Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 19-09-2015, 13:12   #1
Registered User
 
Immanuel's Avatar

Join Date: Apr 2008
Location: eastern N. Carolina
Boat: 10m Catalac, Immanuel
Posts: 30
yanmar 3gm30 issue

I have installed two rebuilt Yanmar engines in my boat 2 yearsago. they have approximately 100 hours each on them. one of the engines has developed an occasional taping noise. Took off valve cover for visual inspection all seems to be in good order however a couple of the rocker arms seem very marginally loose. could this be a simple valve adjustment or something else. again the rapping noiese is intermittent and not consistent.any input much appreciated thank you
Immanuel is offline   Reply With Quote
Old 19-09-2015, 15:30   #2
Moderator Emeritus
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
Re: yanmar 3gm30 issue

Intermittent light tapping could be lifters if they are hydraulic, I don't know if they are, or loose valve adjustment although valves usually wear tight. Valve clearance is very easy to check and adjust though, so check it.

My bet would be dirty fuel injectors that can cause a rattling sound as the spray pattern is bad and fuel isn't being atomized as well.


Sent from my iPad using Cruisers Sailing Forum
a64pilot is offline   Reply With Quote
Old 19-09-2015, 15:48   #3
Registered User
 
Cheechako's Avatar

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,477
Re: yanmar 3gm30 issue

some rockers will be "loose" if you are not rotating the engine to the proper place to test them.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 19-09-2015, 16:02   #4
Registered User
 
four winds's Avatar

Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
Re: yanmar 3gm30 issue

Quote:
Originally Posted by Cheechako View Post
some rockers will be "loose" if you are not rotating the engine to the proper place to test them.
Interesting satement. In my opinion the position to perform adjustment (on the heel or base of the lobe) coresponds to the position where clearance would always be the greatest.

If a rocker appears too loose, it needs adjustment. Performed at or near TDC on the compression stroke for that cylinder of course.

To the OP, a valve adjustment after 100 hours of break in on rebuilt engines seems reasonable to me. The first service intervals are usually short on most engines. And loose tappets can produce intermitant taps.
__________________
Life begins at the waters edge.
four winds is offline   Reply With Quote
Old 19-09-2015, 17:56   #5
Moderator Emeritus
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
Re: yanmar 3gm30 issue

Only real wear on the valve train should be between the valve and it's seat, which reduces valve clearance. I say should be, but should bees don't make honey do they.
Either way a valve clearance check is so easy that it should be done just to eliminate the possibility. Always start with the easy and or inexpensive stuff first when trouble shooting, you never know you might get lucky, Been a long time ago, But I heard an engine that I was certain was the bottom end worn, you know the hollow knock. Turned out it was a torque convertor flex plate that was cracked and nothing wrong with the engine at all.


Sent from my iPad using Cruisers Sailing Forum
a64pilot is offline   Reply With Quote
Old 19-09-2015, 18:13   #6
Registered User
 
four winds's Avatar

Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
Re: yanmar 3gm30 issue

Agree a64pilot. However on rebuilt engines some components get replaced and some not. So a new valve stem head or rocker can experience break in wear. Or reused lock nuts can be an issue. Or a new valve guide can have a slightly different angle if not carefully installed leading to a new wear pattern.

Not every builder puts the rockers back in the same spot as well. So lots of variables on a rebuild not there on an all new engine.

I usually add 10% to the lash clearance on a rebuild to compensate for the freshly faced seats. The lash spec is a range anyway.

BTW, good call on the damper plate. Random and similar light ticking sound.
__________________
Life begins at the waters edge.
four winds is offline   Reply With Quote
Old 19-09-2015, 18:29   #7
Registered User
 
Cheechako's Avatar

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,477
Re: yanmar 3gm30 issue

Quote:
Originally Posted by four winds View Post
Interesting satement. In my opinion the position to perform adjustment (on the heel or base of the lobe) coresponds to the position where clearance would always be the greatest.

If a rocker appears too loose, it needs adjustment. Performed at or near TDC on the compression stroke for that cylinder of course.

To the OP, a valve adjustment after 100 hours of break in on rebuilt engines seems reasonable to me. The first service intervals are usually short on most engines. And loose tappets can produce intermitant taps.
and what if it appears "very marginally loose" to quote the OP? Apparently you are the expert I guess, so from your statement "If a rocker appears too loose" is that .009 or .013"?
:>)... it depends on your assessment of the OP's statement "seem marginally loose".... My thought was that simply looking under the rocker cover, "yes some will appear loose and some will appear tight". I have no idea of his experience with engines. I assume little if he's asking here.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 19-09-2015, 18:51   #8
Registered User
 
four winds's Avatar

Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
Re: yanmar 3gm30 issue

In doubt a novice would consider 9 or 13 either one to be "loose", unless they considered that there should be no play at all.

Probably should have said if a lash appears loose it should be checked, not necessarily adjusted.

Not an expert. Just a guy that's rebuilt most every engine that I've owned.
__________________
Life begins at the waters edge.
four winds is offline   Reply With Quote
Old 20-09-2015, 17:59   #9
Registered User
 
Immanuel's Avatar

Join Date: Apr 2008
Location: eastern N. Carolina
Boat: 10m Catalac, Immanuel
Posts: 30
Re: yanmar 3gm30 issue

Thank you everyone for the input. I agree, a valve adjustment is in order. Will get back and let you know how it works out.
Immanuel is offline   Reply With Quote
Old 20-09-2015, 19:08   #10
Registered User

Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
Re: yanmar 3gm30 issue

Quote:
Originally Posted by Immanuel View Post
Thank you everyone for the input. I agree, a valve adjustment is in order. Will get back and let you know how it works out.
Not so fast. If the engine has solid lifters, there would be no such thing as intermittent. If it has hyd lifters and you felt a loose rocker, then that lifter has collapsed.
model 10 is offline   Reply With Quote
Old 20-09-2015, 19:17   #11
Registered User

Join Date: Oct 2009
Location: australia
Posts: 539
Re: yanmar 3gm30 issue

They are solid lifters and very capable of noise as described.
shakey doug is offline   Reply With Quote
Old 20-09-2015, 19:22   #12
Registered User
 
four winds's Avatar

Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
Re: yanmar 3gm30 issue

Quote:
Originally Posted by shakey doug View Post
They are solid lifters and very capable of noise as described.
Correct. As the uncontrolled position of an excessively loose rocker will vary at the moment the stem contacts it.
__________________
Life begins at the waters edge.
four winds is offline   Reply With Quote
Old 20-09-2015, 19:30   #13
Registered User
 
four winds's Avatar

Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
Re: yanmar 3gm30 issue

Maybe a lock nut backed off.

Though could be an injector or cracked damper plate as a64pilot mentioned.

Could even be a fresh water pump bearing. All these are very similar noises.
__________________
Life begins at the waters edge.
four winds is offline   Reply With Quote
Old 20-09-2015, 19:38   #14
Registered User

Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
Re: yanmar 3gm30 issue

Quote:
Originally Posted by shakey doug View Post
They are solid lifters and very capable of noise as described.
He said, "Intermittently". Stuck solid lifter, I don't think so. Maybe something else.
model 10 is offline   Reply With Quote
Reply

Tags
3gm, 3gm30, yanmar

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Gallons / Hour with a Yanmar 3gm30 Dave in Eugene General Sailing Forum 32 18-01-2013 13:23
Yanmar 3gm30. Jacana Engines and Propulsion Systems 4 19-03-2008 09:14
3gm30 Yanmar full of hose water.... Dave in Eugene General Sailing Forum 14 12-02-2008 19:15
coolant water take off from Yanmar 3gm30 Dave in Eugene General Sailing Forum 6 31-12-2007 20:39
Hard Starting Yanmar 3GM30 sailcruz Engines and Propulsion Systems 2 15-05-2007 13:47

Advertise Here


All times are GMT -7. The time now is 04:40.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.