Antique Engines and Old Iron
[Home] - [HELP] - [Forums] - [Groups] - [Classified Ads] - [Subscribe] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Antique Engine Community > Magnetos, Ignition Coils and Spark Plugs
Forgot Password? Join Us!

Notices

Magnetos, Ignition Coils and Spark Plugs Discussion about magnetos, buzz coils, spark plugs, ignitors and low tension coils.

Magnetos, Ignition Coils and Spark Plugs

Exhaust Valve Adjustments


this thread has 8 replies and has been viewed 1003 times

Reply
 
Thread Tools Display Modes
  #1  
Old 02-23-2018, 12:19:07 PM
Geochurchi Geochurchi is offline
Registered
 
Join Date: Jul 2014
Location: Bartlett, New Hampshire, USA / Toronto, Ontario, Canada
Posts: 167
Thanks: 20
Thanked 20 Times in 12 Posts
Default Exhaust Valve Adjustments

Hi again, I now have a copy of the horizontal timing chart however I need a starting point, how should I start with the valve lifter rod, lets pretend it’s all new with no rod installed.
Geo.
Reply With Quote
Sponsored Links
  #2  
Old 02-23-2018, 12:58:07 PM
Andrew Mackey Andrew Mackey is offline
Moderator
 
Join Date: Nov 2004
Location: Rockaway, New Jersey USA
Posts: 14,149
Thanks: 1,992
Thanked 6,767 Times in 4,301 Posts
Default Re: Exhaust valve adjustments

What engine?
Reply With Quote
  #3  
Old 02-23-2018, 01:00:13 PM
Geochurchi Geochurchi is offline
Registered
 
Join Date: Jul 2014
Location: Bartlett, New Hampshire, USA / Toronto, Ontario, Canada
Posts: 167
Thanks: 20
Thanked 20 Times in 12 Posts
Default Re: Exhaust valve adjustments

Sorry, it’s a FM 1 1/2 HP Z
Geo
Reply With Quote
  #4  
Old 02-28-2018, 01:50:37 PM
Geochurchi Geochurchi is offline
Registered
 
Join Date: Jul 2014
Location: Bartlett, New Hampshire, USA / Toronto, Ontario, Canada
Posts: 167
Thanks: 20
Thanked 20 Times in 12 Posts
Default Re: Exhaust valve adjustments

Still can’t get the exhaust valve adjusted,it states that the crank rod should be facing up, I assume that means that the nuts on the rod cap should be parallel with the base, what affect does the governor have on the rod adjustment?
Geo
Reply With Quote
  #5  
Old 02-28-2018, 02:32:44 PM
Andrew Mackey Andrew Mackey is offline
Moderator
 
Join Date: Nov 2004
Location: Rockaway, New Jersey USA
Posts: 14,149
Thanks: 1,992
Thanked 6,767 Times in 4,301 Posts
Exclamation Re: Exhaust valve adjustments

There is no set clearance for the exhaust valve rocker. The valve opens about 20 degrees before BDC on the power stroke, and is closed at TDC intake. Holding the intake valve open, turn the engine BACKWARDS (counter clockwise from the cam/mag side) until the engine reaches TDC, between the exhaust and intake stroke. The valve should just close at the TDC point, if not slightly after (before TDC). Once you have that right, the second point should be OK, unless your cam timing is off. Turning the engine CLOCKWISE from the mag /cam side, the valve should open at roughly the 20 degree position, late in the power stroke. The governor has nothing to do with the valve operation, only throttle control
Reply With Quote
  #6  
Old 03-01-2018, 09:06:50 AM
Geochurchi Geochurchi is offline
Registered
 
Join Date: Jul 2014
Location: Bartlett, New Hampshire, USA / Toronto, Ontario, Canada
Posts: 167
Thanks: 20
Thanked 20 Times in 12 Posts
Default Re: Exhaust valve adjustments

Thanks I’ll give that a try,what is the best way to determine the 20* angle?
Geo
Reply With Quote
  #7  
Old 03-01-2018, 09:29:24 AM
J.B. Castagnos J.B. Castagnos is offline
Registered
 
Join Date: Nov 2004
Location: South Louisiana USA
Posts: 2,738
Thanks: 931
Thanked 3,593 Times in 1,127 Posts
Default Re: Exhaust valve adjustments

Google degree wheel, images, find one that opens clearly and print it, paste it to cardboard, cut center to slip over crankshaft. Make a pointer and you can follow the valve opening-closing. This is really too technical but it will show you what's going on. It will run if it's close.
Reply With Quote
The Following User Says Thank You to J.B. Castagnos For This Post:
  #8  
Old 03-01-2018, 02:00:58 PM
Andrew Mackey Andrew Mackey is offline
Moderator
 
Join Date: Nov 2004
Location: Rockaway, New Jersey USA
Posts: 14,149
Thanks: 1,992
Thanked 6,767 Times in 4,301 Posts
Default Re: Exhaust Valve Adjustments

The opening point is not too critical, the close point is. The valve must be closed at TDC between strokes. The valve should open about 1/4" if not a little more, at full open if I remember right, the F/M Zs had a spring on the rocker that kept it in contact with the exhaust pushrod. it helped keep the pushrod against the cam follower.
Reply With Quote
  #9  
Old 03-07-2018, 10:24:03 PM
Geochurchi Geochurchi is offline
Registered
 
Join Date: Jul 2014
Location: Bartlett, New Hampshire, USA / Toronto, Ontario, Canada
Posts: 167
Thanks: 20
Thanked 20 Times in 12 Posts
Default Re: Exhaust Valve Adjustments

Hi All, I believe I have the exhaust valve set however I think there is still a problem in that the push rod is adjusted out to full length and seems sloppy,almost like it is to short, also when I spin the engine over it will pop once and not continue to fire.
Geo
Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
Exhaust Valve Box Keven Withers Hit & Miss Gas Engine Discussion 5 01-24-2013 08:09:21 PM
1-1/2 HP IHC M Exhaust Valve John Cunningham Hit & Miss Gas Engine Discussion 6 07-14-2009 06:38:10 AM
Stuck Exhaust Valve Tom Herd Hit & Miss Gas Engine Discussion 11 02-08-2009 01:06:15 PM
H&M exhaust valve clearance gafisk Hit & Miss Gas Engine Discussion 1 12-14-2007 03:01:20 AM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 02:40:52 PM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2019 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277