Gelignite is quickest ! .
PROBLEM numero uno , is Dried Castor . Assuming its a old R C motor thrown in a draw unoiled .
There was pulse jet fuel with polypropolene , proplene dioxide and other delights , that disolved set fibreglass from paint brushes .
I figure soaking in this would be the best way to FREE IT , if STUCK .
A HEAT GUN is near essential .
Pre Organise a lever . wear gloves . Aim for 135 Degrees . Waters useless . even boiled . As a rule .
Very Carefull use of a 3/8 ish screwdriver flat , under the skirt AT the Bypass , to nudge it free .
After if hot , you can carefully lift it by the top lip / flange .
THE IDEA is to get it so the Lower Edge is just above the rear access hole for the wrist pin. So the PISTON is still SUPPORTED .
Now Comes the fun part .
Easy to break a drill tap of in it . Easy to pull out the end cap . if its truely glued up .
So a weeks pre boiling / crock potting , CRC in etc before hand on old junkers is essential .
A well maintained oiled carefully stored one should come out freely however .
ROTATE it to see if free .
Dried Castor between rod & piston on the pin , is a culprit for sticking - all the way . Plus many are Nitro Oxidised .In Place .
Liner Out , a timber packer down ea side at the front , then forceing the pin FORWARD to start it . Then carefully pushing the piston forward .
Repeat a few times , Heating Piston & oiling / crc / penetrating oil . possable to without damadgeing piston or ring , if youre carefull .
The odd engine someones got desperate and drilled a second ' accesss hole ' in the FRONT of the case !! .
A old OS max 40 took about five days to get the thing out . Many Ex R C S Tigre are siezed in . Hence the above advice .
Tapping the cap 4-40 may help . ( a DS is tapped M 2.5 fine . )
Prime obstruction culprit is dried castor forming donuts on the wrist pin , second oxidation .
Liner may take a few heat cycles and squirts of CRC to free off .
Some loosen the case for a light hand ( thumb ) push fit .Clear out & oil the bolt holes in the case .
Clean 7 oil any oxidised / rusted screws .
Heat Gun on Prop Driver to free . And on case for bearings . Boiling water is barely adequate . And may not be .
The 135 Deg. is got with a heat gun . Free Fit at that Temp .
Leather Gloves or the Wifes best Tea Towel or Oven Mits are essential .
The 3M Green pot scourer pads are good for cleaning gunk . A bit harsh at first . But soften quickly .
Carbon up inside the piston crown usually chips off easy ish useing a screwdriver tip. Judiciously .
Likely one with soft corners so as not to scratch it .
I dress the sharp edges on the piston baffle with a knife edge , and the baffle cut ots in the head , so THEYRe not ' knife edge ' .
Very Carefully clean out the ring land . Handle end of a muddle knife blades o.k. for that . Often sit parts in thinners to soften gunk .
Singer sewing Machine oil seems good assembly lube .
Any oil on the prop driver -collet area however may see it spin till you overtighten it , and break it if its a cast one .So a dry fit there .
Normally polish the Crank & pin/s with 800 wet & dry . wet or oil . on a hard flad surface . Like a straight edge .
Use the 3M scourer twirled strip on a screwdriver or suchlike to clean out the crank induction passage ,
and ' twirls ' say 1/4 wide through rod ends and wrist pin piston holes , if they need ' De Gunk ' ing .
A really awkward one , if its been pulled out of a river , youd cut the rod or drill the piston apart .
Fit washer under sleeve , tube over case , and use a draw bolt & heat to pull the sleeve .
Theres a Hole . !
Clean any discolouring like that off the crank web . Brass wire brush or the 3 M .
Boil steel bits in pot of water with baking soda if theyre all shirty . or a two second dip in hydrochloric & imediate rinse . Disolves Aluminum
however . If you only wish to recover the ferrous parts .
Topic: ST 60 Cylinder and wrist pin removal? (Read 792 times)