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Stripped Exhaust Maifold Thread

Started by headejm, July 29, 2017, 02:38:47 PM

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headejm

@Chryco Psycho Rebuilding my 383 HP engine and the front passenger exhaust manifold thread in the cylinder head is shot. Not a big fan of using heli-coil and was wondering if I could just tap it oversize and use a bolt? It's one of the holes that goes into the water jacket and that's one of the reasons I don't want to use a heli-coil. Do you see any problems using a bolt to secure the exhaust manifold?

Chryco Psycho

You can do that you may have make the hole in the manifold a bit larger or add learane for the nut or bolt head .
there is also a product called a Timesert it is similar to a Helicoil but is solid so coolant cannot seap up the threads http://www.ebay.ca/itm/Time-Sert-03815-3-8-16-x-750-Carbon-Steel-Insert-10-Pack-/280789503724?hash=item41605bceec:g:Xr0AAMXQjWtRMPYd

Chryco Psycho



RUNCHARGER

Good find CP! As I was reading the post I was thinking how I would thread in a larger bolt and maybe cut threads to 3/8 to use a regular nut But there's the solution right there.
Sheldon

Chryco Psycho

Yup thread the head install the stud , no water leak & use the stock size nut  :banana:

headejm

#5
Quote from: Chryco Psycho on July 29, 2017, 05:40:56 PM
This is probably a better solution , tap the head & thread this in  http://www.allensfasteners.com/detail.asp?Product_ID=23003A

Thanks @Chryco Psycho! Much better than a larger bolt. You da man!  :cheers:

Edit: I just looked up the stud. $1.60 for the stud and $7.15 for shipping one stud. Huh?  :pullinghair:

Burdar

I had the same problem on one of my 360 heads. I drilled out the hole and tapped it 3/8. Then I machined down one end of a 3/8 stud to 5/16. With the manifold installed, you can't tell. It uses a stock nut.


Shoooter

I was thinking the same thing. I used one similar when I did the head studs on my Yamaha rhino.  Did you check the local parts store?

Chryco Psycho

Find a different supplier , $7 to ship it is stupid , that was just the first place I found that carried it  :Thud:

73440

While looking at Fastenal website , saw this manufacturor who may have what you need.

https://www.auveco.com/default.aspx

RUNCHARGER

Man: I had a stubborn, broken one on the front left head on my Road Runner. I pulled the manifold and there was nothing I could do to get it out. I finally welded onto the stud to build it up and then I jigged up another half stud outside of the broken stud in mid air and welded that to the weld build up. I torqued the manifold nut about half tight and it held.
Sheldon