Question on 1725 Oil Gally

[mark mcdonough]

Hi Guys,

I am new here so sorry if this is known folklore. I happen to be fixing some oil leaks from the side tappet cover on the motor and noticed something unusual. The oil drain pockets cast into the engine block in this area are all through drains except for the 2nd drain pocket which appears to be just a cast pocket. In the attached photo, the 2nd pocket (from the front of the engine) is just a pocket, whereas next to it, the 1st pocket is a through drain, as are all the remaining pockets in this area. Are all 1725 motors made this way?

Regards,
Mark

 

[puff4]

It's a casting flaw. All those holes should be open to the sump. Not sure how you can fix that without stripping down the motor, but I doubt it's causing any serious issues as-is.

 

[RootesRacer]

I dont think its even a casting flaw, every 1725 I have had was that way and they are always full of oil when I pull the side cover.

I suspect that the center main saddle merges into that area on the underside making a drain point problematic.

In any case, so very little oil goes down that way that so many drains are unneeded.

If there is any defect here its that Rootes didnt provide enough oil up top to necessitate more drain paths.

 

[puff4]

Well, all I can tell you is what mine looks like and what I've experienced in the past.

For example, here's the motor I'm building right now...

All of the passages are open, and I didn't bang them open. I'm assuming that those drains provide some additional lubrication to the cam surfaces, so the more that are open, the better, I figure. Of course, other lubrication to the cam comes from the drip hole in the lifter and the squirt hole in the right side of each of the connecting rods (though most of the latter will end up on the cylinder wall, as it should).

(For those wondering about the yellow/green coating, I always coat the inner oil-contact areas in my motors with epoxy. Makes for cleaner oil changes, less rust when the engine is over-wintered and less sludge accumulating in the motor.)

 

[mark mcdonough]

Oil Gallys

Very interesting. It also appears to my eye that the tappet bores on your engine appear to have a slightly different treatment to them. From what I see of your picture, your tappet bores appear perfectly cylindrical. Mine have a step in them atthe top, although I'd be the first to say I have no knowledge of the past history on the engine I'm now working on.

My overall concern is something that you rasied in your reply. It appears that the cam turns in journals just below these drain holes. From your photo, I can make out that the third drain hole from the front of the engine appears to have a lobe under it, or at least perhaps partially under it. It also appears from the close up photo that where the 2nd drain hole should be, there appears to be just the rough cast portion of the cam below this hole. Naturally I cant see any of this on my motor. Can you confirm this for my peace of mind? Thanks.

Regards, Mark

 

[RootesRacer]

Very interesting. It also appears to my eye that the tappet bores on your engine appear to have a slightly different treatment to them. From what I see of your picture, your tappet bores appear perfectly cylindrical. Mine have a step in them atthe top, although I'd be the first to say I have no knowledge of the past history on the engine I'm now working on.
Regards, Mark

That would be a tappet "wear" step.
You may need to buy oversized lifters and have your lifter bores reamed.

My overall concern is something that you rasied in your reply. It appears that the cam turns in journals just below these drain holes.
Regards, Mark

The cam in general turns below those holes, but think about it, the lobe are directly below the lifter bores, not those drain holes.
Oil that goes anywhere else (besides the cam lobes) arent going to do much good so far as the cam is concerned.

 

[puff4]

Very interesting. It also appears to my eye that the tappet bores on your engine appear to have a slightly different treatment to them. From what I see of your picture, your tappet bores appear perfectly cylindrical. Mine have a step in them atthe top, although I'd be the first to say I have no knowledge of the past history on the engine I'm now working on.

You may have an actual metal ridge because of wear, but frankly I doubt it... I suspect you just have a build up of burned oil on the unused portion of the tappet bores. Try scraping it off.

As to mine, I have honed the bores and had tappets made to fit very precisely. I'm building this motor to a *very* high standard, so the clearances will be pretty tight. (My crank's main bearings, for example, are clearanced to 0.0015") You don't need to really have special tappets for a standard motor, and tappets can be somewhat loose in their bores with no real issues.

My overall concern is something that you rasied in your reply. It appears that the cam turns in journals just below these drain holes. From your photo, I can make out that the third drain hole from the front of the engine appears to have a lobe under it, or at least perhaps partially under it. It also appears from the close up photo that where the 2nd drain hole should be, there appears to be just the rough cast portion of the cam below this hole. Naturally I cant see any of this on my motor. Can you confirm this for my peace of mind? Thanks

There is no lobe under the drains - they're all under the tappet bores, except for ONE... the fuel pump cam *is* under the oval front drain and that one, IMHO, *must* be open. However, as oil runs down the drains and directly onto the camshaft, it's likely that it will be then slung off and drip down onto the nearby lobes anyway. But this is not the primary lubrication of the lobes - that's done via the tappet weep holes, so it's important to make sure those are clean and clear on any tappets you service.

If it were my motor and I was doing a full strip-down I'd use a punch or grinder and open those vents. But I don't think it will cause any serious issues leaving it as-is until you do.