Yanmar SB8 issue/questions - SailNet Community
 3Likes
Reply
 
LinkBack Thread Tools
post #1 of 19 Old 09-08-2016 Thread Starter
Junior Member
 
Mattybunns's Avatar
 
Join Date: May 2016
Location: Vancouver Island, BC, Canada
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Question Yanmar SB8 issue/questions

Hey all. I have an old inboard Yanmar SB8 in my Sun 28 that I am having issues with. First off, I am not very familiar with diesel engines and rely a lot on friends, and here, for help. So, the engine has seized. Pulled the head off and looked at the piston. Springs on the head were a bit rusty, but everything else was fine. Tried to manually turn the crank and it doesn't move. At all. Tried the old WD40 down the cylinder with no luck.

My questions are many, but here's a few off the bat.

1 - Should I take it out and overhaul it? Is it that hard to do?

2 - If I replace it, what's a decent engine I could use while considering the dimensions?

Many thanks!
Mattybunns is offline  
Sponsored Links
Advertisement
 
post #2 of 19 Old 09-08-2016
Senior Member
 
bristol299bob's Avatar
 
Join Date: Apr 2011
Location: Oriental NC
Posts: 433
Thanks: 120
Thanked 29 Times in 22 Posts
Rep Power: 9
 
Re: Yanmar SB8 issue/questions

I'd say that a simple, one cylinder, diesel like the SB8 is the perfect engine on which to learn. I'd encourage you to pull it and rebuild it. It's not hard to do, and you will learn a lot. Depending on access to the engine, pulling it out might be the hardest part.
Towguy likes this.

1977 Bristol 29.9
Surprise
Hull #5
Oriental NC
bristol299bob is online now  
post #3 of 19 Old 09-08-2016
Senior Moment Member
 
SloopJonB's Avatar
 
Join Date: Jun 2011
Location: West Vancouver B.C.
Posts: 13,215
Thanks: 91
Thanked 127 Times in 122 Posts
Rep Power: 9
 
Re: Yanmar SB8 issue/questions

^ This.

I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.
SloopJonB is online now  
 
post #4 of 19 Old 09-08-2016
Senior Member
 
RichH's Avatar
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 5,021
Thanks: 54
Thanked 326 Times in 310 Posts
Rep Power: 21
   
Re: Yanmar SB8 issue/questions

Be patient with the WD40 down the cylinder stuff.

Suggest you try some Marvel Mystery Oil into the cylinder now that you've got the head off.
Just a tablespoon or two to soak the rings and their ring grooves.
DO NOT 'force' the crankshaft!!!!!!
If the engine did not seize while running, just keep adding MMO every few days with an attempt to turning the crankshaft nose bolt with a long handled bar and socket - gently 'rocking' the breaker bar back and forth . It will/may take time; but, it usually WILL free up. DONT force the crankshaft to turn as you will inevitably break the piston rings.

Last edited by RichH; 09-09-2016 at 11:23 AM.
RichH is offline  
post #5 of 19 Old 09-09-2016
Senior Member
 
JimsCAL's Avatar
 
Join Date: May 2007
Location: Glen Cove, NY
Posts: 4,441
Thanks: 5
Thanked 202 Times in 194 Posts
Rep Power: 13
 
Re: Yanmar SB8 issue/questions

Some info on what happened to cause it to seize would help.
RichH likes this.

S/V First Tracks
1985 Cal 33-2
JimsCAL is online now  
post #6 of 19 Old 09-09-2016
Senior Member
 
mf70's Avatar
 
Join Date: Nov 2014
Location: Washington DC
Posts: 187
Thanks: 11
Thanked 5 Times in 5 Posts
Rep Power: 5
 
Re: Yanmar SB8 issue/questions

It will be MUCH easier to work on out of the boat. Workshop manuals exist. I've got rough PDF's for the 12...

Sent from my GT-P3113 using Tapatalk
SloopJonB likes this.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

"Sanderling" 32' Sharpie Ketch
mf70 is offline  
post #7 of 19 Old 09-09-2016
Senior Moment Member
 
SloopJonB's Avatar
 
Join Date: Jun 2011
Location: West Vancouver B.C.
Posts: 13,215
Thanks: 91
Thanked 127 Times in 122 Posts
Rep Power: 9
 
Re: Yanmar SB8 issue/questions

Quote:
Originally Posted by mf70 View Post
It will be MUCH easier to work on out of the boat. Workshop manuals exist. I've got rough PDF's for the 12...

Sent from my GT-P3113 using Tapatalk
I replaced a YSM (same basic engine) in one of my boats - two guys can easily hump it in & out. Could do it by yourself if your boom is strong enough to hold it.

I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.
SloopJonB is online now  
post #8 of 19 Old 01-03-2017
Junior Member
 
Join Date: Dec 2015
Posts: 5
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Quote:
Originally Posted by mf70 View Post
It will be MUCH easier to work on out of the boat. Workshop manuals exist. I've got rough PDF's for the 12...

Sent from my GT-P3113 using Tapatalk
Sorry to hijack this thread, but I saw you post that you have a rough pdf of the Yanmar SB12 shop manual. I'm burning oil, rapidly, and thinking about replacing my valve guides. Willing to email me a copy of the manual? [email protected]

Thank you so much!

Phil Magistro
s/v Tanager, 1978 Bristol 29.9
pmagistro is offline  
post #9 of 19 Old 01-03-2017
Senior Member
 
Join Date: Apr 2012
Location: On our boat.
Posts: 299
Thanks: 21
Thanked 12 Times in 12 Posts
Rep Power: 8
 
Re: Yanmar SB8 issue/questions

Quote:
Originally Posted by pmagistro View Post
Sorry to hijack this thread, but I saw you post that you have a rough pdf of the Yanmar SB12 shop manual. I'm burning oil, rapidly, and thinking about replacing my valve guides. Willing to email me a copy of the manual? [email protected]

Thank you so much!

Phil Magistro
s/v Tanager, 1978 Bristol 29.9
Phil,

We also have a B29.9 and have a PDF of the exploded parts manual for the SB12 if you think that would help. Let me know.

"Pegu Club"
1977 Bristol 29.9

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
cthoops is offline  
post #10 of 19 Old 01-05-2017
Senior Member
 
mf70's Avatar
 
Join Date: Nov 2014
Location: Washington DC
Posts: 187
Thanks: 11
Thanked 5 Times in 5 Posts
Rep Power: 5
 
Re: Yanmar SB8 issue/questions

RE:
Quote:
Re: Yanmar SB8 issue/questions
Quote:
Quote:
Originally Posted by pmagistro View Post
Sorry to hijack this thread, but I saw you post that you have a rough pdf of the Yanmar SB12 shop manual. I'm burning oil, rapidly, and thinking about replacing my valve guides. Willing to email me a copy of the manual? [email protected]

Thank you so much!

Phil Magistro
s/v Tanager, 1978 Bristol 29.9
Phil,
We also have a B29.9 and have a PDF of the exploded parts manual for the SB12 if you think that would help. Let me know.
Here's the link to the manual PDF:

https://www.dropbox.com/s/ud4t67dds6...12002.pdf?dl=0

cthoops: I could use the parts list PDF as well. Could you post a link?

mark


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

"Sanderling" 32' Sharpie Ketch
mf70 is offline  
Reply

Tags
diesel engine , engine rebuild , inboard , newbie , yanmar

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











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
Yanmar SB8 in portsmouth VA hernando Diesel 4 09-11-2014 02:46 PM
Yanmar SB8 Maintence mandrewman Diesel 5 11-07-2013 09:15 AM
Looking for a Yanmar SB8 diesel Skipper Dave Diesel 2 04-28-2013 12:44 AM
Yanmar SB8 diesel emptycooler C & C 8 11-07-2008 02:58 PM
Yanmar SB8 emptycooler Gear & Maintenance 2 07-15-2008 11:17 AM

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