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Cyl block damage repairable after blown head gasket ?

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Motion Avatar
Motion Gold Member Dale Spooner
Danville, VA, USA   USA
1977 MG MGB
IMO there's no way that will weld successfully. Welding always sounds simpler than it is. In this case, you have the parent block material and the sleeve material (undoubtedly different) that have both been essentially flame cut. You will need to grind much of it away to reach clean metal. Historically cast iron does not weld well cold. If you can even get weld to adhere, you will get cracks extending from the weld as it cools. This is why cast iron needs to be pre-heated in an oven prior to welding, welded while hot, then cooled slowly in a controlled environment. Of course the affect on the sleeves as soon as they see weld will be to shrink in away from the block, creating all sorts of issues that you cannot resolve. Hopefully by now you've already decided to go with a different block.


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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
So you're saying it will probably ruin the already ruined block? Where's your sense of adventure, man? I say heat the poor thing up with a rosebud and bronze it! (with previous disclaimer...)

If nothing else, the guy takes great pictures and it would settle the issue either pro or con. You always learn something when you step outside the norm.

Adrian

Edited 3 times(so far) for spelling!



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Edited 3 time(s). Last edit at 2018-04-30 04:16 PM by pinkyponk.

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chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
In reply to # 3727410 by Motion IMO there's no way that will weld successfully. Welding always sounds simpler than it is. In this case, you have the parent block material and the sleeve material (undoubtedly different) that have both been essentially flame cut. You will need to grind much of it away to reach clean metal. Historically cast iron does not weld well cold. If you can even get weld to adhere, you will get cracks extending from the weld as it cools. This is why cast iron needs to be pre-heated in an oven prior to welding, welded while hot, then cooled slowly in a controlled environment. Of course the affect on the sleeves as soon as they see weld will be to shrink in away from the block, creating all sorts of issues that you cannot resolve. Hopefully by now you've already decided to go with a different block.
Stove welding was the only thing I could think of that might work, didn't suggest it because of the low probability of success, and your explanation is good enough to convince me it won't work. I'm not real convinced on the brazing either.


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Rick Fawthrop Avatar
Rick Fawthrop Richard Fawthrop
Langley, WA, USA   USA
Dale what are your thoughts about the reliability of the big bore with sleeves compared to a 60 over no sleeve engine?

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HiPowerShooter Avatar
HiPowerShooter Gold Member James Booker
Lake Winneconne, WI, USA   USA
1973 MG MGB
I've done MUCH riskier fixes. Some have worked...some haven't. I know I'd give it a shot...I suppose it's all down to the individual's "stomach" for the risk but in reality there's only "reward" as at this point it's lost without any questionable intervention.

Some of the "liquid" ceramic's on the market are extremely hard and can be molded to fit/fill whatever you can get it into. Surface prep, pre-heating and proper cooling period are essential however I've seen some nasty cracks in blocks be permanently fixed with it. Between it and about 40 stitch pins...we saved an "ancient" Waukesha engine. Still running after a year as far as I know...

In reply to # 3727407 by pinkyponk I'm not sure I'm comfortable being described as recommending it. grinning smiley I certainly suggested it... and I would do it myself, if it was my block. Geoffrey needs to look into it, think about it, and decide for himself.

I'm thinking bronze would do the trick and be easy to get off later on... if need be.

Adrian



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Nickh6511 Avatar
Nickh6511 Geoffrey Huggonson
Orleans, France   FRA
Firstly, thanks to all you guys who spent the time to reply! Canada & US are clearly the main hotbeds of MG fever, far ahead of Europe, at least on this forum.
I bought the car (off ebay!!) to do some local low-level slalom competitions while having fun with a rear wheel drive which won't lose value. So I'm not looking for ultimate power, but a reliable torquey fun car. The spec is:
Stg 2 head, Weber 45DCOE, stainless 421 manifold, vented discs, uprated shocks, rest seems standard.

It seems like I've got 2 choices
1. Find a good welder who could fill up the gap by welding the liner tops together, then clean up, find a suitable gasket and put the lid back on. For a while at least...
or
2. Look for a block. This would ideally match with current pistons (i.e. linered and machined 84,2mm dia) which could be as troublesome as the current one. Or look for a 1950cc or smaller block and pistons to go with the existing setup.

Changing for another complete engine would seem quickest, but you don't know what you're buying until you try it (as I just found out).

What experience do you guys have with big bore blocks?


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pasraf Avatar
pasraf raf Vermeiren
antwerpen, Belgium   BEL
Geoffrey

I have 2 spare engine blocks, one 1967 and one 1968
nothing in it, just the block
one on standard size and one +40 (I think)
Best one is the standaard size....
problem is ...I live in Belgium
regards Raf


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sweep Avatar
sweep Gold Member Chris W
Gosford, NSW, Australia   AUS
1966 MG MGB "Basil"
2013 Volkswagen Tiguan
2015 Audi A3
Mate, it's on the same continent. Half a days drive one way. Go for it.

If it was mine, I'd certainly have a go at a bodge fix. Cast iron is a bugger to weld. I'd use a thin 4" cutoff wheel in an angle grinder and carefully put a slit between the sleeves. Fashion a thin piece of steel to slip in there and file it flat - a piece of glass with some valve grinding paste to get it smooth and level with the deck (or ever so slightly proud). Fill each side of that with something that will take the heat. Slap a gasket on, button it up and cross your fingers. As others have said, you don't have much to lose.

In reply to # 3727713 by pasraf Geoffrey

I have 2 spare engine blocks, one 1967 and one 1968
nothing in it, just the block
one on standard size and one +40 (I think)
Best one is the standaard size....
problem is ...I live in Belgium
regards Raf



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Rick Fawthrop Avatar
Rick Fawthrop Richard Fawthrop
Langley, WA, USA   USA
Geoffrey a patch job on that block is not going to work, period.
A 1950 engine build is common at my local MG engine shop. Right now there is a six week backlog of work.
In the US we have no builders of 1950 or larger engines with an exchange program that I am aware of.
I think you need to proceed with a tear down and assess the damage.
The exchange engine option in your case looks appealing to me.

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pinkyponk Avatar
pinkyponk Gold Member Adrian Page
Berwick, NS, Canada   CAN
In reply to # 3727783 by Rick Fawthrop Geoffrey a patch job on that block is not going to work, period.
A 1950 engine build is common at my local MG engine shop. Right now there is a six week backlog of work.
In the US we have no builders of 1950 or larger engines with an exchange program that I am aware of.
I think you need to proceed with a tear down and assess the damage.
The exchange engine option in your case looks appealing to me.

I don't know if I could repair that block or not but I find it interesting that you are absolutely certain it isn't possible. Is this opinion based on your numerous failed attempts to repair blocks with this exact configuration and damage? Or are you just guessing?

Adrian



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Mustangsix Avatar
Mustangsix Gold Member Jack Collins
Orlando, FL, USA   USA
I once had a similar failure on a small block Ford repaired by having the decks milled by about .020" to remove a little melted spot between two cylinders. We ordered new pistons with an adjusted pin location to give us back the same deck height. We also had to mill the intake a bit.

If it had been a run of the mill engine it would have been WAY more cost effective to find another block, but in this case it was a K-code 289 that was original to the car. It was date-coded and serialized to the car so we had to try and save it.

You MIGHT be able to fix this block, but boring another one will likely be less expensive than repairing this one.


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chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
In reply to # 3727702 by Nickh6511 Firstly, thanks to all you guys who spent the time to reply! Canada & US are clearly the main hotbeds of MG fever, far ahead of Europe, at least on this forum.
I bought the car (off ebay!!) to do some local low-level slalom competitions while having fun with a rear wheel drive which won't lose value. So I'm not looking for ultimate power, but a reliable torquey fun car. The spec is:
Stg 2 head, Weber 45DCOE, stainless 421 manifold, vented discs, uprated shocks, rest seems standard.

It seems like I've got 2 choices
1. Find a good welder who could fill up the gap by welding the liner tops together, then clean up, find a suitable gasket and put the lid back on. For a while at least...
or
2. Look for a block. This would ideally match with current pistons (i.e. linered and machined 84,2mm dia) which could be as troublesome as the current one. Or look for a 1950cc or smaller block and pistons to go with the existing setup.

Changing for another complete engine would seem quickest, but you don't know what you're buying until you try it (as I just found out).

What experience do you guys have with big bore blocks?

0.060" is as far as I have ever gone because the wisdom is that getting further out there you run the risk of boring through the cylinder wall due to core shift in the casting process. There are stories of people on the big bore quest going through multiple blocks trying to find one that isn't problematic. Good luck!


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Ryan Reis Avatar
Beatrice, NE, USA   USA
1968 MG MGB
Years ago my Dad (an experienced welder) attempted to fix a chevy block with similar damage by welding. If I recall, he bought special rods and used a stick welder. It did not work well, as the weld would not "stick" to the cast iron block. After making a mess of it, I actually think he put it back together with JB weld and got rid of the car as it was basically junk. It did run but can't speak to the longevity. I guess there's no harm in trying and failing, but you mentioned finding a welder so there's SOME investment beyond the cost of a head gasket involved.



Ryan

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Rick Fawthrop Avatar
Rick Fawthrop Richard Fawthrop
Langley, WA, USA   USA
The photos indicate the liners are cracked and the pistons are scuffed.
My opinion is that it is not cost effective to replace two liners, two pistons, a cast iron weld, and the machining of the deck surface and the top of the bore, and the repairs to the head.
If you can find a shop to do the work and find the parts.
But that’s just my opinion, actual results may vary.

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Burrell77 Avatar
Burrell77 Silver Member Craig Burrell
NH, USA   USA
Just as an FYI, there are welding rods made for ARC welders that are specifically for cast iron and you do not have to preheat to use these rods they are expensive. . or you can use castaloy rods with a propane torch . This would be the easiest to do.

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