distributor Cam Screw

3

30coupeguy

Member
The cam screw is set down tight and I am wondering if there is a trick to loosing it up. The distributor was overhauled along with the engine and I have not been able to back it out to time the engine, I do not think there is any corrosion, or the like. It is just too tight to turn ( there may be a certain amount of trepidation here). Am I correct in believing the screw is "lefty- loosey"?

Thanks all
burt
 
Hi Burt,

A. Do you have a distributor wrench that fits over the cam and has a lug that fits in the slot?

B. The cam screw also has a lock washer under it.

C. In a pinch, one can hold the very top of the cam with a pair of pliers but it will make your cam look like Hillary's neck.
 
Use a good large screwdriver that fits the width and length of the slot and has a nice flat gripping surface. If it still won't come loose, try an impact driver.
 
Just a trivial comment, i.e., if anyone ever wants a professional looking:

"Model A Ford Distributor Screw Driver"

that fits the distributor screw perfectly every time, one can be made from scratch.

Professional gunsmiths shape their own screw drivers often from larger screw drivers to remove custom made delicate engraved screws from high quality expensive rifles, shotguns, and pistols.

FWIW, if interested, I made a couple of these years ago as follows and have use them often:

1. Obtain a spade bit for an electric drill which is exactly as wide or a little wider than the Model A Distributor Screw Slot.

2. With a Dremel tool, cut off and remove the protruding point from the spade bit.

3. With a grinding wheel, grind the thicker flat surface of the metal spade bit until it fits snugly into the screw slot.

4. If one notices, a regular flat screw driver has tapered flat surfaces whereby when one applies force, it move upwards and out of the slot always "buggering up" the upper part of the slot ....... quite a dumb tool to use on difficult screws that one does not want to replace often.

5. On the other hand, a fine gunsmith's custom screw driver has both wide flat surfaces parallel so when torque is applied it does not lift itself out of the slot where it ruins the slot.

6. If a flat screw driver is too narrow in width, one experiences that when force is applied, it will cut into and mash the wider screw slot every time.

7. A Model A Distributor Screw Driver Tool Handle can be made with hard maple, or other hardwood by:

a. Providing an elliptical hole in the center of the wood handle , (as opposed to a round drilled hole which can later allow epoxy rotation in shear); and,

b. Filling the hole with epoxy; and,

c. Inserting the hexagon end of the spade bit in the epoxy filled hole; and,

d. Allowing this assembly to cure for 24 hours.

e. Placing and tightly pressing about a 3/4" long copper or brass pipe over the screw driver end of the wood handle can prevent the handle from splitting under extreme stress ...... also looks neat.
 
BudP said:
Thanks, Henry, for sharing your knowledge of a great idea!
Click to expand...
For difficult slot screws, I save old screwdrivers & grind the tips into a concave shape, so they don't spiral up out of the slot. I read that a little dab of valve grinding compound on the screwdriver tip, affords a good grip, to keep it down in the slot. MAIN THING, is to hold DOWN TIGHT, on the screwdriver handle.
IF all else fails, clamp the bottom of the distributor shaft in a vice, using a really sharp, skinny center punch, make a ding in the outer edge of the cam screw. THEN, angle the punch & tap it counter clockwise, to break the screw loose. Chief had a set of ALL kinds of really small punches & chisels & a REALLY small Ball Pein Hammer & I've seen him do MIRACULOUS things with them!!! (TAP-TAP-TAP!) GOD, I MISS him & I LOVE to pass on his "TIPS"!
Bill W.
 
The distributor cam screw has an uncommon thread pitch. From time to time I have run across repro cam screws that were a bit off in this regard and were hard to turn in either direction. I haven't seen this for a while but it could be something to consider.
 
I observed this, take it for what it's worth?? I've only tried it on 1 distributor.
APPARENTLY, the cam screw lockwasher doesn't compress fully?? Once, while making a MINUTE timing correction, I didn't loosen the screw, used the handy dandy holding tool & applied a little pressure & it went "click" & the cam turned a MINUTE amount & my timing was PERFECT! Yes, I know the cam doesn't have "detents", it has a "waffle" like pattern, for grip. BUT, it worked, "might" have just been a "FLUKE"---I'll try it again, when I install my 1 piece shaft distributor, in Vermin. AND, don't lecture me on the "pitfalls" of the 1 piece shaft distributor, cuz mine worked PERFECT, when I ran Vermin, 2 1/2 years ago.
Bill W.
 
I have a large wooden handle screwdriver that has a square shaft so when holding it down on the screw a cresent wrench will fit on it and give you extra leverage so the screw can be removed.
 
Have run into a couple of distributors with this issue. There were some screws sold that were close but not the original thread which bound like was mentioned. Seems like the original was metric or not SAE.
 
This has been annoying me of late! What exactly is the thread of that screw? I seem to recall somewhere that its another HF brainfart and HF used metric. If i'm correct, then there are three metric dimensions on a model A, The carb. jets (5 x .75), The shackle bolt dia, (14.5 mm) and the dist, cam screw. Am I correct?
 
Roger V said:
Have run into a couple of distributors with this issue. There were some screws sold that were close but not the original thread which bound like was mentioned. Seems like the original was metric or not SAE.
Click to expand...
Roger Dodger,
Someone here mentioned that on a tight repro screw, he removed the chrome plating from the threads, with a thread file, & then it fit well. But then you would need a METRIC thread file.
I just bought 2 extra screws, but haven't checked the fit, yet. The Dog:cool: asked, "Ur them HENS TEETH"?:confused:-----"yep!":p
Bill W.
 
As an update, I mentioned this situation to Ron Ehrenhofer, the M.A.R.C. Technical Director at the national in Niagara Falls. He was going to pursue it and put in his column in the Model A News. Remembering that most of the fasteners are listed in the Ford Parts Book, I looked the other day and it is listed. It's not SAE nor Metric but apparently special as it is .325 diameter with 30 tpi. I can see now how a 5/16 NF may have been forced or thread filed and used(though binding) since that is .3125 with 24 tpi. Ron is planning to ask in his column if anyone knows (not guesses) why Ford specified this odd size.
 
BILL WILLIAMSON said:
For difficult slot screws, I save old screwdrivers & grind the tips into a concave shape, so they don't spiral up out of the slot. I read that a little dab of valve grinding compound on the screwdriver tip, affords a good grip, to keep it down in the slot. MAIN THING, is to hold DOWN TIGHT, on the screwdriver handle.
IF all else fails, clamp the bottom of the distributor shaft in a vice, using a really sharp, skinny center punch, make a ding in the outer edge of the cam screw. THEN, angle the punch & tap it counter clockwise, to break the screw loose. Chief had a set of ALL kinds of really small punches & chisels & a REALLY small Ball Pein Hammer & I've seen him do MIRACULOUS things with them!!! (TAP-TAP-TAP!) GOD, I MISS him & I LOVE to pass on his "TIPS"!
Bill W.
Click to expand...

During my apprenticeship, a really good toolmaker took me under his wing and showed me how to make proper screwdrivers. I made several in different sizes using silver steel rod (drill steel in US terminology?). All were carefully hollow ground or concave, with the edge of the blade at a true 90 degrees to the shank.

After all grinding and other shaping was finished, each was carefully tempered, I think to a pale straw colour.

Wish I still had them but gave them up, with all my other tools, on my move to Canada due to not having cash for excess baggage.

Also, always use the longest screwdriver possible/available to reduce the effect of tilting the driver.
 
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Mine was rusted in... PB plaster for a day, a large screw driver and light tapping on the screw driver won the day....
 
Gunsmiths have used them for years. I wished I had one yesterday. It was not a screw but the bottom adjustment on a steering box. The adjuster was stuck and I couldn't move it and the standard screw driver was spiraling out of the slot as soon as I put any real force on it. There's no doubt hollow ground screw drivers are best for any type of restoration. Buggered up screws are ugly.
Terry


ian Simpson said:
During my apprenticeship, a really good toolmaker took me under his wing and showed me how to make proper screwdrivers. I made several in different sizes using silver steel rod (drill steel in US terminology?). All were carefully hollow ground or concave, with the edge of the blade at a true 90 degrees to the shank.

After all grinding and other shaping was finished, each was carefully tempered, I think to a pale straw colour.

Wish I still had them but gave them up, with all my other tools, on my move to Canada due to not having cash for excess baggage.

Also, always use the longest screwdriver possible/available to reduce the effect of tilting the driver.
Click to expand...
 
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