Head bolts; 1.5 vs 2F what's the difference and why?

[Pighead]

I pulled my cylinder head the other day, routine valve job, 4 of the head bolts have washers, 11 are shouldered. They look pretty much the same otherwise.
What is the actual difference between the Late F and the 2F head bolts? Why are they different? Is the difference in the blocks or in the heads?

 

[charliemeyer007]

No clue. When I do mine I'm going to chase the threads in the block. I like washers, as they can "slip" easier when torqueing IMHO.

 

[Texican]

THE 2F AND THE 1974 1.5 F REQUIRES THE STEPPED BOLT IN THE HOLE THAT FEEDS OIL TO THE ROCKER ARMS!!!

 

[65swb45]

The 1.5 head bolt is approximately 1” longer than the bolts in both earlier and later years. Because it was the FIRST year that the internal oiling system for the rocker assembly came online, it’s reasonable to assume that they cast the deeper pockets in the block to be EXTRA sure the torque was adequate to seal the newly-designed internal oil passageway.

As far as the washer situation, the earlier bolts used them, but had standard hex heads. The later heads had flanged hex heads to make them more idiot-proof.

I have had not one but two earlier engines in the last three years that the head gasket failed because one or more washers were missing from the original head bolts. The extra penetration depth of the bolt without the washer caused it to bottom out, causing a false torque reading during assembly.

 

[EWheeler]

The 1.5 bolt is approximately 1” longer than the bolts in both earlier and later years. Because it was the FIRST year that the internal oiling system for the rocker assembly came online, it’s reasonable to assume that they cast the deeper pockets in the block to be EXTRA sure the torque was adequate to seal the oil passageway.

As far as the washer situation, the earlier bolts used them, but had standard hex heads. The later heads had flanged hex heads to make them more idiot-proof.

I have had not one but two earlier engines in the last three years that the head gasket failed because one or more washers were missing from the original head bolts. The extra penetration depth of the bolt without the washer caused it to bottom out, causing a false torque reading during assembly.

Liked. Great info. Thanks Mark!

 

[65swb45]

I recently acquired a 1.5 long block from @LCMoneyPit which reminded me of something else. A couple of customers came by the shop before I started disassembling the engine and commented on a very unusual hose that had been added to the engine. It ran from a T fitting on the boss for the oil pressure sending unit up to the galley in the head that feeds the rocker arms. I didn’t think about it at all for the first week it was here.

Once I started the disassembly of the engine and actually had to unhook the hose, I chuckled. The odds are that the engine has had work done which included replacing the camshaft.

The 1.5 was also the first year the rocker feed was moved from the second journal of the cam to the third one. Odds are that when I pull the camshaft, I will find a pre-74, second-journal cam. Rather than pulling the cam to remedy this mistake, they created a bypass oil delivery.

 

[peesalot]

At least they knew enough to adapt something, not bad.

 

[DeskJock]

I recently acquired a 1.5 long block from @LCMoneyPit which reminded me of something else. A couple of customers came by the shop before I started disassembling the engine and commented on a very unusual hose that had been added to the engine. It ran from a T fitting on the boss for the oil pressure sending unit up to the galley in the head that feeds the rocker arms. I didn’t think about it at all for the first week it was here.

Once I started the disassembly of the engine and actually had to unhook the hose, I chuckled. The odds are that the engine has had work done which included replacing the camshaft.

The 1.5 was also the first year the rocker feed was moved from the second journal of the cam to the third one. Odds are that when I pull the camshaft, I will find a pre-74, second-journal cam. Rather than pulling the cam to remedy this mistake, they created a bypass oil delivery.

Interesting. assuming your going too put in back into stock configuration? or is that work around good?