Crooked Block Stud

P

PeterinNH

Senior Member
I have one new block stud that's out of alignment with the other studs on the
top row of my left engine bank. It's definitely nothing to do with the stud as I
chucked it in my metal lathe and it's straight as an arrow. It needs to be moved
an eighth of an inch in order to be able to get the head on. According to my
straight edge all of the top holes are in perfect alignment as the studs come out
of the block. There is no evidence that anything has been done to repair/replace
the threads.

It makes the most sense to me to try to adjust it while it's in place as it's going
to be the easiest way to tell when it's been straightened enough.

What advice might any of you have concerning this predicament?
 
The thread may not be concentric with the shaft.
If you remove the offending stud and install the head, can the stud be installed with the head in place? If so, a couple of nuts locked on the thread and install the stud.
 
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I thought about trying that method but that area is the thickest part of the head
and I'm concerned about cross threading the stud.
 
Peter in NH said:
I thought about trying that method but that area is the thickest part of the head
and I'm concerned about cross threading the stud.
Click to expand...
You won't know unless you try it.
That's the way 8BA head bolts are installed, generally with little concern about cross threading.
 
If the holes in the block are correctly aligned, why can't you just install a new stud?
Could it be that the hole in the head is "off"? Try the other head for fit.
 
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Have you tried that stud in a different hole to see if it's the stud or the hole
misaligned.


Bob
 
I have used 2 different measures to align studs. One is with a piece of pipe that just fits over the stud to use a lever to move the stud. The other is to use two nuts on the top of the stud and then using a hammer to coax it into alignment.
 
Try to do it the right way now, you'll be much happier in the end!

We do these "fixes" all the time on all the different mfr's units! Customer attempts the fix, can't get it quite right, and calls us in!

Previously repaired bolt holes can generally be corrected with the help of a pipe plug install first, usually a 3/8" NPT, then a fresh 7/16" hole installed! The repair depends largely on the location of the area needing the fix.

Recently did a similar repair on the oil pump stud hole in a BBC. Fortunately this was a simple 7/16" heli-coil fix.

Thanks, Gary in N.Y.

P.S. It does help to have the necessary tools at hand to make it an easy chore! We have a large choice of tools here. Here's a couple shots, one "before" and one "after", on a recent head bolt hole fix!
 

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Bob C said:
Have you tried that stud in a different hole to see if it's the stud or the hole
misaligned.


Bob
Click to expand...

Exactly. Trade this stud with the one beside it.
If the problem moves to next hole, the stud is at fault.
If the problem stays in the same place, it's the threads in the block.

If it is the stud, I'd get another stud.
If it's the block, and it's only 1/8" out at the top, I'd put a pipe over the stud, and carefully coax it to where the head can be installed.

Good Luck
 
Full disclosure: I have not worked on a flathead in at least three decades.
With that said when the offending stud is in the lathe it should be easy enough to see if the coarse thread is concentric with the rest of the stud. With the stud screwed into the block is it square to the deck? If not you might try taking a soft hammer and a square with a 12” blade on it and bop the stud with the hammer checking to see when it is “adjusted” enough to be able to install the head. If the stud was square with the deck from the get go then I guess the head comes into question. Is it an aftermarket head or factory? Either way I would imagine that the holes were gang drilled but if they had been drilled one at a time surely they were drilled with some sort of fixturing which pretty much eliminates the head but I guess stranger things have happened.
 
This is a problem I've been thinking about for a while now. I bought a new set of Roy Nacewicz replacement studs and they are dead nuts straight. I tried several different
new studs in this hole and it makes no difference. I personally believe it's the hole in
the block that's the culprit. This is a rebuilt engine that came with my car. After noticing
this problem I gathered up all the long studs that were in the block when I bought it
and began chucking each one in my metal lathe to check for straightness. After about
the sixth one I came across one that the rebuilder had obviously bent to rectify this problem. As I wanted to use one of the new studs in this hole i decided to get some
opinions as to what could be done. I don't feel comfortable trying to tweak the new stud
while it's in the block as old cast iron doesn't like to be stressed therefore I'm going to
simply use the odd ball stud that's been bent.

Thanks for all of your help and suggestions.

Peter
 
You can give yourself some extra room by cleaning the inside of the holes on that head.
 
If the hole has been helicoiled, the person that did it may not have tapped it straight.

Just put the tweaked stud in, check for straightness and test a head on it. If it fits ok just try and pretend it never happened.

Good job you haven't told anybody.

Mums the word, wink wink.

Mart.
 
Sounds like he's got it figured out... On a semi-related note!

If you have an old block, and want to replace the old, original studs that have been rusted in place for 80 years... do so very carefully. The first time I did this, I just tried to back them out with a stud remover and penetrating oil. After breaking three of them off flush with the deck, I decided discretion was in order. lol

Do NOT try and remove the studs unless you have a torch. Heat the studs up red hot in order to break the rust bond with the block. If you've gotten it hot enough, it will back right out. If it doesn't back right out, don't force things... heat it again, and get it a little hotter.

(edit) A standard Propane torch will NOT get it hot enough. Oxy/Acetylene torches are where it's at. MUST be red hot... then they back out like magic. :)

It's a LOT easier if you do it right the first time. lol

Good Luck!
 
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Mart>>>pretend it never happened.>>>Good job you haven't told anybody.>>>

Someone I know busted two 7/16" studs flush with a tractor deck? Felt welded washer-nut & torch extractions were fairy tales. So hand-drilled & tapped for 3/8" galvanised threaded rod. Rods seemed straight & good enough using oversize 3/8" nuts so nobody would notice. Pretended it never happened. Promised not to tell anybody who the great pretender was. 8^) Jack E/NJ
 
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