Timing Cover and Water Pump Installation

Applicable to A-block and LA 273, 318, 340, 360 Engines

Cleaning and Preparation

Before cleaning anything, I verify the type of timing cover I have and its condition. Aluminum covers corrode badly in the pump chamber, so I inspect them well for any holes that will cause coolant to leak into the oil. A-block iron and aluminum covers have one additional bolt than LA covers (Figures 1 – 2). If I’m using an A-block cover with the additional hole, I can move onto the cleaning step below. If I’m using an LA cover without the additional hole on an A-block, I need to plug that threaded boss in the block because it goes through into coolant. An extra-long 3/8″ Allen setscrew (not a tapered pipe plug) can be used, or I can cut off a grade 2 bolt’s threads 1/2″ long and use a cuttoff wheel or hacksaw to cut a slot into the head. I coat the plug liberally with Permatex 80003, tighten it until it seats snugly on the bottom of the boss, and wipe off any protruding sealant. At 1/2″, the plug should be down in the hole about 1/8″.

  1. If I’m replacing the cover on a running, assembled engine (versus during rebuild), I drape rags around the timing set and plug rags into the front of the lifter valley drain-back holes and oil pan to keep debris off the timing set and out of the engine.
  2. I use a gasket scraper to remove any loose gasket and sealant from the block, cover, and water pump. For the block and iron covers, I use a 3″ abrasive pad on a pneumatic angle grinder to make quick work of cleaning, but doing so on aluminum will remove aluminum and create an uneven sealing surface. For aluminum covers and pumps, I use the scraper and am careful to not gouge the aluminum.
  3. After the surfaces are clean, I remove any protective rags and inspect for and remove any debris from inside the engine. I blow off the timing cover and pump with compressed air.
  4. I dip a bit of rag into lacquer thinner and wipe the surfaces to clean off all oil residue.

Installation

I don’t like using RTV silicone whenever possible because it is a pain to clean off for future work. For the timing cover and pump fiber gaskets, a gasket sealant like Permatex 80019 or Gasgacinch works very well.

  1. I place the cover and pump gaskets on a piece of cardboard and brush the sealant onto one side of the gaskets and let them tack up until the liquid doesn’t transfer to my finger (about five minutes).
  2. I press the sealed side of the gasket onto the cover and onto the pump, brush the sealant onto the other side of the gaskets, and let it tack up.
  3. While I’m waiting for the sealant to tack up, I install the washers on the bolts and apply a liberal bead of Permatex 80003 sealant to the threads I note in Figure 3 and smooth the sealant into the threads. All but the top bolts go through to coolant and can and often will leak if left unsealed. The two top pump bolts can either be blind threaded bosses or can go through into the lifter valley
  4. I carefully install the cover onto the block using a couple bolts and the bottom block alignment pegs to help keep the gasket aligned. I tighten the bolts finger tight at this point.
  5. I install the pump onto the cover remembering to include the ignition timing pointer and tighten the bolts finger tight.
  6. Using a 3/8 ratchet, I torque all the bolts in a three-step sequence and in an “X” pattern until I feel the gaskets seat, which is around 35 ft.lbs. for iron covers and 30 ft.lbs. for aluminum. The four pump bolts may require a fourth sequence since they crush an additional gasket. Note that one bolt behind the pump inlet can’t be reached with a socket and requires a wrench.
  7. Since the gaskets and bolt sealant will be under both temperature and pressure, I allow the sealants to cure for 24 hours (48 in temperatures under 60°F) before filling the coolant and firing the engine. Leaving the coolant passages empty will introduce more oxygen to help cure the sealants quicker.

For details on how I fill the cooling system, see the later section (around step 27) of my technical article on installing the intake manifold.

FIGURES

Poly A-block 318 Timing Covers
Figure 1: A-block Timing Covers
LA Timing Cover on a Poly Engine
Figure 2: LA Timing Cover (note that early LA covers don’t have the integrated timing tab)
Poly A-block 318 LA Timing Cover Bolt Sealant
Figure 3: A-block Timing Cover Bolt Sealant Schedule