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37silverstreak

Head bolt questions

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Hey everyone,

I decided to pull the head on my '48 Plymouth, just because I just don't seem to have enough frustration in my life, and also to check for carbon buildup, cylinder condition etc. This car hasn't been started since 1995 so I've been going through it before trying to bring her back to life.

Anyway, two of the head bolts broke off. One near the top of the head and another at the base of the block, so now I have the fun of removing them!!! My questions are.

1. Can I reuse the old head bolts? I planned on cleaning them up and running a tap and die on them and the holes in the block. No matter what I'm going to need at least two replacements.

2. If not, where can I buy replacements? There is a seller on Ebay offering a set of new headbolts but wants $87 bucks plus shipping which works out to about $4.50 a bolt which seems high to me.

3. Would the head bolts from a truck engine be the same as the car engines. Again, there's a seller on Ebay selling a set of used headbolts from a same era truck engine.

Any input is always greatly appreciated, thanks!

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Only problem with doing something for poops and giggles is that you have to deal with the fall-out from it.  If you already snapped off two of the head bolts it would be wise to replace all of them, since there is no telling how, who, what torqued what you have now.  I would not use used head bolts, regardless of origin.  There are plenty of sources for new ones.    

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1 hour ago, 37silverstreak said:

Hey everyone,

I decided to pull the head on my '48 Plymouth, just because I just don't seem to have enough frustration in my life, and also to check for carbon buildup, cylinder condition etc. This car hasn't been started since 1995 so I've been going through it before trying to bring her back to life.

Anyway, two of the head bolts broke off. One near the top of the head and another at the base of the block, so now I have the fun of removing them!!! My questions are.

1. Can I reuse the old head bolts? I planned on cleaning them up and running a tap and die on them and the holes in the block. No matter what I'm going to need at least two replacements.

2. If not, where can I buy replacements? There is a seller on Ebay offering a set of new headbolts but wants $87 bucks plus shipping which works out to about $4.50 a bolt which seems high to me.

3. Would the head bolts from a truck engine be the same as the car engines. Again, there's a seller on Ebay selling a set of used headbolts from a same era truck engine.

Any input is always greatly appreciated, thanks!

Well,you  already have a set of used head bolts. How has that worked out for you so far?

 

Have you tried suppliers like Fastenal and Summit Racing for new ones?

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1 hour ago, greg g said:

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Less than a dollar when I got them a dozen years back for Gm applications but nearly identical.

Thanks for the tip! I Googled the part number and Summit Racing carries them. I just ordered a set, comes to just over $1.00 a bolt with shipping. Thanks again for your input.

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19 hours ago, 37silverstreak said:

running a tap

Using a tap to clean threads will often make the threaded bolt hole larger in a very old block!  Not the best idea I learned on this forum. Can make the somewhat sloppy on the treads and more prone to leaks if nothing else, since almost all go into cooling water. Always put thread sealant on all head bolt threads. I prefer permatex  aviation  sealer in the tube-Not the silicone type. Had bad luck with silicone  for water sealing before!

Buy a new proper sized thread chase to use instead. They are much easier on already tapped holes.

Best of luck on the broken bolt removal!

 

DJ

Edited by DJ194950

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Take the best old bolt you have and clean it up with a wire wheel.  Then with an angle grinder or dremel cut three or four vertical cuts along the length of the threads opposite of each other.  Don't fret if the cuts are evenly spaced or completely vertical, they are just a space for crud to slide into.  Use lots of penetrating oil and put the bolt down the hole in stages, backing it out and cleaning the threads till they go all the way down.  Remember to account for the head thickness they don't need to bottom out.  Then buy a brass spiral wire brush slightly larger than the holes and chuck it up in a slow drill and give them a go with some more penetrant or Marvell Mystery oil.

Edited by greg g

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Hey everyone,

Thank you for the input! Here is an update and hopefully a last question. I have a new set of correct head bolts and was able to remove one of the broken bolts with a stud removal tool. The other one was not so easy as it broke off near the base of the block and It just wouldn't come out. So, I filed it flush and with a lot of care I now have a 1/4 inch pilot hole drilled down the center of the bolt, so I'm making progress. My question is, should I try drilling it out and tap the hole for the 7/16 bolt or do I just go ahead and install a Heli-coil?  

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1 hour ago, 37silverstreak said:

Hey everyone,

Thank you for the input! Here is an update and hopefully a last question. I have a new set of correct head bolts and was able to remove one of the broken bolts with a stud removal tool. The other one was not so easy as it broke off near the base of the block and It just wouldn't come out. So, I filed it flush and with a lot of care I now have a 1/4 inch pilot hole drilled down the center of the bolt, so I'm making progress. My question is, should I try drilling it out and tap the hole for the 7/16 bolt or do I just go ahead and install a Heli-coil?  

If it were me,I think I would try to drill out the center with a drill at least half the diameter of the head bolt,and then immediately use a broken stud remover to try to unscrew it. The heat from drilling it out  just might allow it to come out easily. If not,keep drilling it out with slightly larger drills until you are close to the threads,and then try to take a punch and tap what is remaining of the threads away.

 

If that doesn't work you can always drill it out close to the threads and then use a tap to cut it out. Chances are the heat build up will have broken the thread "seal" long before that,and the broken stud remover will back it out,though.

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Have you thought about arp studs. Worked great for my 218

image.jpeg

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You can purchase left handed drill bits from McMaster Carr or similar company. They will also help as you will be drilling in reverse and usually will back the broken bolt out.

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Not trying to hijack this thread, but I've been wondering what you guys do to mount items to the top of the engine, when you no longer use the factory bolts that have the threaded recesses in the heads?  For example, on my engine, there are short bolts that hold the horn in place by threading into the recesses in the heads of the head bolts.   Many people use new bolts that are intended for Chevy engines, and they work fine for the primary function of holding the head in place, but they don't have threaded recesses to accommodate the bolts for the horn and other items.

Edited by Matt Wilson

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Check- vintagepowerwagons.com

They sell NOS head bolt for bolt on accessories.  😉

 

If it works- see-

DJ

Vintage_Power_Wagons_Parts_Catalog-Group_01_Engine.pdf - Google Drive.html

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John,

   Now that is one beautiful engine!!!!! Best regards to you . . . .

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3 hours ago, DJ194950 said:

Check- vintagepowerwagons.com

They sell NOS head bolt for bolt on accessories.  😉

 

If it works- see-

DJ

Vintage_Power_Wagons_Parts_Catalog-Group_01_Engine.pdf - Google Drive.html

Ok, I wonder if they got some more in stock.  Last time I inquired about them (last year, I think?), they said they could not get them anymore.  I may have to check back with them.  Thanks.

Edited by Matt Wilson

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You might have to heat up around the broken stud. Another trick is drip some melted wax around the broken stud. 

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