M38 : OK, Boomer

Post by **jake138** » Thu Mar 31, 2022 5:35 am

Naugha wrote:But then, being a sucker for shortcuts, I opened a can of internet worms by reading about how some folks replace unwanted studs one at a time without removing the head. I began having the fantasy of an ‘easy fix’ but thought it best to check in with HQ before I venture into yet another disaster.

Between the time spent reading how to do things wrong on the internet and the time it took to write your post, you probably could have taken the head off and been done with it by now, especially since everything was just freshly assembled.

Buy a new head gasket and follow your torque sequence. The risk of needing to replace the head gasket in the future is not worth the reward of saving, honestly, 20 minutes of time now. It's a flat head. You've shown up to this point that you have the mechanical ability to pull that head, replace the studs, and torque it back down in no time at all.

Naugha · Post by **Naugha** » Thu Mar 31, 2022 6:26 am

Hi Jake. Everything below is said with a big smiley face.

That’s one vote yes. One vote no.
BTW. Two professional mechanics ignored the head stud length issue and other ‘best practices’ rules.

Have you ever asked three mechanics which way a freeze plug should be inserted into a block?

And which side of that new totally unmarked head gasket should go up

Emperor Constantine locked all the Top Dogs in a room with the understanding that they must hammer out a final, absolute, complete version of the facts. I don’t think this ever happened in the history of auto mechanics, or at least the word never got out to everyone. For non-mechanics, it can be very confusing when experts don’t agree.

You know who usually steps in with the final word?

While we wait.... I will take out one stud and (assuming all the short ones are the same length).... I will find seven slightly longer studs.

Naugha · Post by **Naugha** » Thu Mar 31, 2022 8:55 am

At the barn.
Pulled two of the seven short studs.
No problem removing the studs. Smooth.

Both measure 3.5” end to end.
Is 3.5” the correct spec for one of the studs in the above diagram and TM?
Not sure. Correct me if wrong.

The studs associated with the oil canister & crossover tube brackets are flush with the top of the nut. One or two of the other shorts have maybe a thread showing.

So 3.5” is too short.

Is there a commonly available over the counter length that would be a good choice for replacing the short head studs? I would rather not get into modifying stud lengths.

Or.... I could replace the 3.5” studs but not bottom out the studs so as to leave a few threads above the nut, which sounds very wrong.

Hold on... I just tried that. Stopping at ‘tight’ gives you maybe two threads above the nut but ‘finger tight’ with strong fingers will take you down another thread which is too short.

I think those seven studs need to be longer than 3.5.”

Post by **jake138** » Thu Mar 31, 2022 10:54 am

Naugha wrote:Hi Jake. Everything below is said with a big smiley face.

As was with my comment friend.

I figured I'd throw in my .02 simply looking at it like my own Jeep: if there's a chance that I would have to replace the head gasket in the future, would I rather do it now with the engine on a stand or reaching over the fenders with the engine installed?

As for the stud dilemma, that's between you and the restoration purists. My Jeep has an L134 out of a truck, I could care less about the accuracy of my head studs! Mine all extend above the head nut, they torqued down nicely, and they're thread sealed, so that's all I care about.

It's hard to tell from written comments on the internet, but it sounds a bit like you're putting yourself down asking questions about the freeze plug and head gasket directions? As a retired school teacher, you should know better than anyone that the only stupid question is the question unasked.

Unless, of course, when I'm in the middle of a lesson teaching micrometer reading and the student in the back raises his hand to ask "Why is the sky blue?". Given the context, now, that was a stupid question

RonD2 · Post by **RonD2** » Thu Mar 31, 2022 11:50 am

Hi Jake,
Don's fresh motor with new head gasket hasn't been started the first time yet and is mounted in his frame without tub or fenders (see his previous photos).
Not quite as easy to work on if it was still in a motor stand, but pretty easy to work on as it is.

I could be mistaken, but thought the stud discussion was less about restoration purity and more about using sound mechanical consideration for proper stud length thread engagement and installing them.
More specifically, the discussion is zeroed in on studs that might (or might not be) long enough to correctly do the job. Studs that are obviously plenty long enough (even too long) haven't been the focus.

Post by **jake138** » Thu Mar 31, 2022 12:16 pm

Ahh that's what I get for trying to follow this thread on my phone, I completely missed those photos!

Now seeing the motor dressed and installed, that does somewhat change things... I thought the stud debate was just about authenticity, now with the pictures I can what you were talking about.

With the studs actually measuring 3.5", that matches the drawing Wes posted as well. So it looks like Don just needs to swap those studs and he should be ready to move on.

RonD2 · Post by **RonD2** » Thu Mar 31, 2022 12:25 pm

Yes, obviously he could replace all the 3-1/2 inch studs with long studs (3-7/8 inch), or try to source some slightly longer than 3-1/2 inch to buy.
Based on a little searching, I think finding those studs might be hard to do.

But before he does that, I believe the lingering question is if it's sound mechanical technique to use his 3-1/2 inch studs but seat them a little short in the block, to give him the necessary 2-3 threads showing on top above the nuts after they're torqued down.

Naugha · Post by **Naugha** » Thu Mar 31, 2022 1:12 pm

Ron may not always be right .... but he is never wrong. Just ask him.

Several variables in play.

Post by **jake138** » Thu Mar 31, 2022 1:22 pm

I think he would be better off not having the studs bottomed out in the block with a longer stud. I think a shorter stud that's threaded by hand to the bottom of the threads, and then backed off before installing the nut, is going to be the best way to prevent the stud from getting over tightened into the block.

RonD2 · Post by **RonD2** » Thu Mar 31, 2022 1:35 pm

I agree.
But I could be wrong.

Naugha · Post by **Naugha** » Thu Mar 31, 2022 2:37 pm

Consensus is a wonderful thing.... even if we are wrong.

Anyone else want to play??

* Buy longer studs? How long? Where do you get ‘em?
* Use the 3.5” studs. Slather them with Permatex #2. Back ‘em out a tad.
* Don’t pull the head? Pull the head and replace the gasket?
* Don’t do anything. It will probably be OK.

Shall I just pick Door# x,y,z and get on to other things?

And yes, by this time I could have already pulled the head and dropped in some oversized studs.

RonD2 · Post by **RonD2** » Thu Mar 31, 2022 4:51 pm

Did you already clean the thread sealer off the coarse ends of those studs?

Naugha · Post by **Naugha** » Thu Mar 31, 2022 7:24 pm

I have not cleaned the studs.

I used thread sealer but now only see a residue in the course threads.
Maybe I missed some studs? Maybe I did not use enough sealer?
Should there be a big glob of Permatex ??

Stuck in the mud again. Need a game plan here.
Tempted to zip it up, move on and fix disasters as they manifest.

RonD2 · Post by **RonD2** » Thu Mar 31, 2022 8:09 pm

What did you use to seal them?
If it was the hardening kind, maybe it just broke off when you pulled it.
If it was the pliable kind I'd think some evidence would stay on the threads. You said there was residue (not visible in the photo).
If you missed some I think you'll know about it pretty quick when you light it up.

Have you decided what you're going to do with studs?

I went back and looked at your first post 18 months ago.
You've come a long way.

Naugha · Post by **Naugha** » Fri Apr 01, 2022 6:39 am

As we now know, I bought 3.5” studs that should have been acceptable ... but no, that’s not how my luck runs. Also, there is now some question as to my proper application of sealer.

So I start over.

Replacing the seven 3.5” (too short) studs with something a few threads longer should solve the problem. Maybe replace all of the shorter studs. I will also pull the head, pull all the studs, chase/clean the stud holes, add sealer, replace the head gasket and torque the nuts to spec.

Finding or making slightly longer studs is my next step. Wonderful.

I see a listing for “WO-A1549 (3 7/8”) studs.”
Is that the three long ones?

The diagram shows WO-A1548 as 3.875”.
Are WO-1548 and WO-A1549 about the same stud?

About how many more threads on a WO-A1548 or WO-A1549 than the 3.5” stud.