Proper oil level in the valve galley

[bavArian]

Hello fellow A-ers,


I'm in the process of changing the oil and cleaning out the valve galley.
There wasn't nearly as much sludge in the galley as there was in the pan and I have it clean enough now.


I also did some leak tests to see if the main bearings were properly lubricated. For that I filled the galley with oil and let it sit. (cold engine, cold oil)
The part of the galley for the middle main bearing only took a few minutes until it was dry and all the oil had leaked into the dipper tray / pan. The front bearing needed around 20 minutes to do the same.

But: The rear part of the galley holds the oil. Because the muffler is still attached I cannot see the drain hole for the rear main bearing. It should be between the backside of the engine block and the last valve, correct?

I've attached 2 pictures of the oil level in the rear part of the galley. Is that about correct or do I need to look further into it?


Have a nice day,


Daniel

[Y-Blockhead]

Have you checked your main bearing clearances? The center likely drains faster because the center main bearing has more (excessive?) clearance.

And yes to the location of rear main oil feed hole.

[bavArian]

Haven't checked the bearing clearances yet. I'd like to avoid dropping the pan again if possible.

[J Franklin]

Call Roto-Rooter! Well maybe just probe the hole.

[bavArian]

I could probe the hole (already did that in fact), but that doesn't tell me if there's sth. down there which blocks the flow. Or is the drain tube so big that there can't be anything blocking it off. Haven't taken a look the inside of the bearings and the oil drain IRL yet, only pictures of it online.

[Benson]

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How fast oil runs out is deterimened by

OIL weight

wear in main bearing

wear in rear camshaft bearing if Service Bulletin installed.

If engine was made after May 1929 when another oil hole was drilled to rear camshaft bearing.

IF car was built after May 1929:
A. DOES IT HAVE SERVICE BULLETIN PAGE 242 AND 243 INSTALLED?

B. Does NOT have 242 - 243 installed?

[bavArian]

It's a '28 A, regular 40 weight oil now and as far as I can tell it doesn't have the second oiler hole from page 342/343 installed.
Is it possible to use compressed air to test if the oil drain is clogged or not? Or will that only compress possible dirt in the drain and lead to problems?

[J Franklin]

You could turn a drill in there by hand and it should bring up any clogs (auger), then use air.

[WHN]

I won’t be poking anything down the drain hole. Do you have a way to use suction to clean it out, or check to see if it is clean.

How was the engine running before you started taking thing apart?

[bavArian]

Currently I don't have any vacuum-tool to suck it out, but I'll see what I can get my hands on. Maybe I will find something.


The engine ran fine (albeit too rich). It did develop a slight knock after I changed the oil to 15W50 last year to clean it up some before the regular 40 would be filled in. (only driven it ~50 mls on short trips since then)


The knock is only present at idle and with the oil warmed up. As soon as you let it idle with a cold engine or rev it up slightly when it's warm it disappears. Didn't knock with the old oil either, so I'm assuming the new oil is simply too thin when warmed up. My plan was to fill in the 40 weight oil and check if it's still knocking before dropping the pan.

[jerrytocci]

Looks fine to me. You could stick the red straw attached to an aerosol can with break cleaner and give it a blast but clean the oil out first and put a white clean rag to see if ant debris comes flushing out

[bavArian]

Hmm, rather than break cleaner I think a proper lubricant would be better? Or is a small amount of brake cleaner in the pan not a problem?

[jack backer]

Your goal is to insure proper lubrication to your main bearings.Its important to state that oil clearance at the main bearing, set by the hydrodynamic principal at .001 per inch of journal diameter is the basis for bearing life, along with oil flow.The model A engine using poured babbit bearings has shim packs that allow you to adjust the bearing clearance for wear.This is important to perform with an 'unknown' engine.

[WHN]

Originally Posted by bavArian

Currently I don't have any vacuum-tool to suck it out, but I'll see what I can get my hands on. Maybe I will find something.


The engine ran fine (albeit too rich). It did develop a slight knock after I changed the oil to 15W50 last year to clean it up some before the regular 40 would be filled in. (only driven it ~50 mls on short trips since then)


The knock is only present at idle and with the oil warmed up. As soon as you let it idle with a cold engine or rev it up slightly when it's warm it disappears. Didn't knock with the old oil either, so I'm assuming the new oil is simply too thin when warmed up. My plan was to fill in the 40 weight oil and check if it's still knocking before dropping the pan.

I think your oil is to thin. How many miles on the engine?

If I get an engine with unknown mileage, I use 20w-50 HD oil and one blue bottle of STP for the last half quart. Plus MMO in gas.

Try it. This has worked for me for many years.

Enjoy.

[bavArian]

Originally Posted by WHN

I think your oil is to thin. How many miles on the engine?

Good question, next question please. :P


No idea, the odometer reads a bit over 6000 mls, but I doubt the engine is that new. On the other hand it does look to be painted fairly recently. That tells me absolutely nothing about the internals of course.
In 1st and 2nd gear it pulls nicely and can keep up in normal traffic, so I doubt it's on its last legs.

[Bob Bidonde]

The oil level in the valve chamber when the engine is running is determined by:
> A hole in the front wall of the chamber;
> The 1st dam in the chamber;
> Last dam at the back of the chamber;
> Oil return tube.
In many engines, the hole in the front web of the valve chamber is improperly cast, so it is out-of-round and or too large / too low which lets oil escape into the timing gear chamber. The oil pump flows much more oil than is necessary to fill the valve chamber plus the center camshaft bearing, and the excess oil flows out to the dip tray via the oil return tube.

[old ugly]

that rear bearing drain is elevated a bit above the gallery deck, and if that engine hasn't been drilled for the rear cam bearing oil gallery it will hold oil, but i would have to check a stripped block to see how much the oil level would be.
-on that rear main is the oil gallery hole below the oil level?
-can you poke a pc of mechanics wire down the hole to test if it is clear? (stop when you touch the crank) see if it is plugged with gunk.
-is there oil leaking out the rear main into the bell housing?
if the bearing clearance is correct, and all the galleries are draining to the mains, i don't think the drain rate is a worry as long as it is not to slow.(oil gallery plugged)

if the engine has a knock at an idle, a lot of the time it is a piston slap. this can be determined by shorting out one plug at a time. when shorting out a cylinder and the knock stops or changes sound that is the problem cyl..

[J Franklin]

Knocks can also be too much clearance cam to cam bearings.

[old ugly]

here is a picture of that rear oil gallery hidden behind the lifter boss. it is a bit higher than the valley floor.
i can't test the level for you because this motor has the cam oil hole and it leak out.
but this gives you an idea of about how much oil will remain in there.

[nkaminar]

Pull the engine and take it apart to make sure all the holes are clear and the bearings have the right clearance. The Model A engine is one of the simplest engines to work on. Why screw around? It is so easy to do a proper job. If it was running well then it means that a major overhaul is probably not needed, just a cleaning and adjustments. Maybe grind the valves while you are at it.