Didja know, on most Stovebolt Sixes, the oil pan must be removed to get the timing cover off? And if you DID know that, didja come by that knowledge the hard way?? They says true wisdom is learning from others' experience. If you ever want to get at your timing chain without all the drama of dropping the oil pan first, all you have to do is make an easy...

Timing cover modification for easy removal
By Chris Sweet
Moderator of the Driveline forum
Bolter 4855
Fredericksburg, Virginia

Discuss this procedure in the Engine Forum

<< click on images for larger view >>

18 Jan 2013

NOTE: This modification is recommended to be done BEFORE installing the engine in the truck, or done on a truck with the front sheetmetal removed like Jim Brads 1957 3100 used in the photos.

So what's the point here?

Ever wanted to remove your engine's timing cover to fix an oil leak, change a gasket or get at your cam shaft? Many of us know how challenging removing the timing cover while the engine is in the truck can be -- you must first remove the oil pan because the bottom bolts for the timing cover are installed from inside the oil pan. The modification we have here is easy and takes less than 20 minutes once you have all the materials.  It puts the heads of the bolts on the outside allowing the timing cover to be removed without dropping the oil pan. We will be using the existing holes to drill out the threads in the timing plate ONLY, then tapping the bearing cap behind the plate to secure the bolts. Easy!

WARNING -- This process creates metal shavings you'll need to clean up completely before putting the engine back together.

Here's what you'll need for the job 

Figure 1 below shows the bottom of the engine with the damper pulley / Harmonic Balancer removed.  Notice the small oil leak under the cover. (This is the reason we are doing this procedure on this engine.)

Here is what you need for this procedure:

  1. finish your "Honey Do" list
  2. 3/8” drill bit
  3. 7/16” drill bit
  4. masking tape
  5. 3/8” – 16 tap
  6. 2 - 3/8” – 16 1” bolts [Actually, install the bolt of your choice with matching thread pattern as the tap. In the photos here, grade 8 bolts are used. Allen-head bolts can be used to increase ease of bolt removal for times when wrench / socket clearance is limited -- a technique that DrewP has used in his version of this procedure.
  7. 2 - 3/8” lock washers

Let's get started! 

Step 1


With easy access to the front of the engine, remove the oil pan and the two bottom bolts (these bolts will be secured with tabs).

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  Fig.1 -- Front of engine with harmonic balancer removed. Click for higher resolution image.   Fig.2 -- View from the inside of the front bearing cap.
Step 2
Mark your drill bit with tape to prevent going too deep.

Using a small piece of cardboard, determine the depth of the timing plate (approximately 1/8”) and put tape on the drill bits to make sure you don’t drill too deep.

Using the 3/8” bit, enlarge the two bottom holes in the timing plate to remove existing threads. Then, switch to the 7/16” bit to enlarge the size of the holes in both the timing cover and the timing plate. 

Drilling the holes in the timing cover itself should be done on a flat surface to prevent the cover from being bent or otherwise distorted.

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Step 3   Step 4

Carefully tap the bearing caps from the front. The holes you just created will help make sure the tap is nice and straight.


Clean up any metal shaving and test fit the bolts.

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Step 5    

Re-install the oil pan and the timing cover using the lock washers to prevent the bolts from backing out.

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for larger view >>

Now put everything back together and stick yourself with a fork ... 'cause U R Done!




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