One wonders where all the melted case went when he burned that big hole - inside your engine? It would have to a huge dia bolt and frankly tapping the thin case that deep to that dia without drifting off centre requires machines, you ain't going to hand tap it by eye with any success. Again, where will the swarf end up? Lastly, somewhere opposite that now huge hole is the oil supply to the oil pump. Your bolt would almost certainly block that too. That's also a problem with my sleeving suggestion, but at least with a sleeve you can cut out a hole for the oil pump supply. You probably get the idea that there will be no quick fix at this point unless you go for the slap some sort of compound over the whole area and hope it stays put idea... which might actually work. If you agree it's bust, you won't hurt anything by pulling the core plug out so you can see inside. Ask how it you decide to do that, it's quite easy with a drill, tap, socket and a bolt/washer. Don't try and pry it out, you'll probably snap bits off the case.
If you stick a long bolt in it, you run the risk of blocking the gallery/feed to the oil pump. That wouldn't be good. That case is scrap, I'm afraid. @Zed sums it all up above. Likely you will need a new set of main bearings if you find a decent used case or buy an (eye-wateringly expensive) new one. A decent recon is your best bet, IMHO.
Bearings come in oversize -outside bigger for machined cases, and undersize inside smaller for machined cranks and combinations of both in steps of .25mm up to about a 1mm I think each way so you need to measure your crank anc case and compare to specification in Bentley or similar..,
I did say it wasn’t going to end well … it’s a mag case and with the oil contamination and corrosion it was never going to weld .. if it was mine and I’ve done this before to a V6 Volvo engine that had a corroded hole in the side ( it lasted 3 years till car was scrapped ) would be to flatten the area as good as possible and make a patch out of 3-4mm aluminium and with a series of M3 /M4 bolts and a bit of RTV sealant bolt a patch over it .. As for you spark plug it will come out again and needs a timesert fitting , which can be done in situ using compressed air to keep swarf out .
So after removing the end gallery plug, this is what I am faced with. It seems that the hole is too far inwards and past the point where a horizontal end bolt could plug it without completely blocking the gallery. The thing that surprises me the most is how rough and corroded it looks like solidified jagged lava rocks. It is even all the way up the right hand side inside the gallery end where the outside wasn’t touched by the welder. Surely this can’t be just burnt thick solidified oil this is corrosion inside?
Use a short tube with a hole dremeled/drilled to face the oil gallery going across to the pump to sleeve the bore, Maybe slightly ream out the bore going in to fit the tube outer diameter, and to make a smooth internal surface. To make the tube fit, slit the tube and adjust it .. use e.g. copper water pipe as this is comparable with magnesium in thermal expansion, then flush the area down as much as possible with carb cleaner, and try and get the tube sealed into the bore with application of e.g. small but adequate amounts of JB Weld. Clear the gallery before the glue sets - you can take out the oil pump to get to the section going to the pump . Even use the Dremel to clean up the hole going to the pump if you feel you have partly blocked it. Not much to lose. I was going to suggest this before you took it to the welder. Then plug the end of the gallery with a tapped plug where theres still some meat. Otherwise, create a long threaded plug and then grind a wide U shaped channel in it for the oil. Drill and tap the hole deep enough, and then insert the plug and then rotate it so that the channel points towards the oil pump. Personally I would go for a sleeve and gluing as you can see what you have done before closing up the gallery with a plug.
I’m guessing this isn’t normal for a recon engine with less than 4k on it either? Had someone look at the engine and didn’t feel any end float at all. Could it have been the flywheel/clutch holding it tight when it was checked in the vehicle? https://youtube.com/shorts/vRaPsQC6jKA?feature=share
That case doesn't look in good shape at all. Looks like it's had water in it at some point? Be interesting to know where the "recon" engine came from. Looks like someone's rescued it from a farmyard
It wasn't reconditioned, it was slapped together with new bearings and a prayer. Either it couldn't be machined anymore or the geezer saved himself the money and you're picking up the tab. The rest of it is probably hopeless too, you were done over. Ebay purchase? At least the likes of even Elite VW actually have a machine shop so they can deal with the case. Your average shed builder does not so a line bore and thrust cut costs him - he'd rather have the profit so doesn't bother.
A symptom of the great case/crank/stock cam shortages maybe. No excuse but there must be people out there relying on selling "reconditioned" engines for a living who are like the rest of us hit with inflation etc and are sweeping the floor for parts they hoped they'd never have to use - desperate times. Or just a barsteward who realises most people only do 3,000 miles a year max and it'll be long gone before it let go.
That is quite hideous end float, and implies the case is beyond saving. As @Zed said, whoever did the engine didn't "recondition" it - they just slapped something together.
My case that had lived in a garden looked just as scabby, if not worse.. but as it cost me £51, and it was in reasonable condition where it mattered..the engine that I built had 0.13mm end float. Which stayed constant, although out of spec. The inside of the oil galleries would have been cast not necessarily bored, except where the plugs were pressed in to a bored section. So there will be rough finish and oil crud soaked into a porous finish. Impossible to weld unless its cleaned and baked to get rid of oil. But it did not have end float like that, except when the flywheel was hanging off because the bolt was loose.. That much end float is like the engine was just checked to be a runner and thats it.
What!? That one was also machined further in for the oil pickup - from the outside. The one I had to adjust was machined right though. I reckon that's 50 years of baked on crud in a dead end + aluminium welding splatter.
Is it possible the flywheel has been not spaced correctly? From what you guys are saying it sounds like a specified gap is put between the flywheel and back of the engine? I ask because I can see in the paperwork that someone has changed the rear seal behind the flywheel since the engine was replaced. Maybe they didn’t put the flywheel back correctly?
Unlikely. Even if you did it up with no shims fitted (assuming the "engine builder" bothered to fit any), I say it's unlikely you'd get that much endfloat. It's the end bearing moving in the case.
They probably changed the seal because with that much end float they tend to leak. The 3 shims total less than 1mm usually or maybe a tad more. If you can get the flywheel off you could of course check they are in there, but I think you might be clutching at straws. The flywheel nut is very very tight and if you get it off don't forget you'll have to tighten it up again to that spec 250 odd ft/lb.
