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Old 07-12-2002, 01:05 AM   #1
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Question 454 engine questions

Hi to all you wonderful Airstream nuts! I've recently become one myself

Just wondering about my 454. I have 73,000 miles on my 1979 MH, I get an average of 11 mpg and I seem to have a lot of power, but the engine does ping on a steep grade or under heavy load.

That doesn't bother me too much, but the oil consumption does...about a quart to every tankful of gas. Imight add that the engine is equipped with Banks headers. I don't see any great external leakage....and I have stuck my head out the window and have not seen any evidence of oil burning through the exhaust pipe.

Any ideas? Valve guides? Worn rings?

The engine is fine for now,but I will keep my eyes open for a decent deal on a new or used 454. Can I replace my current engine with a later model fuel injected engine?? Or is that a big headache?

Cheers to all and thanks for this great forum!!
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Old 07-12-2002, 07:07 AM   #2
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you might want too try senthetic (sp)? oil, my 95' c3500 would use about 1/2 qt of oil when towing my 36 foot fourwinds too mrytle beach and back and i switched too mobil 1 10w30 and can go till it's time too change at 3000 miles
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Old 07-12-2002, 01:00 PM   #3
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I have a 1997 Chevy C3500 C-C Dually with 454 and auto trans. It has 162,000 miles and doesn't use any oil. I use Mobil-1 10W30 weight, change it every 5,000 miles along with the oil and fuel filters and have no oil consumption. I did have to change the valve cover gaskets around 150,000 to stop the seepage of the slick oil.
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Old 07-12-2002, 05:59 PM   #4
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the pinging you describe is bad for the motor.
Causes for pinging are:
low octane fuel (use at least mid grade)
timing too advanced
bad timing chain
I found the best timing on Motorhomes is to set it a few degrees before pinging under load, which in some cases may not correspond to manufacturers recommendations.
My previous Class C Motorhome had a GM 400 engine.
When I checked the timing it was set to 12 BTDC. I freaked out and set it to 6BTDC per label on the air cleaner. It ran ok down here in Texas, until I drove it to the mountains of New Mexico and Colorado. I couldn't even get up any of the smaller grades. All stressed out, I finally advanced the timing to just before pinging and was able to go over Wolf creek pass with no problems.
I assumed the mileage and age of the old 400 was the reason for having to run so advanced.
A year later I replaced the 400 with a 350 crate motor from GM. Lo and behold, the only way it would run properly was around 12 BTDC.
Since i doubted myself, I took it to a very knowledgable mechanic friend of mine, who said, you can not run that new motor that advanced.
After he was done, he had it back to 12 BTDC.
If you check your timing and you find it to be running advanced, back off only a bit to get out of the pinging zone.
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Old 07-12-2002, 06:23 PM   #5
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Chevy engines

All Chevy engine love advance. When good fuel was available, we would always set the static timing at about 18 BTDC. Today it is easy to set and control the timing with a dash unit with a rotary knob. A few ignition companies make these devices. One such company is MSD, who makes many fine products for the racing and RV worlds. The engine oil loss is most probably the intake valve seals. They are just small "o" rings around the valve stems. A good method to stop valve stem seal leaks is to use Ford umbrella seals. The stem size for Chevy is 11/32. Maintaining a stable water temp is very important in getting the max from a Chevy. A single 3 inch exhaust will flow greater volumn than dual 2 inch. An open element air cleaner is a necessary plus. There is a very long list of engine enhancements available for most engines as used in a RV. Heat is the biggest engine killer.
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Old 10-04-2003, 11:52 AM   #6
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What is an open element air cleaner? I just replaced my air filter with a Fram Extra Life III, part # CA326. The cleaner or filter housing has a couple of vacuum hoses on it and it has an air intake tube that really doesn't reach very far out to the front of the engine compartment where all the good fresh cool air is.

This thing hasn't ever been cleaned it looks like. I had to wash with a degreaser and actually painted the outside to make it look better. It sits on a new Edelbrock 1906 electric choke carb.
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Old 10-04-2003, 12:50 PM   #7
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What is an open element air cleaner?
Like on a hot rod, a base, filter element and cover, with no housing like you painted. They are not what you really want on one of these, the snorkel is designed to quiet the air flowing into the carb and when you kick the secondaries open it is loud. I am not sure if it will work on these but some of the old Chevy's you could flip the cover and it would leave the element open, but there was a lot more clearance under a hood than under the dog house cover.

If you get some cool air into the carb it will help the engine run cooler and stronger. That is on my to do list, so if you beat me to it post some pictures.

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Old 10-04-2003, 01:01 PM   #8
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climate and traveling area

You need to say where you live in your bio info for good responses.....

If you live in a warm climate going to a straight 40 weight oil might help reduce oil consumption or a 20-50 and the georaphy you live in ( flatlands or Mtns.)will also determine gas, spark, and other recommendations. If in colder areas multi-viscousity is a more needed issue.

I would stick with dino oil in my area as synthetic is much more detergent and will remove sludge, etc. in an older motor that might be better left alone if it is not a
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Old 10-04-2003, 01:42 PM   #9
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The big question I asked my mechanic which does alot of overhauls and works on tour buses as well as motorhomes was what was the best oil to use, I asked him about synthetic oil and he said that was a BIG NO NO unless that was what you have used since the beginning of the engines life, it could cause leakage by changing. He recommended Mystic motor oil 15/50 which is a mineral motor oil without the breakdown properties as most mineral oils under such heat. I also changed out the old carb. with a edlebrock 650 dbl. pumper and my 1987 345 will almost burn rubber now and gets better gas mileage...These few changes as well as new sparkplug wires,distr.air breather etc. have made a world of difference in power even on grades. And best of all I hardly use any oil at all.
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Old 10-05-2003, 05:58 PM   #10
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I asked him about synthetic oil and he said that was a BIG NO NO unless that was what you have used since the beginning of the engines life, it could cause leakage by changing. He recommended Mystic motor oil 15/50
I agree with your mechanic about the synthetic oil, there are sometimes leaks when it is started later in an engine's life. But I disagree with using an oil as heavy as he recommended.

An engine is designed with bearing to journal clearances for a specific weight of oil. Increasing viscosity will reduce flow, increase pressure, and require more power to drive the pump.

BB cams are driven by a chain from the front of the crank. The distributor and oil pump are driven from a gear on the distributor shaft at the rear of the cam. There is a lot of torsional distortion in the cam from compressing valve springs and driving the oil pump. This affects ignition timing and increasing the power needed to drive the pump increases distortion.

The gear that drives the distributor and oil pump is held on with a small pin through the distributor shaft. This is a weak point when increasing oil pressure. An intermediate shaft drives the pump and is held in alignment with a piece of plastic. This is another weak point when you increase pressure.

Unless your engine is beginning to use a lot of oil and you are trying to get a few thousand miles more before rebuilding it I would use the recommended weight. IMHO that heavy of an oil is testing some weak points in the oil system.

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Old 10-06-2003, 06:22 AM   #11
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oil consumption

As mentioned before, Valve stem seals will cause oil usage, it is usually reconized by a cloud of smoke upon start up after sitting a few hours or over night.
The temperatures these engines run at, as well as age cause the seals to become hard, extreamly hard and they just break.
I have seen parts of the "umbrella" seals actually just laying on the head. they can be changed without the heads being removed.
I don't know your ability, but it can be done, and the seals are inexpensive.
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