420A 1997 420 A burning oil - how to diagnose seals or rings as the problem?

[Myjr]

Hello. I am very new to this and we got our 1997 420A running about 3 weeks ago after it had set for 3 years. We put just a splash of mystery oil in the cylinders and manually turned the motor over about 100 times to be sure there wouldnt be a problem when we went to start it. Once it fired over it smoked heavily for a little while but then seemed to subside. 3 weeks later we have burned 3 quarts of oil and there doesnt seem to be any major leads around the motor. Is there something we can do to test the rings or seals to make sure that is the issue before heading down the road of rebuilding the head? Am I even in the right universe with my line of thought?

Any advise would be greatly appreciated.

 

[99dsmer4g63]

Perform a leak down test on the car. This will point in the direction whether it’s intake or exhaust valves or piston rings. The fact your burning oil leads me to believe it’s in the bottom end.

Do Google search on a leakdown test. Where the air is escaping from is where your problem lies.

-Daniel

 

[Myjr]

I will research that. Thanks for your response.

is there such a thing as a crate motor you can order for these things to just swap out if necessary?

 

[Dericsh]

Are you seeing any sort of smoke, such as when you’re sitting idle for a while it smokes a lot after you start going again?

 

[CKOPOCT]

If you are losing oil and are not seeing smoke (and the coolant doesn't look like chocolate milk) then you most likely have worn rings. The combustion gasses are blowing past the rings, burning the oil in the pan. Your oil will be black. A leak down test will confirm this. If you hear the compressed air hissing and echoing through the dipstick tube and up through the valve cover you have worn rings (or worn valve guides, but bad guides would also produce blue smoke coming out of the exhaust as the oil leaks down into the combustion chamber).

You can also perform a minor test for weak rings by doing a wet compression test. Do an initial compression test, then redo it after putting a little oil in the cylinders. If your numbers improve significantly then you have weak rings - the oil settles down around the rings and helps seal them, improving the compression numbers. If the rings are bad enough, however, the increase won't be that much.

As to a crate motor, others will have to chime in as my experience comes from the mouths of others who have bought or sold crate motors; I myself have never used one. According to the aforementioned others, crate motors are built in large quantities. Tolerances tend to be on the loose side, so while some come out okay, others have excessive slop. It's a crap shoot. They will run for the duration of their warranty (60-90 days), and for a while after... but they seem to begin to go bad long before what you would expect. A quick search shows a crate motor to be around $6,000. Kinda pricey (about 3x what the car is worth), but not much of a market for these engines anymore.

You could also get an engine from a junkyard. Search www.car-part.com. You can get a junkyard engine for a grand or two - just be aware that you should not just drop-and-go with a boneyard engine. Replace all belts (especially timing belt and water pump) and inspect it thoroughly (compression test, leak down test, fasteners, the works). Even if the engine comes with a warranty and has been "tested," you have no idea what the engine has been through or how long it has sat. I consider boneyard engines to be more of a temporary fix or band-aid versus a permanent solution - something to get the car on the road for a couple of months while the factory engine is getting rebuilt.

Your best option IMO is to have the engine rebuilt by a reputable shop. It will cost you roughly $1500-$3500 depending on what the engine needs, but it should come back to you in like-new condition and should give you 100,000+ miles of life.

 

[Myjr]

If you are losing oil and are not seeing smoke (and the coolant doesn't look like chocolate milk) then you most likely have worn rings. The combustion gasses are blowing past the rings, burning the oil in the pan. Your oil will be black. A leak down test will confirm this. If you hear the compressed air hissing and echoing through the dipstick tube and up through the valve cover you have worn rings (or worn valve guides, but bad guides would also produce blue smoke coming out of the exhaust as the oil leaks down into the combustion chamber).

You can also perform a minor test for weak rings by doing a wet compression test. Do an initial compression test, then redo it after putting a little oil in the cylinders. If your numbers improve significantly then you have weak rings - the oil settles down around the rings and helps seal them, improving the compression numbers. If the rings are bad enough, however, the increase won't be that much.

As to a crate motor, others will have to chime in as my experience comes from the mouths of others who have bought or sold crate motors; I myself have never used one. According to the aforementioned others, crate motors are built in large quantities. Tolerances tend to be on the loose side, so while some come out okay, others have excessive slop. It's a crap shoot. They will run for the duration of their warranty (60-90 days), and for a while after... but they seem to begin to go bad long before what you would expect. A quick search shows a crate motor to be around $6,000. Kinda pricey (about 3x what the car is worth), but not much of a market for these engines anymore.

You could also get an engine from a junkyard. Search www.car-part.com. You can get a junkyard engine for a grand or two - just be aware that you should not just drop-and-go with a boneyard engine. Replace all belts (especially timing belt and water pump) and inspect it thoroughly (compression test, leak down test, fasteners, the works). Even if the engine comes with a warranty and has been "tested," you have no idea what the engine has been through or how long it has sat. I consider boneyard engines to be more of a temporary fix or band-aid versus a permanent solution - something to get the car on the road for a couple of months while the factory engine is getting rebuilt.

Your best option IMO is to have the engine rebuilt by a reputable shop. It will cost you roughly $1500-$3500 depending on what the engine needs, but it should come back to you in like-new condition and should give you 100,000+ miles of life.

That sounds like good advice. I will search for a reputable shop to work with. Thanks for the advice