1970 134 Fhead Head Gasket Replacement

Magnetic base drill press. You should be able to rent one locally.

 

Where is everyone getting the 4.25" head bolt length? I just did my head gasket with these bolts and they fit just like they are supposed to at 4.5"

https://www.summitracing.com/parts/arp-hap4500-5

Kaiser Willys also stocks a 4.5" bolt for the heads.

 

1955 Jeep Parts book.

JeepPartsWiki - CJ-5 Parts List July 1955

 

Interesting... well I can attest to the fact that 4.5" bolts fit without any issues.

 

i stuck a punch down that hole. it goes awhile. that's why I was surprised the bolt length was only 4.25"

 

and now im incredibly gunshy about snapping the other bolts. I quit at 60 when I got to bolt 9. still had 6 more bolts to go...thoughts or suggestions?

I think since I am helicoiling one, why not do them all?

 

I guess while they're out you could chase the threads and get out all the old grime left in the bolt holes while you're back in there to ensure a proper torque.

 

i think so. i bought it years ago, and its been sitting on the shelf collecting dust forever. as for oil, I just sprayed on the gasket sealant, same stuff that I sprayed in the head gasket, onto the threaded ends of the bolts.

my options as I see them:

1. I get a longer bolt, since I have room for a 5" bolt easily. if it doesn't work, and I blow a head gasket, I have to take it all apart and helicoil it at that time.
2. I have to helicoil the bolt hole, and to do that I need to change the head gasket anyways, because I cant reuse it.

im leaning toward option 1, because this isn't a show boat motor. its old and tired. I want to do what's right, but at what cost? a 3 dollar longer bolt, and save the headache of removing the rest of it all.

 

I did that before I started. if I take it all apart again, I would.

 

This tells me your bolts aren't long enough. A general rule of thumb is: the bolt should grab a length of threads equal to the width of the bolt (at minimum), when bolt and threads are of similar metals. In this case, your bolt is hardened steel and your threads are cast iron (mush in comparison). The fact that you have less than 1/2" of bolt sticking out before you begin threading tells us that you have less thread length than width.

When you say your bolts are 4.5", is that the overall bolt length including the head or not counting the head?

When you have the head off, screw your bolts in by hand until they bottom. This will tell you how much thead depth you have to safely work with. Eliminate the guesswork.

 

4.5 is from the underside of the bolt head. the actual length of the rod with the threading on it. not overall length.

 

no Costco near me.

 

7/16 14

 

How deep is that hole? Does it just have some threading material in the block and then it opens up to the inside of the engine bay below it? Because I can fit a 10 inch zip tie down there with no bottoming out in sight.

My 5 inch bolt could be hand threaded to the stud head and then the same thing happened