Tech Tip: Lifter Bank Angles of a Chrysler ‘A’ Block – UnderhoodService

Tech Tip: Lifter Bank Angles of a Chrysler ‘A’ Block

The latest version of Chrysler's "A" engine block features a different lifter bore angle. This block is commonly called the "R" block.

The latest version of Chrysler’s “A” engine block features a different lifter bore angle. This block is commonly called the “R” block.

The angle of the lifter bore is changed to help straighten out the pushrod angle. The standard lifter angle on the “A” engine is 59 degrees from vertical. This points the lifter away from the center of the block and angles the pushrod toward the outside.

Most of the blocks and some highly modified versions of the “A” engine have a 48 degree lifter angle. This points the lifter more directly at the rocker arm and helps to eliminate deflection at very high engine speeds. No standard production blocks were made with this modification, so if your block is not a special “race only” part from Chrysler, you probably have the 59 degree lifter angles. These cams are not interchangeable, so it is important to note the lifter bank angle prior to ordering any racing cam. If no special lifter bank angle is stated, the standard 59 degree cam will be used.

The same changes are common on some of the newer aluminum aftermarket Hemi blocks, the difference being much more subtle, from 45 to 48 degrees. It is extremely important to make sure which lifter angle your block is machined for prior to ordering a cam. As with the small block, if no special lifter angle is requested the cam will be ground as with the standard 45 degree lifter angle.

– Tech Tip courtesy of COMP Cams.

You May Also Like

Cartridge Oil Filters

Mistakes made can result in costly comebacks.

An oil change is probably one of the least expensive services your shop offers, but it can result in one of the most costly comebacks if a mistake is made. Cartridge oil filters make potential mistakes more likely because they require more knowledge and tools to properly change the oil than a canister filter.

Solving Intermittent Overheating

New cooling systems anticipate and influence changes in coolant temperature.

How (And Why!) To Clean An Engine

Beauty is more than skin deep. Here are 11 steps to help clean any car’s engine compartment.

Spark Plug Fouling

Understanding why spark plugs get dirty.

Aging Plastic Intake Components May Cause Leaks

BMW valve covers and intake manifolds made of plastic are susceptible to warpage and gasket failure.

Other Posts

Diagnosing Intercooler Boost Trouble Code P0299

The criteria for setting the code is very basic.

Understanding Coolants

All-season coolant used inorganic acid technology and worked great for almost 30 years.

Misfire Codes P0300, P0301-P0312 and P0313+P0314

The only way to clear the code is to use a crankshaft position relearn with a scan tool.

Belt-In-Oil Timing Systems

Oil contamination of the belt drive has been a death sentence, due to the rubber and fiber construction of the belt.