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King of Smart Gadgetry
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Discussion Starter #1
Hello again. As most of you know I just dropped my engine and removed the head and replaced all the valves and guides and seals because it kept lighting the check engine light for a P0303 error "misfire on cylinder 3" and this was on an engine with 36,000 miles.
Before the teardown I was getting a consistent 43 mpg out of it, but I really babied it. Now that it is all back together it runs alot stronger than it did before the teardown, but the mpg has taken a nosedive. Now it is a given that I am running the rpms up more as some of my friends here on the forum recommended that I do, but I'm getting about 33 mpg out of it. That's my observation from a couple of tanks of gas. Maybe the valves are a little tight? But losing 10 mpg is pretty drastic and I know it can do better. It has new plugs, belts and air filter.
The engine sound is a little louder to me than before. At idle it is really putting out the exhaust out of it's factory tailpipe. It blows the grass all around it as it idles.
I run the interstate to get home and by the time I pull in my driveway the exhaust is really hot and it smells like burned paint everytime. Could this new smell be from the Marvel Mystery Oil I added to the engine oil? I never added any to the fuel.
I thought maybe the flange gasket needed re-torqued on the exhaust. That would account for the loudness and also maybe it makes the fuel system richen up and therefore less mpg? But it's a major thing to get to it to check it, so I haven't done that yet. DCO
 

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Isn't MMO something from 50's and 60's? Why did you feel the need to put it in a modern engine? I'd do a 2,000 mile break-in before checking mileage but assume you adjusted the valves after putting it together.
 

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Many things affect mileage...

I would check tire pressure, then change the oil and filter...

I use the long oil filter, Fram 7317, Purolator 14610, it's a third longer, same base and bypass..

I like the Castrol Edge and Pennzoil Euro 0W-40, the Mobil 1 did not run so well...
 

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I use the long oil filter, Fram 7317, Purolator 14610, it's a third longer, same base and bypass..
Be careful with that extra long oil filter, I had one once and never again because I realized it was the lowest hanging object under my car. A perfect target for road debris.
 

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King of Smart Gadgetry
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Discussion Starter #8
I kind of thought the same thing. I love the ideai of it. A longer filter would mean a little more oil capacity and maybe an ever so slight bit more cooling of the oil, and more filter area so less chance of filter bypass. But the filter is so low (probablt by design) that I am afraid of it being danaged by road hazards. Maybe that opinion is unwarranted on my part because I have't read on the forum of anyone breaking their oil filter. I'm still going to try to get at that exhaust flange gasket and check it for tightness. The exhaust seems louder to me than it used to be. Maybe it's just me, but an exhaust leak I would think would make the computer richen out the fuel mixture, but not to the tune of 10 mpg difference. DCO
 
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