Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 14-01-2015, 02:42   #1
Registered User

Join Date: Aug 2004
Posts: 8
Yanmar YSE12 cylinder head removal.

Any suggestions as to how to get the cylinder head off ?
I've removed the four nuts and the rockers and rocker shaft etc.
I've removed the injector.
I've removed the inlet pipe and the exhaust pipe.

The head just seems to be just stuck on tight. I've sprayed WD40-type penetrating oil around the studs, and I'll leave that a while, but I'm not hopeful that it'll achieve much.
A mate suggested sticking some rope down the injector hole and using the piston to ram the head off, but having taken off the injector, there doesn't seem to be direct access through that hole to the combustion chamber. And looking through the parts book I think there's some kind of pre-combustion chamber down there.

I have a 3ft wrecking bar and have been levering with that against the stub of the exhaust pipe, but with no effect. I could try a longer bar, like a 5ft crow bar, but I wouldn't be surprised in the exhaust stub broke first.

I've just about run out of ideas. The reason the head is coming off is because the valves are sticking and/or there's a blown head gasket. So there's no compression, so the idea of getting it running to compress the head loose is a non starter......

Any thoughts on the subject, or should I just resort to the longer crowbar ?



Scaffi S28 is offline   Reply With Quote
Old 14-01-2015, 05:23   #2
Registered User

Join Date: Nov 2013
Location: Slidell, La.
Boat: Morgan Classic 33
Posts: 664
Re: Yanmar YSE12 cylinder head removal.

I like to use an old wood chisel and hammer. Insert the edge of the chisel between the head and the block flat side down, parallel to the block head interface at the point where the head bolt goes through, and tap lightly. The chamfer of the chisel will lift the head up with little or no damage to the head. If the studs are rusted into the head, it may be necessary to remove them first. Depending on the configuration and their condition, you may be able to use two nuts locked together on the stud to unscrew them, or a stud remover like this

to remove them, or it could even be necessary to weld a nut to them.

jimbunyard is offline   Reply With Quote
Old 14-01-2015, 13:25   #3
Registered User

Join Date: Oct 2009
Location: australia
Posts: 432
Re: Yanmar YSE12 cylinder head removal.

G'day, The rope trick will not work on a Yse 12 it is fitted with a pre combustion [Lombardo] cell. The clearance between the head studs and the head is large allowing corrosion to weld the head in place as you are finding out. I spent 10hrs removing one once using heaps of wd40 and Fox wedges[ Google].Give it good touch up in all directions with a sledge hammer crude but helps. Have you disconnected the oil feed pipe underneath the head? Patience and a sense of humour is the key.
shakey doug is offline   Reply With Quote
Old 16-01-2015, 11:40   #4
Registered User

Join Date: Aug 2004
Posts: 8
Re: Yanmar YSE12 cylinder head removal.

Thanks Jim and Doug. The wood chisel and a 1.5kg lump hammer did the trick, followed by the judicious application of a 3ft crowbar ! I'm generally a bit more sympathetic to a poor dumb engine when I'm working on it, but in this case the cast iron head and cast iron block came off totally unscathed: not a scratch !

In the end, only one of the studs was seriously rusted up. The others were a bit oily- probably indicative of the leaking head gasket.

I'll clean it up tonight and pull the valves out. Hopefully a regrind will suffice, and maybe valve guides.

There was a slight lip around the top of the bore, but only slight. So I'm thinking just the valve job will do.

Thanks for your help.

Scaffi S28 is offline   Reply With Quote
Old 16-01-2015, 12:21   #5
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 11,569
Re: Yanmar YSE12 cylinder head removal.

Have the guides reamed or better yet, replaced. Not that hard and not that expensive
a64pilot is online now   Reply With Quote

head, removal, yanmar

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
Yanmar YSE12 Powergen75 Engines and Propulsion Systems 7 04-04-2014 23:49
Yanmar YSE12 Nomad57 Engines and Propulsion Systems 2 30-07-2012 08:43
Diesel - Two Cylinder vs Three Cylinder Surveyor Engines and Propulsion Systems 8 04-09-2011 13:12
YSE12 Engine Rebuild Scaffi S28 Engines and Propulsion Systems 4 10-09-2009 06:14
Yanmar YSE12 Diesel Engine Sign this Classifieds Archive 0 08-08-2009 04:51

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 15:32.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.