small cord air might get pressure loss at most un-opertune time, like oops there goes the valve into chamber. Just be sure to leave enough cord out so you can pull it out.

Richard
Author:  ceej [ Wed Jul 17, 2013 10:47 pm ]
Post subject: 
I always use air, but then I like living on the edge! :twisted:

I always leave the connection, regulator and hose attached. I set the regulator down around 20#. It doesn't take a lot of air to hold them.

Better yet, use the cord method Richard suggested. It isn't subject to compressor problems, power outages, and so forth.

Fopar really is smarter than he looks. Well, that isn't too hard. :twisted: :twisted:

CJ
Author:  crater [ Thu Jul 18, 2013 9:29 am ]
Post subject: 
Looking to buy the valve spring compressor and the rope/string i need. What width string would be good. I'm looking at nylon stuff now. Would 5/16 " be a good size? thats what, like 8 mm? plugs are 14mm, so I'd think it would slide right in, and 100 feet of it will be plenty to hold on to :-).
Author:  DusterIdiot [ Thu Jul 18, 2013 9:46 am ]
Post subject:  You have mail...
The envelope went in the mail this morning, so you should have them Monday.

:wink:
Author:  crater [ Thu Jul 18, 2013 9:47 am ]
Post subject:  Re: You have mail...
Quote:
The envelope went in the mail this morning, so you should have them Monday.

:wink:
Very cool, thank you so much. Such an awesome community of people here. Glad to have found it.
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