[Mg-mmm] MMM Engine News

[Bob Grunau]

Hi All,
Good news, bad news on the Canadian MG MMM engine front. List has been quiet
so I thought I would update listers.

A-J-3017 engine started reasonably easily after resting for over 30 years
and seems to run OK . Started easily alright after the dumb mechanic ( me )
figured out that firing order 1342 was different when the distribiutor shaft
is rotating clockwise viewed from the top. I'm using a Morris Minor
distributor for now as I had several and internal parts, except rotor plate,
are the same as MG TC so no problem . However it confused me as I had the
firing order right, but based on a TC anti-clockwise rotation of the rotor.
So cylinder 1 and 4 were OK, but 2 and 3 were reversed. Engine started,
tried to run, but immediately died.  Once I switched plug leads 2 and 3 it
started OK and seems to run OK.

B-NA-0686 engine has now been partially stripped, only crank to come out of
the block. You may recall the engine had a VERY expensive rebuild by a high
end shop in Mass. Engine had water in the oil from day one as the new
sleeves leaked water. I have purchased a new block and new Phoenix
crankshaft from the UK. Original engine rebuild had new 58.5 mm pistons and
new Phoenix rods but used the original crank. The rebuild engine had about
200 miles on it before the water problem was painfully apparent. So it all
has to come apart to replace the block and crankshaft.

Here is what we found so far, not pretty!!
1-removal of the water jacket side plates show about 1 1/2" of soft crud
lying in the holes. All water jacket plate bolts were tapped 5/16"BSF.  I
think this is the sediment from excessive amounts of some type of magic
radiator sealant used in a desperate attempt to seal the sleeves to block
leak. Sealant didn't work. At least 3 of the 6 sleeves leaked between the
block and lower sleeve joint. I will get the rad flushed out prior to use.

2-Home made ( shop ) top hat sleeves were used and the top hat lip is huge,
appears to be about 3/8" wide all around. Diameter of the top hat is well
beyond the gasket bore hole. Wonder what that did to block integrity? Also
photos taken during the sleeving pricess showed huge empty holes in the old
block to the extent that essentially no original bore remained. Weakened the
block? No matter, new block being used.

3-new 3/8" BSF head studs had been provided by owner but apparently some
block tappings were weak so the shop Helicoiled the block 3/8" NC and made
new head studs using an apparent 3/8" NC grade 8 bolt, cut the heads off,
and threaded the upper section with a very rough 3/8" BSF thread.  No wonder
some of the head nuts had to be worked all the way off with a wrench.

4-Original crank was ground 1.635" on the rod journals. Weird size. How to
fix? see #5, unbelievable!!

5-nice new Phoenix rods had a weird assembly of shell bearings. First an MG
Midget/Sprite shell bearing was installed using JBWeld between the rod and
shell. Then the bearings were line bored to enlarge the hole and additional
shells were installed INSIDE the Midget bored out shells. These inner shells
were four piece with an oil groove left between the halves, ( or is that
quarters ). In any case, six bearing shell pieces came out of each rod. Is
this some type of new technology or just a bodge?? Thankfully it appears
that they did not massage the rod itself so these should be OK after
removing the JBWeld.

As a result of all this, I need:
1-new set of 3/8" N Type head studs and nuts. Who is best supplier?

2-new head gasket. Old gasket is 0.063" thick copper/asbestos. Probably go
for a 0.060" solid copper. Comments?

3-MG Midget standard size rod bearings. I have to check, I may have these in
stock.

4-Pistons? new block has approx.  0.375" bore walls so can easily use
oversize pistons. What is recommended? Pistons in the block were 58.5 mm and
could be re-used as they look as new.  Maybe bore wall thickness and
cooling/heat transfer concerns dictates a larger bore? Seaking advice.
Piston supplier ecommended? Venolia in California??


All for now. Trust this is of interest.

Looking for advice as I have no experience with MMM engines but am trying to
learn .
Thanks, Bob Grunau
J-3017
PA-0531
NA-0686