Morris Minor
How Matt’s engine refresh escalated out of control
It was at the Goodwood Revival in 2018 that I took my Morris Minor’s engine block, crankshaft and pistons to the Owlesbury Crankshaft Services exhibition stand for MD Mike to cast an expert eye over.
At that point, the idea was to hone the bores and hope to ‘get away with’ the factory pistons. Mike’s eyebrows rose skywards, but he promised to take a look, have a measure, and let me know what he thought. I respect Mike’s opinion greatly, so,when he called to let me know his diagnosis, the plans for this ‘freshen-up’ changed drastically. Building an engine with known weaknesses would be a false economy and, as the car was a definite keeper, who knows what further tweaks it might get in the future.
The original A+ block was fitted with factory liners, as I’ve previously explained in PC, which sported a three thou bore-step in each. Given that this engine was to be supercharged, Mike suggested either fitting step liners or sourcing another block. I opted for the latter – a thickflange MG Midget block with the same two-inch
main bearings as the complete A+ engine I’d started with. OCS bored then honed the Midget block to accept my chosen forged, dished Omega pistons (the best pistons possible for the application – already the build was escalating) and skimmed the sump face of the block before line-boring then honing the main bearings. The con-rods were cleaned up, then the shiny new Omega pistons were sweated on, before each assembly was balanced end-to-end.
The crankshaft was ground before the full assembly – starter dog, new Vmaxcart twingroove aluminium front pulley, crank, flywheel and clutch – were dynamically balanced to allow free-revving and smoothness, as well as increase the lifespan of the engine’s bearings by reducing the internal centrifugal loads.
Hone and dry
Finally, after a line-hone, new cam bearings were fitted. The block is now as good as it can be.
Camshaft choice was next on the agenda and, after a huge amount of research, I plumped for Piper Cams’ METSC1 cam, which is specifically designed for supercharged applications and
promises a power band between 1700–7000rpm. I’ll team this with a Vernier timing chain, also from Piper, to enable me to set the valve timing absolutely spot-on. The next decision to be made will be the cylinder head. I’ve got two 12G940 heads on the shelf, so will get both cracktested before having one rebuilt with unleaded valve seats and valves, new followers, springs and proper valve stem oil seals. I’m also considering treating the engine to the ultimate finishing touch: a set of roller-tipped rockers. Watch this space.
As with any project that’s evolved as much as this one, I’m running so far behind that my original schedule has been torn up and thrown away. I’ll soon be heading back to CBR Classic Restorations, where the rolling shell currently resides (see PC, August 2019), for a big push on the body prep. In my absence, CBR’S Andy Waters has been further finessing the panel gaps I’d started to adjust at my last visit, so I hope to make some real strides.
Project snowball
Many of you reading this will understand the curse of starting along a path and not knowing where or when to draw the line. It’s like replacing a single piece of chrome, only to find that it shows the rest up. Then, when the chrome is all shiny, the paintwork looks drab Then it’s the wheels and interior. It’s a slippery slope but, let’s face it, it’s an adventure we all love. For me, this is a car I will never, ever sell, so if it takes a bit longer to get it right, then so be it. I don’t want a car with in-built weaknesses. Now, where did I see those competition half-shafts for sale?