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02-12-2021, 12:07 PM | #1 |
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New video: Larry Brumfield's block thread test
About a month ago I made a short video showing my take on Larry Brumfield's procedure for testing the strength of engine block stud threads. This procedure is posted on fordgarage.com, but it's pretty high-level and leaves room for interpretation. So I took some liberties with the protocol for convenience.
I subsequently heard from Larry, who is alive and well, though no longer participating on FordBarn. He was, I should mention, very nice. Over a couple dozen emails, he explained the entire procedure and his reasons for doing it that way. So I have now re-shot the entire video to faithfully (I hope) reproduce the Brumfield block thread test. I've also included some of the research I did on my own to figure out the science behind the choices, in case anyone is interested. Link: https://youtu.be/ibaPf0FQnZM In the end, I probably agree about 95% with the test protocol. I still think it would be better to torque the nut up in steps as would be done in the real cylinder head install. But I promised Larry that in this video I would stick to his version of the test. I will say, in the process of researching and shooting this video I sure learned a lot about fasteners. |
02-12-2021, 03:02 PM | #2 |
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Re: New video: Larry Brumfield's block thread test
Larry is Very knowledgeable on Heads and installation process! I have followed his recommendations on all head work and Never had a problem!
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02-12-2021, 05:01 PM | #3 |
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Re: New video: Larry Brumfield's block thread test
Great, informative video. Thanks.
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02-12-2021, 08:44 PM | #4 |
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Re: New video: Larry Brumfield's block thread test
I have some questions.
1- Why did you use that particular thread lube? 2- Why did you use stainless steel for the spacer block? 3- Why did you use plated standard grade 8 nuts instead of hard high nuts like Larry does? 4- Why did you NOT use a hard heavy machine washer under the nut? 5- Why did you use that torque value for testing? |
02-12-2021, 10:23 PM | #5 | |
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Re: New video: Larry Brumfield's block thread test
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02-12-2021, 10:39 PM | #6 | |
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Re: New video: Larry Brumfield's block thread test
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02-12-2021, 11:02 PM | #7 |
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Re: New video: Larry Brumfield's block thread test
My question posed is what stretch or deformation does the coarse thread experience in the cylinder block? Since to my knowledge most studs use rolled threads and in most of the thread engagement is based on 75%, what effect does this point produce. If you were to check with the correct tap drill size diameter in the cylinder block holes, what oversize say .005 or .010 would be acceptable and still get good stud allowable stretch?
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02-12-2021, 11:18 PM | #8 | |
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Re: New video: Larry Brumfield's block thread test
Quote:
For the studs, this reduced engagement may not matter much, because we're using stronger alloys than the factory studs. However, the cast iron engine block is the same as it was 90 years ago, and in fact probably substantially worn. So over time, you're putting more and more psi on less and less internal thread. That's why the testing is important. Regarding the issue of how much the coarse threads deform in the block under load, my understanding is that, because these are Grade 8 studs, a clamp load of 8-10k lbs is well within the stud's elastic deformation range. In other words, when the tension is removed, the stud will return to its unstressed shape and unstressed thread pitch. However, one might also ask whether the same is true of the internal threads in the block – are they still within their elastic deformation range, after 90 years? We really don't know. It is certainly possible that these blocks all have a "countdown" of the number of times they can be fully torqued down before one or more threads fail. I worry about that – about whether the testing is shortening the useful life of the block. |
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02-13-2021, 07:45 AM | #9 |
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Re: New video: Larry Brumfield's block thread test
What is the advisability of using helical coil inserts?
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
02-13-2021, 07:50 AM | #10 |
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Re: New video: Larry Brumfield's block thread test
The main difficulty with thread-repair inserts is that they have to be installed carefully and correctly to ensure that the axis of the insert is precisely aligned with the axis of the original bore. Otherwise, they're great. Here's a really helpful article that explains your options for thread-repair inserts.
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02-13-2021, 09:37 AM | #11 | |
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Re: New video: Larry Brumfield's block thread test
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02-13-2021, 09:59 AM | #12 |
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Re: New video: Larry Brumfield's block thread test
Good job Colin.
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02-13-2021, 11:05 AM | #13 |
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Re: New video: Larry Brumfield's block thread test
Thanks everyone. I’m still planning to make the cylinder head installation video I posted about a couple months ago. Both this video and the stud hole cleaning video spun out of that project as I realized they were too long and complicated to be part of a larger video. I’m also splitting off a separate video that’s just about the preflight checklist for a cylinder head installation.
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02-13-2021, 01:15 PM | #14 |
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Re: New video: Larry Brumfield's block thread test
A very precise and well communicated video. Exceptional!
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02-15-2021, 02:52 PM | #15 |
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Re: New video: Larry Brumfield's block thread test
Funny story about this video: Someone posted it to VFF and a discussion ensued. I tried to register there to respond to the discussion, but I somehow violated an obscure TOS during registration and have now been banned from VFF. Oh well! One less forum is probably good for my health anyway.
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02-15-2021, 03:07 PM | #16 | |
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Re: New video: Larry Brumfield's block thread test
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02-15-2021, 03:11 PM | #17 |
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Re: New video: Larry Brumfield's block thread test
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02-15-2021, 03:13 PM | #18 |
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Re: New video: Larry Brumfield's block thread test
So true....LOL
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02-15-2021, 10:18 PM | #19 |
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Re: New video: Larry Brumfield's block thread test
What’s a TOS?
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02-15-2021, 10:28 PM | #20 |
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Re: New video: Larry Brumfield's block thread test
"Terms of Service," like the rules for the forum. Apparently there is a rule that if you register, but have no activity after 15 months, it blocks you and you can't re-register. Not actually stated anywhere on the site. So I registered back in 2019 but then didn't post or visit. So now I'm banned. Who knew?
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