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By ronsplace - 16 Years Ago
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Need some advice, please: My 312 motor is fouling spark plugs big time (I can see signs of fouling after running just 300 miles). Here's some back ground on the motor: just professionally rebuilt: bored .060 over and running a Mummert Blue thunder intake, Edelbrock 500cfm carb, and Mummert's mild street cam. Removed the road draft tube and machined a plate to cover the hole where the tube was mounted on the block. Ran an aluminum tube from this plate to top of the block where I installed a PCV valve and ran a rubber hose into the base of the carb. Heads were gone through, too--hardened seats, new seals, etc. Is there a clue in there some where as to why my plugs are fouling so quickly (the #3 plug fouled so bad recently it completely shorted out after less than 2,000 miles). Many thanks for all suggestions! Ron...
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By charliemccraney - 16 Years Ago
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Pull the hose at the carb nipple and see if it is oily on the inside.
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By Ol'ford nut - 16 Years Ago
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To start off I would remove the piping for the PVC and see if it is getting oil in it and sucking up to carb. I would also double check that you have the correct PCV valve. Is there a reason why you ran your line from the breather location? Most run them from the valley pan. You might think about changing that, especially if you find oil in line.
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By oldcarmark - 16 Years Ago
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If you are drawing from the old road draft opening there is no baffle to prevent drawing oil.On the valley pans with the PCV(old road draft opening) there is a baffle on the underside to prevent sucking oil up.Vapours are what is drawn into the PCV valve.You should seriously look into changing your setup.You are burning oil not fumes.
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By ronsplace - 16 Years Ago
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I'm sorry, but I didn't give enough detail in my original post: I have a tube & rubber hose running from the side of the block where the road draft tube was up to the bottom side of my air cleaner. This is the "vent" side of the pcv system. I then have rubber hose and pcv valve running from the valley cover to the vacuum outlet on the back of the carburetor. As some of you suggested, I checked and found quite a bit of oil on both the "vent" hose and on the pcv hose, so this might be my issue. Question is, where do I vent the pcv system if I no longer use the spot where the down draft tube originally attached to the side of the block? I'm running an original set of T-Bird valve covers so I don't have a vent on them and I don't want to alter them because of their rarity. Thanks, Ron
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By oldcarmark - 16 Years Ago
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You can block off the opening in the block with an 1 1/4 frost type plug.Air "in" is through the filtered oil fill cap.Do you have a "baffled" type valley cover or the original with a hole drilled in it?You need a baffled type cover.Thats all you need for a PCV system.You can create a "closed" system by drawing air from the bottom of the aircleaner to a nipple on the correct closed type oil fill cap.You dont need the setup from the old road draft hole in the block at all.Close it off.Hope this helps.Make sure your PCV valve has the small diameter end facing the carb.
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By ronsplace - 16 Years Ago
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Oldcarmark: Thanks for that information. I believe my after-market valley cover does not have a baffle, so that is an issue I should address. Also, do I need a "vent" side to my pcv system? In other words, if I have the pcv valve between the valley cover and the vacuum source at the rear of the carburetor, do I then need a vent side running from under my air cleaner to a location that will vent the motor? I have a vented, push-on cap on my oil filler tube on the front of the valley cover. Is that sufficient for venting, or do I need a closed system? Thanks, Ron
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By oldcarmark - 16 Years Ago
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Air in through the vented oil fill cap should be sufficient.Thats the setup on mine and most everyone elses.You will need to do something about the valley cover.Maybe you can make a baffle for yours.If someone else has a pic of the underside of the T-Bird cover maybe they could post it so you can see how it looks.Your PCV valve and hose to the base of the carb are fine.
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By ronsplace - 16 Years Ago
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Many thanks. I'll see if I can fabricate a baffle on the bottom of my valley cover based on a picture of one I found on John Mummert's website. If I'm not happy with the results, I'll buy one of his. Thanks for all the input. Ron
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By Ted - 16 Years Ago
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Moved to the technical forum. My ’55 Customline is currently getting new paint so no wash jobs for at least a month.
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