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Nollaig

RB30 Block problem

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Hi,

Just came across this RB30 block with a bit of an issue.

Not much damage apart from the hole in the block, any ideas on what caused it?

I'm contemplating welding the hole up and rebuilding it with standard rods and pistons to see how it holds out. 

RB30's are hard to come by where I'm from.

Is it worth it, has anybody done anything like this to any other block?20201022_183044.thumb.jpg.c1c7157a774b47fad4c5a4cf29b6cfa4.jpg20201022_183101.thumb.jpg.cbc287c3e68f90283ac83c083e23fb7f.jpg20201022_183132.thumb.jpg.9e2cecdf52e0bcecb6db5b183e66d8d2.jpg20201022_183143.thumb.jpg.bb5ee3a267299fecf6e27e12bd110305.jpg20201022_183201.thumb.jpg.b6d72f0b850b0d5e64ff4c8f7a39c13f.jpg

 

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Are you sure its fatal, crank is perfect, bore is perfect. Weld it up, add a conrod and we'll see how it goes.

My only concern is where it will be welded is the area where the engine mount goes. Just have to heat, weld , peen and heat treat properly.

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Block has been horribly compromised. Significant stress in the casting where that force was applied. Probably deformation.

The only reason to use an RB30 block is to make bulk power. Who's going to want to trust that block to stay together?

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I've seen (and done) old cast iron blocks welded up before and it can be done . . . . however . . . 

if you really want to save it then you should get the block crack tested before you start.

As GTSBoy states no point in welding up the hole if there is structural cracking in the surrounding areas.

As to welding you will have to find the best cast iron welding rods (or wire) that are as close to the parent metal in the block.

Then find yourself a specialist cast iron welder

You will also have to heat the entire block up to a very high temp over a long period of time and hold the temp there while it is being welded.

Then you will need to bring the temp of the block down very slowly to avoid cracking.

One method I have used for this is using heated sand, which you place the block in and let it cool over a day or so back down to ambient temperature.

Another method is to braze the broken piece back into place.

This is a specialist welding method also and will again require the above heating/cooling method.

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Thank you PLYNX, I was hoping someone had actually seen this done before.  I'm a welder by trade myself and a welding inspector so I believe i have the ability and the knowledge to do it. Also I know a few welding engineers that will help with the composition of the welding rods required.

Crack testing here we come.

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Be sure NOT to sand blast the block clean as it can leave residue in the porous cast iron which can affect the welding process.

If you are going to attempt the cast iron welding yourself. best to practice on scrap cast iron first.

As you say if they are hard to find where your at you'll only get one shot at it to get it right so your preparation work is paramount. 

Just out of curiosity where are you located ?

And looking back at your pics, my guess would be a rod bolt failure.

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Here is a couple of pics of the inside of the block from the sump side.

I dont think the dent at the bottom will interfere with the piston skirt so I'm going to give a go at the welding and see where we go from there.

20201023_172401.jpg

20201023_172354.jpg

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Bores being perfect might be a bit of an overstatement!

I'd be pretty dubious about welding this, the last of the guys who I would've trusted even attempting this repair used to operate a backyard furnace in the 70s and the last of the partners died about 20 years ago.....all the good ones here were ex-railway workshop it seemed.

If the thing is anyway salvageable and you're desperate, machining, tapping and gluing might introduce far fewer stresses. One Ayrton Senna, won a championship, running just such a repaired engine which had a serious  "alternator failure" at one stage.

 

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On 24/10/2020 at 3:27 PM, 2pee said:

One Ayrton Senna, won a championship

He also died apparently because of a re-welded steering column.
I'd get a another block/engine/V8
or get a billet block yolobro

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On 10/26/2020 at 7:23 PM, niZmO_Man said:

He also died apparently because of a re-welded steering column.
I'd get a another block/engine/V8
or get a billet block yolobro

Ha, the prosecutor's line! ☺️ 

Surprise, surprise, story is online even, patch

Do agree, this bloke (in the US?) would be better off biting the bullet rather than trying to resurrect crap.

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On 26/10/2020 at 9:23 PM, niZmO_Man said:

He also died apparently because of a re-welded steering column.
I'd get a another block/engine/V8
or get a billet block yolobro

Pretty sure you cant run the billet block on the street.

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1 minute ago, Predator1 said:

Pretty sure you cant run the billet block on the street.

Really ? Why not ?

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I'm not sure, I've been advised that its a 'race only' block, and its not suited for the street. I've been trying to dig up info on this but no-one seems to want to disclose. I also heard that some people advised on pre-heating the coolant prior to starting or some crap.

Another thing I found is that billet blocks need lots of oil pressure(dry sump) as apparently the clearances become tight when at temperature.

These are just claims I've heard, so I don't know how accurate they are.

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