8BA & 8RT engines in LP Bren Gun Carriers

[Tony Smith]

Originally Posted by Darrin Wright

Hi, over the years I have looked at and thought about placing a 8BA (car) or 8RT (truck) Ford side valve engine into my Bren Gun Carrier.
My question is, has anyone done this? if so what problems did you encouter and what advice can you pass on?

The WW2 Ford V8 engine is 85hp and is 221ci.
What I have read, the 8BA or 8RT engine is 100hp and is 239ci. The main differences are (apart from the exta horsepower) a bolt on bell housing, water outlets on the heads are to the front, distributor is more conventional and mounted at the right front of the block/head area, bolts to secure the heads to the block (both are 24 stud).

specific questions/concerns are:
will a ford truck/carrier gear box bolt on to the different bell housing?
will bren gun carrier manifolds bolts to the 8BA block?
are the water pumps the same on both engines?
will 221 heads bolt onto the 239 block (this would give the appearance of a 221 engine) compression ratios are the same for both engines.

thoughts and feedback appreciated.
I would assume that the same idea/logic would also apply to those who have Universal carriers.

The Sidevalve engine used in Aust LP carriers and all Ford Blitzes is already a 239 engine (the 99A, or Mercury engine) with identical bore and stroke as the 8BA engine. The wartime V8 was rated at 95hp, while the same engine was rated as 100hp only due to the advances in fuel quality post-war. It is only UK/Canadian carriers and Ford Commercial Trucks (Incl Marmon-Herringtons) that used the 85hp 221.

As far as fitting an 8BA into an LP Carrier goes, it can be done but there are some issues. The 8BA/8RT engines use a conventional bolt-on bellhousing. For applications in Ford and Mercury Utes and Trucks (which still used the old 4 speed gearbox with integral b/housing), there were 2 types of adapter bellhousing made, a cast-steel and a stamped steel. The cast steel one was made for trucks and will clear an 11" clutch, while the stamped steel was for 1/2 ton utes and will only clear a 9 1/2" clutch (Carriers and CMPs use an 11" clutch). You will need to replace the clutch disc on the 8BA to one with a 10 spl 1 3/8" hub to match the carrier gearbox, to replace the 10 spl 1" hub it probably has fitted.

The earlier 24 stud heads will fit onto an 8BA block and will function, but the water passages through the head gasket are different and will lead to overheating! The 8BA heads have the water outlets and thermostats at the front of the head, and if using the generator-mounted fan of the wartime engines, the fan diameter will have to be reduced to clear the hoses. The 8BA fan is mounted lower on a bearing approximately where the dizzy is on the early engine and with the fan in this position it won't clear the shroud on the radiator. The frontal position of the thermostats and dizzy also interfere with the accelerator linkage in a CMP, but not a Carrier.

There is also an issue with the water pumps. The 8BA used in Ford cars has a different front engine mount set up from the early engines. However, the Ford and Mercury Truck pumps have the proper foot arrangement for fitting into an earlier chassis. You cannot use an early waterpump on the 8BA block because the water passages to the block are slightly different and also because the pulleys are set further out away from the block so the belts clear the angled distributor. For many years, these pumps were fairly hard to find, but they are now being reproduced as new castings in either steel or aluminium from Flatattack Racing

The starter on an 8BA engine has a different design Bendix drive which makes the starter non-interchangable with the early starter, and they were only available in 12v. This isn't an issue of course if you've changed your electrical system to 12v, but a problem if you're still running 6v.

And finally, the sump. The most common (Car) versions of the 8BA sump have the lowest part (ie drain plug) centred on the engine, while the early engines have it positioned toward the rear. In a carrier, this won't cause any clearance issues, but you will need to cut another access hole further forward to drain the oil. On a CMP, this sump will be foul of the front diff and disaster awaits! There is a version of truck sump that has a rear reserviour and drain plug, but these are rare and highly sought after (read: expensive). An early engine pan won't fit an 8BA engine due to the integral bellhousing on the early engines fouling the 8BA bellhousing adapter.

But the good news! The exhaust manifolds will bolt straight up without modifying the system. The carb is in the same place and the air inlet or filter will fit exactly the same way as on the original engine.

In light of the issues, you'd have to ask yourself why you'd want to put in an 8BA for negligible benefit, when your 99A engine can be "Built" to perform just as well as any 8BA, or better!