Pinless intake valve yokes for Mack E-Tech diesel engines. - Engine Builder Magazine

Main Navigation

Advertisement
Social Connect
Resources
Our Brand Family
Engine Builder Magazine
Content for engine professionals and enthusiasts
Tech Center

Pinless intake valve yokes for Mack E-Tech diesel engines.

Engine Builder
By Engine Builder

Related Articles

Engine Builders: The AERA Technical Committee offers the following information concerning pinless intake valve yokes for Mack E-Tech diesel engines.

Beginning March 2, 2000 (engine s/n 0D0120), pinless valve yokes p/n 891gc328 were phased into production of all E-Tech engines. The pinless yokes are used for the inlet valves only. This change went into effect with cylinder head p/n 732GB5359M, and cylinder head assembly p/n 732GB3491M when yoke guide pins at the inlet valve locations were eliminated.

The pinless yoke (Figure 1) is self-leveling in operation and does not have a yoke leveling adjustment screw. Inlet valve lash adjustments are performed in the normal manner with the rocker arm adjusting screw. For all exhaust valve locations, it is still necessary to adjust the valve yoke first, then the rocker arm lash.

The bottom of the valve yoke that bridges the two inlet valves has a round hole and an elongated hole that fit over the valve stems. The nose of the yoke with the elongated hole has two notches in the casting. When installing the pinless yokes, it is important that the end of the yoke with the two notches faces away from the valves rocker shaft. If the yoke is installed incorrectly, the yoke will contact the rocker arm (See Figure 2).

Engine Builders: AERA members have reported an engine oil gallery leak on 1998-2002 Chrysler 2.7L VIN R engines coming from the gallery plugs located throughout the cylinder head.

Each cylinder head has 6 external oil gallery cup plugs located throughout the head. Locate the cup plug that has the external leak by visually examining the plugs or, if necessary, performing an engine oil dye leak test.

It is not necessary to remove the cylinder head to fix an oil leak and the original cup plug does not need to be removed to install a new plug. The bore for the cup plug is deep enough that you can drive in the replacement plug. To see if this repair procedure has already been done, check for the cup flange to be just inside the chamfered edge of the cup plug bore about .039˝-.078˝ (1-2 mm). If there is already a second plug in the head, removal of the head must be done.

To install the cup plug, clean the cup plug bore solvent and compressed air, lightly coat the new cup plug with sealer, p/n 04318083 or equivalent, and drive the cup plug in the head until it is just about .039˝-.078˝ (1-2 mm) inside the chamfered edge of the bore as shown in Figure 3. Allow the sealant to cure for at least 20 minutes.

You May Also Like

Engine Components

Choosing the Correct Block for Your LS Engine Build

Whether you’re scouring junkyards, ordering cores, investigating factory options, looking at aftermarket cast iron or aluminum blocks, or spending big bucks on billet LS blocks, you’ve probably noticed it’s been harder to find exactly what you want for the foundation of your LS build than it historically has.

Greg Jones
By Greg Jones

Has it become more difficult?

As we’ve often written about in the pages of Engine Builder, and certainly in recent LS-focused issues, the LS engine family is still a hot commodity. The reasons are many and those reasons are valid. However, as that popularity has remained high from more and more people seeking an LS engine build or doing an LS swap or boosting a junkyard find, the availability of LS blocks are taking a hit. The result has been higher prices in some cases and longer waits in others, leaving people with a more difficult choice.

Read Full Article

More Tech Center Posts
Open Loop/Closed Loop and Learning

Closed-loop control can be programmed to either add or subtract up to a certain percentage of fuel in order for the engine to reach the target air/fuel ratio.

By Andrew Starr
Shop Solutions January 2023

Next time you have set of large journal small block Chevy connecting rods to resize, consider honing the big ends of them for a +.002” outside diameter bearing that the LS engines with fracture cap rods use.

By Shop Solutions – The Power of Knowledge
Shop Solutions December 2022

Everyone misses occasionally, and this helps avoid dents and damage.

By Shop Solutions – The Power of Knowledge
Jesel Certified Performance Rebuilds

Engine components are serious investments for any racer and maintaining that investment could be the difference between winning a championship and losing it.

By Engine Builder

Other Posts

Going the Extra Mile with Cylinder Head Porting

It’s not just the port work alone that creates spectacular cylinder head performance. The most critical areas of a cylinder head are those which pass the most air at the highest speed and for the longest duration. Your bowl area, the valve job, the throat diameter, and combustion chamber are all crucial parts. 

By Greg Jones
Tight Tolerances and Building Power

As you ascend Mt. Everest, you reach an area called the death zone. Once you climb high enough, the margin of error becomes perilously thin. That death zone also applies to engines. As the horsepower per cubic inch and rpm increase, the margin of error decreases. 

By Lake Speed, Jr.
CNC Update: Features and Automation

Precision is key when it comes to automotive parts; the complex designs of connecting rods, pistons and rings, blocks, cylinder heads, and other parts require super tight tolerances that are getting more and more difficult to be met by hand or with other machining processes outside of CNC.

By Evan Laux
All Things Media Blasting

Engine building is a segment of the automotive industry that has always been ahead of the curve in media blasting, and no matter the engine shop, cleaning equipment is a common bond.

By Eric Garbe