Why no lock-washers?
 

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

Re: Why no lock-washers?
 

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.

Re: Why no lock-washers?
 

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.

Re: Why no lock-washers?
 

100IH got up one minute earlier than I did.

Re: Why no lock-washers?
 

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

Re: Why no lock-washers?
 

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.

Re: Why no lock-washers?
 

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

Re: Why no lock-washers?
 

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

Re: Why no lock-washers?
 

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)

Re: Why no lock-washers?
 

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

Re: Why no lock-washers?
 

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 :rolleyes:

Re: Why no lock-washers?
 

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

Re: Why no lock-washers?
 

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

Re: Why no lock-washers?
 

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

Re: Why no lock-washers?
 

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.

Re: Why no lock-washers?
 

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.

Re: Why no lock-washers?
 

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 .

Re: Why no lock-washers?
 

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

Re: Why no lock-washers?
 

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.

Re: Why no lock-washers?
 

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.