I Can’t Bear It Any More!

Posted: May 4, 2013 in Uncategorized



Cleaning out the bottom of the valve chamber


Oil return


Scott and showing off mad skills

I blogged about the valve chamber and gunk yesterday. To clean the valve chamber you need to make certain that any gunk doesn’t head down the oil passageways (narrow holes). To do this properly, you try to find the holes, plug them up with something that won’t get stuck, clean the chamber, remove the plugs in the holes, and then clean the oil passageways which should readily drip fluid through to the other end. Knowing the location of the holes helps if they are hidden by or blocked with gunk. I started looking for these holes at 9AM.

The valve chamber has three areas. I was told to make certain to plug the two small holes in the front area, the one mid-size hole in the center area, and the two small holes in the back area. This is where it gets fun. Evidently not all Model A engines are alike. 2 hours after I started (and with the help of a neighbor) we found one hole in the back area. Apparently the early 1929s didn’t all have two holes in this chamber. If it wasn’t for Scott Hanson (the neighbor across the street), I wouldn’t even believe that this one existed. Here is a shot of him and me in a matching pair of fashionable coveralls. When challenged with working on a car, Scott insists on wearing all white.


Scott Hanson and Seth Kestenbaum

To make certain that the passageways are clean, I decided that if I sprayed WD40 (spray oil) into the passageways, the WD40 would flow readily and a stream of it would hit the ground. So, I put cardboard under the car and unloaded a lot of WD40 into the passageways ……. NOTHING! This is bad and sent me into a panic (with posting to Fordbarn and calls out to mechanics). One person told me the WD40 should flow free, another said I needed to blow air through the system (BTW, a small straw does fit into some of the channels and can be used to blow air). Still, nothing. The neighbor suggested break out carburetor cleaner. Apparently, carb cleaner flows better than WD40. From under the car I hear “its dripping”. I should mention that the day has now passed and it was about 2:30PM.
We wiped things up and then went out for beers, chili, and ribs.

At about 4:30 we returned with more carb cleaner, PB Blaster, black enamel engine paint, and some other supplies. Scott also insisted that we use his jack stands, which are about a foot taller than the ones we were previously using. At about 6:00 we moved from cleaning on to checking bearing clearances.

For those whom aren’t car-savvy, there are some things you need to know.

Let’s start with bearings and clearances.

A “bearing” is something that helps support/direct/constrain movement. Loosely grab your left wrist with your right hand. Now twist your left hand like you are turning a door knob. If your hold too tight with your right hand, you can’t move your left wrist. If you hold too loose, you can flap your left arm around and its motion isn’t really being constrained to the door knob. Your right hand holding the wrist like this is the “bearing”. How tight or lose your grip is using your right hand is your “bearing clearance”. You are now an expert on bearings and clearances.

In my situation, the bearing is effectively metal rings (your right hand and a few more hands) that hold a metal stick in place when it spins. The stick is held tight enough not to bang around haphazardly but lose enough to allow oil to get between the ring and the stick allowing it to spin. Multiple bearings (hands) hold the stick in place. With the car, this metal stick has a bunch of funny zig-zag bends in it and is called a crank. The “main bearings” hold the crank in the engine. There are three of these main bearings. One in the front, one in the center, on in the rear.

Attached to some of the zig-zag bends in the crank is another bearing that connects the crank to a metal arm that is connected to the pistons. The pistons move up and down in the engine. As the pistons are forced to move (because of the small explosions in the engine) they turn the crank. This metal arm is called a “rod”. The bearing that connect the rod to the crank are “rod bearings”. There are four of these in my car. If you can’t follow this mentally, that is ok. My description isn’t great.

With the oil pan off, there is a way to “check bearing clearances” to make certain that there is no excess movement and that the grip isn’t too loose or tight. Checking clearances every 10,000 miles or so is a great idea in old cars. Some folks do it every 2,500 miles. I suspect it hasn’t been done in my car for 40+ years.

All this prep! All this learning! All this work! All this anxiety!

So, what happened? Let’s go back to the hand/wrist thing. Let’s say you want to measure your clearance. If you take a small piece of clay in the palm of your right hand and then grip your left hand like you did before, the clay would squish. If you figure out how much the clay squished, you would know how “loose” the grip was around your wrist.

You can do this with the bearings in a Model A. The rings that hold the rods in place are made of a top and bottom that are bolted together. You can open the grip by taking these pieces apart. You just need to open the grip, insert a piece of plastigage, and then retighten it. Plastigage is a wax material that squishes. Once it is squished you again open the grip, measure the squish, and adjust the clearance by adding or removing “shims”. It sounds really easy and simple, right? It shouldn’t take long, right?

I decided that I wasn’t going to do all the main bearing and would do the rod bearings. Scott and I started at the front rod bearing. We were able to remove the nuts on the bolts but unable to get the two pieces apart and open the grip. If you can’t get them apart, you can’t do what needs to be done to measure the clearance.

I know that “when the oil pan is down, you should check the clearance”. This is an old engine. Everything looked fine. As of this evening (9PM), I am thinking that I should probably not go looking for problems. At some point over the next few years I am certain I will drop the pan again or get the engine overhauled. It is an old engine and needs a refresh. At that time I will likely have a specialized shop (J&M or somewhere like that) do the job right. As for now, I can’t bear the thought of not driving the car for yet another beautiful weekend.

The plans, as of 10:30PM are to get some sleep and wake early tomorrow to work on the car. One of the local Model A club guys is scheduled to come over at 9AM and help me raise the pan back. I still have a few pieces that I wanted to clean and paint before this happens. I guess they too may have to wait.

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