On a charger web site there was a interesting discussion about what causes the "ticking' sound in modern Hemi engines and how it can be quieted. Here is the post:
Many here know what we do to stop the Hemi Tick, but we figured that since there are so many new faces here, they may not have heard that you don't have to have it in your engines.
We have discussed previously that there are 3 culprits that cause the "Hemi Ticking" that is heard in idle and just off idle.
1) Intake and exhaust valves do not have any kind of cushioning from the fuel. Fuel usto have higher amounts of sulfur and tetra ethyl or tetra methyl lead to lubricate and cushion intake and exhaust valves in the old days. When EPA decided to go to unleaded fuels, hardened valves and seats were produced trying to deal with the lack of lubricant. This was adequate at best, but did allow engines to live longer than if they had soft valves and seats. However, when they went to ethyl alcohol, that all changed. Alcohol absorbs moisture and strips lubricity. That was bad enough, but when they reduced the sulfur content from 130 parts per million (ppm) to 30 ppm, it really produced a perfect storm. Both the intake and exhaust valves are now hitting against the valve seats with no cushioning at all. This causes wear, and then of course....noise or TICK.
2) Fuel injectors depend on at least 70 ppm of sulfur to stay alive. When EPA went to the ethyl alcohol and less than 30 ppm, they have no cushioning allowing them to click or tick also while building up gum and varnish. This restricts the flow of fuel and turns the vaporized spray pattern into an atomized spray pattern. Atomized fuel doesn't burn as well, and helps wash down into the cylinders and wipes out the detergents and dispersants much faster. This is the second part of the Hemi Tick.
3) Because the Hemi has a very short skirt and thin rings with virtually no land area, the piston wants to rock in the bores. This is another reason for the moly piston skirt coatings. It is designed to cushion the short skirt. The problem is that as miles rack up, the moly is worn off and a louder engine or tapping noise begins to occur. This is the third part of the Hemi Tick. This part actually contributes to more aluminum in your oil analysis. An oil analysis is always important to do on any engine you want to take care of as a baseline, and then every 3rd oil change, do one just to be sure nothing is leaking or causing problems.
BND Automotive has addressed these issues by:
1) ACES IV Gasoline Formula introduced into your gasoline to replace the lack of lubricity. However, this is not just for the valves, but also for the injectors and the in tank fuel pump. The pump is cooled by the gasoline, but it needs plentiful or copious lubricity as well. ACES IV addresses these three issues to produce a protected, lubricated, and more powerful engine with a great quieting effect stopping 2 parts of the Hemi Tick. This is the injector and the valve ticking.
2) QuantumBlue Custom Blended Lubricants are designed for the different aspects that make up not just the piston slap by adding the right ratios of additives, but also producing much better filmstrength that is necessary to protect the Moly coating that is put on from the factory. This works great not just for the 5.7 and 6.1, but also the 2.7 and 3.5L 4 valve Polyspheric Hemi V6 engines as well. Taking all these into consideration..... cast iron block or aluminum block, cast heads or aluminum heads, carbureted or injected, what RPMs and what mods are added to the car along with what temperatures and conditions the car will encounter matter. Salt from the sea shore is different than what comes from snow removal. Silicates from desert conditions and extra high temperatures need to be addressed as well. Really cold temperatures in Canada and British Columbia also need to be adjusted for. Upper cylinder rocker assemblies are important to consider whether single rocker (SOHC) V6 or double rocker shaft (DOHC) V6. The 5.7 and 6.1 also have duel rocker shafts and are a weak spot for scuffing. Dads SRT even showed on a billet steel cam that the typical Mobil 1 0w40 is NOT protecting the cam. The rollers need to spin on the cam, and not slide. Without proper lubricity, correct filmstrength, and frictional capabilities of the lubricant, engine will damage and wear will occur!
These two in combination will address the Hemi Tick noises which will increase the life of your engine and keep your peace of mind.
Many here have taken advantage of these technologies and are now thinking about other things other than ticking engines since they don't have them any longer.