Left rear cylinder head bolt 172

William Fissell · Mar 9, 2016

Hi, All,

the head I had worked fine. I have one bolt that wont tighten. just spins. Is the left rear tapped hole in the block
tapped for a larger cylinder head bolt than the rest? All the through holes in the head are the same. The Ford manual
makes no mention and the CNH website seems to indicate they are all the same bolts, 7/16-14 x 4

thanks

Bill

BBq-Bob · Mar 9, 2016

Sounds like the threads may have stripped out of the hole. May need to drill and tap for next larger size bolt or possibly install a helicoil. Evaluate the condition of the threads you have and take note of the available wall thicknesses.

JWA · Mar 9, 2016

All the head bolts are the same size in that block unless it has been tapped oversize.

BBq-Bob · Mar 9, 2016

If you haven't removed the bolt yet; it's likely that the bolt was over torqued and snapped, leaving the head portion to spin. This is not so bad because it means you will still have good threads in your block when the remainder of the bolt is removed.

William Fissell · Mar 9, 2016

I'll look again. I removed the head and replaced it with another. I didnt think about the bolts *at all*

all the holes in the head same size. I ended up with ONE bolt too big to fit in the head and ONE hole that the 7-14-4 bolt just spun around in.

So I'll pull the head back off and see whats up. I have to put thread sealant on the bolts that go in the water jacket anyway.

William Fissell · Mar 14, 2016

Well, the answer was that the hole in the block was tapped for a 1/2 inch bolt. I assume PO did so after stripping or snapping. I looked at the head and drilled the 7/16 out ot
9/16 and put the head on. we'll see what comes.

Left rear cylinder head bolt 172

William Fissell

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BBq-Bob

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JWA

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BBq-Bob

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William Fissell

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William Fissell

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