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MG TD TF 1500 - Real difference between XPAG blocks

I have a lot of spares hanging around that I can use to build up a spare short block. I have both - the round hole and the banana hole.

Beside the water holes, what is the EXACT difference between the blocks? My banana-hole block has wet sleeves (2 & 3) and is approx 1340 cc, but if not as good as the round hole, than I would err on the side of prudence.

Do they both have the vapour release hole in them?

Gord Clark
Rockburn, Qué.
Gord Clark

What is a "vapor release hole"?
Gene Gillam

Best to read Neil Carins treatise on the XPAG, lots of small differences during TD production alone. Early blocks: two vs three oil filter bracket holes, I think oval blocks had both kinds of oil filters, and supposedly the round holes don't have the MG cast in. You almost need a spreadsheet to chronicle all of the changes. If one is not sleeved, I think that would be better, depending on bores. Of course need to crack test, check deck for flatness, main bearing housing bore/diameter, etc. etc George
George Butz

Gene,

The Vapour Release Hole is a tiny hole high in the block between water jackets. Its almost invisible, but should nonetheless, be kept clear to allow for vapour transfer to prevent pressure build-up in any one water jacket.

I have a picture of it, but despite a thorough search, couldn't find it. When I do, I'll post it. Maybe someone else has a pic ??

Gord Clark
Rockburn, Qué.
Gord Clark

That's a new one on me, Gord. I've never ever heard of it. Love to see a photo if you or someone else can provide it.

Gene
Gene Gillam

Gord, is there just one vapor release hole in a block or several? Where would one look for its presence?
Jim Merz

Yup. Its for real, but that's why I was asking about the differences in the XPAG blocks. I'm not sure which one, if not both, its on. And as far as I can recall, there's only one hole.

I'll have a better look for the photo. It may be on an old IDE hard drive, that I've archived years ago.

My spare blocks are stored with all my A;fa stuff and other old car stuff (Abarth, Ferrari, Porsche, Jag, etc, etc.)I should have disposed of years ago, and its not at my house.

... stand by ...

Gord Clark
Rockburn, Qué.
Gord Clark

Gene, I think he means the hole in the bottom front and back of the water passageways under the core plugs, which can be drilled if missing. George
George Butz

Those are in the this link: http://www.mg-tabc.org/library/the_hidden_water_passage.htm

I know all about those 8^)
Gene Gillam

George is correct.

The TF 'round hole' blocks have two(2) holes,one toward the front,one toward the back. They are often totally blocked and difficult to see.
Careful use of a hand drill/punch will eventually show up the hole for
total clearance.

Banana blocks in my experience only have one hole.Can't remember whether it was located at the front(side) of the block or toward the rear.

BTW, not all facts on the XPAG written by others are correct!

Gordon,hope this helps you in your quest.

Cheers
Rob Grantham
TF3719("Aramis"),TF9177("Athos").



R GRANTHAM

Hey Gene and Rob. Problem solved.

Thanks.

Gord Clark
Rockbu4rn, Qué.
Gord Clark

There is one big structural difference in the blocks. The early (banana) blocks have a horizontal strengthening web about half way up the water jacket, while the later (round hole) blocks do not. Some would say that the early blocks might be better for mods where BIG wet liners are fitted as that web would help support the liners half way up. I assume the omission of the web coincided with the change to round water holes but I am not certain.

Bob Schapel
R L Schapel

Did you mean these 2 holes in the block behind the front and rear lower core plugs?
Found on Bud Krueger's TTalk Site
http://www.ttalk.info/XPAG_Cooling_System.htm
from an entry by Gene Gillam.

Rod

R. D. Jones

This thread was discussed between 18/08/2015 and 20/08/2015

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