One More Head Gasket Tip
In addition to the past two articles discussing head gasket failures, other head gasket failures can be caused by installation mistakes. Head bolts can stretch out. Many manufacturers recommend the head bolts be changed each time they are removed. Another common mistake is not cleaning the bolt and hole threads. Use a tap to clean the holes in the block, and use light oil on the threads. Some head bolts can be shimmed up with hardened washers to keep them from bottoming out in their bores. Cleaning surfaces properly is a key element; keep in mind dirt and gasket material can keep gaskets from sealing. So use abrasive pads very carefully as well, especially on aluminum! This can cause small indentations that can prevent the gasket from sealing. Don’t forget to torque properly and go over sequence twice. A careful approach to this problem will reduce comebacks and lost profits.
Bill Crum
Engine Pro
Tech. Committee
Avoiding Flat Cam Syndrome
Along with the use of assembly lubes, break-in oils with ZDDP (Zinc Dialkyl Dithiosphate), and a lifter bore grooving tool our shop does this; on all flat tappet cam engines our shop has added one step before final assembly.
With the block in a bare and clean state we’ll put in the two end cam bearings and install the cam with only light oil. Next we install the lifters with only light oil. Install a bolt in the front of the cam and spin it quickly clockwise with a speed handle and observe each lifter’s spinning action when the engine is running. You can use a felt pen to mark the lifters so it’s easier to see them spinning. If you find any of the lifters not spinning, this could be a potential problem if it leaves your shop like that. Lifter bore or even cam bore alignment could be the problem.
Many times the cam bearing bores get closer (fall) towards the crank centerline going front to back, (especially on BB Chevys) which in turn causes the taper on the cam lobe to be lessened towards the back of the motor. Zero or too little taper can keep the lifter from spinning, and this can cause the cam to fail shortly after fire-up.
To remedy this problem without reboring lifter or cam bores check local listings or the internet under custom cam grinding to have the cam reground with more taper grind into the lobes. After regrinding we do the test again. We’ve had great luck and no flat cams when all of the lifters spin before we fully assemble the engine, even with today’s lousy oils! Yes this will cost more, but what will really cost more an extra cam grind, or a flat cam, or a comeback and angry customer? Thanks and good luck.
Norm Johns
Norm’s Auto Machine
Petaluma, CA
Cheap Valve Spring Installed Height Tool
Use a bronze bushing that measures exactly 1? in height. Slide it over the valve and install the retainer. Now, measure the difference between the retainer and the bushing with a simple hand caliper and add 1 inch. You now have your installed height. You will find that this is much faster and easier than using the expensive height micrometer.
Jim Foley
Reid’s Automotive
Whitman, MA
Break Up With Broken Bolts
One of the hardest, most time consuming jobs for me is the removal of a broken bolt, drill bit or broken tap. I have found a fast and simple solution for the problem. I use a hammer drill and hammer drill bit. It is quite effective and just seems to peel the broken bolt or drill bit away. The bits also work very well in a drill press.
Roger Munn
Roger’s Engine Works
Naples, FL
The Sleeve Saver
To avoid deck surface or sleeve damage while loading/unloading and line honing, here is a good idea. I have laid nylon straps over the v-block cradle risers in the line honing machine. Simply secure them in place with tie wraps around the base of the riser. This virtually eliminates the possibility of dinging the surface or the sleeve, especially the fragile nitro and alcohol blocks with O-ring and protruding sleeves.
Rev. Ron Flood
Cedar Machine Service/Toxic Cycle Inc.
North Branch, MN
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