Valve cover bolt size I6 258 - the one that's different

[Flex BT]

My valve cover didn't have the rearmost bolt on it. It is smaller than the rest but I don't have anything handy that fits. Can anyone tell me what thread / size / type this bolt is supposed to be?

Edit: It's an aluminum cover, the thread pattern in the engine block is what I'm looking for.

 

[IOPort51]

this is a new one on me. Are you sure someone didn't break something off in the hole? I would take the cover back off and climb up there to get a good look. these bolts are all the same size.

My valve cover didn't have the rearmost bolt on it. It is smaller than the rest but I don't have anything handy that fits. Can anyone tell me what thread / size / type this bolt is supposed to be?

Edit: It's an aluminum cover, the thread pattern in the engine block is what I'm looking for.

 

[tinman]

Just went out and pulled that one out of my old engine and it's smaller. I'm thinking 1/4" 20? I put a nut on it that I just got from the local hardware store that they sell in bulk, course thread, and it fit just fine. I think the rest of the valve cover bolts are 5/16".

 

[Flex BT]

Just went out and pulled that one out of my old engine and it's smaller. I'm thinking 1/4" 20? I put a nut on it that I just got from the local hardware store that they sell in bulk, course thread, and it fit just fine. I think the rest of the valve cover bolts are 5/16".

Thanks!! I hope that's the one...

 

[IOPort51]

that's one of those things that make me go "Huh".

pretty sure the original 77, the 81 and all the 4.0 heads I have had anything to do with have all been the same size but if you have two 81s that this occurs on maybe I am mistaken.

 

[tinman]

Not sure why either....both the my 81' and 84' heads were that way, but my 95' 4.0 bolts are all the same. I haven't been around long enough to see any other heads.


And I meant "coarse" of course.