Best Approach for Rebuilding Your 3406A DITA Engine: Genuine Cat Parts, Cat Classic Parts, or Aftermarket Brands?

Question:

Struggling to decide the best approach for rebuilding my old 3406A DITA engine. Contemplating between Genuine Cat parts, Cat Classic parts, or an aftermarket brand. While the engine runs adequately, it requires revitalization due to excessive blowby and difficulty starting at temperatures below 5C. Considering a basic out-of-frame rebuild, including 6 liners/pistons, head, oil pump, water pump, bearings, and resealing the front cover and retarder. The goal is to use the engine for bobtailing to shows or towing a 35-foot RV, with an estimated usage of 10-20k kilometers per year.

Top Replies

I have always been cautioned by a retired Cat engine expert to avoid aftermarket components. However, I believe that using Cat Classic parts should be acceptable. At the time of his warnings, my trucks were operating across all 48 states and Canada, so my expectations for longevity and warranty were different. Considering your planned usage, it may be worth exploring aftermarket options from reputable suppliers. Personally, if I were to rebuild the C15 engine in my W900, I would consider aftermarket parts, except for the head. While I have never personally used aftermarket parts in a Cat engine, I am open to exploring this option. I am interested in rebuilding two engines without having to invest in expensive Cat parts. These engines will have limited usage, mainly moving around my property and operating the crane and compressor. The nature of my work results in my service truck only accumulating 13,000 miles in 2-1/2 years, as most of my customers are nearby and the truck does not have to travel long distances. This may not be the typical life of a large diesel engine, but it serves its purpose well in my operations.

I recommend avoiding classic parts when it comes to engine repairs. In general, classic parts are only suitable for engines that are used for 500 hours or less per year and for non-internal components. Genuine parts are a better option as they cover contingent damage, such as receiving a new rod and block if a faulty rod causes damage. When it comes to aftermarket (A/M) parts for a 3406 engine, there are many reliable suppliers to choose from. While most of the time aftermarket parts are sufficient, opting for OEM parts is recommended to avoid potential issues post-rebuild. It is advisable to consult with your Caterpillar dealer when purchasing parts, as they may offer discounts, especially when buying a complete package. Caterpillar provides a 1-year parts warranty for both classic and genuine parts, with additional discounts available if they handle the labor. Ask about gold or platinum kits for additional savings. By comparing prices between classic and genuine parts, you may find that the partsman is willing to offer a better deal on genuine parts to ensure customer satisfaction and prevent the purchase of classic internal engine components.

If you're only using it for shows, consider reusing the head and replacing the pistons and liners. Inspect the counter bores for any pitting and use a sled gauge to check their height. The oil pump should be fine, but replacement oil pumps for retarders can be expensive. It's recommended to replace the cam follower clips and verify the follower diameter. Don't forget to check the bushings in the geartrain of the front structure and reseal the engine. While aftermarket parts may be cheaper, it's worth investing in OEM internal parts. Using Cat gaskets and O-rings is crucial to avoid future problems. Trust the experts at the Truck Shop for all your needs.

Thank you to everyone for their responses. It seems like the head will need to be repaired or replaced. The previous owner ran the engine with broken exhaust studs on the first two cylinders for an unknown amount of time. The vibrating manifold may have caused damage to the head. I won't have a definite answer until I take a closer look. I am preparing for the worst-case scenario. Additionally, this engine has a spacer plate between the head and block. Would it still have counterbores? Are there any specific concerns I should have with this setup?

Hello everyone, I appreciate the responses.I believe the cylinder head will need to be repaired. The previous owner operated the engine with broken exhaust studs on the first 2 cylinders, causing the manifold to vibrate and potentially erode the head. I won't know the extent of the damage until I inspect it further, but I am prepared for the worst-case scenario. Additionally, this engine has a spacer plate between the head and block. Is it likely to have counterbores? Are there any specific concerns with this setup? It is not unusual for some studs to be broken, as this was common for the A's and B's. Removing them may require patience. If there is a buildup of oil or soot around the valve stem at the top of the valve guide, the guides may need to be replaced. There is a counterbore in the block below the intermediate plate, so be sure to check for erosion and replace the plate if necessary. Keep in mind that the plates come in various thicknesses.

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Frequently Asked Questions (FAQ)

FAQ: 1. What are Genuine Cat parts, Cat Classic parts, and aftermarket brands?

Answer: - Genuine Cat parts are manufactured by Caterpillar and are designed to meet the specific requirements of their engines. - Cat Classic parts are remanufactured by Caterpillar specifically for older engine models like the 3406A DITA. - Aftermarket brands are parts produced by third-party manufacturers not affiliated with Caterpillar.

FAQ: 2. Which parts should I consider replacing during a basic out-of-frame rebuild for my 3406A DITA engine?

Answer: - It is recommended to replace components like liners/pistons, head, oil pump, water pump, bearings, and reseal the front cover and retarder during a basic out-of-frame rebuild.

FAQ: 3. What are the common symptoms that indicate the need for rebuilding a 3406A DITA engine like excessive blowby and difficulty starting at low temperatures?

Answer: - Excessive blowby and difficulty starting at low temperatures are signs of worn-out components such as piston rings, cylinders, or valves, indicating the need for a rebuild.

FAQ: 4. Which approach - Genuine Cat parts, Cat Classic parts, or aftermarket brands - is best for rebuilding a 3406A DITA engine for recreational use like bobtailing or towing a 35-foot RV?

Answer: - The choice between Genuine Cat parts, Cat Classic parts, or aftermarket brands depends on factors like budget, desired performance, and

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