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MG MGB Technical - Engine bolck

HI All
I need advice here on weather i should proceed by getting off the engine block to skim or not...
i noticed there was cooling fluid in the engine oil so decided to remove the head to check, the two middle spark plugs were also rusty, so i see the fluid entered through between the two middle cylinders as you can see picts.
yet i run a clock on the surface were its damaged and there is about -0,01mm runout.
my question is weather i should proceed by getting off the engine block to skim or not..
if so what is the best way to get it off the car with or without gearbox.(the clutch is ok).
thank you.


a rodrigues

another picture

a rodrigues

Are you sure its the block that needs skimming and not the cylinder head?
I K Jackson

Rarely does a B block require skimming. They have a very high nickle content and are extremely strong. They can usually be cleaned up with a straight edge and some light wet/dry sandpaper. The cylinder, head on the other hand, is a common place to find a bit of warping. I'd recommend having it skimmed about .010" to bring it back to a straight, smooth surface. RAY
rjm RAY

Given how much more work it is to remove the engine & have the block skimmed, if it were my car I'd try the head skim as above and see how it went. It is probably all that's needed, but in the event that it isn't all you have lost is the cost of the head gasket and a couple of hours' work.
Paul Walbran

the engine head is not as bad..

a rodrigues

cilinders needs cleaning they already 0.4 oversize

a rodrigues

i mean pistons are 0.4 oversize..the bad ones are the 2 on the midle.

a rodrigues

At .01mm (that's .00039") runout there is no need to skim the block. As for the head, check not only the runout in between the cyl's but across the full length and width and skim if needed.
What do you mean by "cyl's need cleaning"? Unless you remove the pistons to "de-glaze" the surface, there´s not much you can do. If you do removed the pistons and the cyl wear is acceptable, I would fit new rings. Are the pistons .4mm over size or .040"? .040" is only one rebore left (without liners).

Best of....
MGmike
M McAndrew

Classic symptoms of a bad head gasket failing between cylinders two and three. The cleaner looking pistons are due to water getting into the cylinders--an old method of decoking (decarbonizing) the cylinder head and piston tops. Check the head for straightness, have it skimmed if necessary, and install a Payen head gasket properly torqued down.

Les
Les Bengtson

this job was done recently about 2000km from some body else, the head was skimmed and new gasket fitted but was not done properly, the head looks still, Les is the Payen gaskets diferent than the normal ones we buy??
Mike about the cylinders they need clean up because the car stood for some time and the water run into them. see picts above.
you right ist 0.040...

a rodrigues

I've been having a good look at your pictures and on close examination of the head it can be seen that the pitting has started to creap in under the area where the sealing ring of the headgasket has to seal
The head will need to be machined to restore the surface
The block doesn't look at all well with it eaten away under where the firing ring of the gasket has to seal as well
It looks ok where the front of the firing ring sits but has been coroded from behind probably by coolant that has been in there too long in the past and become corrosive
Really the engine needs to come out and have the top of the block machined
If not it is going to keep failing on you
The bores can be cleaned up using some wet and dry sandpaper about 320 grade is good and some kerosine
Just get the piston right down ,put some rag down in there and then clean the bore up with you wet sandpaper rubbing round the bore or figure 8 patern NOT up and down
The only possible way that I can think of restoring this block to a useable condition while still in the car is to get someone in your area that builds race engines to have a look at it
Your only savior here is that it has been corroded from behind leaving the front part of the sealing edge in resonable condition Therefore he should be able to ''O'' ring the top of the block and save you the job of pulling the engine out
O ringing is a process where a groove is cut into the block around each cylinder and a small diameter wire ring is inserted around each cylinder roughly around the
area where the rear or the sealing ring sits
cheers willy
William Revit

Also check the head for cracks, this is common.
Allan Reeling

BAck on business, i run a straight edge and feeler gauge on the block surface and there is a deviation of about minus 0.03 to 0.04 thou on the middle, put the head on just tight 3 bolts on without the gasket an i got the same reading..
also check the head gasket and no deviation at all( was skimmed about 2000km ago.
i measured the thickness at cylinders side on the old gasket( unbranded one)and noticed that on the middle its thinner than the rest about 0.02 thou.
So iam stuck here what about if i use a better Payen head gasket and give it a try??
thanks

a rodrigues

head

a rodrigues

block

a rodrigues

gasket top side

a rodrigues

old gasket bottom side

a rodrigues

Back... i really need to remove the engine because the nē2 cylinder is badly pitted cant clean up, now they are already 0.040 oversize, how much can i go over before re-sleeve??
Also what is the best way to remove the engine,complete or just off gearbox set up??Thank you.
regs
Alfredo
a rodrigues

Alfredo,
As mentioned earlier, .060" is the next step and that's the last one! If you don't get a clean bore at +60 it's time to sleeve or you could just jump right in and increase the capaicity to 1950!

Check out the Moss web site for more info...
http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=188

and

http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=12879

Best of...
MGmike
M McAndrew

forgot to say....
Engine out on it's own is easier but getting it back on the gearbox in situ can be difficult.
you choose ;)

Best of....
MGmike
M McAndrew

thanks Mike, i may get the engine complete out...the trouble i havnt got a shop lift..
do you think is necessary to do the big crank ends too?
regards
Alfredo
a rodrigues

That all depends on what you find when you strip it down and measure the crank. New bearings would be the minimum I would do but if the crank has any wear or scoring, a re-grind will be required.

Have you had this running to find out what oil pressures it produces?

As it's had a re-bore at least once before you might find the crank has been reground as well. Fingers crossed for you...

Best of...
MGmike
M McAndrew

Mike
the was running and oil pressure was good around middle scale...will see what happen and keep this posted here...this was my first classic i got it for about 14 years, needs a restore...i might do it now since iam going to strip most of mechanical, its a 71 model low suspention, i like this more than the Le on the picture...also got a honda s800 67 model very nervous car but, i prefer the mgb to this honda...i will post the mgb pict just now.

a rodrigues

mgb 1971

a rodrigues

I'm coming to you for a holiday and to try the honda.... Looks like fun ;)

Best of....
MGmike
M McAndrew

Mike u are welcome to try it
...i have started to strip the car, got the engine out and gearbox apart, when i drain the gearbox oil 2 pieces drop out a spring and i suppose to be spring housing, to me they are ufos...any ideia where this come from?? the car was running and gear shifts ok...
Alf

a rodrigues

I think since i got the engine out iam going to give the car a restyling same as the white one..

a rodrigues

Those parts look like the lever damping spring and plunger to me, they can fall out when you remove the gear lever from the remote housing.
Paul Hunt

ok Paul i will check tomorrow, thanks
a rodrigues

PAul that plunger is on there, i had a look at the parts manual i see nothing close to that, this springs fits in halfway in the plunger...its a 4 syn gearbox with overdrive.
a rodrigues

This thread was discussed between 20/09/2014 and 04/10/2014

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