Keeping Chevy 4-Bolt Mains From ‘Walking’
All four-bolt small block Chevy main caps “walk” when used with either studs or bolts. The factory cap or a splayed cap relies on the register to locate itself because bolts and studs don’t fit well enough to keep the cap from walking. What I have decided to do when working with a stock block is to eliminate cap walk altogether. Here is how I do it.
I place 7/16? x 1/2? dowels as used in aftermarket connecting rods in the outer bolt holes. Since the O.D. of the dowel is 1/2? it is easy to locate the proper reamer. No drilling is necessary.
Set the block up and indicate hole locations. The bolt holes are already recessed. Ream to one half the distance of the dowel, and then do the same with the caps. Be sure to sink the holes at least .015? to keep from bottoming the dowels into the cap. This also leaves room for line honing.
Done correctly, the line hone should not change. The block we used (pictured) required line honing anyway for the proper tolerance.
Paul Milano’s Service
No Guesswork: Machine Down Valve Guides
When putting in a “bigger” camshaft, it is often necessary to machine the valve guides down to retain proper retainer to seal clearance. Instead of doing this by guesswork, I have devised a precise way to machine all the guides to the same height.
Here is my method. I machine the first guide to the proper height and then stack shims of the right size and thickness to the height of the newly machined guide. Then I move the shims to the next guide and machine it. When the cutter body reaches the shims, the top shim will spin, and you know that guide is the same height as the last one.
When you have finished machining them, all the guides will be exactly the same height and you will not have harmed your cutter. The guesswork is gone!
The Engine Shop
Upper Darby, PA
Manufacturer’s Shop Solution: How To Install Timing Tensioner
The timing chain tensioner is often blamed for timing system failures. Many of the reasons are due to improper tensioner installation.
Here are some rules to follow when installing tensioners:
1. Most tensioners are spring loaded. Do not remove the securing pin or activate the tensioner until the chain and tensioner are installed.
2. Most tensioners have cast iron bodies. Overtorquing the mounting bolts can distort the plunger/spring chamber and prevent the tensioner from fully activating.
3. Torquing specifications vary with tensioners, so check your technical source.
4. Tensioners need clean oil to operate properly. Dirty oil can clog the tensioner and reduce tension on the chain.
By following these steps a timing chain tensioner should function properly.
S.A. Gear, Inc.
Bedford Park, IL
Hints For Painting SB and BB Chevy Blocks
I paint my engine blocks prior to assembly and let them dry. This results in a better coat of paint because there are no oils and lubes from assembly to contaminate the paint. In some areas, overspray can be a problem. One area on both small and big block Chevy engines is the oil filter area. I use an old coffee can to mask this area. The can fits perfectly in the machined recess. I also have an old canister type filter housing that I use.
Jeff “Beezer” Beseth
Newtown Square, PA
Making An Oiling Primer From An Old Distributor
Here is how to do it: First, remove the cap, rotor, spring, weights etc. from the top of the distributor, then grind off the gear teeth. Then, using an old socket, preferably 3/8? so it will fit your 3/8?air drive, weld the socket onto the top of the distributor shaft.
Now you can insert the distributor shaft into the intake of the oil pump driveshaft and turn it with your air ratchet (Do not use an impact!) to prime the oil system.
DK Motor Services
Editor’s Note: For instructions on oil pump and engine priming see the Manufacturers Shop Solution presented by George Richmond in the March issue.
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