Why no lock-washers?

[wingski]

This is not just an weird question like I sometimes ask. It is a very important question that deserves a really good answer.

Every time I’ve checked the nuts on the intake-exhaust manifold on my A, they could be tightened more. If I remember correctly, the head bolt nuts on a model A have to be tightened on a regular basis. It seems that everything that does not have a lock-washer has to be tightened periodically.

Why weren’t lock-washers used in all these places? I don’t care if they were split-washers, star-washers, or even bell-compression washers. Why wasn’t something used to keep those nuts from working loose as that engine heated and cooled.

If there is a good reason why they weren’t used, I’d really like to know.

Mike

[100IH]

Lock washers stop the nuts from backing off. That is not the issue with the head nuts. The issue is that the head gasket is compressing with heat cycles, will stop after about 4 heat cycles. As the gasket thickness shrinks the nuts must be snugged.

[700rpm]

I have always thought that it isn’t that they work loose, it’s that the high temps on the manifold cause the metals to expand and contract which changes their relative fitment. On the head I have assumed it was the head gasket getting settled in. No science here, just my assumptions.

[700rpm]

100IH got up one minute earlier than I did.

[wingski]

OK, I accept the fact that the head gasket compresses. All gaskets compress including the intake-exhaust gasket.

But still, why were no lockwashers used. You would think that in any situation were there is metal expanding and contracting a lockwasher would be used to lock that nut in place especially a place as important as the manifolds.

Mike

[Jim Brierley]

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For one thing, lock washers will provide a place to leak, water or oil. Another thing is that lock washers will deteriorate from heat, perhaps break and the nut will no longer be tight. If a nut is tight, it will not back off by itself.

[100IH]

Rust,the original Lock-Tite. You know that works !

[1930-Pickup]

Heat cycling along with vibration will harden the lock washers, then they will become brittle, and then break.

[johnbuckley]

Why no lock washer? Here's one for the forum .....Because they don't work!... (find me some proof and I'll change my mind)

[daren007]

apparently the engineers decided they were not needed. They were right.

[1930-Pickup]

If you need a solution to exhaust manifold nuts backing off, you could use interference-fit brass nuts. This was a fairly common item and solution in years gone by. They would have cost a few cents more, so that's probably why Henry didn't use them

[wingski]

OK, guys. I agree with the probable leakage problem on head bolts due to lockwashers. I agree with the fact that lockwashers become brittle and break.

However, a bell or compression washer wouldn’t allow leakage and sure wouldn’t break. My god, you could even put Permatex under them and really seal that head when that bell was torqued down. I think they would even look good under the nuts. They would sure look better than a double nut.

I’m not trying to be a wise-ass, but I really do think that there is a better way than just the nut.

Mike

[rustythumb]

had lock washers been invented when model a's were new?

[BILL WILLIAMSON]

If you think something needs a lockwasher, PUT ONE ON!
Bill Ownman

[Kevin in NJ]

Two thoughts..

First as mentioned, the heat cycling and the type of metal used for a lock washer would not work.

Second, not needed. I would guess that Ford used tight tolerance threading here also. So the nuts would be kind of snug.

I do not know if those are the right answers, but I am guessing that Ford had a good engineering reason they were not needed.

[George Miller]

We use to build hyd cylinders up to 24 inch bore. Never used lock washers on the tie rods or pistons. If you torque to the popper torque the bolts or studs will not come loose, they stretch and hold a constant pressure what ever they are used for.

cars do not use lock washers on the connecting rods or main bearings or cylinder heads.

[SeaSlugs]

I have backed off some old nuts on model A parts before and the lock washers are either A flat or B crumble into bits undoing the nut.

Yes lock washers job is to prevent stuff from turning but heat cycles it does not prevent.

Ive put nuts in a vice and tighten them till i just barely see the nut squash. By the time you release it will spring most of the way back but it will be an interference fit .

[1930-Pickup]

Originally Posted by George Miller

We use to build hyd cylinders up to 24 inch bore. Never used lock washers on the tie rods or pistons. If you torque to the popper torque the bolts or studs will not come loose, they stretch and hold a constant pressure what ever they are used for.

cars do not use lock washers on the connecting rods or main bearings or cylinder heads.

That's true... split lock washers tend to break, then fall off, especially on reciprocating or vibrating parts.

[1930-Pickup]

Originally Posted by SeaSlugs

I have backed off some old nuts on model A parts before and the lock washers are either A flat or B crumble into bits undoing the nut.

Yes lock washers job is to prevent stuff from turning but heat cycles it does not prevent.

Ive put nuts in a vice and tighten them till i just barely see the nut squash. By the time you release it will spring most of the way back but it will be an interference fit .

Boy, I sure know what you mean!

I have found that the harder the split lock washer (Grade 8 for example), the faster it looses its spring and easier it is to break.

[kimeccles]

I believe the Henry design accounted for several things. The washers on the exhaust manifold are curved and also very thick. When you tighten a nut onto a stud with a flat washer it is normal torque, but if tightening a curved dome shaped washer it introduces extra push back force on the nut (sort of like a lock washer). The thickness and correct cast material reduces the risk for brittle heat breakage as parts have similar thermodynamic characteristics.

Just saying there may be very good reasons. I can imagine that the engineers were doing a good job and did a lot of testing. I try to go original.

[redmodelt]

My creed is; never reinstall used lock washers anywhere on the inside of the motor, like the oil pump and if possible use new ones everywhere else.

[jimalabam]

A lot of very good and correct answers above. In Henry's favor LOCK WASHERS COST MORE TO MANUFACTURE...

[Railcarmover]

The torque value on a fastener its the rated tension that pulls all the stretch out of the fastener,this tension holds the fastener under load without a locking device.this is why head bolts don't have lock washers

Castellated nuts and cotter pins hold a fastener assembly together,they do not hold a torque value.Backing a torqued faster off to catch a castle for pin insertion is a mistake.

Modern chemical locking compounds are superior to any mechanical locking device,like a lock washer or a castellated nut/cotter pin.

[Mike V. Florida]

Originally Posted by wingski

OK, I accept the fact that the head gasket compresses. All gaskets compress including the intake-exhaust gasket.

But still, why were no lockwashers used. You would think that in any situation were there is metal expanding and contracting a lockwasher would be used to lock that nut in place especially a place as important as the manifolds.

Mike

Because the nuts don't move, the gasket acts like a lock washer providing back pressure to the nut.

[George Miller]

How about the wheels on your car. Have you ever seen any with lock washers?
I do not think so. There are lots of places with out them.

[Railcarmover]

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another clear example of tensions effect on threads is a soda bottle..isnt the cap tight when the soda is gassy? the pressure of the soda gas puts the cap threads in tension. Thats one place on a Model A where modern techniques actually help,fastener locking. Given Ford used time management techniques to speed production IMO they would have used locking nuts and chemical locking agents instead of cotter pins and lock wire had it been available at the time.

[Growley bear]

If you will notice the fiber int/exh manifold gasket has a metal surface on one side. This side is placed against the manifolds to allow for movement during the heating and cooling cycle. The manifolds move much more than a person might realize and if there were lock washers installed I am sure that they would be displaced quickly and then the nuts would really be loose.

[katy]

Originally Posted by 1930-Pickup

If you need a solution to exhaust manifold nuts backing off, you could use interference-fit brass nuts. This was a fairly common item and solution in years gone by. They would have cost a few cents more, so that's probably why Henry didn't use them

Ford used brass nuts on the exhaust manifold to exhaust pipe studs on the flat head V-8s for many years.

FWIW, about 25 years ago I worked w/a fellow that was a heavy equipment mechanic that had worked for a CAT dealer for a number of years. He told me that CAT had stopped using lock washers because they had done tests that showed that fasteners stayed done up just as well w/out them as with them.

[Bob Bidonde]

Those big washers on the exhaust - intake manifold attachments are cupped, so they are actually springs to cope with thermal expansion. If you repeatedly tighten those nuts, you defeat the purpose of the cup washers.

[BILL WILLIAMSON]

Picture this: On a wood base, 2 black stick figures, made from welding rod. One was a Female, with a nut for a body, she was being chased by a Male, with a screw for a body. The caption read, "NO, NOT WITHOUT A WASHER"!!----LOL
Bill Twisted

[Growley bear]

The cylinder head and the int/exh manifolds expand at different rates than the block so a ridged mount is not desirable as this needs to be a somewhat flexible joint.
Henry spared no expense on R&D as is observed in the amount of money spent on the 1932 60 HP V8 engine. Almost half a billion dollars. The amount of Model A research was phenomenal. You can bet that if Henry did/didn't do it that there was a very good reason for it. His idea was to pay the highest wages, use the best material, and hire the best people.

[Jim Brierley]

I agree with Bill, the guru of stuff, if you want to install them, go ahead and do it! To add to your confused state, I don't put cotter pins on rods or mains. I was a truck mechanic for many years and never found a nut actually being held on by one. In the case of the Model A engine, I believe the racing fraternity back in the day built and used a variety of heavy rods when the problem was the castellated nuts, they only have a few full threads! I raced Model B engines with B rods, turning 6200 RPM and never had a rod fail. I now use ARP nuts.

[katy]

Originally Posted by BILL WILLIAMSON

Picture this: On a wood base, 2 black stick figures, made from welding rod. One was a Female, with a nut for a body, she was being chased by a Male, with a screw for a body. The caption read, "NO, NOT WITHOUT A WASHER"!!----LOL
Bill Twisted

I remember them signs, they were advertising for some hardware company.

[BILL WILLIAMSON]

Chief left me a HUGE Electric Soldering Iron. It will solder a thick 1/2" flat washer to the bottom of a Coffee Can! Instead of using lockwashers, I could just SOLDER the NUTS to the BOLTS/STUDS!
Bill Hotterthanhell