Installing Headers
Tuned
Joined: Sep 2014
Posts: 454
Likes: 92
In the machine tool industry we have used a basic formula for many decades....
a minimum of 1.5 times the diameter of thread engagement in steel,cast iron and a minimum of 2 times the diameter in aluminum.
Having built brand new machine tools for years, this is a tried and true formula.
a minimum of 1.5 times the diameter of thread engagement in steel,cast iron and a minimum of 2 times the diameter in aluminum.
Having built brand new machine tools for years, this is a tried and true formula.
Lead Driver
Joined: Apr 2007
Posts: 5,958
Likes: 105
From: Houston
In the machine tool industry we have used a basic formula for many decades....
a minimum of 1.5 times the diameter of thread engagement in steel,cast iron and a minimum of 2 times the diameter in aluminum.
Having built brand new machine tools for years, this is a tried and true formula.
a minimum of 1.5 times the diameter of thread engagement in steel,cast iron and a minimum of 2 times the diameter in aluminum.
Having built brand new machine tools for years, this is a tried and true formula.
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
In the machine tool industry we have used a basic formula for many decades....
a minimum of 1.5 times the diameter of thread engagement in steel,cast iron and a minimum of 2 times the diameter in aluminum.
Having built brand new machine tools for years, this is a tried and true formula.
a minimum of 1.5 times the diameter of thread engagement in steel,cast iron and a minimum of 2 times the diameter in aluminum.
Having built brand new machine tools for years, this is a tried and true formula.
Lead Driver
Joined: Apr 2007
Posts: 5,958
Likes: 105
From: Houston
Ive always used a 3/8" wrench and work the closed end over the bolt head and starting in the middle I work my way out snugging down through multiple passes till I cant get the bolts to turn anymore. I also strongly advise to double check them, Ive had customers come back in a year later and not bringing it back like I tell them to at 500 - 1000 miles for me to check the header bolts and in a years time they have bolts missing or backed out. Dont care what you do with actual ARP header bolts they have to be tightened down again. I thought of putting something like loctite 242 on them but going form memory I dont think the 242 is rated high enough temp for exhaust use. Plus if you are going into aluminum heads may pull the threads out on removal.
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
I always laugh at that, they have a fastener torque spec but yet how are you supposed to torque header bolts to their spec when you cant even get a ratchet on them in the first place.
Ive always used a 3/8" wrench and work the closed end over the bolt head and starting in the middle I work my way out snugging down through multiple passes till I cant get the bolts to turn anymore. I also strongly advise to double check them, Ive had customers come back in a year later and not bringing it back like I tell them to at 500 - 1000 miles for me to check the header bolts and in a years time they have bolts missing or backed out. Dont care what you do with actual ARP header bolts they have to be tightened down again. I thought of putting something like loctite 242 on them but going form memory I dont think the 242 is rated high enough temp for exhaust use. Plus if you are going into aluminum heads may pull the threads out on removal.
Ive always used a 3/8" wrench and work the closed end over the bolt head and starting in the middle I work my way out snugging down through multiple passes till I cant get the bolts to turn anymore. I also strongly advise to double check them, Ive had customers come back in a year later and not bringing it back like I tell them to at 500 - 1000 miles for me to check the header bolts and in a years time they have bolts missing or backed out. Dont care what you do with actual ARP header bolts they have to be tightened down again. I thought of putting something like loctite 242 on them but going form memory I dont think the 242 is rated high enough temp for exhaust use. Plus if you are going into aluminum heads may pull the threads out on removal.
650°F is more than hot enough for headers, if the cylinder head that the bolt is screwed into gets up to 650° you will have will bigger things to worry about than lose headers....
Lead Driver
Joined: Jun 2013
Posts: 5,643
Likes: 1,154
From: Tolland, CT
Is it just me or do other remember lock washers on header bolts...?
If you really wantto torque them to spec, I doubt most of us do, there are a few "attachments" that will let you get at the bolt head, one example would be a "crowfoot wrench".
But in the real world, you just need to check them from time to time, just like you should be doing a few times a year when you look over the truck and engine for issues.
If you really wantto torque them to spec, I doubt most of us do, there are a few "attachments" that will let you get at the bolt head, one example would be a "crowfoot wrench".
But in the real world, you just need to check them from time to time, just like you should be doing a few times a year when you look over the truck and engine for issues.
Freshman User
Joined: Apr 2021
Posts: 37
Likes: 7
From: Clarksville TN
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Lead Driver
Joined: Jun 2013
Posts: 5,643
Likes: 1,154
From: Tolland, CT
That's what I was thinking too.
I hope this doesn't turn into a issue. It's just 1/4" or 5/16" header bolts we're talking about not a 3" bolt the holds a bridge up or the something like the 7/8" bolts we use to hold the 11,300lbs.Oxygen Generators in the Virginia class Submarines.
Hopefully we can just move on.
I hope this doesn't turn into a issue. It's just 1/4" or 5/16" header bolts we're talking about not a 3" bolt the holds a bridge up or the something like the 7/8" bolts we use to hold the 11,300lbs.Oxygen Generators in the Virginia class Submarines.
Hopefully we can just move on.
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
Yes true. A quick example would be AMS5484 material bolts whose tensile 80% stronger than Grade 8 when fully torqued or in a torque to yield application on a course thread in some of the low tensile untreated mild steels and cast irons you would pull the threads right out. Do I need to show the calculations to prove it to you ?
Lead Driver
Joined: Nov 2013
Posts: 7,155
Likes: 1,167
I just ordered one of these for forum use:
https://www.webstaurantstore.com/par.../380CLP14.html
Lead Driver
Joined: Jun 2013
Posts: 5,643
Likes: 1,154
From: Tolland, CT
Lead Driver
Joined: Nov 2013
Posts: 7,155
Likes: 1,167
Sorry to drift off topic by posing a technical question, but would there be any advantage to ditching bolts in favor of studs and nuts?
The stud length could be chosen for adequate engagement in the block (any opinions on that?). The protrusion could be adjusted for the thickness of the nut plus a couple of extra threads.
Installation overall might be easier as you could hang the gaskets on the studs, versus trying to align them with the bolts.
The stud length could be chosen for adequate engagement in the block (any opinions on that?). The protrusion could be adjusted for the thickness of the nut plus a couple of extra threads.
Installation overall might be easier as you could hang the gaskets on the studs, versus trying to align them with the bolts.
Lead Driver
Joined: Apr 2007
Posts: 5,958
Likes: 105
From: Houston
You could try something like Loctite 2422 it is an Ultra High Temperature (650°F) Threadlocker in the medium strength range. It is blue in colour,
650°F is more than hot enough for headers, if the cylinder head that the bolt is screwed into gets up to 650° you will have will bigger things to worry about than lose headers....
650°F is more than hot enough for headers, if the cylinder head that the bolt is screwed into gets up to 650° you will have will bigger things to worry about than lose headers....
Is it just me or do other remember lock washers on header bolts...?
If you really wantto torque them to spec, I doubt most of us do, there are a few "attachments" that will let you get at the bolt head, one example would be a "crowfoot wrench".
But in the real world, you just need to check them from time to time, just like you should be doing a few times a year when you look over the truck and engine for issues.
If you really wantto torque them to spec, I doubt most of us do, there are a few "attachments" that will let you get at the bolt head, one example would be a "crowfoot wrench".
But in the real world, you just need to check them from time to time, just like you should be doing a few times a year when you look over the truck and engine for issues.
That's what I was thinking too.
I hope this doesn't turn into a issue. It's just 1/4" or 5/16" header bolts we're talking about not a 3" bolt the holds a bridge up or the something like the 7/8" bolts we use to hold the 11,300lbs.Oxygen Generators in the Virginia class Submarines.
Hopefully we can just move on.
I hope this doesn't turn into a issue. It's just 1/4" or 5/16" header bolts we're talking about not a 3" bolt the holds a bridge up or the something like the 7/8" bolts we use to hold the 11,300lbs.Oxygen Generators in the Virginia class Submarines.
Hopefully we can just move on.