valve rockers

How to keep the Cessna 170 flying and airworthy.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

Post Reply
User avatar
davevramp
Posts: 126
Joined: Mon Nov 08, 2004 10:41 am

valve rockers

Post by davevramp »

Does any one have a easy way to install valve rockers? Is there a tool that I am missing?
Thanks
Dave
User avatar
Bruce Fenstermacher
Posts: 10320
Joined: Tue Apr 23, 2002 11:24 am

Post by Bruce Fenstermacher »

Dave

There is no tool to install the rockers. The rocker shaft should slide easially through them and the rocker boss on the head. Of course for this to happen the cylinder your working on must be on TDC of the firing stroke. You will probably also have to push slightly down on the rocker pushing in on the pushrod to collapse the lifter in order to line everything up. Don't force anything.

:!: I'm not sure how prevelent this is or if it even applies to C-145 cylinders but on some later small Continental heads there is a set screw in the center head boss which holds the rocker shaft in place.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
cessna170bdriver
Posts: 4063
Joined: Mon Apr 22, 2002 5:13 pm

Post by cessna170bdriver »

N9149A wrote: :!: I'm not sure how prevelent this is or if it even applies to C-145 cylinders but on some later small Continental heads there is a set screw in the center head boss which holds the rocker shaft in place.
I've never seen such a set screw in a C145/O300 cylinder, but it probably would have been a good idea. I replaced all of my valve covers this overhaul because the originals were worn about half way through by the rocker shafts. I seem to remember that there have been cases where the shafts wore all the way through the covers :o. In my ECI cylinders, the ends of the rocker shafts have been specially machined and haveTeflon buttons pressed in to prevent that kind of wear. It is that attention to detail that swayed me toward ECI cylinders.

Miles
Miles

“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
HA
Posts: 353
Joined: Thu Jan 20, 2005 11:41 pm

Post by HA »

hey Dave, you may find that you have to compress the valve spring a bit to get the rocker shaft to slide it, especially when doing field work on cylinders. the only time it'll slide right in otherwise is if the lifter is compressed, not likely unless doing a build up on the stand.

so, an easy helper tool I use is an eye bolt (1/4 x 20 thread) that screws into one of the valve cover screw holes. then stick a screwdriver (flat blade, wide as will fit through your eye bolt) through the eye and use it to lever down your valve. then while you've got it all lined up use your third hand to slide the shaft into place. ta da.

easy with practice.
'56 "C170 and change"
'52 Packard 200
'68 Arctic Cat P12 Panther
"He's a menace to everything in the air. Yes, birds too." - Airplane
User avatar
Bruce Fenstermacher
Posts: 10320
Joined: Tue Apr 23, 2002 11:24 am

Post by Bruce Fenstermacher »

HA that's a great idea. Only hope I remember it next time I need to use it. :x
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
sphillips
Posts: 104
Joined: Sat Dec 24, 2005 2:33 pm

Post by sphillips »

The later Continental cylinders had the bolt to hold the shaft in place
N3598C, C170B
User avatar
davevramp
Posts: 126
Joined: Mon Nov 08, 2004 10:41 am

Ta Da

Post by davevramp »

HA

You Are The Man

Used your ¼ 20 I bolt trick and it worked well. I would like to add that I screwed the ¼ 20 I bolt into the valve cover hold down female threaded and backed it up with a ¼ 20 nut were it exited on the out side of the gkt area. There is no way to pull out the treads on the cylinder gkt area with the nut on the back side. I was putting in new springs and it looked like a good thing to do. This one tip was worth the price of admission. I owe you one.
Thanks
Dave

If you ever get out this way drinks are on me (nj74)
User avatar
blueldr
Posts: 4442
Joined: Thu May 02, 2002 3:16 am

Post by blueldr »

There is a valve spring depressing tool made for removing or installing valve springs.
BL
User avatar
GAHorn
Posts: 21010
Joined: Fri Apr 12, 2002 8:45 pm

Post by GAHorn »

At the chinese tool store (Harbor Freight) I bought a cute little valve-spring compressor ( fits in the palm of your hand) that looks like it'd work just fine, for about $9. Hope I never need it. 8O
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
Post Reply