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Studebaker Light Six Engine Rebuild

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Well, like I didn't have enough projects going on (currently working on the trans from the 1921 Olds and am doing an engine rebuild and chassis system upgrade on the 1962 F85), I decided to rebuild the engine in my 1923 Studebaker Light Six. I'll just focus on any of the more interesting aspects of this project though.


First a little history....I bought the car back in 2010. I don't think I ever told the story on this forum so, I'll do the Readers Digest version. I was teaching a client (Pierre) how to fly helicopters, we became friends, he invited my boys and I over to his lake house for some tubing on the lake and showed me this old car that was in the garage across the street that came with the house when he bought it 15 years earlier.

DSC04423.JPG.297d8640bd0b930f1dee37291385f353.JPGFast forward 6 months.... Pierre decided to sell his lake house and I inquired about the car. He told me to make an offer and I bought it. It turns out that the guy Pierre originally bought the house from also got the car with the house, so I know it had sat there at least 35 years. I brought it home and out in the sunlight.

DSC04537.JPG.9241153f6213c729535de0d1d19684e7.JPGIt needed a little work. After 5 years of a nut and bolt restoration....



It was finally done.



3000 miles and a number of awards later, I decide to rebuild the engine. Why??


When I was restoring the car I had two kids in private school and a mortgage to pay and I had to cut somewhere so new piston/bores were the choice. The crank and all the bearings were nice, so a little bearing shimming, new timing chain and piston work and I was able to have a decent working engine. I cut the piston ring grooves and used new rings and added ring spacers to get the clearances back to acceptable levels.


The bores were pretty loose with some taper and I knew one day in the future I would need to address that.


It has been about 8 years since I completed the restoration and after more recently hearing about two Light Six owners having their original 100 year old cast iron pistons fail, taking out the block and half the accessories, I decided it was time. I love driving the car and don't want to be having this nagging feeling in the back of my head.


The car is near pristine, so I'm having to be very careful trying not to scratch and chip paint.





Edited by Stude Light (see edit history)
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Step one....drain fluids and pull all the accessories out of the way.


Note - I having been running only water with NoRosion in this engine the last 8 years (cast iron block, aluminum head, brass thermostat housing, copper radiator). It looks pretty nice inside the block still.


And this is the 4 year old fluid I drained from it. Looks like the day I put it in.



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The aluminum cylinder head on this engine can be a bear so I thought I would work on it while still in the car for a stable platform. This head is held on with 26 steel studs and the galvanic corrosion between the two dissimilar metals generally makes the removal close to impossible. I started with many screwdrivers as this worked when I first got the car.


Removinghead.jpg.a23ae6a3df4ded2b39cece89c7f7f500.jpgYou laugh but gentle tapping along multiple points avoids really messing up the aluminum. I started with some penetrating oil and smacking each stud with a hammer to try to break any rust bonds. No go! So, I fished some rope down into one cylinder at a time and would spin up the hand crank to try popping the head off with the piston coming up to compress the rope into the head. Nope. So I gave up.


I removed the hood, radiator, front splash pan, headlight bar, unhooked the transmission and anything else attached and gently removed the engine. No scratches so far.



Since this engine does not bolt to the transmission, there is no flange in the back to support it on an engine stand. I had saved the wooden stand I made so many years ago and grabbed it from out back, added casters, ran a few more screws in and it still works.


My biggest dilemma was getting that head off. After years of driving (rain or shine) and washing the car, water had gotten down in the studs from the top and that head was stuck on those studs. After a week of penetrating oil, I removed the pistons and crankshaft and used a length of wood (3"x2") down the cylinder bores and proceeded to beat the head off the studs. I moved cylinder to cylinder as it gradually started to move. After at least an hour, it finally came off.


I figured it would crack in half but a good cleaning and inspection reveled no issues. The real test is when it goes back on the engine.


Looking at the oil pan, inside the timing chain cover and under the lifter cover, it looks pretty clean inside but I would expect that using modern ashless dispersant oils and only around 3000 miles of driving.



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Scott is a true master engineer so I have no doubt that he would 1. Get the head off successfully and 2. Will rebuild it to perfection.  


On several occasions Scott and I parked adjacent to one another at various shows though we never competed head to head as our cars were always in different classes.  I've always been glad of that as he would have whipped me in the process! 


As beautiful as the car looks here, the photos do not do it justice.  The car is breathtaking in person. If you know what I mean,  it has "a presence."


Like all of Scott's work,  I will follow this thread with interest.

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4 hours ago, r1lark said:

I bet beating on that head to get it off was scary...........glad to hear there was no damage.

Yes, it was rather stressful but more stress was coming.....


With the engine apart, I did some measuring and found that the bores were a bit more worn than anticipated - like almost 0.015" piston to cylinder diametrical clearance. With the great work they did on my Oldsmobile engine, I decided on Harts Machine in Cecil, OH to do the machine work. So here is the block with the head off.


I figured you just turn the block over, use the flat bottom of the block to set up on and bore the cylinders from that end. After some discussion I was told I needed to pull all the studs. Noooooo!!!


Other than 2 that had been replaced with threaded rod at some time in its history, those studs have been in that block for 100 years and, to make matters worse, they all terminate into the water jacket. I didn't sleep well after hearing that. So, with the stress of trying not to break the head getting it off forgotten about, I now was faced with 26 more stressful events. I had to crack open the bottle of Highland Park 14 year old scotch I picked up in Scotland this past summer 🤪.


Step 1: Soak with Kroil for a few of days. You can see that in the photo above.

Step 2: Heat the stud at the base as close to the block as you can get it. Get it red.


Hotstud.jpg.2d4915019242a77e7e9e0b8cdac32caf.jpgStep 3: Let stud cool but while still hot add more Kroil.

Step 4: Double nut the top of the stud and tighten the nuts as much as you can without stripping them. I also aligned the flats so either a 6 point or 12 point socket would go over both nuts.

Step 5: Lock a set of Vice-Grips onto the base of the stud using all the strength you have.


Step 6: Simultaneously use an impact gun while smacking the Vice-Grips with a small sledge hammer.


Last Step: Hope and pray for a good result.


I thought I would break them all but was astonished that I got all 26 out with no failures and no pulling of threads.


That was a tiring and stressful day.


The idea for this process is you want to break the brittle bond of iron oxide (rust) between the stud and the block. While heating the block red hot to expand the hole and putting a heat sink (like Vice-Grips) on the stud would do the job more efficiently, the risk of damaging the block is very high. This method is low risk for the block and the temperature extremes causes the stud to expand in the threads just enough to break some of that bond. The impact of the air gun and sledge do the rest.

Edited by Stude Light (see edit history)
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I put the head in the ultrasonic tank and got it nice and clean. 


If you zoom in you will see a lot of erosion around the water ports. When I originally installed this head, I used JB Weld to fill those in to get a seal on the copper/asbestos head gasket. After 8 years and then the ultrasonic tank, the JB Weld softened enough to be able to get it all out.

Headwaterports2.jpg.8b705ac023cc2424739f0ba667f3c547.jpgThere are a few particularly bad ones and a couple close to the combustion chamber seal. I decided to do the job correctly this time around. If you are thinking welding....absolutely not! This aluminum is really dirty so difficult to weld and it is very prone to cracking when welding, even when you heat soak/cool it properly. I decided on installing aluminum insert plugs, then milling flush. The first step was to contact one my friends, Mike, who has a really nice Cincinnati mill he restored. We then bored the eroded holes oversize to accept the aluminum plugs. Then for each hole we carefully measured the hole and machined some aluminum stock down to be a very slight press fit (like 0.0005" - 0.001"), depending on diameter.


The next step was to heat the head up to about 250 degrees F. I used my grill as it wouldn't quite fit in our oven  not to mention that the use of the oven would have been vetoed by my wife.

Heatinghead.jpg.2966386eadba3d887361ec7448e7cc7e.jpgWith the head heating in the grill, I had all the inserts in the deep freeze at -10 deg F. This allowed most of the inserts to be gently tapped in. I made sure to liberally apply Loctite retaining compound to each one before inserting.


With all the inserts installed, the next step is to use the mill and get them close to flush and we will use the head gasket as a template to drill all the holes to the center of the gasket port. Note - some of the inserts were installed off center to bias the hole to the eroded side of the port so we will be using the gasket to create new centers.

Gasketastemplate.jpg.5e9f51519fdb5288c679440f187813cc.jpgOnce done I'll have the head milled flat.


Okay, I'm caught up to real time now so the posts will not be quite as often.


Edited by Stude Light (see edit history)
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The aluminum heads on these engines are famous in Studebaker circles for being very difficult to work with. You are fortunate to have one in better condition than most.


And folks! This is one of the best writeups I have seen about how to remove the head, and then remove the studs which often are also very difficult! Good pictures, actual temperatures given. A combination of the right kind of penetration oil, soaking time, heat and more penetrant, where and how to get ahold and apply selective force and vibration to break parts loose.

The way to fix the passageway corrosion I don't think can be beaten. Welding on this sort of aluminum is problematical at best. It takes a real specialist to even attempt welding, very careful temperature balances are required or severe breakage of the head would be almost guaranteed! Plugs, properly fit, with frozen plugs into a very warm but not too hot head can make a "permanent" repair that will likely outlast the head itself.


The last time I removed a similar studded head (not a Studebaker), after soaking with Kroil for a couple weeks (sometimes applied after heating), I used over twenty screw drivers, chisels, and assorted wedges around the block. They were literally two to three inches apart all the way around the block! It took a couple hours carefully tapping and wiggling each and every one around and around and around! The head came off with no harm to the head or block.


Don't force it! Finesse it!

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On 1/28/2024 at 4:11 PM, Mike "Hubbie" Stearns said:

After thinking about it, I have a couple of suggestions. First is when you reinstall the studs, I would use a thread sealer at the block. And second I would coat the studs with antiseize. It will keep the corrosion from happening. Mike

I am planning on Permatex #2 for the studs back into the block and also using Permatex #2 to seal the top of the stud to the head so water can’t get down into the stud area. I’ll keep that seal to less than 1/4” down the stud so it can be easily removed when the head has to come off in the future (hopefully that is the next owner’s problem). 

I’m not convinced that coating the studs with antiseize will help if water gets in that interface. If you totally packed the cavity between the bore and the stud, then yes, but just coating the stud, probably not. Painting it would probably be more effective which is probably what I’ll do.

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this is just so interesting and educational, sets us all up for What NOT to do and what SHOULD be done and how as well. THANK YOU

Your photos are excellent as well.

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6 hours ago, Stude Light said:

I am planning on Permatex #2 for the studs back into the block and also using Permatex #2 to seal the top of the stud to the head so water can’t get down into the stud area. I’ll keep that seal to less than 1/4” down the stud so it can be easily removed when the head has to come off in the future (hopefully that is the next owner’s problem). 

I’m not convinced that coating the studs with antiseize will help if water gets in that interface. If you totally packed the cavity between the bore and the stud, then yes, but just coating the stud, probably not. Painting it would probably be more effective which is probably what I’ll do.

I use a gasket maker from Napa. It’s a soft set and works great. The antiseize is just a coating. And yes, it won’t stop the water, but will stop the electrolytes between the two dissimilar metals. Mike

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Oh yeah....the water outlet where the thermostat housing attaches is also a bad spot (brass to aluminum). I did not get a very good before photo. Ignore the machining chips in the inlet and look at the erosion.


Last time I used JB Weld in this area - got soft over time.  I decided to try out Marine Tex this time. I've used it before with excellent results.

Marine Tex Epoxy Putty Repair Kit Gray

This is not really a critical area as its easy to access and easy to see a leak. There is enough aluminum for the gasket to seal but I would rather have more material so....

Erosionrepair.jpg.5c7d67a67bbec26422329365128efef5.jpgIt sets rock hard. When we mill the water port inserts down this coming weekend, we'll hit this interface too.

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Got some time to do a little machining this weekend. We started on the water outlet repair first. Indicated off the surfaces around the bolt holes first to get the head square, then started cutting.


It came out quite nice and will make a good seal.


Next, we used the same end mill and cut down all those inserts to within about 0.015" proud of the head surface.

Millingdowninserts2.jpg.5c4030c8df04d28a17f7c6b442fc8b78.jpgMillingdowninserts.jpg.0e135d7233c1763d05fd42ab8b6b801e.jpgI wanted to get them cut down close to the finished surface so we could lay the gasket flat on the head and start marking the hole centers. Once we got those all marked we used various size endmills to bore the holes in the new inserts to the correct size and location.

Drillingoutwaterport.jpg.041290e3b070f5825a4e125665699c59.jpgRecall that some of the inserts were installed off-center of the hole to repair the eroded areas which were not always concentric with the original hole. 

Waterportrepair2.jpg.1700f0baf9023af3ee3e65911ec0bad2.jpgWaterportrepair3.jpg.26f78decf808cd20facefd89d0602ae0.jpgThis is how the head looks once we got done today. There are a few dabs of JB Weld just to fill in a few occlusions and screwdriver dents. The entire head is going to get milled next so all the surfaces will be flat and will seal with the new head gasket.


I am quite happy with the results so far.

Edited by Stude Light (see edit history)
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I received a shipment from Egge. New pistons are 0.030" oversize and were machined from billet aluminum. My rods are set up with a really odd size pin which is 23/32". The other Light Six engines I've disassembled were 1921/1922 cars and had an 11/16" pin. Not sure if that was a later change or what but I do know that piston and rod part numbers had changed around the time my car was built.


The 11/16" pins I have seen in the earlier engines had a slot that a washer in the small end of the rod went into, to hold the pin in place along with clamp load.


On my engine, the washers were ground flush and just used the clamp load around the pin to hold it in place. Since my rods were already set up for 23/32" pins I am just replacing with that size and using the clamp load as before but I'll also be applying Loctite retaining compound for some added retention.


Originally, the pistons used 3/16" rings for all 3 or 4 rings (depending on year). As technology evolved, thinner rings designs were used to reduce friction: 3/16" => 3/32" => 5/64" => 1/16" => 1.5mm => 0.043" => 1.0mm => 0.8mm.  I opted to use 3/32" compression rings and a 3/16" oil control ring which will greatly reduce the friction I had with the old 4 x 3/16" ring design. 


I also had new valves made. You can see the old vs new below.


Note that the old ones had really no margin below the sealing surface. This leads to poor sealing and edge overheating which causes damage and pre-ignition.


I also had my camshaft reground. It had grooves worn in the lobes from the cam follower rollers. They do not weld up the lobes but regrind the entire lobe to regain lift and opening/closing profiles. The entire lobe is smaller around so you do need to make up for that by having the ability to adjust overall valve train geometry by using the lash adjustment set at the heel of the lobe, which all these old engines can easily do.

Camshaftregrind.jpg.20df3a0329821da54001a976e556f2c1.jpgThey did a nice job and it isn't overly expensive (something like $100 or $120). There are a number of shops offering this work. I used Egge since they were making my pistons and had to box stuff up to ship anyway. Seems like shipping costs can become like 50% of the cost to get a part nowadays.



I loaded all this stuff up, along with the cylinder head to get surfaced, and drove it to Hart's Machine in Cecil, OH so I'll be in waiting mode for a bit. The only other thing I can work on while waiting is to clean up some parts and to make 26 new studs.





Edited by Stude Light (see edit history)
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