Oil Report-Time to Rebuild?

Ownley1

Ownley1

Junior Member
Take a look at this oil report I just got back. Is it time to rebuild the engine?

View attachment Blackstone.pdf

Here's the background I sent them:

The heads were rebuilt 2,372 miles ago due to a burnt valve. After re-assembly I ran it for 16 miles on the old oil then 1,004 miles on the first (2021) sample that I sent in. After I sent that sample in I changed the oil and added 395 miles and sent the second (2023) sample in. I changed the oil after 79 miles, then added 656 miles at which point I added 1/2 quart of Lucas Hot Rod 20W-50 make-up oil (I only chose this weight because it was what I had around). Then I added 222 miles which gets us to today. I do not use leaded fuel or a lead additive, just Sta-bil 360.

The odometer shows 14,180 miles (rolled over at least once). It’s hard to estimate mileage on the short block/bottom end. The cylinder walls had good crosshatching, but the spark plugs get oily so I assume it is burning some oil. Based on the condition of the paint I’m assuming the car went through a somewhat cheap restoration in the 1980s and the engine may have been rebuilt at this time. The cylinders were stamped .040 so it’s definitely been rebuilt. The casting number on the block and the engine color leads me to believe it may have started life in a Ford pickup or was a replacement motor from Ford back in the day.

I sampled through the dip stick after a thorough drive then sitting for about 30 minutes.

I am open to increasing the viscosity to 20W-50 if that would help with wear, etc.
 
The high copper, lead and tin indicate the rod and crankshaft bearings are in poor shape. The high iron isn't good either. I have oil samples from a diesel with 30,000 miles on the oil that look better than that. Since the engine has been bored to the limit I suggest you source another engine. Yours isn't long for the world. BTW, cross hatch doesn't mean much. I tore down an 800,000 mile 5.9 Cummins that had visible cross hatch but it burned a qt of oil every 800 miles and several rod bearings were down to the copper.
 
Last edited:
I know the lead wear is pretty bad. It’s not knocking or making any other weird noises yet and it runs great. I’m considering just rolling in new bearings. But I know that the rest of the motor is likely to be just as worn out. A rebuild is certainly in my future, but how long is what I’m trying to discern. I don’t have the time or expertise to do the rebuild myself either, so there’s that expense I’d like to put off.
 
Back in the old days we sometimes replaced rings or bearings in the car. Not the first choice, but what we had to do. If you’re burning a qt of oil every 1200 miles or so and the plugs aren’t fouling, you’re ok there for a while. Bearings are more iffy, you really don’t want to hurt the crank. But i remember guys polishing with emery cloth strips and doing that too. If it’s a low miles per year just in the local area you could have years.

We also used 30w oil a lot in older engines just to get us by. I’m not sure that’s true now, oils have come a long ways in the 60 years I’ve been changing them.
 
I only have the dash light for oil pressure but it never lights up while running. Using Lucas 10W-30 and plan to switch to 20W-50
 
I pulled the front main bearing and the cylinder one rod bearing

IMG_5273.jpg

IMG_5279.jpg

IMG_5287.jpg

IMG_5285.jpg
 
In aviation, mechanics look for trends more than what an oil analysis will tell. Oil pressure is set after overhaul or on a new engine if it's found out of spec during test run. If it maintains specified oil pressure then the bearings are working. It has to have a direct reading gauge to do that. The other trend is oil consumption. If it takes a quart of oil every hour then it's going out too soon. Generally the plugs will be oily if it's an oil burner. Ideal would be no oil added till the 25 hour or to the 50 hour oil change depending on whether it has a screen or a spin on full flow filter.

Filter screens are checked at the 25-hour oil change. Spin on filters allow oil change at 50-hours. Spin on filters are cut open and pleats are inspected for metal same as the oil screen. Metal should be limited to ring wear which are tiny particles of steel or some aluminum from piston pin plugs. There should never be a lot of anything visible by eye. 100-hour compression checks tell the story about piston ring condition or valve seat problems. Valves are checked for wiggle at various scheduled times depending on type of valve and valve guide. All aircraft engines have a Time Before Overhaul or TBO that varies between 1200-hour and 2000 hours depending on overall performance of each category of design and test experience of each design.

On an old design Ford V8, there isn't as much to go on but the basics like oil pressure, color of spark plugs, and color of the exhaust pipe. If oil psi drops off then the bearings will start rattling at some point. Oil filters can be inspected at each oil change just like for aircraft if you have a proper filter cutter tool or your still using cartridge filters. Any large amount of visible metal is a bad sign. I don't use spectro analysis. It was always a day late and a dollar short on engine bearing failures.
 
Put it back together, and put a mechanical oil pressure gage on it. Change the oil. The heavier oil may push some oil past the rear main (drip).

Drive the car and enjoy it. If the engine goes south, or lets go put a 302, or a 351 in it.
 
Last edited:
did you happen to measure the rod journal? The main looks good, rod bearing looks a little worn. Check the upper rod bearing, they tend to wear more.
 
No, I saw the copper on the rod bearing and figured it was curtains. Gotta rebuild or replace the motor.
 
If you’re looking for an engine, put your location in. Chance are you’re too far away from me, but I’ve got 3 useable ones in storage. Can’t find anyone around here that wants one for free.

Like I said above, 60 years ago we were polishing journals in the car, dingle hones in the cylinders, and rings on used pistons. I’ve still got a ridge reamer my Dad had from cleaning up flatheads. Grandma told me that they came home from vacation early and he had an engine in the living room with sheets of cardboard under it to catch the oil. She was still miffed 30 years later.
 
miker98038 said:
If you’re looking for an engine, put your location in. Chance are you’re too far away from me, but I’ve got 3 useable ones in storage. Can’t find anyone around here that wants one for free.
Click to expand...

I'm in central Illinois. I may be willing to drive anywhere in the lower 48 to get one assuming the price and condition is good. Would prefer a 1959 292 block since that's what the car is.
 
You must log in or register to reply here.
Back
Top