Valve Adjustment for the Studebaker V8

Well, I finally set aside the time to adjust Barney's valves, and got it done today. I should have done this right after the rebuilt engine was brought back to life, but I was hesitant because the job intimidated me, and after all, the car was running, right?

But solid-lifter valves need to be properly adjusted in order to maximize efficiency and power. And Barney's gas economy has been, shall we say, less than stellar. I knew it was needed and overdue. Actually "valve adjustment" is a misnomer -- you're not adjusting the valves themselves, but the valvetrain "lash," or the air gap between the rockers and valve stems when the valves are closed.

Of all the maintenance operations in Studebakerdom, I think this one may be the source of the largest amount of questions, concerns and fear. But I learned that it's much easier to actually do the adjustment than it is to read about it! You just gotta get your hands dirty, and it all makes sense. Part of the problem, I think, is that the process is often described, but never illustrated. You'd think that a common operation like this would be thoroughly documented on the Web, but it isn't - so I hope the following illustrated tutorial will help future Studebaker seekers.

The Studebaker V8 in its natural habitat

It'll take about 2 hours to do the job in your garage, if you work like I do. You'll need a spark plug socket, a good set of feeler gauges, a socket set, a 1/2" wrench and a test light. A remote starter switch is useful too. A tube of anti-seize and silicone grease will come in handy for reinstalling the spark plugs, but they're not necessary.

First, you need to know the firing order of the Studebaker V8, because you have to adjust the valves in that order.

Firing Order:
1-8-4-3-6-5-7-2

As the illustration shows, the left bank of cylinders (driver's side) has the "odd" numbered cylinders (1,2,5 & 7), while the right bank has the "even" cylinders 2,4,6 & 8), so you'll be moving back and forth from side to side during the adjustment process.

After much reading of various folks' recommendations for adjusting the valve lash, I decided to stick with the factory method outlined in the Studebaker shop manual. Studebaker gives a proceedure for adjusting the valves either with the engine hot and running, or stone cold. I chose to do it cold, since I don't like the idea of working on a hot running engine, especially one that's flinging oil around like a congressman spends cash!

To start, I numbered the spark plug wires prior to removal so that I'd get them right upon reinstallation, and pulled them off.

Then, I removed the valve covers. This is accomplished by removing the nuts from each of the two studs that exit each cover. I laid them across the air cleaner so that I wouldn't have to remove the wires from the built-in clips on the covers. On the left-hand valve cover, there's a spring that provides return tension to the throttle bellcrank; I unhooked this from the bellcrank and kept it with the valve cover.

After the valve covers were off, I removed the spark plugs. I like doing this with the valve covers off, as it provides more room to work. The #6 plug is a little fishy to work around due to the close proximity of the oil dipstick tube; #7 is also a bit tricky because of the master cylinder plumbing. Just work gently to avoid cracking the spark plug insulators during removal and reinstallation.

All my plugs looked good - normal deposits and nice and clean, except for the plug from #5 cylinder (3rd from left, above), which had some crusty ash deposits on it. The spark plug guide chart says this is due to a bit too much oil in the cylinder during combustion; I'll have to watch this - could be a leaky valve guide seal.

By the way, I'm a big believer in an orderly workspace :)

Now to perform the first valve adjustment. This is done by finding the Top Dead Center of cylinder #1. Top Dead Center is also called "firing position;" it's the point in the engine's rotation just after the compression stroke, during which the spark plug ignites the fuel charge in the cylinder. It's also the point at which both exhaust and intake valves are completely closed.

To find TDC for #1, I connected a remote starter switch to rotate the engine easily. The Studebaker vibration damper has several marks stamped into it; one reads "UDC 1". (UDC stands for Upper Dead Center - Studebaker stuck with this older terminology to the end.) When this mark is exactly under the timing pointer, #1 is at TDC.

BUT there's a caveat: in a 4-stroke engine, the cylinder is at the top of the bore on both the compression AND the exhaust stroke. You need to make sure the TDC you're finding is the one just after the compression stroke.The easiest way to do this is to put your thumb over the #1 plug hole and rotate the engine with the remote switch. When your thumb gets blown off the hole, that's the compression stroke! Stop spinning the engine. You'll rotate the engine the rest of the way to TDC by hand - it turns pretty easily with all the plugs out.

If you have a fixed radiator fan, you can grab the fan blades and turn in order to ease the engine to TDC. But this won't work on engines with clutch-type fans. SDC Tech maven Dwain Grindinger wrote in one of his how-to pieces that you can use a socket wrench on the alternator (or generator) pulley to turn the engine, and it works! I also grabbed the crankshaft damper with my right hand and gave it a turn while using the wrench with my left. This provides the leverage and control needed to move the engine a small amount at a time.

 
Once you've found TDC for #1, it's time to adjust the valve train. Studebaker mandates a clearance of between 0.025" and 0.027" for cold engine adjustment; I split the difference and adjusted to 0.026". to do this, you simply slip the blade of the feeler guage between the valve stem and the surface of the rocker arm; the adjusting nut is on the opposite arm of the rocker. These are pretty stiff; they're self-locking adjusting nuts so there's no locking nut to loosen - just put your 1/2" wrench around it and go!

 
If the feeler slips right into the gap, great. If not, you'll need to loosen the adjusting nut - turn it counter-clockwise to open the gap. You want to feel a bit of resistance as you pull the gauge through the gap, but not too much -- "the feeling should be about the same as putting a table knife through a stick of cold butter," according to an excellent article on valvetrains I found on the Century Performance website. All my valves were tight, and had to be opened up in order to get the gauge in. once it's there, though, small adjustments to the adjuster nut achieve the proper resistance very quickly.

Finding TDC is easy with cylinder #1, since its position is marked right on the vibration damper. How do you find TDC for the other cylinders? That where the test light comes in. Look at your ignition coil and find the wire that leads from the coil to inside the distributor - NOT the high-tension wire that leads from the center of the coil to the center of the distributor; the wire you're looking for is a thin (likely black) one that is screwed to one of the two small terminals on the coil. It leads inside the distributor to the points. Connect one of the leads from your test lamp to the post this wire is screwed to; connect the other end of your test lamp to a clean ground.

Now put your key in the car's ignition and turn it on -- No, not to "START"! Just the first click, to the ignition "ON" position. Now, as you rotate the engine (by hand), the test lamp will illuminate when the distributor's points close. When that happens, you've found Top Dead Center for the cylinder you're going to adjust.

Remember the firing order? You've just adjusted cylinder #1. Next in the firing sequence is #8, so rotate the engine by hand until the test lamp just lights, and adjust both valves for cylinder #8. Continue to hand-turn the engine and set the valve lash for cylinders 4,3,6,5,7 and 2.

After the first couple of valve sets, the process gets incredibly easy. Before you know it, you're done! Now it's time to put it all back together.

If your spark plugs are all in good shape, clean them and inspect the gap. I like to smear a little silver anti-seize on the threads to ease removal and protect the threads in the head; I also put a bit of silicone lube inside the spark plug wire boot to make sure they seal well and come off easily later.

Put the valve covers back on, reconnect the plug wires and fire it up - you're ready to go!

After adjusting the valves, Barney came to life immediately and ran like a top. The difference was amazing - not only did he idle smoother, he warmed up faster. ON the road, there was less engine vibration, and he revved quicker. Also, the usual smell of fuel was missing during my test drive. (I knew Barney was blowing fuel out the back because the exhaust tips are sooty...) My son and I took him for a full-throttle blast through a nearby industrial park (empty on the weekends), and the difference in performance is dramatic -- I actually got rubber in 2nd gear.

After doing a valve lash adjustment, be sure to check your timing afterward, as valve adjustment affects timing. I will actually need to lower my idle, since the engine is running so much more efficiently now that the idle speed is noticeably increased.

I hope this brings some clarity to a mysterious procedure, and helps other newcomers to the Studebaker hobby!