Inliners International Forums General Discussion Engines My 250ci uses lots of oil, am I missing anything?

I would change the oil, run it hard (but not so hard the rods exit the block!) for a few hundred miles, change the oil again. Do this several times. If this does not help then I doubt anything short of a teardown will. My opinion.

Adding to what Stroker6 said. Use rotella 15w40 diesel oil. It is a high detergent and will also help dissolve carbon deposits.

Alternatively, using a quart of ATF also adds tons of detergent. Drive it lightly for a week and it will clean out.

I have already gone through almost 30 gallons of gas. I can't believe how well it runs. I'd have never guessed it would have this problem. I have a T5 MT with the 0.73 OD gear and a 3.73 rear with 29" tires and hills are no problem even if the RPMs get down around 1700, I can still accelerate and pick up speed easily. Seems to have plenty of "pep".

I'm using 5W30 oil right now. Is that making things worse?


Should I just add ATF to the oil and skip the kerosene wash out?

Any comment on which block to build if it comes to that?

I don't like the kerosene idea. Could damage bearings.
To me, the blocks are equal to use, unless one has been bored previously. But do build as a 250.

Then I'll use ATF. Thanks. Yes, I heard that a 230ci is the same block but has different pistons. I'll ask more questions about how to build the 250ci later if it comes down to that.

Jay

I did an oil change in my old 292 and ran a quart of ATF. Cleared carbon within minutes. I had a valve sticking and I left the engine at about 1500 rpm....poured a quart of ATF in and misfiring stopped a few minutes later. Ran it for about 20 miles...drain and changed the oil. Never smoked At All which was surprising for an engine with 150,000 and 95 pounds of compression vs at least 130. Could be weak rings for sure....Engine Restorer seems to help as well. I used a can of that and it bumped my compression up to about 115 pounds in all cylinders...hence the conclusion...Weak Rings.

Thanks for the input. I plan to do a compression test tonight. Report hopefully tomorrow.

Just finished a dry compression test. Took pics of my plugs too. Engine and plugs were stone cold when I pulled the plugs. Plug #3 looked slightly darker than the other 5 plugs.
All plugs were out and my wonderful wife cranked the engine for 4 complete bumps of the gauge needle. Here are the compression numbers. Factory service manual says a 230ci should have 130# and I imagine the 250 would be the same.

Cylinder #1 - 125
Cylinder #2 - 125
Cylinder #3 - 110
Cylinder #4 - 125-130
Cylinder #5 - 125
Cylinder #6 - 120

Wow, those look like really great shape plugs for a quart of oil every 200 miles. All my old oil burners looked much worse. Your #1 looks off on color, maybe there's something there. I've been told compression is most important to be wearing evenly across the cylinders and that #6 is usually the worst. From that your #3 looks "not like the others". But your performance is great.

For reference, mine measured 100-110 compression.

I don't think your rings are leaking the oil. It's gotta be going somewhere else. Rear main seal or somehow directly into the exhaust manifold? Where else could it be going?

Oh yeah, I hate never-seize that I see you put on your plugs. We used to put that on the handles of peoples tools in the canning factory for laughs. Nasty stuff, but it does work even in salt-water environments.

1 and 3 look the worst. Weird, I would think the oil comsumption would show more on the plugs.

My guess, you have a broken #2 ring on #1 cylinder. Hence the good compression and poor oil control. Maybe it is just stuck and will be cured with the ATF treatment. Got my fingers crossed.

First video is 30 seconds after a cold start. Choke is still on and RPMs range from 1500 - 4000. White and black smoke on start up. Looks pretty grim. Next 2 videos look better, sorta, maybe. Last video is just under the hood for a few seconds.

Could any of this be caused or made worse by having the wrong size oil filter on the engine?

I run a quart of kerosene for 10 min's at idle right before I shut off the engine and drain the oil... works really well to clean out the varnish..

On a 3.9 dodge V6 after about 10 oil changes with kerosene the oil started coming out nearly clean.. I had the engine out to change the rear main seal and it was spotless inside.. pulled a rod bearing apart from not getting an oil change for a unknown amount of time before I got the truck it was ok...

First oil change it came out like tar..

I take back what I said about the oil going somewhere else. That's a lot of smoke coming out the pipe. I think your plugs look as good as they do due to the good compression, it's effectively burning the oil.

I really appreciate the willingness everyone has to try and help a novice like me.

Here's an update. FYI, this is the third time I've eaten Humble Pie this month. Not very fun.
My 1971 250ci engine is pretty on the outside and junk on the inside. I added ATF to the oil and drove it maybe 40 miles. I saw the oil pressure light flicker once or twice at really low RPMs and that made me wonder if some gunk had blocked the oil pressure sensor.

I added a quart of kerosene to the oil and idled the engine in the yard at 1500 RPMs for 14 minutes. Drained everything while hot and changed the filter and replaced the oil pressure sensor with a new one. Oil came out dark brown but no chunks. (That was no surprise because I had removed all the gunk from the oil pan, timing cover, rocker cover and then changed all the seals 2 years ago.)

Added straight 40 weight oil to the engine in hopes that the thicker oil would reduce how much oil it was burning. Took the wife for a drive to the lake that evening and noticed the oil pressure light would flicker when at idle at the light - 800 RPMs. Light would go out immediately once I started driving. No funny noises from the engine. Checked oil level and it's all fine.

Tonight I got out my new Stewart Warner electric pressure gauge. You better read this sitting down. Operating temperature pressure is 10 at idle of 800 RPMs and never goes over 20 when driving. Stays at 20 with RPMs 2000 - 2500 and will drop to 15 if RPMs drop to 1500.

I have never rebuilt an engine. Working on this truck has been a real education and very humbling.

I really like the idea of keeping an inline 6 cylinder because you don't see that many these days. Other reasons are purely financial. The pros for installing another 250ci are many.
Keep the same (new) wiring under the hood.
Keep the brand new exhaust.
Keep the same radiator and (new) hoses
Keep the same new HEI dizzy & wires

I've already checked some prices. Crate 250ci with 3 year unlimited mileage is $1500-$1600 and I give them mine as a core.
Local shop wants similar money but only 12 months warranty.

I have an engine stand and a garage to work in this winter.

Let's hear what you think.

Same thing I said on the other forum. lol!

Fix what you have. Rings, hone cylinders, replace valve guides and seals (A full valve job) and bearings. Couple hundred in parts, maybe $200 in the head labor. Hoping the crank doesn't need machining due to bearing journal imperfections. You can do all of it without pulling the engine if you have room to drop the oil pan. Much more than that will get you close to the crate engine price range.


Oil burning: running the engine in park does not tell much. Have someone drive behind it and make note of when it smokes.

1. Smoking under heavy throttle while accelerating, continuously smoking = piston rings.

2. NOT smoking continuously under long acceleration, but puffing out a cloud of smoke after sitting at idle waiting for lights to turn green, just as you start giving it gas = intake valve stem seals and guides passing too much oil through

3. black smoke = too much fuel.

i would start with the valve job suggested, looking from the plug no 1 it would probably have a leaking valve, my ford had this (300cid) after a couple miles (1000or more) looked the same as yours, don't have to tell how it looked after 15000miles.
anyway if its a valve don't really hurt the engine but after a while you'll have so much deposit it will run a cyl less.

Send Tom Lowe a PM. He probably would have a good one laying around.

If your short on cash - try changing the oil pump and rebuild the head first.

If the oil pressure comes up after changing the pump, then the bearing are serviceable - yes its extra work and it might cost you a head gasket if at the end you need to take the engine down completely.

Personally I prefer to rebuild the parts I have rather then replace the engine unless I'm doing a swap.

Lugnutz,

What ever way you go, keep in mind that you have set the bar pretty high with your T5 information pages. We DO expect the same documentation from your engine building experience!

Jim