a very difficult fix 1965

[Bruce W.]

Hey guys,
Well I know where the valve cover is leaking. The passenger side top front valve cover thread is stripped. I have been told the only way to fix this is to take off the head and take it to a machine where they will weld it and re tap the hole. As you know it takes a 1/4 20 bolt. I thought about a heli coil but the hole is to big for a 1/4 20.
I am hoping that someone has an easier way? since I can't snug that bolt oil comes out of the cover. There are far better minds out there than I have. Anyone have a solution. This is a tough one. Appreciate your help.
Bruce

[David H.]

Re: a very difficult fix 1965

Hey guys,
Well I know where the valve cover is leaking. The passenger side top front valve cover thread is stripped. I have been told the only way to fix this is to take off the head and take it to a machine where they will weld it and re tap the hole. As you know it takes a 1/4 20 bolt. I thought about a heli coil but the hole is to big for a 1/4 20.
I am hoping that someone has an easier way? since I can't snug that bolt oil comes out of the cover. There are far better minds out there than I have. Anyone have a solution. This is a tough one. Appreciate your help.
Bruce

Bruce

NCRS or just something that works?

Dave

[James G.]

Re: a very difficult fix 1965

can you tap it for 1/4" -28? If so you can probably find a fine threaded 1/4 NF with similar head markings.
1/4 -28 NF takes a #3 drill - .213

1/4 -20 NC takes a #7 Drill- .201

Would .012 oversize clean up the hole well enough to give you adequate meat to tap?

[Joe L.]

Re: a very difficult fix 1965

Hey guys,
Well I know where the valve cover is leaking. The passenger side top front valve cover thread is stripped. I have been told the only way to fix this is to take off the head and take it to a machine where they will weld it and re tap the hole. As you know it takes a 1/4 20 bolt. I thought about a heli coil but the hole is to big for a 1/4 20.
I am hoping that someone has an easier way? since I can't snug that bolt oil comes out of the cover. There are far better minds out there than I have. Anyone have a solution. This is a tough one. Appreciate your help.
Bruce

Bruce------

You might be able to use a Time-Sert, Thread-Sert, or Keen-Sert if a Heli-Coil won't work.

Here's another approach that some folks might scoff at but I think will work very well: clean the existing hole scrupulously with acetone or a similar solvent. Brake Clean should also work well. Make sure that any trace of oil is removed from the hole. Then, install JB Weld to completely fill the hole. Use regular JB Weld and not the fast setting. Let the JB Weld cure for at least a day, better longer. Last, drill and tap for 1/4-20.

JB Weld is very strong and these bolts do not require a very high torque AND SHOULD NOT BE TORQUED TO A HIGHER THAN SPEC TORQUE.

I think that this repair will last as long as you're going to need it to. But, if it does not, nothing that you've done will foreclose the opportunity to use other suggested repair methods.

[Edward J.]

Re: a very difficult fix 1965

Bruce what about using a metric equivalent (6mm)they are slightly bigger I believe, not NCRS correct .being it’s on the top it really should not be a problem, just don’t over torque.If your car has aluminum covers you may have to get creative as the bolt head are generally 3/8th inch heads. Which means grinding the head to a 3/8ths head.

[Bruce W.]

Re: a very difficult fix 1965

Joe, thanks for your help. JB weld sounds like a good idea!!
Bruce

[Frank D.]

Re: a very difficult fix 1965

I've done the JB-Weld thing before in similar circumstances and it worked until I sold the car.
In my case I stuffed a grease-laden bit of paper towel down the hole before tapping to catch most of the residue.
Pull it out with tweezers when done.

[David H.]

Re: a very difficult fix 1965

Joe, thanks for your help. JB weld sounds like a good idea!!
Bruce

Bruce

If you're going to use JB Weld, JB Weld the Heli-Coil insert in place.

Dave

[Daniel T.]

Re: a very difficult fix 1965

Can you drill/tap it deeper and use a longer bolt? I know finding a longer bolt with the same head might not be possible but it would be a better fix vs epoxy imo.

[Perry M.]

Re: a very difficult fix 1965

Personally, I would tap the hole for a 1/4''-20 Heli-coil, even though it is somewhat too large, then use Joe's suggestion with the JB Weld. Stuff the Heli-coil with a clean piece of shop towel and thread the coil into the tapped hole. Don't use too much epoxy because you don' want to force the paper out. Let set until completely cured. Now you can clean the threads with a 1/4''-20 tap.

[Michael G.]

Re: a very difficult fix 1965

[QUOTE=Daniel Tonn (66026);901956]

[Patrick H.]

Re: a very difficult fix 1965

Bruce------
Here's another approach that some folks might scoff at but I think will work very well: clean the existing hole scrupulously with acetone or a similar solvent. Brake Clean should also work well. Make sure that any trace of oil is removed from the hole. Then, install JB Weld to completely fill the hole. Use regular JB Weld and not the fast setting. Let the JB Weld cure for at least a day, better longer. Last, drill and tap for 1/4-20.

JB Weld is very strong and these bolts do not require a very high torque AND SHOULD NOT BE TORQUED TO A HIGHER THAN SPEC TORQUE.

I think that this repair will last as long as you're going to need it to. But, if it does not, nothing that you've done will foreclose the opportunity to use other suggested repair methods.

Here's a tip to make this easier -

Clean as Joe suggests.
Clean one of your original bolts in a similar manner.
Apply Kiwi shoe polish to the original bolt, similar to waxing your car and then removing the wax. I usually do ti twice, but be sure to buff off ALL of the excess polish.
Apply JB Weld ( I use Devcon 10110, but not worth buying a whole can for this) inside the hole, using a toothpick to apply it to the outer edges (threads) of the hole.
Screw your bolt into the hole.
Use Q-tips BARELY wet with WD-40 to remove any JB that oozed out. They work great, but you don't need much WD-40.

After 24 hours, unscrew your bolt.

As Joe notes, you don't want to overtighten this bolt, but this is a LOT easier than trying to drill it out as per his method.
I use this trick on Corvettes as well as "things that go bang" in my other hobby, and it works.
You may want to see how much of the bolt normally sticks out as a pre-test so that you know how deep it will go when you screw it in.

Patrick

[Michael G.]

Re: a very difficult fix 1965

Ok, so I removed a normal 1/4-20 screw from one of the heads of my 65 327 emgine and inserted a #7 (13/64) (correct for a 1/4-20 thread) tap drill into the hole. The drill went more than .25 deeper than the standard screw. This means you can tap this hole 1/4 inch deeper and use a standard 1/4-20 screw that is 1.18-1.25 long without any problem. This should give you plenty of thread engagement without stripping at the normal recommended torque.

Your engine may be slightly different than mine, so I'd repeat this measurement with your actual parts before proceeding.

[Mark M.]

Re: a very difficult fix 1965

Bruce, a method I've used a few times to get me out of a pinch (get a bolt to tighten enough with bad threads) is to stick enough strands of bare copper from thicker gauge wire in the hole. It takes a few tries to get the amount needed and shape it with a small bend at the top, L shape pieces, but it works. It's a temporary fix till a repair can be made but every time I've done it, I'm surprised how well it holds and the copper causes no further damage. An insert from my 1/4" heli coil shows .32" OD. More than 3/8" of material would be needed to drill and tap into.

[Donald O.]