how to change a crank

[metal man]

we have heard a few times how do i change the crank in my block . well here we go .....read part one http://www.oldminibikes.com/forum/e...177-how-remove-flywheel-rope-trick-way.htmlif you still have the flywheel on the motor if not lets get going

ok well we want the crank out of this block

. you will need to remove all the case bolts .

note if your crank is rusty or has any burs on it clean them off . it will help save the seal and makes removing the crank much easier .emery paper work great and is real cheap lasts a long time too

and a little playing the shoe shine boy gets us

now just tap on the case with a hammer and it should pop open . you just want to tap on each side of the case till it opens .

now should be able to grab the case on each side and walk it off . wiggle it a little on each side and pull it off . there is a gasket in there it may hang up or come out with no problems

it came out in one piece cool

and now we are in the case

ok now pull the cam out , there is 2 lifters in there try and keep track of where they came from . mark them if you can as to where they go . marker works great , just wipe off the oil first . if you dont put them back in the same place your valve clearance will be messed up and you will be back in the case to redo them .

now we need to remove the rod bolts and cap . mark the rod and cap with a marker so you can put it back together the wright way . you can see the rod bolts and the locker tab . you need to flatten out the tab for the bolt to come loose . a screw driver or small punch works nice here . just tap with a hammer you dont need to go wild on it just need to get the bolt free to turn .

see marker line ?

you may find it easier to flip the block on its head to remove the bolts and tabs i have it on its head and sides to get to them .

and with the bolts out we can remove the cap

now carefully turn the crank to get the rod to the top of its stroke . removing the plug makes this much easier .

now if we turn the crank and push the rod we can slip the crank out of the block with the piston in the cylinder . and the head still on no need for a head gasket , or ring compressor . its like playing twister but it will come out . dont force it .

ok now if you have a older motor from like 1987 and before you will have points in your motor . under the flywheel you will find this

remove the cover we need to undo the plunger and moving point . so we dont wreck it .

i find that lifting it up and pulling it to the side works best just watch the wire that hooks to the block . dont break it .

g

 

[metal man]

stick a finger in the bearing and push up the plunger and remove it

ok now put some oil in the bearing and on the crank . and put it in the block . wiggling it around the rod like you did on removing it .

this is the oil dipper , dont forget it . check it for cracks and makes sure you put it under the locking strip .

now just put the cap back on line up your marks and put the bolts back in . torque your rod bolts to spec . for briggs here is a link http://www.smallenginesuppliers.com...ggs/common_specs_single_cyl_lhead_engines.pdf
if you dont have a torque wrench ... well you can just tighten them up real good and try to get them the same tightness . you should really use the torque wrench .but you can do it with out one and it will work too .

now with the bolts tight bend the tabs back up so you lock the bolts on place

punch and light hammer hits work just fine
ok with them locked in

now put the lifters in place and lets set the cam . there is a mark on the cam and one on the crank . you need them to line up .

here the cam has a red dot and the crank has a line on a tooth . there is your timing marks .
now replace your gasket and bolt the cover back on . using a new gasket if the old one broke . if you gasket did break or tear clean off all the old bits before you put in a new one . it will leak if you dont .
now if you have points time to put them back together .

put a drop of oil on the plunger and put it in its hole . make sure it moves free . and put the moving arm back on the stand in the reverse of how you removed it . and we have the new crank in the block . turn the crank and check for any binding and funky noise . fill with oil and reassemble the rest of the block and go for a ride .


note there is a few different rods and dippers and lock tabs you will find . here i have a 1961 block with 1985 guts . some of the other rods and dippers you may see are

i have had a request on how to service a max torque clutch . so im thinking ill do a install and cleaning of one. with some tips and and things i like to do .

if you have any suggestions for tech threads or stuff you would like to see let me know . please note i have mostly old briggs ,1955 to 1987 and only one tec hs 40 . so dont ask me about clones or hondas i wont be able to help you on them .

 

[Strigoi]

good write up. :thumbsup:

 

[VWFamily]

Metal Man, you should change your name to IRONMAN, because you are my new hero!! :thumbsup:

FYI - if your camera has a macro setting (looks like a little flower) you should try to use that on your close-up photos. You'll get a clearer image.

Most camera's have them and most people don't know what it's for, it's for close-up photos, like pistons, cranks, carbs or flowers, hence the logo.

update: on second look, looks like you probably are using it, sorry, back to my hole.

 

[gbones]

you sure do like dr.pepper and dr.thunder. i had some mr.bob yesterday. im looking forward to the cluch thread. nice job once again:thumbsup:

 

[metal man]

thanks guys .

VWFamily i do have the macro flower thing , most of the fuzzy photo is me shaking .needing to work on that :doah: may get a stand and put camera on that . i noticed some the pics looked fuzzy and dark after i got them posted . :censure: oh well hope it helps someone to get there motor going again . ill try for better pics .:anon.sml:

 

[VWFamily]

thanks guys .

VWFamily i do have the macro flower thing , most of the fuzzy photo is me shaking .needing to work on that :doah: may get a stand and put camera on that . i noticed some the pics looked fuzzy and dark after i got them posted . :censure: oh well hope it helps someone to get there motor going again . ill try for better pics .:anon.sml:

Kool, did not want to sound critical, they do convey the message so that's what counts! :thumbsup:

"Do you know why Dr. Pepper comes in a bottle?"


















"His wife died!" LOL :1orglaugh:

 

[gbones]

why does it come in a bottle:shrug:

 

[mmisterbungl]

metal man uses a polaroid camera and scans in the pictures. he knows nothing of macros.

 

[metal man]

Kool, did not want to sound critical, they do convey the message so that's what counts! :thumbsup:

"Do you know why Dr. Pepper comes in a bottle?"
"His wife died!" LOL :1orglaugh:

oh man funny but so wrong :laugh::laugh::laugh:

and understood on the pics :thumbsup: they looked ok on the cam but not so much when i got in the house and uploaded them .

 

[metal man]

metal man uses a polaroid camera and scans in the pictures. he knows nothing of macros.

oh come on now give me some credit here i do have a digital camera:laugh:
its a samsung digimax 201 , not bad for only being a 2.0 mega pixel .

 

[Oldsalt]

Again Kudos! I'm certain this will help a lot of young would be mechanics overcome their fear of opening up a mini engine. This is a lot better than a factory manual.

 

[GraveBugger]

wow that joke was a three time laugher 1st when you hear it, 2nd when you remember it, and 3rd when you get it lol :laugh: alright back to being the resident idiot ut: