Lockwashers revisited

[lippy]

I know there've been posts on this in the past that have said split lockwashers are useless. Live and learn, I never would've guessed. I hate the way they dig into surfaces anyway, so I'll be glad to get rid of them.

At any rate, I asked my brother in-law, who works at Monterey restoring high $ vintage racers. He told me they only use them when they are required for correctness. Otherwise, they use different types of locking nuts or Loctite.

I also sent an email to ARP tech support (below), and I thought their response was interesting.

So my take is that you should just use thread lube, proper torque, and flat washers for bolts, with Loctite for particularly difficult vibration applications. But what do you do when you need the non-galling properties of thread lube (say a stainless bolt in an aluminum block) but you want to use Loctite? The Loctite requires a clean thread so you can't use both.

Email from ARP

Jeff,

We have never made or sold any lock washers for any of our products. Calibrated torque with a specific lube is all you need. A bolt is like a big spring, when you tighten it stretches and that holds everything together. Normally we recommend washers with most installations, it helps to keep from damaging the contact surfaces. On high strength fasteners, head bolts, mains, flywheels etc. our washers have a known surface finish (roughness) which promotes consistent clamping loads and using our high strength bolts we supply ID chamfered washers to properly fit up to the head of the bolt.

Always the rule: If you change the lube you change the torque. That's why we supply our lube with most of our kits & torque specs. On the bolts for a pulley to the balancer you could use blue Loctite, washers we supply and appropriate torque for the bolts you have.

Best regards,
Alan
Sales & Technical


QUESTION:
I just purchased a bunch of your bolts plus your ARP lube. I noticed none comes with lock washers. I then Googled lock washers and read that many studies say they're useless. What do you recommend? For example, on the bolts that hold a pulley onto a balancer or water pump, would you just use the bolt (with or without a washer) and blue Loctite, no lockwasher? Also, when should I use a flat washer and when should I leave it off?

[Jaydee]

I saw an interesting video with bolts under vibration.
The nut would just wind itself of the bolt if it's not tight, with a spring lock washer, the same happened. The nylock one will just ensure it doesn't wind of the bolt, it will never prevent it coming loose in the first place. It needs to be torqued up right. A split pin being the ultimate lock. Try cutting a bolt with a nut on it with an angle grinder, you'll see it wind along the bolt with the vibration.
JD

[Tommy]

Lippy,
I had a similar question recently when I was replacing some suspension components for the rear of a 1990 Corvette. The components were bolted to the thick aluminum case of the rear diff with steel bolts. Plainly I did not want the suspension components to vibrate loose. Nor did I want the dissimilar metal situation to casue the bolts to bind so tightly to the aluminum that I could not get them out in the future. ... I noticed that the factory installed bolts were not difficult to remove and showed no signs of corrosion after 25 years in place. My investigation revealed that the bolts had been coated during manufacture with something that prevented the dissimilar metal reaction. The factory did not use anti-sieze or locking compound. So I just cleaned the original bolts and holes well and reused them.

I have no idea what to call or where to get the coated bolts. So when I am faced with the choice you face, I rely on anti-sieze and the proper torque to hold things together. If I am particularly concerned about the bolts coming loose (e.g., low torque header bolts into aluminum heads), I will use one of the locking devices such as safety wire through the bolts.

[blykins]

Just remember, on critical fasteners, i.e. main studs, rod bolts, head studs, etc., all fasteners are usually torqued once, then re-torqued in sequence, one at a time. Fasteners stretch after the initial pull and sometimes it takes 2-3 stretches to get them to settle in. It's not uncommon on rod bolts that require a stretch spec to have to seat them, unseat them, re-lube, burnish in the mating surfaces, then seat again.

When you start introducing (and relying on) torque specs for small fasteners, such as pulley fasteners, valve cover fasteners, oil pan fasteners, etc., then you open another can of worms. To be honest, I've been in many race shops, including Valvoline engine labs dealing with Cup motors, and I've never seen anyone "torque" an oil pan bolt/stud...

If a torque spec was required for all fasteners, then you'd hear a lot of small block guys (Ford, Chevy, etc.) whining about the same oil pan leaks, valve cover leaks, etc. It simply doesn't happen with them on the same scale as it does with the FE. As a matter of fact, you would be torquing/retorquing for a week straight, as you go around trying to compensate for the compression of two oil pan gaskets, a windage tray, etc.

IMO, the issue here is the engine family, being compounded by aftermarket parts and a block material that shrinks/grows with heat. The equalizing bars/plates that go around the oil pan flange are a good idea, as is the use of a sealant on all surfaces. A fiber lock nut probably wouldn't hurt either...

The fact of the matter is that an FE *should* have the easiest oil pan to seal up: one piece gasket, all flat gasket surface, large number of fasteners, etc. You just have to wonder why it has more trouble sealing than the other engines...

[bobcowan]

Carrol Smith spent a lot of time talking about locking devices. Get the books, "Nuts, Bolts, Fasteners, and Plumbing Handbook". Very interesting reading.

Split lock washers do have their place. But it is limited. Star washers are a better option for almost everything else that needs a locking washer. Any kind of lock washer or locking bolt/nut surface is going to dig in to the surfaces to varying degrees. That's just how they work.

I use nylock nuts almost everywhere. When not using a nut, I use an internal star washer.

[DanEC]

I don't use split washers without a flat washer under them to protect the component surface - even in OEM applications that may have omitted a flat washer, I add one. I would not be surprised to learn that a flat washer further increases the chances of loosening when there is a lot of vibration. I now use blue loctite more than I used to - but on any aluminum component I rely on anti-sieze and a lock washer and figure I will have to re-tighten them later.

Interesting thread.

[mdross1]

With so many choices we all have our own unique ways of doing things. Mine have come from so many years of experience of what works and looks good at the same time. Everything I build will need specialty washers in all areas. Loctite, anti-sieze and whatever it takes to satisfy a specific need gets used. Every so often the car gets raised and all hardware checked.

[Morris]

That's why we grab a hand full of wrenches and nut & bolt a car before each session......

[lippy]

To Brent's comment, I'm speaking more generally and not so much about the oil pan. I don't plan to use a torque wrench on all fasteners.

But on the oil pan, because it is problematic, I will use the stainless rails that I fabricated so I can put more torque on the studs without distorting the thin pan rail. Rather than torque the studs to the limits of the pan rail, which is usually 5-6 ft-lb, I will torque them to the limits of the studs themselves. ARP tells me that with their high strength studs I can go to 18 ft-lbs safely this torque should stretch the bolt. With the serrated bottom flanged nuts, I'm hoping they won't loosen.

For things like pulley bolts, I'll probably use Loctite and a flat washer.

[dallas_]

Originally Posted by bobcowan

Carrol Smith spent a lot of time talking about locking devices. Get the books, "Nuts, Bolts, Fasteners, and Plumbing Handbook". Very interesting reading.

What Bob said. This should be required reading for anyone who turns a wrench.

[blykins]

Good plan, Jeff. Glue it and screw it.

[bobcowan]

[quote=DanEC;1379499]I don't use split washers without a flat washer under them to protect the component surface. QUOTE]

That doesn't work. The whole point of a locking washer is to lock the face of the fastener to the material underneath. You're locking the face of the fastener to the flat washer, and nothing is locking it to the material. Might as well leave the lock washer out.

[DanEC]

[quote=bobcowan;1381762]

Originally Posted by DanEC

I don't use split washers without a flat washer under them to protect the component surface. QUOTE]

That doesn't work. The whole point of a locking washer is to lock the face of the fastener to the material underneath. You're locking the face of the fastener to the flat washer, and nothing is locking it to the material. Might as well leave the lock washer out.

Bob, I basically said that in the rest of my post. " I would not be surprised to learn that a flat washer further increases the chances of loosening when there is a lot of vibration. I now use blue loctite more than I used to - but on any aluminum component I rely on anti-sieze and a lock washer and figure I will have to re-tighten them later."

And, you will find that a bunch of Detroit bolted connections used both a lock washer and a flat washer in many applications. Considering how they watched pennies cost on units of mass production, not getting rid of un-necessary flat washers seems odd if they didn't serve a purpose in some connections. But, it was probably a constant tug-of-war between the engineers and the cost accountants.

[lippy]

Dan brings up a good point about cost and Detroit. Surely they would know if the lock washers were totally ineffective and would save the money. But I think the use of lock washers only applies to older cars. I've been looking now and I have not seen a single one on my newer Chevy truck or BMW.

[G-Pete]

[quote=bobcowan;1381762]

Originally Posted by DanEC

I don't use split washers without a flat washer under them to protect the component surface. QUOTE]

That doesn't work. The whole point of a locking washer is to lock the face of the fastener to the material underneath. You're locking the face of the fastener to the flat washer, and nothing is locking it to the material. Might as well leave the lock washer out.

NO!

The washer underneath protects the surface and widen the holding point.

Lock washers have their place - especially with high stress and side load applications. All our Grill Guards (work) have lock washers where the bracket meets the upright. Here is experience speaking, we doing that now for 37 years - we have sold close to a million guards and they do not fall off like the competition ones.

Lock washers are used widely at railroad, cranes and heavy earth moving equipment. If you cant a use a fine thread bolt on press brakes (i.a. example), it is common to use a lock washer.

The auto industry have developed over the last 100 years their own specialty bolts, nuts and washers - and combos.
Most decisions are made based of cost - Dodge uses many fasteners on their vehicles without any coating. They actually rust in place while on the way to the dealership.
Ford created a whole can of worms with their Alu bodies, I'm watching that very closely...........but that is a different subject.

Happy wrenching!

[DanEC]

Originally Posted by lippy

But I think the use of lock washers only applies to older cars. I've been looking now and I have not seen a single one on my newer Chevy truck or BMW.

I was speaking in terms of older cars (should have said so) and I think you are right about newer cars. It seems like they are using a lot more specialized fasteners in newer cars. A lot of them have captured washers, an integral spread head under the hex/tork head bolt, etc. With aluminum components - like Pete-G said, you really need to have flat washers to spread the load. There are some guys around who have started up nice little businesses from fixing broken bolt hole ears on vintage aluminum manifolds and other parts.

[Jaydee]

With aluminum heads etc, I always prefer to locktite in a stud first. To much undoing and tightening into ali will wear out the threads. Sometimes it'll bind up over time and totally pull out the thread. Especially for exhaust flanges and inlets.
I wonder if lockwashers stopped being used since nyloc nuts were introduced. A quick hint, don't use a impact gun or drill to spin on nyloc nuts as the heat generated will melt the nylon.
JD