yanmar 3gm30f 1 cylinder bad condition - Page 2 - SailNet Community
Reply
 
LinkBack Thread Tools
post #11 of 16 Old 09-03-2011 Thread Starter
Junior Member
 
Join Date: Jul 2006
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
As you suggested, I did adjust valve clearances but did not see much difference. I did ask an engineer here to take a look after all. After careful examination (He pointed my valve adjustment was all bad), we found out that one piston head was a lot lower than others. We are planning to take the engine out to pontoon for further examination and repair. So this is becoming a semi-overhaul.

Because cost is major concern to me now, the engineer will fix the main problem and take care of parts in very bad condition (injector rebuild and replace oil pipe, mixing elbow and thermostat).
I will do minor maintenance, cleaning and have the engine repainted (in red).

My heart is hurt for the extra expenses and time, I am learning a lot at least and happy to finally be able to clean my engine room.
If there is anything I should know before the engine rebuild, please let me know.
Thanks.
yjchun is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #12 of 16 Old 09-03-2011
Senior Member
 
dabnis's Avatar
 
Join Date: Jul 2007
Location: Truckee, CA
Posts: 8,677
Thanks: 2
Thanked 116 Times in 114 Posts
Rep Power: 9
 
Sounds like a badly bent connecting rod? Perhaps water got into the combustion chamber either through the exhaust manifold or a large leak from the head gasket or a cracked block or head? You might want to get a detailed estimate from the mechanic before attempting to re-use the existing engine. Don't know if Yanmar offers "short blocks", just the block and internal moving parts, but you might explore that possibility. Also while the engine is out you might want to inspect or remove the fuel tank or anything else that is hard to get at with the engine in place.

Dabnis
dabnis is offline  
Quote Quick Reply Share with Facebook
post #13 of 16 Old 09-03-2011
Senior Member
 
fryewe's Avatar
 
Join Date: Dec 2004
Posts: 1,671
Thanks: 31
Thanked 52 Times in 52 Posts
Rep Power: 11
 
Water can also get into the exhaust if you crank and crank and crank and the engine doesn't start. Exhaust pressure expels the cooling water, and if there is no exhaust pressure, and the engine is being spun for a long time by the starter (with the cooling water pump pumping as a result of that), water can flood into the engine.
fryewe is offline  
Quote Quick Reply Share with Facebook
post #14 of 16 Old 09-03-2011
Senior Member
 
Join Date: Jul 2011
Location: marylands eastern shore
Posts: 127
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 5
 
I just want to say to anyone that's having these sort of issues, do a compression check before you start monkeying around. At the very least you'll have a baseline to refer back too. Your dealing with some high pressures in a compression ignition engine(diesel) so your normal gas powered automotive tester is not going to work. Harbor freight has a rather inexpensive compression tester kit for diesels some will use the glow plug hole and some you'll have to pull the injector.
bandaidmd is offline  
Quote Quick Reply Share with Facebook
post #15 of 16 Old 09-03-2011
Senior Member
 
dabnis's Avatar
 
Join Date: Jul 2007
Location: Truckee, CA
Posts: 8,677
Thanks: 2
Thanked 116 Times in 114 Posts
Rep Power: 9
 
Quote:
Originally Posted by dabnis View Post
Not even close to being an expert on anything but do have some years working on gas and diesel engines. The crank being hard to turn when only the #1 valve train operates is interesting, perhaps an out of tolerance camshaft, bent valve stem, seized valve guide, galled cam lobe or rocker arm? For starters a compression test on all cylinders should be done.
When things settle down when operating the de- compression lever on #1 leads me to think of the above valve issue(s) or perhaps a blown head gasket in the #1 area. Let us know what you find.

Dabnis
Bandaid,

A compression test has been suggested a couple of times. Don't know if one was done, but it sounds like the head has already been taken off. If #1 piston doesn't come all the way up it is likely to be a bent rod.

Dabnis
dabnis is offline  
Quote Quick Reply Share with Facebook
post #16 of 16 Old 09-05-2011
Junior Member
 
Join Date: Feb 2008
Posts: 21
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
one can check for a bent con rod using a test with a piece of solder bent at a right angle to see whether the solder compresses evenly when each piston is (manually) raised, details of how to do this test are in the service manual..(not the owners manual..) if the piston travel (and smash pattern on the solder pieces for each cylinder) is different between the 3 cylinders, that suggests a bent con rod as dabnis points out. if it's a bent con rod that would be important to know from a $$$ standpoint.
MitchM is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Bleeding a Yanmar 3GM30F jlmarra Gear & Maintenance 6 07-12-2015 09:38 AM
Cylinder head for yanmar sb 12 RepDom Gear & Maintenance 4 06-14-2010 03:46 PM
Yanmar 3GM30F aa3jy Diesel 7 11-23-2009 08:45 AM
Yanmar 3GM30F Bill Mc Gear & Maintenance 30 11-28-2007 07:51 PM
yanmar three cylinder edwinh Gear & Maintenance 2 08-31-2007 12:46 PM

Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome