Generators and Motors
[Home] - [HELP] - [Forums] - [Library] - [Photo Gallery] - [Groups] - [Classified Ads] - [Subscribe] - [Links] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Vintage Electrical Equipment > Generators & Electric Motors General Discussion > Onan Generators
Forgot Password? Join Us!

Notices

Onan Generators Restoring, operating and maintaining vintage Onan generators.

Onan Generators

De-carbonizing Heads and tops of Pistons


this thread has 13 replies and has been viewed 1686 times

Reply
 
Thread Tools Display Modes
  #1  
Old 02-19-2014, 08:40:53 PM
tdarden tdarden is offline
Registered-I
 
Join Date: Jan 2014
Location: Dallas Texas USA
Posts: 220
Thanks: 115
Thanked 47 Times in 39 Posts
Default De-carbonizing Heads and tops of Pistons

Looking for some inexpensive things I can do to a 5.0CCK in really bad condition while I wait on a few parts to try and get it running. I ran across a post of someone who "de-carbonized the heads " of a smaller Onan gen. I popped the head off of mine and indeed there was a huge carbon build-up on top of the pistons as well as the heads.

Is this something I can clean with some elbow grease and ?????? or is this machine shop stuff. Also the piston tops.

If this can be done myself what is the procedure and tools/products necessary. Any thing I need to pay close attention ....NOT TO DO ?

Thanks
Reply With Quote
Sponsored Links
  #2  
Old 02-19-2014, 08:44:41 PM
Billy J Shafer's Avatar
Billy J Shafer Billy J Shafer is offline
Subscriber
 
Join Date: Nov 2004
Location: Centerville, Texas
Posts: 16,372
Thanks: 8,340
Thanked 13,690 Times in 6,443 Posts
Default Re: De-carbonizing Heads and tops of Pistons

Just get a soft wire wheel brush that mounts on a drill. Guide it over the head with just enough force to break up the carbon.Same with the piston
Reply With Quote
The Following User Says Thank You to Billy J Shafer For This Post:
  #3  
Old 02-19-2014, 08:53:13 PM
tdarden tdarden is offline
Registered-I
 
Join Date: Jan 2014
Location: Dallas Texas USA
Posts: 220
Thanks: 115
Thanked 47 Times in 39 Posts
Default Re: De-carbonizing Heads and tops of Pistons

Thank you sir
Sounds like a snap !
Reply With Quote
  #4  
Old 02-19-2014, 09:08:13 PM
Billy J Shafer's Avatar
Billy J Shafer Billy J Shafer is offline
Subscriber
 
Join Date: Nov 2004
Location: Centerville, Texas
Posts: 16,372
Thanks: 8,340
Thanked 13,690 Times in 6,443 Posts
Default Re: De-carbonizing Heads and tops of Pistons

Just be prepared to get dirty.
Reply With Quote
The Following User Says Thank You to Billy J Shafer For This Post:
  #5  
Old 02-19-2014, 09:09:43 PM
BlkBeard BlkBeard is offline
Registered-III
 
Join Date: Feb 2012
Location: Bridgeport, Connecticut, USA
Posts: 515
Thanks: 241
Thanked 215 Times in 156 Posts
Default Re: De-carbonizing Heads and tops of Pistons

There are Scotch Brite Pads that go on a mandrel with a 1/4" shaft.

They fit in a 1/4" Air Angle Grinder or a drill if you don't have a grinder.

They come in course or fine and work great for cleaning carbon, removing pieces of baked on gasket etc.

You can find them at your auto parts store, Ebay, etc.

They're about 1-1/2" diameter

Here's a sample chosen at random
http://www.ebay.com/itm/3M-Scotch-Br...ecc953&vxp=mtr
Reply With Quote
The Following 2 Users Say Thank You to BlkBeard For This Post:
  #6  
Old 02-19-2014, 09:45:59 PM
rmchambers rmchambers is offline
Subscriber
 
Join Date: Dec 2011
Location: Stratford, Connecticut, USA
Posts: 601
Thanks: 105
Thanked 379 Times in 195 Posts
Default Re: De-carbonizing Heads and tops of Pistons

Don't scour up the mating faces where the head gasket goes nor the bore of the cylinder. For areas where the brush can't reach I've sharpened a 1/2" wooden dowel into a point and a screwdriver shape and use that to scrape the gunk out. It's softer than the aluminum so it won't gouge it up. If you use the scotch brite afterwards but a little metal polish on it and buff up the heads and piston to a nice shine.. it will make it that much harder for the carbon to stick next time.

Take pictures too or we won't believe you.
Reply With Quote
The Following 2 Users Say Thank You to rmchambers For This Post:
  #7  
Old 02-19-2014, 09:48:38 PM
len k len k is online now
Registered-III
 
Join Date: Jun 2012
Location: Manchester, New Hampshire
Posts: 14,938
Thanks: 390
Thanked 5,409 Times in 3,930 Posts
Default Re: De-carbonizing Heads and tops of Pistons

Also clean carbon from arround valve seats and arround them with valve open, so it can breath better. I use a wood popcycle stick, with end ground to flat edge , like a paint scrapper.
Reply With Quote
The Following User Says Thank You to len k For This Post:
  #8  
Old 02-19-2014, 10:26:51 PM
yellowlister yellowlister is offline
Subscriber
 
Join Date: Feb 2010
Location: Granada Hills, California
Posts: 3,973
Thanks: 1,858
Thanked 1,975 Times in 1,284 Posts
Default Re: De-carbonizing Heads and tops of Pistons

i use scraper type tool.. think of it as a flat head screwdriver an inch wide only machined down on one side. works really good for the flat spots and not as messy as chemicals or wire brush.. and a small flathead for smaller areas.. just dont push to hard if u use one... after that some starter fluid and rag or paper towl and compressed air and its as good as new.. good time to check the valve seating and ammount of play in the valves and pistons and if any scoreing is in the cylinder bore.
Reply With Quote
The Following User Says Thank You to yellowlister For This Post:
  #9  
Old 02-19-2014, 10:40:42 PM
len k len k is online now
Registered-III
 
Join Date: Jun 2012
Location: Manchester, New Hampshire
Posts: 14,938
Thanks: 390
Thanked 5,409 Times in 3,930 Posts
Default Re: De-carbonizing Heads and tops of Pistons

I've also used a putty knife and a butter knife with tip sharpened to a flat putty knife. But guys here told me the resulting scratchs will make it carbon up faster next time.

On small engines (snowblowers & ect) I also reuse head gasket, no problems.
Reply With Quote
The Following User Says Thank You to len k For This Post:
  #10  
Old 02-20-2014, 02:53:33 AM
Motorhead's Avatar
Motorhead Motorhead is offline
Subscriber
 
Join Date: May 2007
Location: Central Coast, California
Posts: 3,409
Thanks: 1,516
Thanked 2,251 Times in 1,209 Posts
Default Re: De-carbonizing Heads and tops of Pistons

If the engine has sat a while, squirt some penetrating oil around the area where the piston rides in the cylinder. This will help un-stick the rings in the ring lands.
On my old '72 cck that had sat a while, I also very lightly scuffed up the cylinders to break the glaze in them. The engine doesn't smoke at all.
Reply With Quote
The Following 2 Users Say Thank You to Motorhead For This Post:
  #11  
Old 02-20-2014, 12:38:54 PM
snowshoveler snowshoveler is offline
Registered-II
 
Join Date: May 2009
Location: south shore of Nova Scotia
Posts: 654
Thanks: 232
Thanked 306 Times in 182 Posts
Default Re: De-carbonizing Heads and tops of Pistons

We use a product from the local Dodge dealer. Its called combustion chamber cleaner. Works great for that sort of thing. Also will clean up carb parts. Not so awefull nasty on your hands or nose. Cheep too.
Regards Chris
Reply With Quote
  #12  
Old 02-20-2014, 07:05:56 PM
grif grif is offline
Registered-III
 
Join Date: Oct 2011
Location: Yakima, Washington
Posts: 1,246
Thanks: 435
Thanked 320 Times in 236 Posts
Default Re: De-carbonizing Heads and tops of Pistons

Not sure hot much difference it makes,,, but after you get things all cleaned up, oil up the cylinder walls, and run the piston up a ways, then down. Wipe the gunk that the rings caught off the wall,,, repeat till clean. It's amazing how much crap can fit between a piston and the wall just above a ring.
Reply With Quote
The Following User Says Thank You to grif For This Post:
  #13  
Old 02-20-2014, 07:59:15 PM
len k len k is online now
Registered-III
 
Join Date: Jun 2012
Location: Manchester, New Hampshire
Posts: 14,938
Thanks: 390
Thanked 5,409 Times in 3,930 Posts
Default Re: De-carbonizing Heads and tops of Pistons

On that note probably a good idea to put piston ~ 1/2 way down and stuff a rag in cyclinder, to keep the junk out of piston/cyclinder gap. Then pull out rag, clean cyclinder walls, and move piston down and clean up any remaining garbage. Then oil up walls.
Reply With Quote
  #14  
Old 02-20-2014, 08:27:24 PM
Gunny Gunny is offline
Subscriber
 
Join Date: Feb 2005
Location: North Carolina
Posts: 3,633
Thanks: 1,439
Thanked 1,529 Times in 978 Posts
Default Re: De-carbonizing Heads and tops of Pistons

Needle scaler works on the top of the piston, just go easy with it.

Try soaking it with some armor all.
Reply With Quote
Reply


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
Spark Plugs with Removable Tops KD5BYB Small Air Cooled Gasoline Engines 6 04-16-2011 01:19:24 PM
Generator Heads Joseph Generators & Electric Motors General Discussion 1 12-06-2010 12:06:24 AM
FH round heads Everett Hayden Small Air Cooled Gasoline Engines 1 12-04-2009 04:08:31 PM
F-M Z Heads Zira Antique Gas Engine Discussion 10 11-10-2009 10:16:04 PM
solar oil,tops/toppings fuel NICK Antique Engine Archives 3 01-31-2003 01:01:21 PM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 08:14:30 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 - 2016 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277