Tick tock—is it your clock?
by Walt Brewer
When checking out your clock to see if it’s working, you want to hear a ticking sound.
When your engine is running, you want to hear a hum and not a ticking noise. For some reason, ticking scares old car owners more that grinding, clunks or thumping, particularly in our old flathead V-8s.
As a rule, the first thing to get the blame is the valve lifters. This is a good guess, but not always. In fact, it may be less than a 50 percent chance. As many of you know, most of my experience and forte is in the ’48 and earlier flathead LaSalles and Cadillacs, however, many of the reasons for ticking apply to many of these old cars. Let’s talk about a few of these reasons.
Everybody wants to blame the hydraulic valve lifters first. The lifter assembly in the early flatheads consists of the lifter body that rides on the cam and houses the two-piece plunger assembly.
If the ticking is coming from the lifter body, it is usually because of poor lubrication or a small crack in the body itself. If it is in the plunger assembly, it is usually a small piece of dirt or sludge in the check valve, possibly a broken spring in the plunger assembly or some other small fracture. In any of these cases, this is not a job for the Sunday mechanic.
More of a chance exists that the ticking is coming from the valve assembly. This assembly consists of the valve itself, the valve spring, the upper washer, the lower washer and two small keepers. Each of these 16 assemblies fit into its own valve guide. Any fracture in any one of these pieces can cause a ticking.
Also wear (either normal or excessive) can cause the ticking sound. You can also get the ticking sound due to inadequate oil flow or pressure. This can be due to a defective or weak oil pump or blocked or leaking oil passages.
In any of the above events, you have major and somewhat expensive repairs needed. These repairs should be done by or with assistance of a mechanic experienced in this field.
I have seen cases where large sums of money have been spent on a “major” valve job and the valve train is still noisy. The reason? Improper assembly, such as failing to properly charge the lifter assembly, valve washers upside down, failing to replace valve guides, et al. Usually it is because the “mechanic” failed to grind the valve stems to the exact proper length. If you grind too much, it leaves a gap and—that’s right—a ticking sound. If not enough, the valves don’t wear well and you get low compression, detonation and sometimes this sounds like “lifter noise.”
It is a shame to see a grown, old car owner cry after spending big bucks for a full valve job (done right) and still have a ticking sound. How can this be, you ask? It means that the ticking sound is coming from somewhere else, as I told you earlier. You may have wrongly accused the valve assembly. So, before you go into an extensive valve job, let’s look at other reasons for “ticking” sounds. I will assume at this time you can distinguish between a ticking and a knocking and don’t confuse the two.
An inexpensive mechanic’s stethoscope can usually at least find the general area of the ticking sound. In most of the old flatheads, you have a double action fuel pump that will make a ticking sound when operating. When rebuilding, the fuel pump will usually get rid of this sound unless the arm that rides on the cam is worn to the point of not keeping steady contact with the cam lobe. In that case, you can get another arm or build the surface up by metal spray technique.
Of course, if it is the cam lobe itself, it is a little more of a problem. Fortunately, the cam lobe that operates the fuel pump can be separated from the cam and can be rebuilt or replaced without removing the cam. Your stethoscope can point this out for you.
The generator can also be a source for ticking that sounds just like valves. Again, your stethoscope will pinpoint this problem. Easy removal and a rebuild by a good generator shop can take care of this.
Sometimes your fan blade can be bent slightly and a tiny corner is hitting somewhere. A little bending can fix this in a hurry. Both the fan and water pump have bearings that with a little dirt or a flat spot can sound just like a bad valve lifter. Again, your trusty stethoscope can find this for you.
Another common problem for a “ticking” sound is a frayed fan belt. This is a little harder to locate. Probably the most heartbreaking incident I can recall for a ticking sound was from a car owner who came to me after spending thousands of dollars doing all of the above, and still the engine sounded like the lifters were sticking and clicking. Using the stethoscope, it sounded like the noise was everywhere. After about an hour of reviewing all of his receipts and bills and correlating the sequence of repairs, we determined that the noise started shortly after installing new fan belts during routine maintenance prior to a tour.
We took off one of the fan belts to help isolate the ticking. It was still there. We then took off the other belt and the engine ran silent like a fine watch. Close examination of that belt showed a half of a lock washer had broken off a bolt and stuck itself in the belt, almost out of sight. Every time the washer hit the pulley on the generator, water pump and crankshaft pulley it make a tick (three times per revolution). The needlenose pliers pulled out the piece of lock washer, the belt was replaced and guess what—it ran great and quiet. I thought he should be happy, but all he wanted to do was bang his head against the garage wall.
I guess it boils down to when you wonder what makes your engine tick—check out the easy and cheap things first before you blame the valve lifters.
See you next month—I gotta go check out a ticking sound. I hope it’s just the old clock on the mantel.