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Oil in air cleaner |
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purple72Gremlin
AMC Addicted Charter Member Joined: Jul/01/2007 Location: Illinois Status: Offline Points: 16591 |
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I can see you have your mind made up on why. So whatever. |
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uncljohn
AMC Addicted Joined: Jan/03/2013 Location: Peoria AZ Status: Offline Points: 5394 |
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Everone? How interesting. I have had an Eldebrock Air Gap intake on my 1 970 Mark Donohue 390 since they have been available, I think it was the first one in Arizona and I do not have any indication of a problem with it.
Oh Well!
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70 390 5spd Donohue
74 Hornet In restoration 76 Hornet, 5.7L Mercury Marine Power 80 Fuel Injected I6 Spirit 74 232 I-6, 4bbl, 270HL Isky Cam |
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nda racer
AMC Addicted Joined: Nov/28/2009 Location: Ohio Status: Offline Points: 2584 |
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Does "most" or "some" work out better, or do you deny there has ever been a problem? |
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uncljohn
AMC Addicted Joined: Jan/03/2013 Location: Peoria AZ Status: Offline Points: 5394 |
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No, I don't deny there has been a problem but frankly it is my opinion those with the problem is self induceed caused by either tr yin g to build some form of a monster motor an d then driving the heck out of it beyond design rpm limitations or using somethin g other than a valley intak gaskeet or modifying it for the oiling modification which arguably does nothin g con structive.
Intalled as designed and driven with in the design limitations of the engine, I do n ot see a problem with it at all.
And th is computer could use a new key board.
As I said, I have no problem with it at all and see no reason to believee there is one.
The only time I have seen oil in an Air Cleaner is if there was some form of blow by increasing crank case pressu re where it over ride s the power of the vacuum supplied by intake manifold vacum to the pcv valve. The passage to the air cleaner is meant to feed fresh air to the engin e crank case thus sucking the vapors into the intake manifold.
On my V8 that happened when two pistons were damaged due to detonation an d too high a static compression for the grade of gasoline used.
And I have never had that as a problem with the AMC 6. But I have never driven one with the valves on a shaft, so if wear sets in, there might be more oil splashing around in the valve cover than the designe was intended to deal with. PCV is somethin g that came about in the early 1960's an d the ea rly 232 with shaft mounted rockers is based on that era of techn ology.
I;ll find out I guess as I have a 232 that will end up in a T bucket with a 4bbl and maybe then I might see it, but then again? I might not.
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70 390 5spd Donohue
74 Hornet In restoration 76 Hornet, 5.7L Mercury Marine Power 80 Fuel Injected I6 Spirit 74 232 I-6, 4bbl, 270HL Isky Cam |
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19611 |
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My 4.6L stroker (4.0L w/258 crank and rods) surprised the heck out of me! I wasn't getting blow-by, but it was using oil at about 500 miles to a quart. Had great power though. Thought I had bad valve stem seals, maybe bad oil rings (I had run it hot a few months before when a cooling fan relay burned out) so I removed the head. It had about 0.016" wear in the top, 0.025" (or more) in the bottom of each cylinder! It only had 70K miles on it.
The reason it wore so had to do with the stroker build. It had been bored too loose (0.006" cylinder to piston clearance -- AMC calls for 0.002" stock) and the stroker crank pulls the pistons way down in the cylinder. The combination allowed the piston to rock a bit from the start, which accelerated wear. This was built in 1999 when we didn't know so much about building a stroker six. The 0.006" should have been max clearance, but that's on a typical V-8. The late AMC six is a tighter engine, but my machinist didn't know the extra clearance would cause that problem... neither did I! It probably wouldn't have is not combined with the extra stroke. |
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Frank Swygert
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nda racer
AMC Addicted Joined: Nov/28/2009 Location: Ohio Status: Offline Points: 2584 |
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Recently we had oil in the Air Cleaner of my Son's 3.1 GM. 150,000 miles, he just turned or is very close to turning. Replaced the PCV valve and no more oil.
Parts quality sucks today, being made overseas, and several parts are junk right in the box, or go junk not long after. So I'd start with another PCV, do the baffle if you don't have one, then go on to a rebuild. |
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Slate
AMC Addicted Joined: Feb/28/2012 Location: Airyzona Status: Offline Points: 2783 |
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Hello, joining the party late. Someone asked what year the engine is. Also, do you have photos of the engine with air leaner, breather, pcv and hoses all hooked up? That kind of information would help in assessing things. Steve |
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uncljohn
AMC Addicted Joined: Jan/03/2013 Location: Peoria AZ Status: Offline Points: 5394 |
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The path the air takes in general is vacuum is applied to the PCV valve by a fitting on the carburetor in intake manifold. It sucks through the pcv valve thus evacuating the residue or gasses in the crank case.. The fresh air is supplied by a fitting on the air cleaner with a filter in it that allows fresh air to be sucked t hrough the li nes going from there to the fiting on the engine, being it something on the valve cover or on the AMC v8 a fitting on the oil cap.
If fumes or what ever end up in the air cleaner it means generally that the pressure and volumn of gases or fumes in the crank case are greater than the amount of vacum used to suck through the PCV valve thus the fumes back up into the air cleaner and oil evaporats out and settles in the air cleaner.
This is caused by excessive blow by from the pistons over powering things or the PCV valve is plugged so nothing can be sucked through it.
Or in some cases it is just a poor design or hooked up totally incorrect.
My AMC v8 filled the air cleaner with oil when detonation broke pistons.
My AMC 6's do not have a problem.
And the engine in my Hornet does not indicate that there will be a p roblem.
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70 390 5spd Donohue
74 Hornet In restoration 76 Hornet, 5.7L Mercury Marine Power 80 Fuel Injected I6 Spirit 74 232 I-6, 4bbl, 270HL Isky Cam |
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Slate
AMC Addicted Joined: Feb/28/2012 Location: Airyzona Status: Offline Points: 2783 |
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Still would like to see photos.
Steve |
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