Distributor retention screw (in cylinder head)...

Trapdoor2

Trapdoor2

Senior Member
Whilst working on my Coupe, I have noticed that the distributor retention screw threads in the head are wallowed out. I bought a new screw from Snyder's but it is just as loose as the old one. It barely tightens up, even if I hold my mouth right.

What's the solution? I've used a lot of helicoils in my day...might have to remove the intake manifold to get a drill at that hole.
 
Trapdoor2 said:
Whilst working on my Coupe, I have noticed that the distributor retention screw threads in the head are wallowed out. I bought a new screw from Snyder's but it is just as loose as the old one. It barely tightens up, even if I hold my mouth right.

What's the solution? I've used a lot of helicoils in my day...might have to remove the intake manifold to get a drill at that hole.
Click to expand...
I have tapped a larger size replace with hex screw or other screw. In place no need to remove!
 
Trapdoor2 said:
Whilst working on my Coupe, I have noticed that the distributor retention screw threads in the head are wallowed out. I bought a new screw from Snyder's but it is just as loose as the old one. It barely tightens up, even if I hold my mouth right.

What's the solution? I've used a lot of helicoils in my day...might have to remove the intake manifold to get a drill at that hole.
Click to expand...
I have tapped a larger size replace with set screw or other screw. In place no need to remove! Using flat bottom tap
 
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You could try multiple wraps with teflon tape. 5 turns is standard for pipe - but pipe thread taper. I have done up to 10 on a straight thread trying to get something to "snug."

Have also tried black electrical tape - three or four turns with the tape "warm" to meld into the threads. This is a little more stout than teflon but there is more of a "threshold" of use. (i.e. narrow window of application - too little doesn't work, too much ends up not allowing the bolt full entry.)

And - for both - you want to wind the tape on so it "tightens" as you tighten the bolt.

Joe K
 
Maybe try a thin coat of JB Weld applied with small paintbrush after thoroughly cleaning the threads on the screw. This is not a high tension fastener placement.
 
Well, I was looking for ideas...thank you all!

I don't like using JB Weld (but I keep it handy anyway). For the number of times I've had this distributor in and out, I'll prefer a solution that will survive many more repetitions.

I like the idea of going up a size...same thread pitch if possible. However, it is just as easy to install a helicoil...and then the original screw works. If I find the right size and have all the parts handy, I'll go with the next size. If not, I'll probably go with a helicoil.

I may indeed go with teflon tape as a temporary measure until I make a permanent fix. Even though it sees very little stress, I don't want it falling out in the street. Some little kid might choke on it. ;-)

Many years ago, I had a set screw in a wallowed hole in a model airplane engine. My Dad took a scrap piece of aluminum plate a little thinner than the length of the screw, drilled a hole in the plate the next common drill size bigger than the major dia...and then laid the plate on the anvil of our big vice, dropped the set screw in the hole and whacked it twice with a big hammer. That swelled up the set screw enough for it to bite...
 
Y-Blockhead said:
You might wrap some aluminum foil around it instead of the teflon tape.
Click to expand...

That thought came to me as one might use the "foil tape" commonly used on foamboard (which itself is a thin aluminum foil on the foam as vapor barrier) The thinking for foam board is not to have "vapor gaps" where vapor could pass into the wall (and condense there) and the foil tape to prevent its passage.

There are a few things I haven't done yet.

Joe K
 
I don't know what size that thread is but I bet there is a metric thread not much bigger. Re tap (metric?), modify the end of a metric bolt and drive on.
 
3/8" is 9.52 mm. a 10 mm thread will be just a little larger and should be enough to hold if hand tight is enough. On the other hand, there are some ham fisted people about.
 
Y-Blockhead said:
⅜-24, according to Bratton's it should only be hand tight.
Click to expand...

Excellent! I can buy helicoils that size at Ace hardware, no problem. I'll double check tomorrow before I spend any money, of course.

10mm is a good option...but I'll stick to "Ford Fractional". ;) Wouldn't want a midnight visit from Ol' Edsel...

That setscrew, having a locknut to boot, is in a perfect spot for ham hands. Heck, you can see evidence on the dist. shaft where the screw dimpled the shaft.
 
midnight visit from Ol' Edsel...
Click to expand...
In a Ford mind this would be important enough to send the "old man."

The Model A story of Henry "borrowing" the Trade School Student's car "Just to try it out - you've done a good job" comes to mind.

Joe K
 
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