18 replies to this topic

[Chelsea_Pete]

Hi all,

Could do with a second opinion on this one.
Had a couple of head gasket failures on my 1275 A+ between cylinders 2 and 3 so before replacing it a 3rd time I've had the head skimmed as suspect that may have been the cause after past overheating.

Question is whether it's worth getting the block skimmed too. I've posted pictures here. Running a flat edge over the offending area it appears flat, but as you can see there is some pitting there. Will be a big old job getting the block out to skim so only wanting to if necessary!

Photos can be found here!

https://imgur.com/gallery/AFNjbqr

Edited by Chelsea_Pete, 04 September 2022 - 11:17 AM.

[nicklouse]

Have you run a straight edge over the block to see what it is like?

 

I would go the whole hog and have it all rebuilt.

[Chelsea_Pete]

Hi nick, yes have done, straight edge shows it's flat, its more the pitting that has me concerned

Am currently thinking to rebuild with the now skimmed head and if it still goes again then to as you say go ahead and get the block done

[Avtovaz]

looks like that has run with out anti freeze in it at some point, the water ways have corroded on the block outwards. As a guess, the water has leaked from by no.4 into the cylinder and the gasket being gone between 2-3 is after that? I may be wrong on that though.

 

It take the head to someone who knows what they are doing, and when you put it back on, id use some head gasket compound on the block. Its a fair job to strip an engine down to skim the block.

[Lplus]

That pitting looks enough to be suspect.  I think if you have an opportunity to get the block skimmed it would be worth it.

[Chelsea_Pete]

looks like that has run with out anti freeze in it at some point, the water ways have corroded on the block outwards. As a guess, the water has leaked from by no.4 into the cylinder and the gasket being gone between 2-3 is after that? I may be wrong on that though.

It take the head to someone who knows what they are doing, and when you put it back on, id use some head gasket compound on the block. Its a fair job to strip an engine down to skim the block.

Youre more or less right yeah, had oil leaking out of the block around 4 onto the water pump so had the gasket replaced a few months ago, shortly after its blown between 2 and 3, twice.

Heads been skimmed now, am going to rebuild without doing the block too first off. Now I've been warned elsewhere about using compound, apparently a series with a good gasket (got the payen black type) shout need it?

[Avtovaz]

yes you are right , it shouldn't need it on a good A+, but you have one with corrosion on the block. 

 

If you where to skim the block, i cant remember, but do the pistons come to the top of the bore? If so, you may need either a thicker gasket, or the pistons skimming too. 

 

I think its worth a go with some sealer first, and check the rest of the cooling system also, if it had run with out antifreeze, the rad could be partly blocked.

 

i hope you sort it ;)

[GraemeC]

Have you fitted the new gaskets yourself each time? Do you KNOW your torque wrench is reading correctly?

[Chelsea_Pete]

Have you fitted the new gaskets yourself each time? Do you KNOW your torque wrench is reading correctly?

Hi, no they were previously fitted at a well established mini garage so trust they had the right torque

[Spider]

The block deck might be flat, but the surface finish has much to be desired. I feel it could do with a clean up.

When torquing down the head, it should be done over a few stages as well as in sequence. The factory advice is to pull it down in 2 stages, I do them over 4;-

 

 

Initially, while not your issue here, run the engine with water, not coolant, then after a couple of heat cycles, change out to coolant and at this time, re-torque the head, back each fastener off 1/4 of a turn, lightly oil and then pull down again, in sequence.

[gazza82]

Youre more or less right yeah, had oil leaking out of the block around 4 onto the water pump so had the gasket replaced a few months ago, shortly after its blown between 2 and 3, twice.

Er, cylinder 4 is the one at the left end/flywheel ... water pump is closest to number 1 ... makes a bit difference when you are timing it!

[Chelsea_Pete]

Youre more or less right yeah, had oil leaking out of the block around 4 onto the water pump so had the gasket replaced a few months ago, shortly after its blown between 2 and 3, twice.

Er, cylinder 4 is the one at the left end/flywheel ... water pump is closest to number 1 ... makes a bit difference when you are timing it!

Oops, yes oil leaking out above 1 I meant, thanks

[mini13]

apart from the pitting, the surface looks to have a load of marks in it possibly from over zealous clean up in the past, I think it really needs a skim,

[Cooperman]

It is interesting that the failures have occurred between 2 & 3, rather at the areas where the block deck surface is 'skanky'.

The corrosion is around the water transfer holes where the pressure is low, compared to cylinder and oil pressure areas.

Since it is a huge job for you to completely strip the engine and take the block to a machine shop, you could try rubbing down locally around the corroded hole edges, then applying some sealant before fitting the gasket. In fact, you could try some 'liquid metal', then file that flat and linish it. That can't make it worse, but it might hold the water pressure, if that is, indeed, the problem.

I know it sounds like a bit of a 'bodge', but I don't think the hole edge corrosion would be causing the gakets to blow between 2 & 3.

If it doesn't work you have only lost the cost of another gasket, but if it does work, you have saved a lot of money.

As Chris says, make sure the torque wrench used is calibrated, although, in truth, the old A-series engine is fairly tolerant in that respect and 'in the old days' I have changed head gaskets without a torque wrench and it always worked OK.

[weef]

Before you strip out the engine for a block skim you could try this.

Remove all the studs from the block and set all the pistons at mid travel. Put some paper towel or rags in the cylinders to capture any debris. Using a fine emery paper clean up the surface of the block face removing the worst of any marks/rusty surfaces.

Now get a new sharpening stone, the double grit versions are handy, coarse one side, finer the other. These stones are flat when new and are a good size to span the block face keeping things nice and square/flat.

After a few passes over the block face any low/high spots will be evident and depending on the extent of the deviation from flat will help you decide the best way forward. 

It may be that the stone will rectify the defects enough and leave a good surface.

Be sure to fully clean any abrasive residue from the bores after using this method.