dry bearings on M20?

So I've added a second car to my GRM Trifecta: A cherry 1990 325i with 140K, Billsteins and Eibachs. There's only one little problem - The owner holed the oil pan, and drove on it for a while. The engine did not seize, and I have experience with a Miata motor that had the same thing happen and continued to run merily once it had oil pressure again. So there's some chance that it's not toast.

So how do I maximize my chances of salvaging this motor by priming the engine prior to startup? If the bearings are mainly dry, more damage will occur while the pump is building pressure.... The only time I've done this was on a 3.4 Chevy motor where you could pull the distributor and rotate the pump with a special tool.

IIRC these have a chain-driven (from the crank) oil pump, so you'd have to spin the whole engine to run that one.

I wonder whether you could do any meaningful oiling by pumping the new oil in via something like the oil pressure sending unit hole... I'm trying to think where you'd have access to the pressurized portion of the oiling circuit in hopes of backfilling the bearings...

OTOH, if it was run dry, pushing oil through the passages backward may be the last thing you want to do. I guess flow probably stopped about the same time the bearings were suffering any damage, but I can't help but wonder whether the last oil to leave the bearings wasn't carrying a lot of metal...

If it were me, I'd probably... Well, I'd probably wait for a better-informed answer right here on the forum. Failing that, I'd probably assume that being driven while empty was probably the worst that was going to happen, and I'd crank it for a while with the fuel pump fuse out to get some oil moved around and then give it a try...

I'd shoot some oil into each plug hole, turn it over by hand a pile of times. Turn it on the starter with the fuel pump off for a couple 10 sec bursts to build pressure and just fire it up.

BUT - before I did any of that... while the pan is off I'd pull one or two bearing caps checking for awfulness, look for scoring on the piston walls from the bottom, pull the valve cover and oogle the cam bearing a bit looking for more awfulness and splash oil on everything before buttoning it back up.

you might remove the oil filter and run a fitting into it... that might provide a route to the bearings....

Pull all of the plugs. Spinning the engine with no compression should put less stress on the dry bearings.

Put a fitting in the oil pressure sending hole and make up a line to attach to the fitting and secure it in the cap of a quart of oil. Screw the cap on a quart bottle and turn it upside down, put a small hole in the bottom and gently pressurize it with 5-10 psi. force all the quart back through the engine and you should be good to go. I have used this method for pre-lubing race motors for years.

It's just an M20. I wouldn't worry too much about it, just turn it over with no plugs for a minute and you should be fine. If it is junk, I'd suggest a dose of S50 B32, followed by donuts in a parking lot.

What Tom said rings true, in case you're looking for a silver lining. I was actually really happy with just a little old M52B28 over the old M20, and having the engine out is a perfect time to swap a quicker steering rack in. The slow stock ratio is one of my least favorite things about these cars.

But I digress...

If the bearings stayed oiled enough to not damage them during that event, cranking it over with the plugs out untill it builds pressure won't hurt anything.

Success! (I think). So I epoxied up the holed oil pan, then put on a layer of silicone caulk for good measure. I filled it with oil, took out the plugs and cranked… At first you could hear the laboring of the engine turning on poorly lubricated surfaces, then as oil pressure built, it turned more easily. Back in went the plugs, and it fired off. The engine ran very smoothly as I ran it around the block. Today I hope to pick up a used oil pan and gasket, and hopefully will have a fun runner for the holiday! Woo hoo!

Damn I love this car!

$1,100 so far

Seriously, Must have pics!!

I'm having trouble figuring out Picasa. Soon come, mon!

OK, I suck at computers, but as I understand it, Google + has replaced Picasa for file sharing and it won't let you link to individual photos. Below is through dropbox, so hopefully it'll work!

btw - what happened to the preview post function?

kreb wrote: OK, I suck at computers, but as I understand it, Google + has replaced Picassa for file sharing

Not quite. Google just made picasa a lot less convenient as they tried to make us all use Google+. You can still - for now - use the picasa interface by typing http://picasaweb.google.com

kreb wrote: and it won't let you link to individual photos.

Nope. That still works, too. I just hotlinked these.

kreb wrote: btw - what happened to the preview post function?

Press "enter" a few times after you insert your image. See if that helps.

That does appear to be particularly nice and has much BMW goodness. And it has many desirable features like fog lights, 2 doors, sunroof, alloys. Good score and what a price!!! I already have a Miata and a Cherokee, maybe it's about time I get an E30 and complete the trifecta?

Get one of those 5 gallon bucket hand oil pumps from Napa, remove your oil pressure sending unit, put a pipe nipple where the sending unit was, plumb it up to the bucket pump, and back flow the oil system while someone turns the engine over by hand