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William Robison -> RE: Welcome to Club SAITO ! (9/10/2005 7:00:44 AM)
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rangerman: You are number 46 in the club. Now to your FA-120. First, look at the cam cover. Do the cylinder fins reach out over the cover, or does it look like the cover can be taken off with the cylinder in place? With the fins out over the cam box you have the ABC engine, the small fins are the AAC cylinder. The ABC version has bronze valve seats, OK to lap the valves. The AAC cylinder has hard chrome seats, plated on the base metal aluminum. Do not lap the valves in the AAC cylinder. If you grind the plating down, it will flake and the cylinder will have to be replaced. Use a pencil eraser (a big one) and spin it on the seat if it needs cleaning, chuck the valve in your Dremel after yu clean the seats and use the eraser again to polish the valve. If the valve leaks after this, replace it. Install new valve springs, they lose their tension after a period of time, and they are cheap. The cylinder bore, whether the ABC or the AAC, is the last thing that will wear out in your engine. I have replaced only two cylinders that weren't crash damage. One was destroyed by an owner who ignored the bearing noise, bits of the bearing scraped nice grooves in the chrome plating on the cylinder wall. The other was an AAC where the owner knew he should lap the valves. Cost him more than he wanted. The piston, if you can check it, should have 0.0005" to 0.0015" skirt clearance. Or give it a good inspection by eye. If you still see the grinding marks over most of the skirt it's fine to re use. The con rod should have about 0.0005" clearance on the wrist pin, up to 0.002" on the crank pin is OK. Install a new piston ring. Wear on the cam lobes is OK, pitting or visible damage is not. If you replace the cam you must replace the tappets at the same time, or risk cam failure. Install a new ceramic bearing at the rear of the crank, and if you wish use a ceramic at the front also. Just be sure the front bearing is a rubber sealed one, the shielded bearings will leak oil badly. The oil leakage from the push rod tubes indicates either a very high time engine, or a plugged crankcase breather nipple. The only way for oil to get there is past the tappets. If the ring has a lot of blowby, the internal pressure can force more than the normal amount of oil past them. Or they themselves are worn to a very loose condition. The tubes don't have o-rings on them anyway, and the rubber seals are only sold with new pushrod tubes. That's enough for now. Read it through, look at your engine, then ask more questions as you think of them. Bill.
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