250 burning lots of oil!

[ScottStaypuff]

Hi guys, my Maverick's original 250ci engine burns a lot of oil. When I put it away the last time it was burning a quart or more a day! The engine has 156,000 miles and had a valve job somewhere along the way but to the best of my knowlege has never been rebuilt. The car gets put away for long periods (6 months to several years) and then ran for several months.

Would this more likely be piston rings or valve seals? Is it likely that the engine would have bigger problems than a rebuild could solve? Thanks

 

[pedal2themetal45]

A Qt a day is quite a bit
Things to check
Does it leak a bunch (leaving a big puddle under it)
Doe is smoke a lot????
156T miles could be rings?? it would smoke like a pig I would think.
Valve guides seals usualy show signs of leaking by a puff of smoke on start up.. But i don't think they would leak a qt. a day..
Could be the PCV valve check it see if the hose is full of oil it could be sucking it in thro there. (baffel may be broke letting oil get to the valve).

I think a rebuild job would fix it anyway, most are not to bad for that.. Might be cheaper just to buy a short block and use your head and stuff.
Tim

 

[MercuryMarc]

My tired 250 burned 1 qt every 100 miles before I rebuilt it last year.
I replaced the valve stem seals (very easy using the "rope trick" mentioned on the site below) but that did not help much. So I rebuilt the engine myself and replaced the rings after honing the cylinders (tool rented from Autozone) and the car runs great - does not use any oil!
Hope this helps:

Here is what I learned:
from http://www.aa1car.com/library/oil_consumption.htm

WHAT CAUSES EXCESSIVE OIL CONSUMPTION

Oil consumption depends primarily on two things: the valve guides and piston rings. If the valve guides are worn, or if there's too much clearance between the valve stems and guides, or if the valve guide seals are worn, cracked, missing, broken or improperly installed, the engine will suck oil down the guides and into the cylinders. The engine may still have good compression, but will use a lot of oil.

Worn valve guides can usually be restored a number of different ways. One popular method machine shops use is to ream out the guides and install thin bronze or cast iron guide liners. Knurling is another procedure that can reduce valve guide clearances. With aluminum heads, the original guides can be driven out and replaced with new ones. With cast iron heads, the guides can be reamed out to accept new valves with oversized stems.

If the oil burning is due to worn or broken rings, or wear in the cylinders, the engine will have low compression. The only cure here is to bore or hone the cylinders and replace the worn or broken piston rings

 

[ScottStaypuff]

Good info, thanks guys.

 

[strat1960s]

I had my motor rebuilt a few years ago and had problems getting the rings to seat properly. I ran valvoline 40wt racing oil and the smoke/oil consumption all but went away. I had the motor re-rings about a year after the re-build and still had problems seating the rings. I tried everything from stop leak to carb and dizzy adjustment to get the rings to seat. The biggest problems was that I parked the car every time I deployed and it sat for 4 to 6 months at a time. You have to really drive the car almost daily and at highway speeds to get some rings to seat properly. I took the car out every weekend for 2 months, found a lonely stretch of highway and drove it 45 minutes one way at 90 MPH. That did the trick. If you can't find a lonely stretch of highway the you might want to run a compression test on each cylinder.
Ted

 

[mugsy]

My guess: rings! My car burned a qt. with every gas tank. When I tore it down the engine was basically shot, the odo said 60,000 miles, my guess is 260,000 miles . Wish I had a camera to show the picture of the piston. Anyway, to burn that much oil it almost has to be the rings. It's an easy check, do a compression check. You can buy the gauge and at any auto parts store. Warm the engine first, make sure the battery is fully charged, take all the spark plugs out, (I disconnect the fuel line to the pump), disconnect the hot lead to the coil and test each cylinder "dry" then "wet". Use about a spoonful of motor oil through the spark plug hole to make the cylinder "wet". Don't use WD-40, it's not thick enough (don't ask why I know). If the compression numbers significantly increase from dry to wet then the rings are shot. If it's a small increase then the valve seals/stems are the likely culprit.

Keep us posted on what you find!! And good luck.