Anatomy of the Oil Pump, MMO

[JayJay]

G'day Barners.

First oil change on my new (to me) '30 Town Sedan I got quite a bit of sludge out of the hole before the oil started flowing. No obvious chunks, though. So I figured I would pull the pan and see how bad it was.

Not horrible, maybe 1/2" of sludge at the very bottom, obvious silver from the babbet but no large chunks. OK, cleaned it all out, cleaned up the gasket surfaces on the pan and engine, ready for new front and rear seals. All pretty straightforward.

I left the oil pump in the engine, but as long as I'm this far I'd like to clean the screen. Can I just remove the four cap screws on the bottom cover and pull the screen without all the guts falling out? I've looked at a couple of exploded drawings but it's unclear to me whether doing this will allow me to reassemble without pulling the pump (which I don't really want to do).

Second question - once I get it back together, I thought I'd run some MMO through the engine to help break down whatever crap is still in there. Is there an accepted recipe for this - how much, how long, etc.

Thanks in advance.

JayJay

[WHN]

I would remove the oil pump completely. Take it apart to clean and check for problems.

As far as MMO, I would not use in the oil. Just add a good high detergent oil and let it do its thing. Change sooner for first 500 to 1,000 miles.

MMO works great in the gas.

[BRENT in 10-uh-C]

The oil pump really needs to be removed, and you can then remove the lower plate at that time. The idler gear and the main shaft are very likely to fall out when the plate is removed if left up in the engine. If it falls onto concrete, it can break the housing.

You are treading on a very slippery slope IMO with the Marvel Mystery Oil. Do you really want to circulate any remaining sludge and/or debris thru the oil pump up into the valve chamber where it could potentially plug an oil line?? Use air pressure to blow up into the crankcase areas to dislodge any remaining sludge and flush everything with a solvent (brake cleaner, Varsol, etc.) while the oil pan still removed. Then reinstall the pan. Be sure and soak the front seal in oil for an hour or so prior to installing to prevent burning on start-up.

[john charlton]

When you remove the oil pan the pump should drop out with it . The plug in the crankcase side does not hold it and is not supposed to . You cannot service the pump when it is still in the engine it comes apart real easy . I put a mark on the gears so they go back as they come out . If you used the special tapered thread tool to hold the pump up thats fine dont use a regular bolt that will damage the thread in the block . I use a cable tie to hold the pump up around the back of the stalk when I put the pan back on as I dont have tapered tool . Clip it and pull clear before you snug the pan bolts up .

John in Suffolk County England .

[Big hammer]

While your at it remove valve cover and clean crud out of it also!

[Bob Bidonde]

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Big Hammer is right on! The valve chamber supplies oil to the crankshaft main bearings and the camshaft bearings. It is most important that this chamber is free of all debris, sludge, etc. Use a modern SAE 10W30 or 10W40 detergent synthetic blend oil to keep the engine clean.

[JayJay]

Well, you guys had it pegged as usual, and I thank you.

I removed and disassembled the oil pump. It was surprisingly tight - virtually no slop of the shaft in the bushings, no lash in the gears, very little wear showing on the teeth, shaft or bottom plate. A bit of large crap on the outside of the screen but easily cleaned. So, I cleaned everything up, new top gasket (it didn't have a lower gasket, but there was clearance on the gears without it), reassembled, and it popped right back in (I had marked the position of the slot in the shaft when I took it out). I feel good about it.

Then I pulled the valve cover, and I'm glad I did. Sludge, babbit fines and old stinky oil in the valve chamber. I cleaned it out, cleaned out the oil transfer line and the cover, and am ready to reassemble. I'll do a much better job cleaning everything when I tear the engine down completely to rebuild it, but this makes me feel much better about driving it in the meantime.

(BTW, Brent, the inside of the crankcase looks pretty good, no sludge trapped on any of the parts, and the rods wiggle equally but not excessively on their journals. Cam is definitely showing some lobe wear. I'll do a couple of doses of a fairly lightweight detergent oil (I have some 10-30) to try to bathe things out. I'll pass on the MMO at your and others' suggestion).

Again, all, thanks for your counsel.

JayJay