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

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

Notices

Onan Generators Restoring, operating and maintaining vintage Onan generators.

Onan Generators

Onan MDJA 3.0-3CR /2268V


this thread has 18 replies and has been viewed 881 times

Reply
 
Thread Tools Display Modes
  #1  
Old 02-06-2017, 01:24:40 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Onan MDJA 3.0-3CR /2268V

Ive had this for years up at my Tennessee cabin. Brought it home to re ring it as it has many hours and smokes a bit and the head gasket is weeping coolant.

The over temp switch screwed to the cylinder head rusted and broke and the new one is unavailable. I think I found the right replacement. Its an empire R1912 switch. Opens at 250 deg F. like the original. Cost $16 ebay. Thought some of you might find this useful.

I need a head gasket and ring set for this unit and cant find one.. Anybody know of a source. I've tried the usual sources.

Thanks

Bob
Reply With Quote
The Following User Says Thank You to Crankpot For This Post:
Sponsored Links
  #2  
Old 02-07-2017, 10:56:24 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

Quote:
Originally Posted by Crankpot View Post
Ive had this for years up at my Tennessee cabin. Brought it home to re ring it as it has many hours and smokes a bit and the head gasket is weeping coolant.

The over temp switch screwed to the cylinder head rusted and broke and the new one is unavailable. I think I found the right replacement. Its an empire R1912 switch. Opens at 250 deg F. like the original. Cost $16 ebay. Thought some of you might find this useful.

I need a head gasket and ring set for this unit and cant find one.. Anybody know of a source. I've tried the usual sources.

Thanks

Bob

I inspected the breather valve. The inside was clean and the four little balls were moving freely.

Here is a video of the little generator. I'm still looking for a head gasket...

https://youtu.be/iz0qRQ2aucM
Attached Thumbnails
Click image for larger version

Name:	IMG_1338.jpg
Views:	63
Size:	57.2 KB
ID:	274291  
Reply With Quote
The Following 4 Users Say Thank You to Crankpot For This Post:
  #3  
Old 02-10-2017, 10:49:53 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

I found a head gasket for $30 and a set of .030" oversize rings also for $30. I will file the rings down to size. It's absurd how expensive parts are for these aging engines are. I saw ring sets for $140 and pistons for $500. I guess someone is paying these amounts or they wouldn't be for sale. The newer Japanese generator engines are looking much better now...
Reply With Quote
  #4  
Old 02-10-2017, 11:13:13 PM
David C David C is offline
Registered-III
 
Join Date: Mar 2006
Location: Lake Jackson,Texas
Posts: 1,274
Thanks: 881
Thanked 779 Times in 514 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

I haven't looked up what the part number is, but there are some .010" over rings on eBay that may be a DJ series engine. I personally would not file down .030" rings for use in a standard bore. I would thing the extra ring tension would be a little hard on the cylinder bore, plus the fit to the bore may not be the best.

http://www.ebay.com/itm/CUMMINS-ONAN...FVCbsO&vxp=mtr

David C.
Reply With Quote
The Following User Says Thank You to David C For This Post:
  #5  
Old 02-25-2017, 06:37:48 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

Quote:
Originally Posted by David C View Post
I haven't looked up what the part number is, but there are some .010" over rings on eBay that may be a DJ series engine. I personally would not file down .030" rings for use in a standard bore. I would thing the extra ring tension would be a little hard on the cylinder bore, plus the fit to the bore may not be the best.

http://www.ebay.com/itm/CUMMINS-ONAN...FVCbsO&vxp=mtr

David C.

Here I fitted the rings to the old piston. The old rings were badly worn with .060 end gaps. I fitted the new rings to the spec at .015". Also the cylinder bore was nasty . Obviously had rust marks and a tiny ridge at the top. The piston was fine except for the top which was chewed up I think from sea water injestion. Everything else inside the case was pretty. I expect this little guy will run nicely with the new rings and hone job. I should have it running by tomorrow...
Attached Thumbnails
Click image for larger version

Name:	IMG_1405.jpg
Views:	53
Size:	90.7 KB
ID:	275886   Click image for larger version

Name:	IMG_1408.jpg
Views:	60
Size:	111.9 KB
ID:	275887  
Reply With Quote
The Following User Says Thank You to Crankpot For This Post:
  #6  
Old 02-26-2017, 09:32:37 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

I worked on it a bit today. Got the oil pan back on after making a new gasket, collected the parts to assemble the head. While putting things together it became apparent by the wear marks on the pushrods that the previous mechanic had installed the pushrods upside down. Anyway they are correct now, and fit nicely.

The rest of it went without issue. I took everyone's advice and applied a layer of kw copper gasket spray to the head gasket. Time will tell if it holds but I feel good. I draw filed the block and head. Both needed help. Both are much better now than before and of course it was seeping coolant. Again time will tell.


I added junk oil to flush out the crud and will change the oil after I get it up to temperature the first time.

It started up easily and settled into a smooth governed idle, but I only ran it a few seconds as my cooling system isn't set up yet, but no major noise, leaks, smoke or other problems.

I'm replacing most of the external wing with new modern stuff as well as added a 20 amp dual marine circuit breaker to the control box.

More coming...
Reply With Quote
The Following User Says Thank You to Crankpot For This Post:
  #7  
Old 02-28-2017, 08:16:41 AM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

I started it up today. It immediately overheated. Oops I hooked up the coolant lines backward duh. I let it cool, corrected my mistake and tried again.

It overheated again. Well at least the new overtemp limit switch works. It's funny because this things cylinder head always ran very hot, like 235 degrees at the head location where the overh switch sits. Been that way for 10 years and I figured its normal. Well....

I disassembled the coolant tank to inspec the thermostat and guess what... I put I together as shown in the parts diagram. Nothing wrong here but it acts like the thermostat is installed backwards. Out of desperation I reverse the thermostat so now the coil spring is down dipping into the hotter coolant and fire it up.... perfection! It warms evenly, cools easily. The max temp I sw was 188deg F with the average coolant temp 160 deg F. I appears its been assembled incorrectly for a decade.

On to break in...
Reply With Quote
  #8  
Old 02-28-2017, 08:32:12 AM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

I did an oil change and readied the engine for loading but geeeez this thing is loud with no muffler! I need to get the exhaust system done before I can run this for break in periods...the old onan exhaust flange was in bad shape from years of use and the previous exhaust system was a cobbled up collection of parts all of which was failing. Time for help from Charlie (neighbor and retired machinist)...

Im no welder but I have a little miller syncrowave box and get by so here is what happened...

First off I found some suitable exhaust pipe...in this case it was a former directv satellite dish mounting pole! I chopped it into a couple 45's and welded them into a 90. Not the best for high performance flow but it met my needs of making a compact turn to allow the subsequent piping to remain close to the engine.Then Charlie took the old flange and chucked it up into his giant Leblond lathe and cleaned it up so it was an interference fit sliding into the newly made 90 degree exhaust fitting. Then he brazed the two parts together.

It's a work of art now! It will outlive me it's strong and proper.
More coming...
Attached Thumbnails
Click image for larger version

Name:	IMG_1414.jpg
Views:	64
Size:	118.4 KB
ID:	276133   Click image for larger version

Name:	IMG_1415.jpg
Views:	67
Size:	112.9 KB
ID:	276134   Click image for larger version

Name:	IMG_1416.jpg
Views:	78
Size:	99.2 KB
ID:	276135  
Reply With Quote
  #9  
Old 02-28-2017, 01:07:25 PM
BTPost's Avatar
BTPost BTPost is offline
Moderator
 
Join Date: Jan 2005
Location: Excursion Inlet, Alaska USA 99850-0090
Posts: 4,764
Thanks: 548
Thanked 1,771 Times in 1,168 Posts
Images: 1
Talking Re: Onan MDJA 3.0-3CR /2268V

Hope you are smart enough to remember to put a section of Flex Pipe at the engine end of your fancy Exhaust System..... Those DJA's jump around a bit when running......
__________________
Bruce in alaska
Reply With Quote
The Following User Says Thank You to BTPost For This Post:
  #10  
Old 02-28-2017, 01:10:07 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

Quote:
Originally Posted by BTPost View Post
Hope you are smart enough to remember to put a section of Flex Pipe at the engine end of your fancy Exhaust System..... Those DJA's jump around a bit when running......

Lol...I'm not too smart but yes it's getting some flex pipe there!
Reply With Quote
  #11  
Old 03-01-2017, 12:16:40 AM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

Here is the new part temporarily Intl led. It works great. When the new muffler arrives I'll paint it all wth high temperature paint to slow corrosion.

I ran It for two hours at full load to complete seating the rings. Now I gets another oil change and a new filter. Only one small oil leak was found. It's a little orange rubber part the surrounds the anti flicker pushrod call a diaphragm. Anyone have a spare? Mines perforated.
Attached Thumbnails
Click image for larger version

Name:	IMG_1419.jpg
Views:	65
Size:	98.7 KB
ID:	276213  
Reply With Quote
  #12  
Old 03-03-2017, 09:26:58 AM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

Now that its been running ok I waned to check the head bolt torque and verify the valve clearance. I again found the clearances way off. Here is a picture showing the elastic stop nut (on left). This cant be what the engineers intended! These valves get hot and there's no way an elastic stop nut can hold its torque in this application...

I added the milspec style metal lock not style shown on the right valve to both valves. Reset them and I expect no further issues.

I also found that by evenly torquing the valve cover head bolts the pesky oil leak has stopped.
Attached Thumbnails
Click image for larger version

Name:	IMG_1434.jpg
Views:	61
Size:	113.8 KB
ID:	276398  
Reply With Quote
The Following User Says Thank You to Crankpot For This Post:
  #13  
Old 03-06-2017, 01:43:31 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

I got the new walker
Muffler in the mail yesterday. A little time with the syncrowave fabricated mount bracket sand voila! It's nice and compact now, quieter. I can push the genset closer to the wall now. My joints leak where the flex pipe joins the pipe
But I'm working on it. I ran it a few hours after changing out the water for real coolant.

Check out the hybrid paint job! As I work on it I paint it green. I figure 12 more years it will be all green. Lol!
Attached Thumbnails
Click image for larger version

Name:	IMG_1465.jpg
Views:	60
Size:	104.0 KB
ID:	276662  
Reply With Quote
  #14  
Old 03-06-2017, 06:39:51 PM
rmchambers rmchambers is offline
Subscriber
 
Join Date: Dec 2011
Location: Stratford, Connecticut, USA
Posts: 587
Thanks: 100
Thanked 383 Times in 193 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

The only thing I'd say is that it's an MDJA which were used out on the water where there was little dust to ingest. That thing on top is a resonator not a filter and the engine sucks raw air in through that little round hole below it on the intake manifold.

My MDJA is like this too so I made a bracket to hold a pleated air filter and put a chrome button in that hole so it gets filtered air now. Something to think about. I also put a clear bottom of a popcorn plastic jar over the air filter to help quieten the intake noise and protect the pleats if it got any moisture on it when it ran.
Reply With Quote
The Following User Says Thank You to rmchambers For This Post:
  #15  
Old 03-07-2017, 09:00:16 AM
PopsGarage PopsGarage is offline
Subscriber
 
Join Date: Dec 2013
Location: Barnegat, New Jersey
Posts: 505
Thanks: 97
Thanked 232 Times in 179 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

Good job, I installed a MDJB at my home back in 1999, I plugged the air intake hole and installed a air filter from a 16 hp kohler engine on top of the resonator.
Bob
Reply With Quote
  #16  
Old 03-08-2017, 03:29:04 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

Yes thanks for The advice. I posted A request for an air cleaner but no Replies so far. I'll cobble up an air cleaner when I can!
Reply With Quote
  #17  
Old 03-08-2017, 06:58:15 PM
armandh armandh is offline
Sponsor
 
Join Date: Aug 2006
Location: Suburban St. Louis, Missouri
Posts: 2,519
Thanks: 142
Thanked 562 Times in 468 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

Quote:
Originally Posted by Crankpot View Post
I found a head gasket for $30 and a set of .030" oversize rings also for $30. I will file the rings down to size. It's absurd how expensive parts are for these aging engines are. I saw ring sets for $140 and pistons for $500. I guess someone is paying these amounts or they wouldn't be for sale. The newer Japanese generator engines are looking much better now...
how many years at the cabin???

average life of a junkeraator in prime service ..... just days
Reply With Quote
  #18  
Old 03-11-2017, 10:15:57 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

I rigged up a little air cleaner. I used one from a Briggs and Stratton engine. I drilled and tapped the intake duct and bolted the air cleaner on with a couple 10-32 bolts. Seems to work just fine.
Attached Thumbnails
Click image for larger version

Name:	IMG_1513.jpg
Views:	238
Size:	102.8 KB
ID:	277167  
Reply With Quote
The Following User Says Thank You to Crankpot For This Post:
  #19  
Old 04-10-2017, 07:42:16 PM
Crankpot Crankpot is offline
Registered-I
 
Join Date: Dec 2016
Location: Jupiter, Florida
Posts: 93
Thanks: 58
Thanked 62 Times in 29 Posts
Default Re: Onan MDJA 3.0-3CR /2268V

I added this little pipe thermometer to the genset. These thermometers are normally held to a pipe with a spring. I used a big blob of silicone. It works great and accurately indicates temperature. My range is 52 c to 62 c fully loaded.
Attached Thumbnails
Click image for larger version

Name:	IMG_1714.jpg
Views:	28
Size:	98.0 KB
ID:	279792  
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
Onan 3.0 mdja RETCPO Onan Generators 4 07-09-2015 07:08:15 PM
Onan 3k MDJA Still water in oil Lloyd T Onan Generators 18 10-08-2014 01:29:05 PM
3kw mdja-3CR/2268V overheats grahamdouglass Onan Generators 5 08-05-2009 08:45:28 AM
Onan mdja not running. Brent S Onan Generators 7 10-24-2007 04:37:37 PM
Looking for Onan MDJA part oldtool53 Onan Generators 2 06-16-2007 07:06:37 AM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 05:55:05 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