Triumph T-120 Engine Restoration

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The" Frozen/Rusted" Triumph T-120 Engine Cases - Can They Come Apart?

I recently came across a Triumph T-120R engine that was caught in a major flood of water in his or her basement. Most people would have least let the water out of the lower end cases, but this was not the case. Here are some pictures of what it looked like and the story of what was required to get everything apart. Typically we all work on things that come apart with ease, however the T-120R was not the case. It is one of the worst case of a collection of rust I have ever seen in these parts.

This is what the engine appeared like when I first saw it. Looked normal enough, but if you look close you begin to see tell tale rust everywhere. Look closely at where the timing/transmission covers screws are - Rusted in place.

Here is a picture of the same engine showing the primary side. When the primary chain was removed it was stiff as a board. Someone has a piece of solid PTFE block as a primary adjustment slipper. Strange!

This shot is seeing into the barrels and pistons. Frozen solid with rust. It very clear that these barrels are an alloy type as they have cast iron liner inserts. Notice the rust in the exhaust tappets.

This is a close-up of the stator. Rusted in place as solid as one can get it.

The timing side of the engine with the transmission and timing cover removed. The small hole just below the exhaust timing cam allows you see the insides that are totally rusted that is incased internally.

The primary side of the engine was easy to remove. I used the Ban-Rust from Premier Fasteners to free up the threads, allowed to soak and off came the nuts and bolts that held everything in place.

Now that I have the engine stripped to the point that I was now prepared to find a large tube, fill it with diesel fuel and let is soak for about 4 - 6 month's.
I was having a conversation with John Oland, Proprietor of MotoParts Inc in Edmonton who had just come from his monthly meeting of the CVMG Noral Group. They had a presentation by a chap named George Kerr who is a representative of a company called CEDA. These people are well known in the oil and gas, particularly on the refinery side for doing vessel piping cleaning of contaminants and hydrocarbons. George spoke of a method using several household chemicals, by heating and submerging what ever rusted in place. With time and heat, the chemical eliminates any rust contaminants. John was kind enough to give me a sheet that George has put together for removing rust in smaller portions. The mixture was simple enough, but for doing smaller bits and pieces. The write up is attached at the bottom of this page for your use. Please note click on the new yellow star and the write up is there!
I contacted George, several emails went back and forth and I was invited to bring the engine in, so that he and his shop could perform his magic. The reason I did this is that I did not have a container big enough to totally submerge the complete engine, nor did I have a means of heating it to the required 185° F.
What you are about to see is nothing short of a miracle to which I am still shaking my head - "Can't be".

The first thing that came apart was the barrel, pistons, circlips removed, grungeon pins removed, barrel base nuts and the cam followers. This was about after being in the heated bath solution for about 1 - 2 hours. Because we didn't leave the pistons in longer to the heated solution, the rings were not as free as I would have like to have seen them. The picture of the top right shows the gaps between the rings were extremely tight. All the pictures show the oil scrapper bottom ring to be loose. The right bottom picture shows the exact position the pistons were stuck in position in the barrel. The corrosion in my opinion is not enough not to allow a rebore if necessary. Notice the neoprene o-ring still attached to the cam follower guide block.

The first picture to the left is a shot down into the cavity of the lower engine cases exposing the crank, cams and con rods. The middle picture is the transmission cavity and the timing side housing. A serial # on the primary side of the lower engine case.

The picture to the left is the crank end on the timing side and the middle picture is from the primary side of the crank. My biggest fear was starting to split the crank halves, as wasn't sure what the sealant was used. Several taps with a leather mallet and the halves start to come apart as pretty as can be! I use the foam thermal insulation for water pipes to protect the con rods.

Both lower engine halves are now split and exposed. Internally the red rust particles that I saw earlier are all but gone. There was some residue of red rust on the crank sidewalls, but that just wiped off. The outer two-piece bearing race, the bearing and the crank ends all turned a black finish. I questioned George Kerr about this and this is his response:

The blackness of the carbon steel components is normal when using this pH. If you want them shiny like a new nickel I would take the separated items i.e. the barrels and other carbon steel parts change the ph slightly then add a chemical which would replate the surfaces with magnetite which is the metal that is in solution and layer it back on thus leaving it shiny like a new nickel. This variation is how we normally leave a typical carbon steel system. To ensure no damage occurs to the aluminum the first part must stay the same, then separate and finish as I have described.

As mention earlier all exposed steel parts turned a blackish in color do to the pH factor in the solution. The surface of the lifts on the cam where perfect with no wear signs. The Babbitt shells on the bottom of the con rods where still coated with engine oil as shown in the middle picture. The crank journals are in perfect shape with oil still present on the surface. I have not checked the tolerances of the surfaces, but it appears the surface does not have to be reground.

As you can see after the crank journals have been cleaned with little pitting or score marks. The center picture shows the crank sidewalls with some rust residue. I simply sprayed WD 40 and wiped clean. A close-up of the Babbit journal. It could very well be re used again.

Pictures of what the underside of the crank looked like after being separated from the lower halves of the engine. The rust residue was sprayed and wiped clean with WD 40. The bearings came out no worse for wear but will be replaced.

The insides of the cases are very very clean. With some soap and water further cleaning will take place and after the welding is completed the cases are ready to be reused. The slug trap plug has seen better days and will be renewed with a hex socket plug.

After completing this particular engine tear down I am extremely pleased with how things came apart. When I first looked at it, I really had no idea how it was going to come apart, and in how many pieces, or was it just junk. From the pictures you have just seen, this process is truly amazing.

The Following Pictures are After the Engine was Put Through George Kerr's Cleaning Method