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Author
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Topic: vacuum leak, engine not right, cont.
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MDF99
Gearhead Posts: 202
From: Hamilton, Ohio, USA
Registered: May 2001
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posted 04-28-2003 07:50 PM
   
My 289 still isn't running like it was, I haven't been able to locate a vacuum leak. The problem is that the idle speed suddenly increased about 600-700 rpm while on a drive. If I reduce idle speed, the idle quality is not the same. I sprayed starting fluid around around the manifold gaskets with engine running and it didn't stumble, also installed new carb. gasket w/ no results, replaced all rubber plugs on carb. I have no vacuum accessories.I've been idling/running the car in our barn trying to track down this problem. When it starts to get good and warmed up it begins to smoke a bit, the smoke is white/blue, burning oil I believe, I think I'm seeing some oil on the plugs after I shut it down. The plugs look clean and have a light coating of oil on them. Any ideas, things to try??, all help appreciated, this engine is driving me nuts!! Thanks, Matt
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steve'66
Gearhead Posts: 7226
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 04-28-2003 08:33 PM
Matt,Does it have power brakes? Maybe a leaking booster on the power brakes? SteveW
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N266fords
Gearhead Posts: 1039
From: Spokane ,WA USA
Registered: Apr 2003
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posted 04-28-2003 08:59 PM
what about a cracked base plate did you spray around the base to see if its leaking how about a stuck needle in you carb Bruce
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Dusty Kiser
Gearhead Posts: 127
From: Bethel,Oh USA
Registered: Mar 2002
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posted 04-28-2003 09:37 PM
Are you using a pcv valve and is it in good condition? Do you have a crankcase breather to allow fresh air into crankcase? If no pcv I suggest you pull the intake and check to see if mismatch in gaskets is allowing oil to be pulled from valley.
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MDF99
Gearhead Posts: 202
From: Hamilton, Ohio, USA
Registered: May 2001
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posted 04-28-2003 10:35 PM
I don't have power brakes nor a pcv valve, I have one breather on each valve cover. I did spray around the carb. base w/ no stumble. Engine makes between 80 and 90 lbs. of oil pressure, according to my autometer gauge. I replaced my edelbrock mechanical fuel pump because it blew a seal and would shoot oil out the two little bleed holes on top. I'm not sure if this was due to excessive oil pressure or just defect in the pump, new pump is OK so far. Could high oil pressure be responsible for the smoke? This engine is newly rebuilt, first class all the way w/ less than 100 miles.
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65_302
Gearhead Posts: 255
From: Bixby, OK
Registered: Jul 2001
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posted 04-28-2003 11:20 PM
That oil pressure sounds high, but I am not an expert. My son's 302 runs at 50 psi at WOT and 30 at idle. I have heard others talk about max oil pressure of ~60 psi. I think I would look into that to start.
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steve'66
Gearhead Posts: 7226
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 04-28-2003 11:54 PM
Matt,The oil pressure is high, but it isn't responsible for the smoke or the fuel pump. It could be an intake gasket that leaked underneath to the lifter valley of the block. I've had that happen to me before on the 351w. Pull the intake off and check it out. Also, try lighter/thinner oil.  You should run one pcv valve on one valve cover, and one breather on the other valve cover. It's a cheap crankcase evacuation system and will reduce crankcase pressure. Crankcase pressure will try to force oil where you don't want it.  SteveW
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MDF99
Gearhead Posts: 202
From: Hamilton, Ohio, USA
Registered: May 2001
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posted 04-29-2003 07:10 PM
So it's possible that a vacuum leak could be under the manifold, on the bottom edge of a gasket and it could be sucking oil at the same place?
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N266fords
Gearhead Posts: 1039
From: Spokane ,WA USA
Registered: Apr 2003
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posted 04-30-2003 04:26 PM
that high of oil pressure usally will be cause a bearing has spun out of place causing more restriction not saying you should tear it down but i would ask steve alex or tony more about it just a thought... Bruce
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steve'66
Gearhead Posts: 7226
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 04-30-2003 04:28 PM
quote:
Originally posted by MDF99:
So it's possible that a vacuum leak could be under the manifold, on the bottom edge of a gasket and it could be sucking oil at the same place?
Yes! It happened to me before.
I thought the engine needed new rings, but that was all it was. SteveW
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MDF99
Gearhead Posts: 202
From: Hamilton, Ohio, USA
Registered: May 2001
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posted 04-30-2003 06:24 PM
I recently had Alex and Tony tune up this engine for me at their place in Chicago. Great guys and great to deal with! My engine was running like sh*t and I don't have the experience to figure it out. They got it running like a champ, night and day difference. I've been out giving it hell (at last) and perhaps destroying it in the process... I'll go ahead and remount the intake tonight and see if that returns the idle to normal. The oil pressure has always been high probably in part due to the high volume oil pump. I'll try a 5W oil and see if that helps.
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