help with engine swap to 8BA engine

[Tony Wheeler]

Originally Posted by Jason Linders

Hi would it be better to change my engine to the 8BA 24 stud head instead of my old 21 stud 1937 flate head in my FGT
Any help would be great

Thanks
Jason

Neither of them is a blitz motor Jason, so it doesn't really matter, just use whichever one gets you on the road quicker/cheaper. However you need to consider your options for the future, which will depend on a whole range of factors as the resto proceeds. For example if you're aiming for strict originality you may want a 39-48 motor eventually, and you may even want to rebuild one. In that case you'd be selling your existing motor, so if you have a complete 8BA you should leave the heads and dizzy alone, as you'll only devalue it by changing them. They're worth good money complete and running, but only to 49-53 car/pickup enthusiasts, who don't want to see early heads or CMP twin belt pulleys!

On the other hand if you have a good running motor you may be happy to leave it there indefinitely. There's more than one CMP getting around with a 21 stud motor, and likewise 8BA motors. As Lynn mentions you can change the heads and dizzy for appearances, and likewise the crankshaft pulley, water pumps and generator if you want to fit twin belts. Of course you can't do anything about the bolt-on bellhousing, which gives the game away to the experts! Also you need to be aware that changing the heads and dizzy is a backward step. You'll lose the extra power and fuel economy of the 8BA, which is owed entirely to the higher compression heads, and you'll lose the much improved engine cooling, particularly around the problematical rear pots. This was corrected on the 8BA with greatly enlarged rear coolant passages, which will be mostly blanked off by an early head. As for the dizzy, we all know what a pain in the neck the crab is for changing/adjusting points, but that's easily solved by fitting an electronic breaker plate. More importantly you'll lose the 8BA timing cover, which unlike the early motors has a timing pointer. That means you'll never be able to time the motor accurately, and instead of using a timing light in a few minutes, you'll have to pull the whole dizzy off and fiddle around with a timing jig to even get close. That particular problem is discussed here: http://www.mapleleafup.net/forums/sh...ight=Milesmore

These are just a few of the factors that could influence the decision, and just like any restorer your plans will change along the way as other stuff becomes available. Which may include cash! As a general resto strategy it's useful to aim for strict originality, but don't hold up the entire project for want of a particular component. That includes motors, which can always be changed later, and often need to be changed, for various reasons including smoke inhalation! One of the best things about strict originality which is never mentioned is that it eliminates difficult decisions. For example in this case I wouldn't have to think twice, I'd simply stick the best motor in as a temporary measure and get on with the rest of the job.

On the question of accelerator cables, one of my F60L wrecks has an 8BA motor fitted with one, which is quite a tidy job and works well. I'll take some photos in daylight and post them as a guide to what's involved.

[Jason Linders]

Thanks for that Tony , the engine that is already fitted is the 21 stud 1937 flatehead and it runs so i might just leave it alone and get on with finding the replacement chassis witch i plane on looking at one later this week if the rain lets up.
is their anything that i should keep an eye out for on the chassis

[Keith Webb]

Originally Posted by Jason Linders

Thanks for that Tony , the engine that is already fitted is the 21 stud 1937 flatehead and it runs so i might just leave it alone and get on with finding the replacement chassis witch i plane on looking at one later this week if the rain lets up.
is their anything that i should keep an eye out for on the chassis

Is the chassis you're looking at a F15A or another FGT? Main thing is to make sure the chassis is intact front to the rear, and then check for rust, not usually a big problem with these... also look to see whether it looks true and straight, and also look for other signs of butchery.

[cletrac (RIP)]

Just so you guys know, the 48 and earlier motors circulated the water different to the 49 and newer motors so when you change the heads you have to do some fiddling with the holes in the block to prevent heating problems. I forget which holes are involved. If you find a 255 Merc engine the crank and rods and pistons will fit in the 48 style engine. I suppose you don't get those Merc engines down under though. Theres always ebay.

[Jason Linders]

It should be a F15A but wont know till late this week or next when the rain stops so i can get into the yard to have a look, but should be a F15A

[John Mackie]

dont forget that if you want to use the 21A disy you wll have to change the camshaft . the waterpumps ase different. there are 3 different pumps for the 8BA . you will need 2 8RT pumps.

[Jason Linders]

I am going to take Tony's advice and leave the engine that is fitted because it runs so their is no real need to change it at the moment
but thanks for the info John

[Tony Wheeler]

Originally Posted by Jason Linders

is their anything that i should keep an eye out for on the chassis

As Keith says, just find one that's not too badly butchered, ie. side rail ends chopped off, reinforcement plates welded on, heavy bumper bar mounts welded to the chassis, etc. All this stuff can be repaired but it's a helluva lot of work, and such chassis will generally have fatigue cracks anyway.

Fortunately most SWB chassis are quite good as they rarely got put to work like the 3 tonners, the exception of course being the FGT, for the sole reason that it had a winch. Without that winch they never would have wound up as yard cranes in sawmills etc, they would have had an easy life as delivery vans like the Sigvans did, and the bodies would never have been chopped.

Anyway good luck with the chassis this week Jason, you'll start making good progress once you have a decent chassis to work with. First step will be to convert it from F15A to FGT, which will be much easier with a FGT chassis to compare. The various differences are covered in post #39 here:

http://www.mapleleafup.net/forums/sh...?t=1929&page=2

Hopefully you can re-use the winch crossmember, in which case you'll just need another rear crossmember and a set of FGT fishplates. I'm planning to get a batch of these made up so if you like I can include you in and send them up.

[Jason Linders]

Thanks for that Tony you can count me in for the fishplates.
I had a look at prices for the chassis rail and had a look at a rail it must be a ford short wheel base it was fitted with a flathead rails looked the same but it was only two wheel drive i think but the diff and front axle where not blitz it was used to move around a large welding unit so do not know if would be any good being only two wheel drive or if it was a 4x4 and they removed the front diff didnt get any pics but will be checking again when the rail goes away just way to muddy and wet in dalby

[Keith Webb]

No good to you if it is a F15 4x2 chassis which is completely different.

[Jason Linders]

Thats what i thought it might be too, they told me they had one but i dont think they would know if it hit them in the head, i told them they have a short chev and they recone they had a short ford still their but there mech reconds they dont when i was their the sales guys were at lunch.
might have to look else were

[Jason Linders]

bloody chassis this is going to be a headache
i might have to try Ross Prince and see what he has.

[Tony Wheeler]

Originally Posted by Keith Webb

No good to you if it is a F15 4x2 chassis which is completely different.

I wouldn't rule it out in this case, because it involves chassis alterations anyway. You'd just have to do a few more with the F15 chassis, ie:

1. provide cutout in front crossmember for diff clearance
2. fit transfer case crossmember
3. fit 4x4 rear spring hangers
4. fit 4x4 gearbox crossmember

Off the top of my head that's all that's required, the only difficulty being absence of pre-stamped rivet holes. That's certainly not insurmountable, and if it's the only chassis available I see no reason to hold up the project. However I'd be checking with Keith who has intimate knowledge of the F15 chassis.

Ideally of course you'd start with an F15A chassis, firstly because you don't have to do the above work, and secondly because the pre-stamped holes for the winch crossmember and the relocated midsection crossmember are present, and thirdly because you get a set of high ratio diffs (assuming it's a rolling chassis). For these reasons it's worth paying a bit more if necessary.

[Jason Linders]

If i have to remove all my crossmembers thats fine i have a good mate of mine thats a engineer but does all the old school blacksmithing so has the tooling and gear to do the hot riveting, but if i can find a F15A it would be better, but no luck as of yet just dont seem to be able to find one up here in QLD