June 2002 - American Bonanza Society

Tool fabricated from a six-inch ·C· clomp, showing piston saddle.cise, I cannot say. But I would think that some reduction in thecorrosion rate would result, at least enough that I don't mindthe small extra effort involved if I know the engine will be sittingfor more than 10 days or so.In doing cylinder change work, the pistons must beremoved from the rods to either clean the old pi stons for reuseor to install new pistons. One of the difficulties encountered isremoval of the piston wrist pins if the engine has very muchtime on it since the pins were last installed.About 200-400 hours of operation will build up a slightvarnish-like deposit on the wrist pins on the exposed pin surfacebetween the rod and the piston pin boss, which will preventpushing the pins out of the piston. The pin is fitted to thepin holes in the piston with very little clearance. Even theslightest deposit of this oxidized oil varnish will stick the pin.Driving on the pin with an aluminum or brass punch is nota good idea since that may cause damage to the connecting rodbearing. There are a number of tools available to remove thepins by pressing the pin out without driving with a hammerand punch.The photos on this page show a tool fabricated from a sixinch"C OO clamp that will remove the pins quite nicely-all ofthem except the #2 cylinder ("E" series engines), unless the oiltank is removed from the engine. The tank and all of its plumbingclutters the space needed to extract the pin. That cylinderwould need the rod removed from the crankshaft. Rod removalis less time-consuming than oil tank removal and allowsinspection of at least that one bearing, which would give someindication of how the engine lower end is doing.The time required for installation of a new top end varieswith the individual airplane and mechanic. Work time will bealtered by multiple instrumentation probes, exhaust systemcomplete removal or merely dropping it out of the way, othermiscellaneous repair work on barnes, etc., as we ll as the speedand care of the mechanic.On this panicular job, my approximate time was:Removal of the cylinders - 5 hoursFitting new rings to new cylinders - 4 hoursTool with piston in placeMisce llaneous under cowl repair - 3 hoursInstalling new cylinders, exhaust system and instrumentprobes - 12 hoursOil filter change, logbook and other paperwo rk - 1.5 hoursI'm not the fastest dude around and not the slowest either.These times are what it took this time. Next time could be different.If reconditioned cyl inders were used and had to beassembled (valves, leak check, etc.), an additional six to eighthours wo uld be required.Also, these new c y linders~ombin ed with reworkedlifter bodies and rocker arms that are found in nearly all "E"engines-require installation of longer pushrods. Continentalhas .030 inch over standard length push rods at $45 each. Ineeded 12, so there is almost $600 in pushrods needed toinstall new Continental cylinders.The .030-inch rods will remove about .045 inch of valveclearance. The specified collapsed lifter clearance is between.030 inch and .110 inch. With standard pushrods, I was gettingabout .150 inch on average. If excess clearance ex ists, theextended lifter (after engine start) may not be able to bring thevalve system lash to zero, and damage to the valve train mayresult. The only solution is longer pushrods.While doing this job, I also used one set of new push rodtubes. I had several sets of these new tubes that were of thepainted variety. 1 stripped all of them to bare metal and hadthem plated with zinc chromate plating. This is the gold colorused on new AN bolts, nuts, etc. I have several sets availablefor sale at $150 for 12 tubes plus Shipping. Such a deal!So the engine is running as it should, and if my luck holdsout, I won't have any cylinder problems for a while.Lewis C. Gage. ABS member. ATP mulfiengine fand with Boeing 707172017471Airbus·310 ratings. Commerciaf single engine land; flight instructor MEI.JSELO/rpfanes and instruments; ground instructor advanced and instrument; flightnowgator; flight engineer; mechanic-airpfane and engine; and FAA parts manufacturingauthoazation. Flight time: 15,OOO-plus hours. Lew may be contacted atSunnse Fillers. Inc .. 2255 Sunrise. Reno. NY 89509. Phone/Fox: 775-826-7184.E·mail: sunrisereno@mymaifststion.comABS June 2002Page 7321