1932-41 Divers Helmet distributor to 1951 8BA?

[gavinnz]

I have done a day of reading and I have not found much information on this conversion....

What's the traditional way of doing this conversion? With swapping parts around?

Can it be done by using the 1932-41 front cover and a divers helmet dizzi on the 1951 block and making a custom pinned extension to fit the 1951 camshaft to turn the distributor (after removing the original 8BA distributor drive gear).

I want electronic ignition so I will look at fitting that conversion inside the divers helmet housing.

What am I missing??

Regards
Gavin
New Zealand

[flatheadmurre]

If you have a mill to machine the camshaft that part will work just fine.
No need for any pinning...just cut the cam to correct lenght and mill the driveslot.
You also need the camgears from an -48 engine or the camshaft will use the distributor as thrustplate.

[gavinnz]

Originally Posted by flatheadmurre

If you have a mill to machine the camshaft that part will work just fine.
No need for any pinning...just cut the cam to correct lenght and mill the driveslot.
You also need the camgears from an -48 engine or the camshaft will use the distributor as thrustplate.

Milling machine lathe all accounted for!
So the 8BA cam is long enough to drive the older dizzi without having to be extended then?
Where does the camshaft thrust go in a standard 8BA engine? I am not understanding why changing the end cover will change that thrust?

[gavinnz]

Ok I see now the thrust goes into the centre of the end cover in the 8BA engine. I wonder if I can make a thrust face inside the older cover around the edge of the hole the shaft to drive the dizzi goes through?

I assume the gears are cut the opposite way on the earlier engine to force the thrust backwards along the camshaft. Where is that thrust applied to the block in those engines and does the 8BA have that designed in??

Can the gears only be changed to reverse the thrust without changing the cam etc?

[JSeery]

Wouldn't it be much easier to just change the cam? Yes, the timing gears a cut in the opposite direction thrusting the timing gear against the block. This would be a fairly simple swap with just "bolt on" parts if the correct parts are used. Either way you go the cam is going to have to be removed.

[gavinnz]

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Originally Posted by JSeery

Wouldn't it be much easier to just change the cam? Yes, the timing gears a cut in the opposite direction thrusting the timing gear against the block. This would be a fairly simple swap with just "bolt on" parts if the correct parts are used. Either way you go the cam is going to have to be removed.

I thought I read somewhere that changing the cam in a 8BA block to a cam from a 1932-41 block had other issues? Was it something to do with cam lobe angles and hence valve timing? I could be wrong??

Machining the 8BA cam shorter and cutting a slot is no big deal for me to do. Engine will be completely striped down for a rebuild so I can fit what ever bits are right. Like buying a set of new timing gears that are the 1948 style to reverse the thrust is no problem.

[flatheadmurre]

For perfectly correct camgeometry you need a postwar camshaft...not that it will be a notisable change in power...
Other thing is keeping the old cam and lifters you can reuse it all.
New cam means new set of lifters or resurfaing them.

[JSeery]

Originally Posted by flatheadmurre

Other thing is keeping the old cam and lifters you can reuse it all. New cam means new set of lifters or resurfaing them.

True. If I was rebuilding an engine it would all get replaced anyway, but that is just me.

As pointed out, the valve location change slightly after WWII.

[gavinnz]

I am yet to strip my two engines but am expecting to have to buy new adjustable lifters as the old ones will not be in good condition going on the general condition of the engines and I will have the cam reground to a hotter profile which I think will require the adjustable lifters anyway. ?

[JSeery]

Originally Posted by gavinnz

I am yet to strip my two engines but am expecting to have to buy new adjustable lifters as the old ones will not be in good condition going on the general condition of the engines and I will have the cam reground to a hotter profile which I think will require the adjustable lifters anyway. ?

There you go. So why not just get a reground cam with the correct configuration? I would think you would at least need one to get the correct measurements off of. Cores should be very easy to come by.

[BUBBAS IGNITION]

AND why not just use the correct engine to start with ??

[rotorwrench]

There are more 8BA type engines still out there than early ones but they don't fit the older cars as well. I'm planning on using all the 59 series stuff on an 8CM built engine so it will fit my model AV8 better. I'm going to use all the front equipment so that I can use a single belt and the crab distributor. All of the 59 series and earlier stuff can be made to fit and work on the 8BA family blocks but it is a bit of work to get it all right. My 29 A-bone doesn't have much room between the stock radiator location and the firewall. On the later 30s cars after the model A era, the Mercury 8CM engine equipment can be made to fit since they have a little more room.

[gavinnz]

Originally Posted by BUBBAS IGNITION

AND why not just use the correct engine to start with ??

That comment made me realise I had not put in my location in! (just added it) These engines are not as common over here in New Zealand and very expensive to buy and the two 8BA engines fell in my lap, but I want an older look for the marine application I am building the engine for,.... a 1930's NZ built wooden 16 foot barrel back speedboat.

On a side note you are the sparks man! I was thinking of getting a divers helmet dizzi in the states and having it sent right to you to rebuild for me and then post it on over to New Zealand afterwards.

[gavinnz]

Originally Posted by JSeery

There you go. So why not just get a reground cam with the correct configuration? I would think you would at least need one to get the correct measurements off of. Cores should be very easy to come by.

Cores are not easy to find here in NZ. I will have to think more about the variables involved with this process. Learning learning...

[cas3]

here's how i did the late cam in the early block if you decide to go that route https://www.fordbarn.com/forum/showthread.php?t=213786

[JSeery]

Originally Posted by cas3

here's how i did the late cam in the early block if you decide to go that route https://www.fordbarn.com/forum/showthread.php?t=213786

Lot of good information in that thread!

[gavinnz]

Originally Posted by cas3

here's how i did the late cam in the early block if you decide to go that route https://www.fordbarn.com/forum/showthread.php?t=213786

Great info thanks. I can see a way forward for my project now.

[Ol' Ron]

JSeery has the answer. The cam timing difference between the early and late blocks would be hard to see on a dyno. The expense if machining an 8BA cam for this application would be much more than just swapping in a 59 style cam.

[gavinnz]

The expense would be zero, as I have an engineering workshop at home with milling machine and lathe. I don't think I could find a good 59 style cam in New Zealand easily?

But I will lesson to you Ron and see if I can find one!

[texas webb]

Quite a few flatheaders in NZ and OZ.Maybe some will see your post.