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

[Mike V. Florida]

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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.

[Jim Brierley]

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

[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.

[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.

[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.

[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 .