Flathead oil gallery warning

[Bob Moseley (RIP)]

Hi Lynn - I was alerted to this years ago. In the early days hot-rodders used to grab Carrier motors for their vehicles. And lo and behold they very quickly cooked their motors due to this oil gallery plug that ran the oil through the oil cooler. My understanding is that it is a grub screw setup but never having to remove one I am not 100% sure.

Bob

[Andrew Rowe]

Good explanation Lynn.
Having removed many of these plugs on our production line, they all have holes in them, just off the top of my head the diameter is about 5mm, but can check.
It sits in the middle of the horizontal gallery when it bottoms out on the thread, between the two vertical galleries.
I think the reason that it had the hole was that if the cooler did get blocked there was at least some oil returning through the bearings.
One motor I checked recently was not running a cooler and it had a vibration when revved up, upon checking this engine it still had the plug with the hole in it.
( so was only getting small amount of oil to the bearings )
The vibration went away when the plug was removed, this carrier does not run a cooler but if it were fitted the plug would then be reinstated.
You could run cooler without this plug , but I presume it would not be that efficient as the cooler would only act as a bypass and the oil would not be forced through it to cool. Cheers

[eddy8men]

thanks for posting up the info fella's, that would be a costly lesson to learn especially for me as I've just spent a ton of money getting a 24 stud rebuilt for the carrier. I will be checking the oil gallery. cheers

rick

[rob love]

Yes, a very good point. After 70 years, engines may have been through a number of different vehicles and applications, from military vehicles to hot rods. A very good idea to check what was done and not done on a new to you engine.

[ajmac]

Agreed, 70 years of tinkering can lead to anything! Always check the details. Lynn, my 24 stud 3.6 litre flathead has a British mod, possibly the one you mention as 'on riveted carriers'. There is a waisted fitting that slips down the vertical bell housing oil pump outlet port this directs all oil flow (except the rear main and associated feed parts) to a cooler or filter etc and back to the horizontal bell housing fitting, as the vertical fitting is waisted oil can flow around it and into the main oil gallery. There is no internal plug or third threaded hole in the bell housing, i.e. standard truck service v8.

[Lynn Eades]

Alastair, I thought the long, waisted fitting went into the (top or extra) angled hole, and went down to the cam gear cavity, and that the short fitting went into the main supply from the oil pump(vertical hole.
You however say it is the other way around. Can someone back up Alistairs info to clarify this.
Andrew have you checked any 21 stud motors? (riveted carrier ones)

Just trying to get to the bottom of this for everyone's benefit.

[ajmac]

Lynn,
Here is a photo of the engine as I found it:


There is a standard 't' piece to mount the pressure switch and what looks like a normal fitting in the vertical passage, however this goes into the block around 1.5". For all I know this could be a post war mod, or a British Generator mod as this engine was used as an Altenator driver at some point. I will get a photo of the waisted fitting when I can and post it up. In my view the angled oil return hole used on carriers and a post war mod would just need to be a standard fitting.

The 59A block (1945-48) I have in reserve is a different casting with an angled boss ready to drill and tap into the main oil gallery.