Monday 5 December 2016

Cleaning the Engine Block

I used a wire brush on a drill to clean all the rust from inside the block - trying hard to get into all the nooks and crannies.
Removing the Liners Revealed Rust in the Block
I used a Dremmel (actually a cheap Dremmel copy) for those hard to reach areas around the bend. I also used a grinding head to remove the flash from when the block had been cast so that there would be better coolant flow when it was all re-assembled.

I used a gasket scraper to clean up the head top surface. There was some pitting where the gasket closed around the water ways. I also used the gasket scraper to clean the flat circular surfaces that the liners (and their delicate paper gaskets) would close against. These surfaces had some really stubborn stuff on and it took quite a bit of effort in the confined space to clean up the flat surface and vertical edges. It's vital this is done properly: if any bits are missed, the liner and gasket will not sit flat and so not seal properly when the engine is assembled. If this happens, coolant will find it's way down into the sump.
Flash Removed and Top Face Scraped
I used a wire brush on a bit of coat hanger to clean out the oil gallery. I removed the side plug and plug at the flywheel end, but not the alloy plug at the timing chain end. These have to be drilled out and replaced: I hadn't managed to find a source for the replacements and from advice I had taken decided to leave that one in situ. 

With the inside of the block cleaned I set about cleaning the outside.
Cleaning The Block - 4 December 2016
The domed cover over the oil breather was removed, as was the dip stick tube, the remaining hex plugs and the petrol pump mounting bracket. Again I used a wire wheel, wire brush to clean. Anything that got in the nooks and crannies.

With the initial cleaning done I hoovered everything out and also used some compressed air in all the narrow channels.

Sunday 4 December 2016

Dismantling The Engines (Part 2)

With the DX engine dismantled, I strapped it up and suspended it from my crane. Freeing it from the engine stand I lowered it  - still upside down - onto a couple of blocks on a work bench.

Using a block of wood and hammer I was able to remove the liners from three of the cylinders. Theses came out reluctantly and with the gift of large amounts of rust. 
Piston Liner Released
The fourth liner came out with the stuck piston still attached. With the piston and con rod still in place, there was no scope to push out the piston from the bottom of the liner. Working from the top end meant hammering on to the crown of the piston itself and meant that the piston might not be usable afterwards. it would all depend on how readily it yielded......

I placed the liner over the jaws of an open vice so that the con rod hound free below. As my hammer blows on the piston got more and more forceful I split several blocks of wood. The piston wouldn't budge. Taking a tip, I bought a plastic fence post driver from my local DIY store. And had soon smashed that into splinters. I bought ANOTHER fence post block from my local DIY store. Splinters. I tried heat. I tried freezing. I tried heat AND freezing. I tried going away for half and hour and then suddenly coming back to tackle it. Nothing worked.
That Troublesome Piston Soaking - December 2015
What finally worked was giving up for the time being. I put the piston/ liner combination in my appropriately numbered tub (that felt good), and tried not to think about them anymore. I moved the engine block to a bench in the other garage and turned my attention to the DX2 engine I had pulled from my DS.

The procedure for stripping the DX2 was pretty much as before, except that this time I had to remove the clutch and flywheel before I could fit the engine to the stand. The clutch was straightforward. The flywheel was more stubborn: I had to replace the clutch assembly bolts back into the flywheel and then use a bar to brace between them to stop the flywheel revolving. With that done it was placed on the engine stand for stripping. 
DX2 Engine - Preparing to Remove The Oil Pump - 18 November 2016
As before,  once stripped the engine was placed on blocks on a bench and the liners removed.
On Blocks - Removing The Liners - 18 November 2016
With this being my second engine strip, I didn't take anywhere near as many reference photos. I was, however, equally careful to put the parts I removed into labelled pots and tubs. 
Pots and Tubs
A few surprises along the way:
  • the tappets were badly worn and pitted
  • The bottom end of the engine was very glued-up with burnt engine oil.
  • The sump was similarly full of sticky tar. 
  • The main and big end bearing shells showed significant pitting and wear tracks
  • There were linear marks on the bearing shells where contaminents had gone through the oil ways and onto the bearing surfaces. 
  • Pushing the pistons through the liners revealed that there were broken top piston rings on two of the pistons (!)
  • There was some pitting on the engine block top surface
Water damage - Pitting In The Block Surface
The next step would be to clean everything up.........