Flathead oil gallery warning

[Lynn Eades]

A month or two back, I was talking to another Kiwi forum member about a little trap we have heard about in the V8 motor.
So Andrew, here it is:

When you decide to find another block to build up, or pick up a complete motor to fit into your vehicle,the motor may have laying inside it a problem that may give you a bad day.
As these motors shift around from truck to carrier to car, they can have their oiling systems slightly altered enough to cause a bearing failure.
In a standard car the oil path is as Henry designed it, All internal.
However if the motor has been fitted in a carrier it will have an extra drilling above the existing oil gallery tappings at the back of the block.
If your new motor has this extra hole, then there are a couple of options as to how it is set up.
On the standard "gallery boss" at the rear of the motor are two holes. One is normally (externally) plugged, and the oil pressure sender unit is installed in the other.
If you remove the horizontal plug, there may be, further in, another plug.
It is critical that this plug, is in there, or not in there, depending on how you intend to have this engine set up.
In the case of the Carriers the oil flow comes along the main gallery and out to a (full flow) oil cooler(there is also a bypass valve, should the cooler become blocked) The oil returns through the 3rd (extra) plug. and goes on to lube the main and big end bearings.
To make the oil flow out to the cooler, there is a plug in the gallery.

I am not sure about the detail between the carriers I THINK?? the riveted carriers don't have a plug because, I think the long return fitting does the job of the plug. I need feed back on this.
I understand that the Australian carrier is fitted with a plug. This plug could be a solid plug, or have a hole drilled through it and act as a restricter. I don't have the details. (a restricter makes no sense to me)
I have been on another forum where a chap kindly posted this picture. It shows the use of a "full flow" filter system, which can only be used if the third plug has been added.
If you don't have an external circuit, and there is a plug installed, then NO oil gets to the crankshaft.
I would like to see the details of these set ups from an Australian, and from a Canadian carrier, preferably from what appears original.
Looking forward to some definitive replies.
Note: the "plug" I am talking about is identified in the picture as a "grub screw"

Ron, What details are identified in that good parts book of yours?

[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.

[Andrew Rowe]

Did some measurements today. Local Pattern New Zealand Carrier plug.
The plug is 7/16 inch long with a 3/16 inch hole in it. Thread is 1/4 NPT,
Has a slot at one end so it can be screwed into the halfway point in the horizontal gallery.

[Lynn Eades]

Alistair, The "boss" on the back of the engine in your large picture has two holes in it that are there for the gallery drillings, and are otherwise common.
The second pic. (59 block) shows the other "boss' undrilled. That is the one the small diameter long fitting goes in.
The next thing after we have confirmation of this, is the details of the drilling (hole dia.)

Andrew; thanks for the dimensions.

[ajmac]

Originally Posted by Lynn Eades

The second pic. (59 block) shows the other "boss' undrilled. That is the one the small diameter long fitting goes in.

I don't see why is would need to be any kind of special long fitting, the hole drilled into the blank boss just breaks into the main oil gallery / the far end of the horizontal drilling from the large boss. Could you post a photo of the fittings? I can compare with those found on mine. There is a good US site that explains how to modify a standard truck / car block to carrier spec. http://midstateantiquestockcarclub.c...t-heads10.html

[ajmac]

Here is the little blighter...

[Lynn Eades]

Alistair, Great clear pictures. Thank you! It seems you are correct , about the long one going in the outer hole.
Your fitting looks different to the one I have. (unfortunately mine is about as far away as you are from Italy) My one steps down in dia. and stays that way.
What is the part number on yours please?

I have checked in the later parts book (from Michael R)
(it gets tricky because the "engine oil cooler outlet" is the "oil cooler inlet" and vice verca, if you follow?)

The long one is CTL 7142 oil cooler inlet. It later became GAE 8741
The short one is CTL 7143.oil cooler outlet. It later became GAE 8739

I have not yet found any text confirming which fitting goes in which hole.

There is a picture showing the layout of all the cooler fittings valve etc. that someone might like to post for us.

My gut feeling is that the restrictor is all about feeding the mains . / big ends, while the cooler is filling.
I have yet to logic this out, to my own satisfaction.


Here is a picture from an un-recalled source.

[universalgrl]

If CTL 7142 is the long fitting then by the picture it goes in the outer hole.
That's my EWAG (educated wild ass guess).
I checked the two blocks sitting in my carport (one is a C59a block) and the gallery's are wide open no restrictors or plugs.
I have never seen the oil filter installation but to my mind you would have it in line first to clean the oil then send it to the oil cooler and back to the block cleaned and cooled.
But what do I know I'm only a Sheila

[Lynn Eades]

Thanks Roberta, that second picture was the one. It shows the long one on the outside.

[Lynn Eades]

Kindly sent to me by a forum member.
See picture.

[universalgrl]

Lynn
That is the missing piece of the puzzle , the pic that ties the oil filter assy in to the oil cooler assy. That will work on a universal carrier just fine.

[Lynn Eades]

Roberta, here's some more, all the way from near you. A spin on will do me, when the time comes.

[RichardT10829]

Hmm... This has me thinking... !!

[Lynn Eades]

The long fitting restricts the direct internal flow to the main bearings and diverts a portion of it through the cooler, just by the fact of the fitting partially blocking the gallery.
Btw. The cooler bypass valve is to let the oil flow continue should the thick cold oil of the day refuse to flow through the long lines of the cooler system) I have installed a full flow filter in my oil cooler line so that as long as oil goes through the cooler it is getting filtered (under normal circumstances, with modern oil, it will never "not" flow.
The two fittings found in the back of a U.C. engine block are in the attached photo.