In September 2022, my rebuilt engine suffered a blown head gasket at around 5000 trouble free miles. When the head was removed I checked the cylinder bores and found deep scores in number four cylinder. This led to removal of the engine and a complete strip down, which revealed that the number four little end pinch bolt had worn away, allowing the gudgeon pin to oscillate sideways, hitting and damaging the bore. See photo below.
As the block had been bored out to the maximum, the option was to sleeve the cylinder or use a spare 1500 block that I had. The decision was to use the spare block bored out to take the other engines pistons and other internal components, as they had only done 5000 miles. The crankshaft was in good shape, so only new bearings were required.
The block was machined and the engine rebuilt over the winter of 2022/2023 and I finally got it fitted in April 2023. Unfortunately, (long story short!) on it’s maiden test drive, after 40 miles, the engine stopped and was found to be seized solid. The engine was removed, stripped down and it was found that it had been significantly under-bored and the piston/ring gaps were too small, causing overheating, damage to pistons and bores, with swarf causing failure of the front crank bearing. Not good!
The machine shop were guilty of the underboring, but I failed to ‘gap’ the rings before assembling. The engine when built up turned over ok, so I was happy….error.
As a result, I decided it was time for me to give up doing it myself and spend money on a professional MG expert built reconditioned engine. I researched the UK market and decided upon Skiptune, who have been building MG engines for over 40 years and have a fine reputation.
At this point I had to make the decision as to whether to go for a later MGB 1800 unit, or stick with the original 1500. I’ve always been an advocate for the 1500, which is a far sweeter engine than the harsher 1800, but I was tempted by the thought of much more power and an oil tight engine.
However Peter from Skiptune convinced me that they could make a great engine from my 1500 unit, giving it around 90bhp.
The chosen spec was:

Increase capacity to 1588cc

Piper 275 camshaft

Balance pistons, con rods, crankshaft and clutch plates

Cylinder head skimmed, larger MGB inlet valves, ports and chamber previously reworked.
In addition the valve gear/rocker assembly was reconditioned, the block was caustic cleaned, all oil galleries cleaned and all machined faces eg block, manifold, head, re machined.
Additionally, I fitted a pair of internal air filter ram pipes that smooth the air flow through the filter into each carb. This is reckoned to add < 3 bhp.

The engine was returned fully painted in correct maroon and ready to fit.
The engine was fitted in December 2023 and gradually run in over the next two months, due to poor weather. Now with 500 miles under its belt, it is really showing what a fine engine it is and the extra power and torque really noticeable. Well worth the investment.