7 bolt head bolt length question and 6 bolt head on a 7 bolt block 1G question

[ck1]

Sorry, I searched and I can't find the answer.

How do you measure the head bolts to determine if they are still good? With or without the washer? Does it matter on a 1994?

If equipped with 1993 vehicle, inspect the cylinder head bolts shank length prior to installation. If the length exceeds 3.79 in. (96.4mm), the bolt must be replaced. Install the washer onto the bolt so the chamfer on the washer faces towards the head of the bolt.

Also, I bought a used head to swap on my 94 turbo that I bent all of the exhaust valves on. When I bought it I thought that all of the 1G heads were the same per the vfaq. However, now I have discovered that there is a difference between the 1G 6 bolt anf 7 bolt heads. Is it just the bolt hole diameter? If so, will this be a problem? I can't see how it would be since there are alignment dowels in 2 corners.

Thank you

 

[Defiant]

Put a straight edge along the threads. If all the thread profile is even, you're good to go. If there's a spot where it has a "waist", or a narrow spot, it's stretched beyond re-use.

 

[turbo23]

The straight edge method only works when the fastener is stretched a large amount. The downside to this is that a fatigued head bolt will typically only have stretched a small amount. It wouldn't be noticed next to a straight edge to the human eye, but it would be considered a failed bolt regardless.

The proper way to measure fastener stretch is with a stretch gauge.
Of course, you would also need to know their free standing length before they were installed and used to compare to their current free standing length. A fastener should always rebound after being stretched. If it doesn't, then it's no good to use anymore.

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[ck1]

thank you for the replies so far. Any idea what the initial length is supposed to be? It seems strange that this is called out on the '93 model and not the '94. I am not sure if this is a typo or if the block is drilled deeper so that a longer bolt could be threaded in further.

Also, any input on the 6 bolt verses 7 bolt head question? I think I can use this 6 bolt head on a 7 bolt 1G with no modification. Correct?

 

[turbo23]

thank you for the replies so far. Any idea what the initial length is supposed to be?

They are all going to vary a little bit. The only way for measuring to work would be if you measured the exact set being used before they were used. ARP even sells info sheets to record such data.

IIRC, the stock head bolts are torque-to-yield. I'd strongly recommend not using them and just replacing them with ARP studs.