Hi all,

Well I just learned that my new little coupe has a thing for drinking allot of oil in less then 1500 miles after a oil change..(2.5 quarts)

This car has sat for about 10 years until I bought at a auction a month ago. It just turned 90k and it's a rust free car, not a spot on it. This is my first fiero base coupe 5spd with NO options at all but a radio. I work 33 miles from home and it's getting 33-35 mpg and only costing me $26 to fill it up once a week. (much better then my Jimmy at 18mpg and $60 every 4days to fill it). So i plan on keeping her for a few years and want to fix it right and have many more years of fun with it.

I haven't done a rebuild on a engine since high school back in 92" and I was wonder what would the best route would be

1. re-ring
2. or just rebuild the whole lower end
3. rebuild the complete motor

At this time i don't have the money to go and buy a new long block for it. and I would rather do the work myself in my little 1440 sq. foot garage..

Any info or help would be great!

Thanks all
Kevin

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1999 GMC Jimmy 2dr 4x4
1996 Chevy Lumina LS

1986 Fiero Base Coupe...NO OPTIONS !!
1985 Fiero GT 3800 N/A-sometime this year 3800S/C..maybe
1984 Fiero Indy-Restoring back to former glory

[This message has been edited by KEV (edited 10-05-2008).]

I would do a compression check first and see what you have. It could be the oil is getting by the valve seals instead of the rings. Also when you pull your plugs to do the compression test see what they look like. If your burning oil that bad they should have some black carbon on them.

Does smoke when you rev it up to 3 or 4 k? How is the oil pressure?
Did you put some oil in the cylinders and let it soak for a day or two before you started it for the first time?

quote Originally posted by 2farnorth: I would do a compression check first and see what you have. It could be the oil is getting by the valve seals instead of the rings. Also when you pull your plugs to do the compression test see what they look like. If your burning oil that bad they should have some black carbon on them. Does smoke when you rev it up to 3 or 4 k? How is the oil pressure? Did you put some oil in the cylinders and let it soak for a day or two before you started it for the first time?

I did the plugs and they look fine no black carbon on them. Only puffs smoke between shifting gears a bit. There is a lot of oil up in the air cleaner (it's pooling). The oil pressure is a rock steady at 40psi. No i didn't put oil down the cylinders the first time I just turned it over with the fuel pump unhooked.

It has no leaks anywhere and it does puff a little smoke when i start it. I'll do a compression check tomorrow after work.

Thanks

Were not looking for carbon on the plugs, thats rich fuel. An oil burner will have thick chunky bits of carbon on the plugs. And yes, Oil in the air filter is blow by, too much air fuel going past the rings going into the oil pan and working into the air filter. Marvels mystery oil or engine oil into the cylinders is a good practice on a engine that has sit for an time.

To suck oil that fast... It would be some pretty obvious smoking. Are you absolutely certain it's not leaking. I'd be looking really hard for leaks while it is running. The oil pressure sender is famous for leaking but there are other places, especially on a car that sat around for ages. Some leaks like this won't leak the expected huge oil stains on the floor.

Nor would I assume it is a ring problem even if it is smoking like hell. As noted above do a compression test. Valve guide seal failure can cause major oil consumption as easily as a ring problem but it's a hell of allot easier to fix in most cases.

You could also have blocked drains holding oil in the head when running. That can make it drink oil even if the valve seals are good as those seals are meant only to stop the small amount of oil sprayed on the rockers to keep them lubed. A flooded valve gallery will drop oil right past them like mad.

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(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top of every forum page...)

Hey KEV welcome to the realm of the mosquito fogger.

Oil in the air cleaner in my experience with the 2.5 means blow by past the rings and too much pressure in the crank case which forces oil into the air cleaner.

Run the engine and pull the 710 cap and there should be a good air flow out of the valve cover.

Smoke in puffs here and there also mean worn valve guides and not just valve seals of which the 2.5 has four, and they're on the intake valves only, exhaust valves have none.

So rings and valve guides sound shot.

I would say at a minimum you'll need to do the cylinder walls and valve guides so yes re-ring but don't be surprised if they can't clean up the cylinder walls without having to go to .030 over pistons.

Oh, and post some pics too.

Steve

Oh and one other thing, are you figuring your oil into you final MPG?

[This message has been edited by fierohoho (edited 10-06-2008).]

quote Originally posted by theogre: To suck oil that fast... It would be some pretty obvious smoking. Are you absolutely certain it's not leaking. I'd be looking really hard for leaks while it is running. The oil pressure sender is famous for leaking but there are other places, especially on a car that sat around for ages. Some leaks like this won't leak the expected huge oil stains on the floor. Nor would I assume it is a ring problem even if it is smoking like hell. As noted above do a compression test. Valve guide seal failure can cause major oil consumption as easily as a ring problem but it's a hell of allot easier to fix in most cases. You could also have blocked drains holding oil in the head when running. That can make it drink oil even if the valve seals are good as those seals are meant only to stop the small amount of oil sprayed on the rockers to keep them lubed. A flooded valve gallery will drop oil right past them like mad.

Yes i very sure it's not leaking oil anywhere.There has been no oil spots on the ground or anywhere on the engine. The oil pressure sensor was replaced because it was bad. Thanks for the info.

You have classic systems of blow by in the air breather. I would try some Marvel Mystery Oil on the pistons over night, or a little longer if you are able to. Maybe find you a good core VIN 'R' and do the overhaul while you are still driving and enjoying the great mileage. Swap them out over a weekend.
Good luck

quote Originally posted by josef644: Maybe find you a good core VIN 'R' and do the overhaul while you are still driving and enjoying the great mileage. Swap them out over a weekend. Good luck

Seconded. Go drop the big $100-150 on a running 85-86 2.5 from a running Fiero, Century, Ciera, Celebrity or 6000, then drop another $131 on an overhaul kit from Northern Auto Parts, buy some .020-.030 over pistons off ebay, spend $125 at the machine shop getting the head freshened, $100 getting the crank ground/polished, button it all up and have like new performance and a long-block you're 100% sure is good for $600 all told.

If the die grinder were to come out and remove a little material from the intake ports while the valves were out, you might see a little extra free power too.
Fierostore also has a drop-in roller cam that will make the car less anemic as the tach needle starts to sweep past 4000 RPM.

Of course, you could also toss in an 87+ crank and rods while you were in there for some added safety factor. They interchange but are stronger.

quote Originally posted by KurtAKX: Seconded. Go drop the big $100-150 on a running 85-86 2.5 from a running Fiero, Century, Ciera, Celebrity or 6000, then drop another $131 on an overhaul kit from Northern Auto Parts, buy some .020-.030 over pistons off ebay, spend $125 at the machine shop getting the head freshened, $100 getting the crank ground/polished, button it all up and have like new performance and a long-block you're 100% sure is good for $600 all told. If the die grinder were to come out and remove a little material from the intake ports while the valves were out, you might see a little extra free power too. Fierostore also has a drop-in roller cam that will make the car less anemic as the tach needle starts to sweep past 4000 RPM. Of course, you could also toss in an 87+ crank and rods while you were in there for some added safety factor. They interchange but are stronger.

I'm looking into rebuilding this engine in a couple months.

So whats the different between the early crank and rods and the 87+ cranks? whats all needed to switch to this crank?

I'm also thinking of having the intake ports opened up some. and do the fierostore roller cam also.

Thanks for the info

What's different?

Here let me show you: (sorry the crappy old Kodak digicam hates the dark)
84-86 rod (has "324" casting number on it)


87+ rod (has "987" casting number on it)


In case you can't read the vernier, let me do a quick overview; The calipers set to the beam width of the newer rods sitting over the older rod:


As far as the crank, I'll freely admit that the 87+ cranks are pieces of sshhiitt, but they do have this little bit of extra mass for the DIS that seems to help damp oscillations and last just a tiny bit longer:

I've blown the 84-86 style cranks up a few times, but I've never blown one of these up.


There's nothing "required" to switch to the later cranks or rods or both. They use the same journal diameters and the extra "disc" on the crank for the DIS clears the older distributor block just fine; in fact I'm using DarkHorizon's old 88 2.5 crank in the 85 roller lifter block in my daily driver/beater. Its the one that I dynoed up to 5250 RPM last fall. https://www.fiero.nl/forum/Forum2/HTML/087194.html anyway, 12k miles later and its still going strong. I never even machined or polished or reworked the crank, I just took it out of the 88 block (they're total $h!t) and dropped into my block with fresh "STD" size bearings.

[This message has been edited by KurtAKX (edited 10-06-2008).]

Well I found a complete remand 85-86 2.5L for $350, so I'm thinking of going this way maybe and just rebuild mine down the road. I'd like to do the 3.0L crank swap if it all turns out.

Make sure its not a VIN U engine. They won't fit the car.

If the head casting isn't a 767, then its not the right engine.

If it doesn't have a head on it (which I would expect at only $350), check the oil filter mounting pad. If its oriented to point the filter "up" then its a VIN U engine and it won't fit your car.

By the time you buy a $350 shortblock, a gasket kit, and have the headwork done on your stock head, you could have built yourself an engine that you know is good- (no .020-.030 under journals on the crank, has the newer rods, etc).

Rebuilders sometimes do some shady stuff. For example, I pulled apart a rebuilt 87 DIS engine I bought recently only to discover that it was assembled with rods from 1985 (the thin beam ones). The crank is turned down pretty far too.

Buyer beware.

quote Originally posted by KurtAKX: Make sure its not a VIN U engine. They won't fit the car. If the head casting isn't a 767, then its not the right engine. If it doesn't have a head on it (which I would expect at only $350), check the oil filter mounting pad. If its oriented to point the filter "up" then its a VIN U engine and it won't fit your car. By the time you buy a $350 shortblock, a gasket kit, and have the headwork done on your stock head, you could have built yourself an engine that you know is good- (no .020-.030 under journals on the crank, has the newer rods, etc). Rebuilders sometimes do some shady stuff. For example, I pulled apart a rebuilt 87 DIS engine I bought recently only to discover that it was assembled with rods from 1985 (the thin beam ones). The crank is turned down pretty far too. Buyer beware.

It is a long block, they have some overstock and willing to let them go cheap. Thank you very much for all the info and help!