Leaky intake Gaskets

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Technotes

Spring has sprung and you are eager to take care of that little intake manifold leak, and check the valve clearances, re-gap the valves and plugs and have that Franklin humming for the summer. This is a no kidding experience that I wanted to share.

I installed 12 new plugs from Carl Baker Co, (805.644.9328) and sent the old plugs to be overhauled. At $3.50 each this is a deal, call (818.787.5680). The intake gaskets are from A-1 Services/ Irene Heinley , phone 903.626.5115 Eve, or .5122 Day. So I pulled the plugs, and put in those nice new Champions in the bottom with just a tad of never cease, coated the intake gaskets with never-cease, loosened the cylinder base nuts, torqued the intake manifold to the cylinders, torqued the cylinders to the block, pressure checked the cylinders, all 78 to 80 over 80 psi, tested the ignition harness (just to make sure) then replaced the top plugs and ran the motor up.

 Bad, Bad, Bad, sort of like a VW on 3 cylinders. Man what’s wrong here? Not to be beaten the Tech-guy and supposedly somewhat knowledgeable dude, pulled all the plugs, ensured all were clean, that the wires were not crossed to any plug, rechecked the valve clearances, .040, all were good, rechecked the ignition harness, it was good, rechecked all the cylinder pressures, all more or less the same, and reran the motor.

BAD, BAD, BAD, if I held my mouth a certain way and squinted just so, it was better than before, but not much, what a mess! How can something so simple turn into a can of worms? I now needed help big time, so I recruited several “heavies” from around the airport, and after all the usual questions, still no answer as to why the engine was running rough. I pointed out to these guys that #4 and #6 seemed cooler to the touch and that the exhaust port on #4 was definitely cooler than all the rest, but apart from that everything was exactly as it should be, no answer seemed forth coming so I quit and went home, imbibed and put the matter to rest figuring I would wake with the answer.

At this point I had put in a good 12 hours on the problem over 2 days. Day 3 I figured it was a sticky valve and re checked all valves and pressures, all OK, after run up the #4 plugs were wet looking and cylinder was still cool, and then I had an inspiration, and found the problem. My money says you don’t know what was wrong, call me, email me write me. Answer in next months technotes…….

Last month I told you about an experience I had, with a poorly running engine,  I had several responses to my challenge, 2 thought I had never cease on the plug, one suggested a rag may have been left in the engine and also a suggestion that the primer may have been a problem. No, the real problem was the #3 (center) gasket was mis-aligned causing the engine to suck air in around the gasket and not fire under a load. This particular gasket is easily mis-aligned and not easy to seen .The whole induction system is prone to failure. After hearing about an old bird go down after one of our fly-in’s, I drilled and safety wired the 12 bolts that attach the intake manifold to the cylinders. Since that time I have found bolts missing on other engines. Be aware that those intake manifold bolts must be checked regularly. Next annual pull them out drill and re-install.

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