Stainless Head/barrel nuts and bolts
- Thread starter Mark F
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Stainless proves to be problematic in an extreme way when mixed with alloy. This goes for timing cover, gearbox covers, fender mounting into fork legs, and the like.
I am not sure about the "soft" claim, have you ever tried cutting stainless? Practically all varieties are tough as hell. Stay away from it in this application. OK for through bolt stuff like mountings and whatnot. Also ok for steel like a stainless nut on a tank mount or rear exhaust mounts.
I am not sure about the "soft" claim, have you ever tried cutting stainless? Practically all varieties are tough as hell. Stay away from it in this application. OK for through bolt stuff like mountings and whatnot. Also ok for steel like a stainless nut on a tank mount or rear exhaust mounts.
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I have used stainless head and barrel mounting hardware for many years with zero problems. They are actually lightly loaded in this application.
The fact that they stretch a little more than a steel bolt will even help them retain torque at low settings like a head or barrel.
Regular stainless bolts are not as strong as good grade steel bolts but there are many stainless alloys available. If you want high strength you can spring for specially treated aircraft stainless or 180 psi stainless from ARP. The price will scare most people however.
Stainless bolts will quickly seize to a stainless nut unless you use antiseize. They make a special formula for stainless against stainless.
Stainless bolts into aluminum or steel is no problem with use of antiseize.
Where I will not use stainless is engine and trans to cradle mounting or axles. These applications need a good steel bolt that is not springy like stainless. Jim
The fact that they stretch a little more than a steel bolt will even help them retain torque at low settings like a head or barrel.
Regular stainless bolts are not as strong as good grade steel bolts but there are many stainless alloys available. If you want high strength you can spring for specially treated aircraft stainless or 180 psi stainless from ARP. The price will scare most people however.
Stainless bolts will quickly seize to a stainless nut unless you use antiseize. They make a special formula for stainless against stainless.
Stainless bolts into aluminum or steel is no problem with use of antiseize.
Where I will not use stainless is engine and trans to cradle mounting or axles. These applications need a good steel bolt that is not springy like stainless. Jim
I've used stainless head and barrel fasteners for years with no problems and that's using stainless studs in the cases and stainless helicoils.
I can't say I'm particularly careful about using antiseize either so I take all the dire warnings with a pinch of salt but there's usually some sort of lube or threadlock used I guess.
I have had stainless fasteners seize solid but not on my Norton. The problem has always happened with machine cut threads with a poor surface finish, rolled threads have always been OK in my experience. Helicoils wire is drawn which similar to rolling gives a surface more resistant to galling.
Like others I stick to steel in the crankcase , gearbox to cradle and engine to cradle areas.
A word of warning with stainless headbolts, there's some real crap out there with welded on heads which can break off at real low torque, choose your supplier carefully.
I can't say I'm particularly careful about using antiseize either so I take all the dire warnings with a pinch of salt but there's usually some sort of lube or threadlock used I guess.
I have had stainless fasteners seize solid but not on my Norton. The problem has always happened with machine cut threads with a poor surface finish, rolled threads have always been OK in my experience. Helicoils wire is drawn which similar to rolling gives a surface more resistant to galling.
Like others I stick to steel in the crankcase , gearbox to cradle and engine to cradle areas.
A word of warning with stainless headbolts, there's some real crap out there with welded on heads which can break off at real low torque, choose your supplier carefully.
JimThis was one of the concerns I had about using stainless. If a nut or bolt needs to be used with antiseize then aren't you effectively lubricating the thread? Wont that then change the torque value required?comnoz said:
So is antiseize required in the head and barrel situation as all nuts/bolts either thread into cast iron or onto a steel stud?
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Reports of shearing of SS in the cradle bolts, even in not report on this forum.
I got Ms Peel SS head hardware from Rocky Point, only issue it the good grade they use is not a stainless as the decorative SS on lessor loaded or heated places.
Lube or no lube, anti-seeze, one should be able to feel the beginning of seating and then the stretching sense to obtain, which means you've hit it when they stay tight and head don't weep oil. Nuts are not much an issue as the bolts in SS so have at them as you like.
I got Ms Peel SS head hardware from Rocky Point, only issue it the good grade they use is not a stainless as the decorative SS on lessor loaded or heated places.
Lube or no lube, anti-seeze, one should be able to feel the beginning of seating and then the stretching sense to obtain, which means you've hit it when they stay tight and head don't weep oil. Nuts are not much an issue as the bolts in SS so have at them as you like.
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hobot said:
I have never seen stainless engine cradle bolts break or shear. The problem is they don't hold enough torque to keep the engine from moving around in the cradle. It is a common cause of handlebar shimmy or weave. Eventually the engine and cradle holes get larger as things are allowed to work against one another. Jim
Mark,
I wouldbe in the beware camp. I thought I was smart and had my old head bolts dull chromed. My son arked me how come I left a bolt out after assembling the head, to my horror the head and some of the shank of one bolt had ejected itself in the garage roof area. Never even got to start the engine. Luckily I managed to extract the remains without removing the head and then I fitted allnew andover hardware. Just my 2 cents worth.
Cheers Richard
I wouldbe in the beware camp. I thought I was smart and had my old head bolts dull chromed. My son arked me how come I left a bolt out after assembling the head, to my horror the head and some of the shank of one bolt had ejected itself in the garage roof area. Never even got to start the engine. Luckily I managed to extract the remains without removing the head and then I fitted allnew andover hardware. Just my 2 cents worth.
Cheers Richard
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Jim and crew, I've read of a number of cradle SS bolts shearing over a decade on NOC list, now private only, and Brit Iron and INOA lists. Its the only failures of SS I've read of. IIRC it was mostly the bottom cradle bolt, where cradles are prone to crack too. These guys knew to remove power coat and nip up good. Can't say what grade they were sold. Believe me or don't. I put AN aircraft interference fit bolts in my hot rod and after seeing what Peels heat did to Rocky Points top of the line SS, turned dark chocolate in a few 1000 miles, decided to go with factory fasteners. Wire brushing only makes them slightly lighter shiny shade towards grayer. They were the old tarnished looking bolts that did not stand out on mocked up Peel at rally. This particular head's CHT got to at least 425' F sustained if that matters.
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Chrome plating a bolt is generally bad news due to hydrogen embrittlement from the plating process. There are ways to avoid it but those processes are not generally available to the average chrome shop.
I use engine oil when torquing stainless headbolts into the barrel. I think anti-seize could be used also without affecting the torque reading enough to worry about. The lubes that cause problems when torquing a bolt are the extreme pressure lubes like STP or EPC. Jim
I use engine oil when torquing stainless headbolts into the barrel. I think anti-seize could be used also without affecting the torque reading enough to worry about. The lubes that cause problems when torquing a bolt are the extreme pressure lubes like STP or EPC. Jim
The problem with stainless is "galling": http://www.estainlesssteel.com/gallingofstainless.html
I use Loctite 222 on all threads and oil everything ( CRC or lanox ), have not had a problem to date.
I use Loctite 222 on all threads and oil everything ( CRC or lanox ), have not had a problem to date.
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Ugh, planned obsolescence or cost cutters leaving it be as cc size increased?
I was told to fit 7/16" and sofari so goodie. Amazed me when Peel over rev'd to bend crank and take out stuff on its ends, slightly beefed up cases came right apart and bolts still would not slide in at all - until just right then suddenly seat all the way through slick as can be. May have beef up cradle holes but sofari...
The more I'm at this Norton stuff the more extreme I'm getting, totally factory warts and all or bounce totally off the Norton wall... in between confuses me no end.
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Yep, provided the source verifies they are of engine grade alloy and proper formed. If locitite is needed on Engine fasteners, then you ain't even in the Norton Torque ballpark. Anti-seize and scare yourself on nip up you bless ant-seize to get off again. Consider too the wear tear over time w/o lube or with crusty thread locker.
Does not hurt to be annal enough to polish up or burnish and chase the threads either.
Does not hurt to be annal enough to polish up or burnish and chase the threads either.
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