The Ford Barn

4tford · 11-01-2015, 11:03 AM

When using a merc crank in a 59a block and a crab style distributor does it matter whether you use the 8ba crank gear and timing gear or do you need to use the early gear set?? Thanks Bill

flatheadmurre · 11-01-2015, 11:13 AM

The early set of gears or all the axial force of the cam will go into your dizzy.

scooder · 11-01-2015, 12:46 PM

Don't really mater, the thrust is controlled by the front of the block and inside of the timing cover, the ignition doesn't (shouldn't) "see" the thrust.
Just get the end play in tolerance, and pay it no more mind.
That's the way I see it.
Martin.

flatheadmurre · 11-01-2015, 12:50 PM

The later gear let the cam go towards the frontplate.
That you dont want with a crab dizzy !!

Fordestes · 11-01-2015, 01:14 PM

Use the 48 back gears to go with the 48 and earlier dist. I have (what used to be a nice crab distributor) that is now Junk from using the later gears in a 59 engine , Ford changed the design for a reason !

4tford · 11-01-2015, 01:14 PM

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I have the early gear set installed. Thanks guys.

Bored&Stroked · 11-01-2015, 05:14 PM

I use the early gear sets on everything - always seems better to me to have the cam thrusting toward the block. I also make sure that my endplay is within spec. I've had to have some custom cams precision ground on the end - due to them being thicker than they should be. Could have doubled up on gaskets - but I don't like that approach.

scooder · 11-01-2015, 05:37 PM

If everything is in spec, there should be no load on the ignition! You guys have seen the large thrust surface inside the timing cover? If this was not the case, with it all being stock, whenever you let off the gas the ignition would be ruined would it not?
As for "Ford changed it for a reason" we all know Ford didn't get it right every time.
Martin.

Bluebell · 11-01-2015, 06:29 PM

Martin, Henry didn't get it right every time, but I'm sure he did reverse the camshaft thrust for a good logical reason with the intro of the gear driven distributor. Isn't it about having the dist. shaft drive gears meshing correctly?
My understanding is that If you a using a cam driven(direct driven) dizzy, then use the old gears, if you are using a gear driven dizzy, then its the late gears.
As you say it is important to have the camshaft end float in spec (same in any motor)
FHM surely at some stage the helical cut gears move the cam the other way when going from drive to over run, so unless there is excessive wear (in the first place) the dizzy should be o.k.????
Note; I am a learner as far as FHV8s are concerned. Im not trying to pretend I know my way around these things. Just looking for the real stuff.

Ronnieroadster · 11-01-2015, 07:45 PM

Quote:

Originally Posted by Bored&Stroked

I use the early gear sets on everything - always seems better to me to have the cam thrusting toward the block. I also make sure that my endplay is within spec. I've had to have some custom cams precision ground on the end - due to them being thicker than they should be. Could have doubled up on gaskets - but I don't like that approach.

As Dale mentioned above I also use only the early gear sets in my engines. All of my engines have the late type distributor drive there's never been any gear wear issues or ignition failures. My engines are high mileage examples of what works you can mix and match Ford parts theres nothing to fear.

JSeery · 11-01-2015, 07:59 PM

Quote:

Originally Posted by Ronnieroadster

As Dale mentioned above I also use only the early gear sets in my engines. All of my engines have the late type distributor drive there's never been any gear wear issues or ignition failures. Using the early gear set eliminates any possible block damage caused by the latter cam gear thrusting the cam into the face of the block. Its much easier to replace a worn front cover than replacing a work block. My engines are high mileage examples of what works you can mix and match Ford parts theres nothing to fear.

Ok, I'm not following this, the early drives thrust the cam gear into the block and the late gears thrust the cam gear into the front covers (on acceleration). Am I missing something? How does the early gear set protect the block at the expense of the front cover?

Ol' Ron · 11-01-2015, 08:21 PM

I think the real problem is: people don't check cam end play. I recently foung an 8BA with .022" end play and even with no cam cover gasket it was still out. I had to install a spacer behind the distributor drive gear.With the right end play it doesn't make much difference.

40 Deluxe · 11-01-2015, 11:37 PM

Quote:

Originally Posted by scooder

If everything is in spec, there should be no load on the ignition! You guys have seen the large thrust surface inside the timing cover? If this was not the case, with it all being stock, whenever you let off the gas the ignition would be ruined would it not?
As for "Ford changed it for a reason" we all know Ford didn't get it right every time.
Martin.

Whoa! Let's back up the bus for a second. How can letting off the gas move the cam forward??! The cam can never overrun the crank and walk forward! The crank/flywheel assembly has far more inertia than the cam, so the cam will decelerate much quicker. Plus, the cam will still have the load of driving the oil pump and opening the valves whether the engine is decelerating or accelerating.

Bored&Stroked · 11-02-2015, 08:27 AM

Cam Thrust: When you have helical gears, the direction/angle of the teeth determine whether the driven gear (if it can move) wants to thrust one direction of another. On the early gear sets, the teeth were angled such that the camshaft thrust was always toward the block. It will be thrusting that direction the whole time it is being driven (I have no clue during deceleration, whether it would move, probably not). The back of the camshaft flange is hardened and precision ground/polished - it rubs against the front of the block - which has an oil supply coming through the cam bearing. I've never seen a block wear due to this - unless somebody used the wrong cam gear bolts (too long) and they dug into the block.

On later 49-53 camshafts, the front journal was drilled and a hole was used to route oil through the cam snout to the front of the cam (where the distributor gear was pressed on). The pressurized oil supplied lubrication between the distributor drive gear and the front of the late timing cover. Ford Engineers probably changed thrust to ensure that the distributor drive gear was always in the same place and timing wouldn't fluctuate due to end-play on the cam. (That is just a guess).

Another reason I run the early gears is because in the case of something like a roller cam, the lifters can cause a bit of side-load - which can try to 'walk' the cam out of the block. Having the trust toward the block helps this - along with correct end-play to the cover (which acts as a stop as well - and has a surface for the cam gear to ride on.)

11-01-2015, 11:03 AM	#1
4tford Senior Member Join Date: May 2010 Location: Regina Canada Posts: 1,335	merc crank in 59a block When using a merc crank in a 59a block and a crab style distributor does it matter whether you use the 8ba crank gear and timing gear or do you need to use the early gear set?? Thanks Bill

11-01-2015, 11:13 AM	#2
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: merc crank in 59a block The early set of gears or all the axial force of the cam will go into your dizzy.

11-01-2015, 12:46 PM	#3
scooder Senior Member Join Date: Jul 2010 Posts: 2,593	Re: merc crank in 59a block Don't really mater, the thrust is controlled by the front of the block and inside of the timing cover, the ignition doesn't (shouldn't) "see" the thrust. Just get the end play in tolerance, and pay it no more mind. That's the way I see it. Martin.

11-01-2015, 12:50 PM	#4
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: merc crank in 59a block The later gear let the cam go towards the frontplate. That you dont want with a crab dizzy !!

11-01-2015, 01:14 PM	#5
Fordestes Senior Member Join Date: May 2010 Posts: 886	Re: merc crank in 59a block Use the 48 back gears to go with the 48 and earlier dist. I have (what used to be a nice crab distributor) that is now Junk from using the later gears in a 59 engine , Ford changed the design for a reason !

11-01-2015, 01:14 PM	#6
4tford Senior Member Join Date: May 2010 Location: Regina Canada Posts: 1,335	Re: merc crank in 59a block Sponsored Links (Register now to hide all advertisements) I have the early gear set installed. Thanks guys.

11-01-2015, 05:14 PM	#7
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,064	Re: merc crank in 59a block I use the early gear sets on everything - always seems better to me to have the cam thrusting toward the block. I also make sure that my endplay is within spec. I've had to have some custom cams precision ground on the end - due to them being thicker than they should be. Could have doubled up on gaskets - but I don't like that approach.

11-01-2015, 05:37 PM	#8
scooder Senior Member Join Date: Jul 2010 Posts: 2,593	Re: merc crank in 59a block If everything is in spec, there should be no load on the ignition! You guys have seen the large thrust surface inside the timing cover? If this was not the case, with it all being stock, whenever you let off the gas the ignition would be ruined would it not? As for "Ford changed it for a reason" we all know Ford didn't get it right every time. Martin.

11-01-2015, 06:29 PM	#9
Bluebell Senior Member Join Date: Nov 2012 Location: Tauranga, New Zealand Posts: 726	Re: merc crank in 59a block Martin, Henry didn't get it right every time, but I'm sure he did reverse the camshaft thrust for a good logical reason with the intro of the gear driven distributor. Isn't it about having the dist. shaft drive gears meshing correctly? My understanding is that If you a using a cam driven(direct driven) dizzy, then use the old gears, if you are using a gear driven dizzy, then its the late gears. As you say it is important to have the camshaft end float in spec (same in any motor) FHM surely at some stage the helical cut gears move the cam the other way when going from drive to over run, so unless there is excessive wear (in the first place) the dizzy should be o.k.???? Note; I am a learner as far as FHV8s are concerned. Im not trying to pretend I know my way around these things. Just looking for the real stuff.

11-01-2015, 08:21 PM	#12
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: merc crank in 59a block I think the real problem is: people don't check cam end play. I recently foung an 8BA with .022" end play and even with no cam cover gasket it was still out. I had to install a spacer behind the distributor drive gear.With the right end play it doesn't make much difference.

11-02-2015, 08:27 AM	#14
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,064	Re: merc crank in 59a block Cam Thrust: When you have helical gears, the direction/angle of the teeth determine whether the driven gear (if it can move) wants to thrust one direction of another. On the early gear sets, the teeth were angled such that the camshaft thrust was always toward the block. It will be thrusting that direction the whole time it is being driven (I have no clue during deceleration, whether it would move, probably not). The back of the camshaft flange is hardened and precision ground/polished - it rubs against the front of the block - which has an oil supply coming through the cam bearing. I've never seen a block wear due to this - unless somebody used the wrong cam gear bolts (too long) and they dug into the block. On later 49-53 camshafts, the front journal was drilled and a hole was used to route oil through the cam snout to the front of the cam (where the distributor gear was pressed on). The pressurized oil supplied lubrication between the distributor drive gear and the front of the late timing cover. Ford Engineers probably changed thrust to ensure that the distributor drive gear was always in the same place and timing wouldn't fluctuate due to end-play on the cam. (That is just a guess). Another reason I run the early gears is because in the case of something like a roller cam, the lifters can cause a bit of side-load - which can try to 'walk' the cam out of the block. Having the trust toward the block helps this - along with correct end-play to the cover (which acts as a stop as well - and has a surface for the cam gear to ride on.)