I went to put my battery ground to the stud on the driver side head and I am having trouble getting the nut to go onto the stud. I am almost certain this is the nut that came with the engine but the issue is that it will thread in until the nut is on the stud. But it wont go all the way down on the stud to tighten the ground wire. The nut gets stuck and it is way to hard to keep turning. I have tried this on both 455's I have and get the same result. I am using a 7/16-20 nut on these threads. Like I said, starts great and then gets super tight real quick. I bought new 7/16-20 nuts at Ace and just tried them and get the same result. I have put WD40 on the stud and then tried a little grease, still gets stuck...

So is 7/16-20 the right thread? If not, what is?

This just seems way tight for this nut to go on...

 

From memory I thought the stud was 3/8 16 the same size as what screws into the block? Apparently it is not if a 7/16 gets tight on it. Maybe we need a picture of the stud.

 

I think it's 3/8 16 too.

 

The studs on the heads are fine thread so definitely not a -16 thread. Just trying to remember if it is -20 or 28. If the car in question is a 69, the negative battery cable is supposed to connect to the front of the driver's cylinder head with a bolt that may be 3/8-16. A picture of what you are doing would be helpful.

 

Whatever it is, i just got it to work...the one went on easier than the other. Both are on now. No cross threads. I just wanted to be sure I wasnt going to mess the threads up. Went on nicely. Part number from ACE is 806-J, which I am pretty sure I picked up out of the 7/16-20 box

Thanks for the help!

Doug

 

Here is a pic of just the stud. And a pic with the nut I just bought on it. Thanks again for helping me out guys....

 

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That's PS stud on a lot of cars and it's 28 thread not 20. The threads stop well before the bottom maybe you just need to add a lock washer.

 

The ground cable from the battery to the block does not go on that stud! It's a 3/8 bolt that goes into the block just behind the PS pump and below the cyl. head facing forward.

 

And for what it is, it is a royal pain to get to. You can see it so easily, but you can't use a socket (at least I've never figured out a way of doing so). Regular conbination wrenches can turn next to nothing. The best wrench on that &!@? bolt is a curved handled combination and the open end is easier to use than the boxed end. No wonder so many people wind up moving where the cable mounts to.

Nothing like a morning rant.

 

Once again thanks for the insight! I will look for the 3/8 stud you guys are talking about and see where this goes. For now as it is, I am grounded to the ground!

Doug

 

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You won't find a stud, just a hole in the head where a BOLT goes.

 

Not sure why I typed stud, I was able to get the BOLT on earlier today, much better now. Thanks guys!

 

Nope. It's a hole in the block. But, as the others said, it's so hard to get to that most people use a hole in the front of the head instead.

It helps if you use the correct bolt. It has a thinner head than the typical 3/8 bolt. Without the thin head, it's hard to even get the bolt positioned straight to start it. Even with the thin head, you'll likely have to loosen the power steering pump. What makes it even more difficult is that you're trying to bolt on a stiff, thick-*** ground cable.