Is this block a write off?

moppit · Post by **moppit** » Mon May 22, 2017 7:47 pm

Was getting a lot of vapour in the catch tank and fearing a head gasket or liner problem in my 3.5, I found this:

Engine is a recent rebuild (by someone else) so was not expecting this...

moppit · Post by **moppit** » Mon May 22, 2017 8:16 pm

bingo! my first picture eventually posted....

Post by **Rossco** » Mon May 22, 2017 8:18 pm

Bigger picture would help but that looks like some heavy corrosion there.

If the deck can be skimmed within reason then it's possible that you could save this.

moppit · Post by **moppit** » Mon May 22, 2017 8:29 pm

I assume complete strip down in order to check this? Is there no special filler or otherwise that could allow a repair in situ?

Can't believe someone built a new engine with a block like this...can't believe I bought it either...

moppit · Post by **moppit** » Mon May 22, 2017 8:32 pm

bigger picture...well you did ask....I cant figure out how to post mid size pic!

stevieturbo · Post by **stevieturbo** » Mon May 22, 2017 11:27 pm

Of course almost anything is fixable.

A light skim might be sufficient for that, as the corrosion doesnt seem to extend to where the gasket would really be sealing anyway.

If it was absolutely vital to restore material in that area, it could be ground out and built up with weld, again this would require machining afterwards. Although this might then disturb the metal at the liner....just wont know until you try.

or whip the liner out, weld it up and install a new liner.

But for DIY prior to paying for machining, I'd be getting a good straight edge and seeing just how bad that area is and how much might need skimmed or welded up to restore it.

With mucho patience you could effect a good DIY repair with a good flat block and varying wet/dry, some good files and the TIG welder.

But yes it is fixable.....some cheap, some not so cheap

moppit · Post by **moppit** » Tue May 23, 2017 8:27 am

Thanks Stevie, this gives me some comfort. Given that I already have a set of head gaskets a DIY solution seems like a pragmatic approach and if that ultimately fails then it's not cost me much. If it works then it gets me back on the road for a few months until I can budget for a new block...

Pulling the engine out right now in the middle of this good weather is going to mean the car off the road for weeks.

Actually, looking at the news this morning it makes my problem seem very insignificant compared to what others are going through...

Thanks for your help.

Simon

DaveEFI · Post by **DaveEFI** » Tue May 23, 2017 8:39 am

I've used Belzona to repair a damaged block face years ago - it was recommended by Rover. It's a very posh type of plastic metal. I dunno how long it lasted, though, as I lost touch with the car, a P5B.
But it was many, many years ago. I'd guess there might be even better products now.

stevieturbo · Post by **stevieturbo** » Tue May 23, 2017 9:52 am

Also, what gaskets are in use ?

standard tin or composite ? And where is the fire ring on each actually situated on your bore ?

unstable load · Post by **unstable load** » Tue May 23, 2017 10:47 am

I once used A4 MetalSet to repair a badly corroded head, you can drill and tap it once set, it's really tough stuff.

https://www.smooth-on.com/products/metalset-a4/

moppit · Post by **moppit** » Tue May 23, 2017 2:32 pm

stevieturbo wrote:Also, what gaskets are in use ?

standard tin or composite ? And where is the fire ring on each actually situated on your bore ?

Tin gaskets came off, I've got some decent quality composites from Paul at V8tuner to go back on. I plan on getting 20 thou skimmed off the heads to preserve comp ratio - is that right or should I go more? Block says 9.35:1, not sure on the heads I have.

Got a bloke coming round Thursday with a view to welding in situ - reckons he has done engine blocks before(?) If he has doubts then might explore the metal filler route - either mixed or heated. There are some low (300 degree) and higher temperature filler alloy rods that can be applied with a blowtorch - these presumably would sit somewhere in-between?

stevieturbo · Post by **stevieturbo** » Tue May 23, 2017 4:58 pm

Cleanliness will be the main hindrance to TIG welding, but it should be doable.

Chemical metal options...not really sure on that

Post by **Rossco** » Wed May 24, 2017 3:53 pm

As Stevie says if you go for the TIG route cleanliness will be a problem. Likewise the minerals/impurities in the alloy will start to precipitate out and cause a really bad weld.

The way to deal with that is to lay a thin bead of weld down then grind it out, do this 3 or even 4 times, this way the minerals and impurities should have all precipitated out. Leave time for the block to cool between each bead, the liner will carry a lot of heat and you could easily wash out a large section of the block.

Then lay small beads and build it back up slowly, again keep the temps down by allowing it to cool.

moppit · Post by **moppit** » Wed May 24, 2017 6:18 pm

Great, thanks for the welding tips. I'll see what the pro-mobile welder says when he gets here tomorrow afternoon. As long as the liner does not get displaced during the heating/cooling session then great.

Whenever I've tried to do anything with older ally castings the problem is always the porosity and the impurities that seep out when heated (eg. powder coating rocker covers horrendous experience!) so I'm under no illusions of this being a success. I'm thinking something like JB weld might be a safer option..

I have managed to locate a top hat 3.9 block as a last resort...but likely this will be £££

stevieturbo · Post by **stevieturbo** » Wed May 24, 2017 6:22 pm

And again...is that are actually flat ?

And if so, how flat where the gasket seals ?

If enough of it is flat already, then it might need no work at all.