Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 20-07-2014, 05:50   #1
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,764
Adjusting Valve Clearances on a Diesel Engine

I have never adjusted valve clearances on a diesel engine -- can anyone give any hints? I've done it a million times on petrol engines. But on a diesel you can't just pop the spark plugs out to relieve the compression, and you've got no distributor to use to check the crank position. How do you do it? Do you pop the injectors out? My engine (Yanmar 4JH3HTE) has no glow plugs. Do you look at the timing marks on the flywheel for crank position? Is there a step-by-step guide anywhere?
__________________

__________________
Dockhead is offline   Reply With Quote
Old 20-07-2014, 06:35   #2
Registered User
 
Fiveslide's Avatar

Join Date: Dec 2009
Boat: JBW club 420, MFG Bandit, Snark
Posts: 603
Re: Adjusting Valve Clearances on a Diesel Engine

http://www.hoyetractor.com/valve-set.htm

A service manual will have a procedure, probably more complicated than in the link above, but that is what it boils down to, finding that "middle position" they reference for each cylinder and adjusting the valve to specs. Removing something or otherwise relieving compression will make it easier on you rather than turning it by hand through all the compression strokes.

This is a critical part of your engines health and overall life and should be done more than most people do it. I think most engine makers recomend it at first oil change and every 1000 hours. Its also relatively easy and there is no reason it should have to be done by a professional.

Certainly something you can handle, Mr. Dockhead. I do think I would want to consult my engines service manual rather than just wing it.

Sent from my SCH-S738C using Cruisers Sailing Forum mobile app
__________________

__________________
Fiveslide is offline   Reply With Quote
Old 20-07-2014, 06:49   #3
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,764
Re: Adjusting Valve Clearances on a Diesel Engine

Quote:
Originally Posted by Fiveslide View Post
Easiest way to set the valves on your Yanmar

A service manual will have a procedure, probably more complicated than in the link above, but that is what it boils down to, finding that "middle position" they reference for each cylinder and adjusting the valve to specs. Removing something or otherwise relieving compression will make it easier on you rather than turning it by hand through all the compression strokes.

This is a critical part of your engines health and overall life and should be done more than most people do it. I think most engine makers recomend it at first oil change and every 1000 hours. Its also relatively easy and there is no reason it should have to be done by a professional.

Certainly something you can handle, Mr. Dockhead. I do think I would want to consult my engines service manual rather than just wing it.

Sent from my SCH-S738C using Cruisers Sailing Forum mobile app
My manual says "this procedure requires special knowledge; refer to your Yanmar dealer"!

I've done it a million times on petrol engines and understand the principles fine -- I just need to know how people relieve the compression (or whether they do so), and what you use for a timing mark.
__________________
Dockhead is offline   Reply With Quote
Old 20-07-2014, 06:58   #4
Senior Cruiser
 
Sailmonkey's Avatar

Cruisers Forum Supporter

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 5,792
Re: Adjusting Valve Clearances on a Diesel Engine

On out little Kubota, I don't relieve the compression, I do however zip tie the fuel stop lever into the off position. For timing, find the timing marks, watch for TDC on a particular cylinder and shove feeler blades between the rocker and valve. Easy
__________________
Sailmonkey is online now   Reply With Quote
Old 20-07-2014, 07:03   #5
Registered User
 
Fiveslide's Avatar

Join Date: Dec 2009
Boat: JBW club 420, MFG Bandit, Snark
Posts: 603
Re: Adjusting Valve Clearances on a Diesel Engine

Quote:
Originally Posted by Dockhead View Post
My manual says "this procedure requires special knowledge; refer to your Yanmar dealer"!
That's just... crazy. This is the service manual, not the owner's manual stating this?

It's probably a straight forward procedure, the "knowledge" of which should in no way be considered special.

I'm really interested in seeing this procedure now and why they print that only Yanmar dealers are capable of doing it.

Sent from my SCH-S738C using Cruisers Sailing Forum mobile app
__________________
Fiveslide is offline   Reply With Quote
Old 20-07-2014, 07:17   #6
Registered User
 
Fiveslide's Avatar

Join Date: Dec 2009
Boat: JBW club 420, MFG Bandit, Snark
Posts: 603
Re: Adjusting Valve Clearances on a Diesel Engine

I found a pdf of the service manual. I will pm you the link or the file if you like. On pade 31 of the pdf in section 3-3 of the manual it tells you how to adjust the valves during an overhaul. I don't see how it could be any different with a complete engine other than the compression issue.

Sent from my SCH-S738C using Cruisers Sailing Forum mobile app
__________________
Fiveslide is offline   Reply With Quote
Old 20-07-2014, 07:41   #7
Registered User

Join Date: Dec 2008
Location: ontario canada
Boat: grampian 26
Posts: 1,743
Re: Adjusting Valve Clearances on a Diesel Engine

If you divide 720 degrees by the number of cylliders it will give you the number of degrees you need to rotate the engine to bring the next cylinder to TDC. Check for valve rock on the cylinder to ensure it is at TDC.
__________________
perchance is offline   Reply With Quote
Old 20-07-2014, 08:27   #8
Moderator
 
HappyMdRSailor's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: North Mississippi
Boat: 48 Wauquiez Pilot Saloon-C22 Chrysler Sunpiper- 19 Potter-Preparing to cruise w/my girl
Posts: 5,980
Re: Adjusting Valve Clearances on a Diesel Engine

DH,

Same exact thing as your petrol engine...

For simplicity, the max gap should be constant until the lifter starts up on the ramp profile of the cam lobe... That being said... You can adjust each valve without figuring out where your particular cylinder is in the cycle... If you watch for max lift of a valve and turn the crank 90 degrees... You are then on the 180 position away from the cam lobe...

Obviously it would be easier to do both valves on a cylinder in the same crank position.... Find compression TDC by watching the valves... It should be no problem bumping the starter, and using a spanner to get your positions...
__________________
In the harsh marine environment, something is always in need of repair...

Mai Tai's fix everything...
HappyMdRSailor is offline   Reply With Quote
Old 20-07-2014, 09:14   #9
Moderator
 
sailorchic34's Avatar

Cruisers Forum Supporter

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 4,815
Re: Adjusting Valve Clearances on a Diesel Engine

Quote:
Originally Posted by HappyMdRSailor View Post
If you watch for max lift of a valve and turn the crank 90 degrees... You are then on the 180 position away from the cam lobe...
Ah, It's the other way, 90 degrees on the crank is 45 degrees on the cam. Cams are half the rpm of the crank on 4 stroke engines.

I too adjust valves one at a time as its quite easy to just watch and see when the valve is closed. I just bump the starter a time or two as needed and go thru the valves. Normally you can do 2 or 3 valves at a time, just not on the same cylinder.

No mystery to it. Gee my dad taught me this when I was 12. I'll sometimes verify that the clearance is not too tight or loose by using one size up and down on the feeler gauges. If in question, its better to be 0.001 loose.
__________________
sailorchic34 is offline   Reply With Quote
Old 20-07-2014, 09:28   #10
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Re: Adjusting Valve Clearances on a Diesel Engine

On yanmars the front balance wheel has a mark for the #1 cyl and a pointer that should be visible.

With the valve cover off and the mark lined up the front valves should be loose. If not then rotate the motor 360 and check again. Once establishing TDC you can place marks on the balance wheel at 90, 180, and 270 degrees.

Once you have adjusted the #1 cyl you can rotate the motor 270 degrees and check for another pair of loose valves and adjust that cyl. Repeat!

I'm in P.I. right now and don't have access to the manual for the gap but if you can get the instructions from a manual (above) then do so. Valve adjusts are critical on motors.
__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
A nation of sheep breeds a government of wolves!

Unprepared boaters, end up as floatsum!.......
delmarrey is offline   Reply With Quote
Old 20-07-2014, 09:32   #11
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,373
Re: Adjusting Valve Clearances on a Diesel Engine

I've not found the need to relieve compression. You can turn them very slowly to where you need to be. IF I remember right watch for the exhaust valve to be depressed and back up and before the intake goes down. There's your adjustment spot. Someone please refine this for me...with more detail...
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is online now   Reply With Quote
Old 20-07-2014, 09:50   #12
Moderator
 
HappyMdRSailor's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: North Mississippi
Boat: 48 Wauquiez Pilot Saloon-C22 Chrysler Sunpiper- 19 Potter-Preparing to cruise w/my girl
Posts: 5,980
Re: Adjusting Valve Clearances on a Diesel Engine

Quote:
Originally Posted by sailorchic34 View Post
Ah, It's the other way, 90 degrees on the crank is 45 degrees on the cam. Cams are half the rpm of the crank on 4 stroke engines.
Hee Hee!!!

Brain... Pffffft...
__________________
In the harsh marine environment, something is always in need of repair...

Mai Tai's fix everything...
HappyMdRSailor is offline   Reply With Quote
Old 20-07-2014, 10:13   #13
Registered User
 
four winds's Avatar

Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,138
Re: Adjusting Valve Clearances on a Diesel Engine

Quote:
Originally Posted by Cheechako View Post
I've not found the need to relieve compression. You can turn them very slowly to where you need to be. IF I remember right watch for the exhaust valve to be depressed and back up and before the intake goes down. There's your adjustment spot. Someone please refine this for me...with more detail...
Again, the other way around. When the intake closes a new charge is present and the piston is about to to rise and compress the charge. On two closed valves.

Just after intake closing then is a good spot to do both valves.
__________________
Life begins at the waters edge.
four winds is offline   Reply With Quote
Old 20-07-2014, 10:27   #14
Senior Cruiser
 
Blue Stocking's Avatar

Cruisers Forum Supporter

Join Date: Dec 2008
Location: St. Georges, Bda
Boat: Rhodes Reliant 41ft
Posts: 4,117
Re: Adjusting Valve Clearances on a Diesel Engine

Depending on your firing order, e.g. 1-4-2-3-, there is a formula that will tell you e.g., that when the intake valve is closed (TBC) on #1, the exhaust will be closed on another cylinder. There is a constant number to add to whichever valve you are working on, to find the other one ready to set. I know that on certain firing order 6 cylinder engines, you add 9 to whichever # valve you are setting, and it gives you the next open valve.

Found it zyra.me.uk has firing orders.
__________________
so many projects--so little time !!
Blue Stocking is offline   Reply With Quote
Old 20-07-2014, 10:32   #15
Registered User
 
mtarcher's Avatar

Join Date: Oct 2009
Location: BVI
Boat: Beneteau 361
Posts: 70
Images: 7
Re: Adjusting Valve Clearances on a Diesel Engine

I concur with FourWinds...I adjust the valves on my 3GM at .008in on a cold engine. If I remember right, the tech who helped me the 1st time said that the intake value needed to be most accurate, while the exhaust could be "fudged" to .001in over (loose) if needed.
__________________

__________________
mtarcher is offline   Reply With Quote
Reply

Tags
diesel, engine

Thread Tools
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
anyone know valve clearances for 2qm20? charliehows Engines and Propulsion Systems 12 13-03-2013 21:01
Gulf ICW Bridge Clearances F51 Navigation 6 11-07-2011 20:07
ICW Clearances/Depths astontz Atlantic & the Caribbean 10 05-10-2008 15:57
Shime for adjusting the height opf the engine on the beds. ribbony Engines and Propulsion Systems 14 21-02-2008 03:10



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 11:43.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.