8BA & 8RT engines in LP Bren Gun Carriers

[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.

[ajmac]

There isn't a lot of point really.

Get a wartime 81 or a 59AB, these are the wartime 239ci and the postwar 239ci, externally they look identical, centre water outlet, same water pump castings, same bell housing and cam mounted distributor, the 59AB has an slightly higher CR and modified block casting internals for improved cooling, but only a little I think.
An 8BA did have improved cooling passages and modern rod bearings, but most of the redesign was a cost down rather than improvement. If you use one, you can get an adaptor plate to use the wartime gearbox, you will need wartime water pumps as the pump casting is different on the 8BA putting the engine mounts in the wrong place. You would need pre 8BA heads (24 stud) and an earlier front cover to use the original wartime distributor, which would mean changing the cam as I think the nose I'd different...in the end you would only be using the short block.
The 'best' engine would be a French 1990s flathead with pre 8BA everything else. When I say short block I include the valve train, 8BA valve gear is much better than pre 8BA as far as fitting and service goes.
All flathead distributors are terrible compared to the last of the line of distributors before full management came in, so having the side mounted unit would not be any better than the front unit, best would be to replace with a later chev or something that has both centrifugal advance and vacuum advance for better combustion at part load.

[peter simundson]

An excellent explanation. Clear, concise and professional.

Peter S

[Marc van Aalderen]

Originally Posted by ajmac

The 'best' engine would be a French 1990s flathead with pre 8BA everything else.

I have a French engine in my Universal and boy does she fly! Last Race to the Bridge in Arnhem we were clocked at 40 Mph trying to keep up with the rest, mainly Jeeps. Had a crew of 10 and a 6 Pounder on tow. Mind you, I did blow a gasket and spray engine coulant all over. My own fault off course. Still need to get my speedo and temperature gauge working.....

Cheers,

[ajmac]

Yes Marc, I noticed you had a French unit in a photo you posted a few days ago. Looked good

[cletrac (RIP)]

For the "best" forties flattie with all stock parts start with a 46 to 48 Canadian truck engine. They had higher compression and a better camshaft for operating at our higher altitude. Then get a 49 or up 255 Merc engine and put the crank and pistons in the truck engine. You need to change to the 239 crank gear so it'll work with the 48 camshaft since the gears are cut the opposite way. Bolt all the older accessories on and you'll have a 140 hp flattie that looks and sounds original. Oh, and Ford didn't use a 12 volt system until 1956 so flatties wouldn't have got them.

[Richard Farrant]

Originally Posted by cletrac

. Oh, and Ford didn't use a 12 volt system until 1956 so flatties wouldn't have got them.

Except the wartime British Ford WOT series of military trucks, the full 12 volts on their flatheads !

[Stew Robertson]

Just put the merc 100 hp in and tune it and it will get at least 40 plu Leave every thing original but the cam.
With the cam and tuned you will get the horses and the RPM
Take it from a guy who has done it
and no one only you will know it is not original

Stew

[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!

[Philliphastings]

Thanks to all involved for a top class thread with plenty of details

cheers

Phill

[rob love]

I put an 8BA truck engine into my carrier as a temporary until I rebuild my carrier engine. In hindsight I should have just rebuilt the carrier engine.

I was able to overcome the oil pan problem by cutting the bottom off the pan and welding a flat plate on. At the same time I was able to relocate the drain plug to the right position.

No problem on the tranny to bellhousing except that the bottom ears of the bellhousing stuck down to the floor and had to be ground off.

You can change the entire front cover over to the early style with the distributor down under, and the water pumps can also be swapped but you will have to plug one extra hole on the block for each water pump. That is as simple as threading the hole and putting in a small slotted pipe plug. That would allow the normal carrier generator to be used.

I think I had to do a little bit of grinding around the starter to get that to fit as well.

So it can be done, but you might be just as well off to keep searching for an early engine.

[RichardT10829]

was going to suggest that the 239 99A (or T) lump was not post war... mine is a 1939 unit..

it is possible to fit a trigger wheel behind the crank damper with a VR sensor and go mapped ignition (over the naff dizzy)...it will run much better however....not exactly wartime or original for that matter.... the coil pack could be hidden away out of sight too, the megajolt style systems i have seen have USB dock to plug in and get the most out of an engine...