MGA Engine rebuild

Clear Out – Rebuilding the Carburettors of the 1959 MGA Twin-Cam

The 1959 MGA Twin-Cam that is currently in the Bridge Classic Cars workshop in our Pettistree, Suffolk HQ isn’t running quite right. So, our incredible team of in-house technicians have been working on the beautiful light blue sports car.

Jon, one of our in-house restoration technicians, has been working on the car along with our other John (workshop Manager). During the inspection and assessment of the car, John noted that there was a misfire when the engine was under load. It was time to look into the issue.

Jon, as a matter course, decided to check the carburettors on the MGA. These aren’t the easiest to get out of a Twin-Cam due to the two large banks on the cylinder heads. Finally, Jon managed to release the set of carburettors from the engine bay and get them onto the workbench. After carefully pulling the units apart, he found quite a few valves and galleys to be full of sediment and sludge. So, with new rebuild kits in hand, Jon began the process of carefully clearing and cleaning each of the carburettors ready to put them back together and back on the car.

Once he had cleared out any form of dirt or sediment from every part of the carburettors, Jon put them back together on the bench. With these carburettors, there is a very specific way of putting them back onto the car. The top bolts for the carbs to fix to the manifold have to be put in off the car or else it is a nightmare to get them in the designated holes. Once the top bolts were in place with their nuts in place behind the flange on the manifold, Jon could use the inspection cover in the front wheel well to get the bottom bolts onto the carburettors.

Now that the units are back on the car, it can be roadtested by John, our workshop manager, to see if the misfire has been cured.

Day 6 – MGA Update

Lots has been happening behind the scenes with our MGA, much of which has happened at our outsourced partners such as Scholar.

Pouring fluid into the combustion chamber of the cylinder head to determine the pressure ratio of the engine. We’ve had the head refaced, so this confirms that the compression ratio is still okay. The results of the test showed that the combustion chamber is functioning correctly.

Ady has been rebuilding the engine.

Ady and James have made the baffle for the engine sump which will stop oil surge whilst the engine is running.

The engine head has also been recently painted.

We’ve also ordered a collection of new components to be fitted into the engine.

Day 5 – Cylinder Headed Welded

Richard Kimberley from Manningtree sent us back the cylinder head which has been welded to replace part of the ring that had corroded. He lined up the gasket to determine how much needed to be welded. We will now be lap in the valves before sending it off to Scholar to be refaced.

Day 4 – Engine Clean And Prep

Our 1960 MGA engine has been cleaned and ready to be rebuilt. The crankshaft, conrods and engine block has been sent off to Scholar who has told us that the crankshaft needs to be totally replaced. The photos below show the extent of the wear on the bearings. The conrods also need to be resized, the bearings need tuning into the conrods and the camshaft bearings need to be fitted by Scholar as well as being honed and cleaned.

Day 2 – Removing Cylinder head

Ady has continued working on our 1960 MGA buy removing the cylinder head in his endeavour to fix the issue with the engine.

Things are heating up for our MGA build

With cold weather approaching, Paul, one of our master classic car technicians was asked by the owner of this majestic MGA to fit a heater box. We elected to import a period correct Smiths heater box from the US. Paul has had to adapt the bracket between the heater unit and the fan motor to perfectly fit the engine bay of our MGA.

After the full engine rebuild, Ady has now installed the engine back into the vehicle. A weak casting caused one of the piston skirts to break. Unfortunately this required a full engine rebuild.