Rosy, a restoration project - Engine

24th October 2006

As I mentioned earlier on the rebuild of 'Rosy' I had had an engine built from an accumulation of spares that I had acquired when I purchased 'Flivver' and at various auto jumbles and friends, etc.  The engine that had had the crankshaft re-metalled and ground, as it was seriously undersize by .060" and still needed about .020" grinding off it to clean it up, had been done.  The company that had done this offered to do the white metal bearings so I agreed that they should go ahead and do the work.  There had been an article in the MG Octagon Car Club magazine about this company 'Holden Engineering' of Derby about them re-metalling crankshafts so that is why I was using them.  Unfortunately it is like recommending a restaurant to a friend after you have had a good meal there, when they go sometime later they have a terrible meal and tell you how terrible it was the next time they see you!  This was the scenario when I had the engine stripped down to find out why it was so tight.

tight piston piston with feeler guage
Pistons being forced against the bores.

When the big end caps were slackened off the engine turned over easily, when two of them were retightened the pistons were forced against the bore, this was the main reason for the engine being tight.  When it was further stripped down it was found that the con rod bolts instead of being 10mm in diameter they had been made out of 3/8" diameter bolts these were then .010" down and therefore allowing the big ends to float.  An oil groove had been missed out at the flywheel end of the crankshaft journal, this meant that the oil that would have been fed through to the clutch would not have done so, this would mean that as the clutch is a "wet one" it would not have been lubricated and would have burnt out.  But as the engine would have seized up because of the two tight big ends by then; that would have paled into insignificance.

The long and short of this is that the block, journals and big end would have to be re-metalled.  As Holden Engineering apparently are no longer trading I took it to Coventry Metalling and Boring, there it was checked by Graham Walker who confirmed what by now I had indicated to me.  The workmanship was in the words of Graham "Not of the quality required to do the job" or words to that effect.  Where the problem with the tight big ends had been addressed it showed signs of having been scraped, filed and emery clothed.  The edges of the big ends where they come together were no longer clean and therefore oil tight but 'feathered' and would therefore allow the oil to escape with a subsequent loss of oil and therefore pressure another reason why the engine would not have lasted 100 miles as that is what I had been informed by both my engine re-builder and the company now entrusted to do the job.

Journals and big ends
The main bearing and big end caps.

The next problem was the journal caps and con rods, too much heat had been used on them by the previous company and they were heat damaged and buckled so as to have scrapped them.  New caps and con rods were required also the centre bearing for the cam shaft had not been done and required re-metalling and as it was made from 'monkey metal' or by its trade name 'Mazak' that would need to be replaced with a phosphor bronze one.  Fortunately amongst my spares I found one and I took that and the old cracked block with me to see if it could be salvaged and the spares that were required to be taken off that block.  Yes they could and whilst they were at it could they use that crankshaft rather than the re-metalled one?  Yes they could and the work was carried out the engine rebuilt so that it can now be turned over with the starting handle!  But in the meantime my re-builder had found more problems that had to be addressed!

These fortunately were not too serious and he could deal with these in his own workshop.  First of all there was too much end float on the camshaft; this was resolved by making a thicker washer to stop it floating.  Also the push rods were bending when the rockers were operating so they and the rocker arms were adjusted accordingly and where fastening bolts for the sump and chain wheel cover were 'dodgy' he modified them accordingly.  All in all the engine is now rebuilt and it is timed and in theory when the carburettors are fitted, the silencer, the battery and a temporary fuel tank, I may be able to put power on for the first time in 35 years.  I can only hope!


Repaired block, view showing core plug side of block. The whole area of the block has been replaced. See photo of damaged block in the investigation section.
Repaired block showing view from tappet block side, two cracks were found on this side when the block was pressure tested.
View from overhead showing two of the stud holes 'filled in' by the welding process and the two centre bores distorted by the welding process. The block will have to be re-bored and sleeved and the stud holes re-drilled and tapped.

Scrap Block Salvaged

In the investigation of Rosy I mentioned at the end, that something to do in the future was to free the seized engine to salvage off it what was any good.  I eventually freed off the seized pistons, they had seized when water had got into three of the four cylinders and the cast iron piston rings had rusted to the cylinder bore.  As I had written in the 'investigation' I had used the cylinder head studs to try and move the pistons down after I had removed the crankshaft.  This had caused a piece of the block to break away where it had been weakened by a previous crack. You can see the damage in the 'investigation' section, but what you will not see is the extent of the damage caused when the block had frozen.  This was covered under several layers of 'Isopon' plastic padding that had been used liberally throughout the 60's renovation.  I should have scraped it off and photographed it but I never thought to and it never got recorded as I was of the opinion that although objects need never be scrapped, I had my doubts about the recovery of this block.  When I took it over to Coventry Boring and Metalling they said it probably was recoverable and they knew a man that would repair it!

It had been pointed out to me that it had been gas welded on at least one occasion before and where the piece had broken off, if you knew what you were looking for, would have been self evident.  Photographs of the welded block are shown on the left.

All that has to be done now is to bore and line it back to standard, re-drill and tap the two cylinder head stud holes and machine the head flat and I will have a block that has been successfully salvaged and can be rebuilt with parts off the original engine.