Metal stitching

Ron, we are all hanging on with bated breath to see how they come out. All I can say after seeing those cracks, better you than me & if this was'nt a family friendly forum probably something worse. Good luck Ron & I hope you do Mammoth proud. Cheers Tim

yeah c'mon ron...yer draggin' the chain a little bit aren't ya.

don't quite know if it's the concrete floors or something but the dear old frame i'm carrying is really starting to feel the pinch!! :-[ :-[

and some rotten thing from left field (like the grinder you mentioned) can stop a bloke fairly smartly.

Given that you seem very accident prone, perhaps weekly reports just so we all know you havent accidently killed yourself working on these blocks.

I have just returned from a sojurn in New Zealand's south island and will post elsewhere about that later when I have some pics. There is a firm there advertising in their old car magazine (Beaded Wheels) cast iron welding by powder spray process.

If it is available in NZ, is there anyone here doing it?

O.K. - I've finally managed to commence a serious attack on these cylinders. First job is to soak the coolant passageways with some mild hydrochloric acid solution.

I blocked off all the openings with pieces of tinplate glued on with Selleys polyurethane sealant, and covered all the cracks with it as well.
Fantastic stuff, sticks like the old proverbial you-know-what, to a blanket.
Then after I finished smearing it every where, I read that it contains iso-cyanates! Yes, the same nasty stuff that's in the hardener in two-pack polyurethane paint! Hmmm .. :

I know this doesn't look particularly professional, but it's the only way I can ensure the coolant passageways can hold the hydrochloric acid solution without it leaking everywhere.

The scale and corrosion inside the coolant passageways is worse than anything I've seen in any motor in the last 40 years.
They might as well have been dragged in out of the sea, where they have been for 40 years, for all intents and purposes.

Previous owners or operators of the truck have taken not the slightest bit of interest in caring for the cooling system. I'd say they've been using brackish water, and probably, muddy, brackish water at that.

The cylinders have to go outside while the acid is doing its job. Hydrochloric acid is potent stuff, the fumes will rust anything within 10 metres inside a building, and the main gas given off as it decomposes, is chlorine. It's nasty stuff, if it gets in your lungs.
So, you don't want this stuff doing its work, inside a building. A well-ventilated area is called for.

In addition, you need to wear protective equipment when using it, and you can't use it if there's kids around, unless you have a lockable area to keep them out.

The coolant passageways were filled with about a 2.5% solution of hydrochloric acid, and left for a week.
As the solution evaporated somewhat, I added more high strength acid (32%, from the bottle), so the solution strength probably went up a little, over the week.
Radiator crowds use about a 3-4% hydrochloric acid solution to clean radiators, but they usually only dip the radiators for a few hours, at most.

The aim here is to get all the scale in the block properly softened up at least, and hopefully, largely dissolved.
The problem is that scale comprises a mixture of iron compounds, and some of those are particularly difficult to break down.

We got 20mm of rain last night .. and with the cylinders being out in the open against the side fence, they promptly went rusty, and look terrible. Not to worry, it's only surface rust, we'll treat that later.

O.K., today I drained all the hydrochloric solution into a bucket (to be neutralised before disposal) .. ripped all the sealant-retained plates off .. and pressure-washed all the coolant passageways in the cylinders.

The result of the hydrochloric acid treatment is initially, quite pleasing. Vast amounts of scale and corrosion have been removed, and serious amounts of much cleaner metal is showing.

However, the acid hasn't dissolved all the scale. A lot has been loosened, and it's coming out with constant and repeated pressure washing.

The bottom pic shows some of the scale that the pressure washer removed. Some of those chunks are nearly 4mm thick, and the bolt for size reference, is a 3/8" x 1" bolt.