Yet another 1/2 overheating MD11! - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 06-25-2007
Junior Member
 
Join Date: Jun 2007
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
technolaser is on a distinguished road
Yet another 1/2 overheating MD11!

Yes, I know this is a recurring theme, but I've tried everything suggested in the archives and I'm still left with a strange problem so any ideas are welcome.

I have a 1976 MD11C raw water cooled in a Moody 30. Starts instantly every time, although does smoke a bit. Running for extended periods at low revs/load everything is fine with very strong water flow. Both heads remain at around 50 deg C (sorry, I'm a foreigner!), and #1 cyl is also fine and opening either drain **** results in a plentiful stream. As soon as I run over about 1300rpm under load, the #2 cyl overheats as if there's no water around the liner.

I've changed pump and all piping, new exhaust elbow and manifold gaskets. Drilled/filed (with round file in drill!) and acid soaked the manifold. Tested all channels with hose pipe and have free flow. Removed heads and drilled/filed all channels. Drilled/filed and acid soaked the cylinders in place, tested with hose from all five channels in top of cyl and have free flow. New head gaskets. New thermostat.

I even tried supplying the cooling water via a hose pipe - no gain.

Having seen so many knowledgable Volvo members I'm hoping someone has an idea.

HELP - I'm stuffed!

TIA.
Reply With Quote Share with Facebook
  #2  
Old 06-25-2007
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
Have you flushed out the cooling passageways in the block? It sounds like the ones going to the #2 cylinder have a constriction someplace. That would explain why it is fine at idle but over heats as you power up.
__________________
Sailingdog

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

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook
  #3  
Old 06-25-2007
Junior Member
 
Join Date: Jun 2007
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
technolaser is on a distinguished road
Sailingdog,

Yes, I have flushed the channels in the cylinder that houses the liners. There are no channels in the block itself.

Is there any way exhaust gasses could be getting into the cooling channels?
Reply With Quote Share with Facebook
  #4  
Old 06-25-2007
Senior Member
 
Join Date: Jun 2006
Posts: 2,394
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 11
cardiacpaul is a jewel in the rough cardiacpaul is a jewel in the rough cardiacpaul is a jewel in the rough
it might be a leaking injector pumping too much fuel?
__________________
We are not primarily on earth to see through one another, but to see one another through

Some people are like slinkies: not really good for anything... but you can't help laughing when you push them down the stairs
Reply With Quote Share with Facebook
  #5  
Old 06-25-2007
Junior Member
 
Join Date: Jun 2007
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
technolaser is on a distinguished road
I'm not a diesel expert so bear with me. Why would a leaking injector keep water from circulating in the channels?

Or do you mean that a leaking injector would make it overheat?
Reply With Quote Share with Facebook
  #6  
Old 06-25-2007
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
The excess fuel by the leaking injector would cause the cylinder to overheat.

BTW, just flushing the system may not remove a constriction, if the constriction is caused by a sediment build-up or broken impeller blade jammed in the channels, usually at a bend. The channel may allow enough water through, so it appears to be clear, but may be restricted enough that at higher throttle settings, not enough water is circulating to dissapate the heat properly.
__________________
Sailingdog

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

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook
  #7  
Old 06-25-2007
JimsCAL's Avatar
Senior Member
 
Join Date: May 2007
Location: Glen Cove, NY
Posts: 2,428
Thanks: 2
Thanked 35 Times in 34 Posts
Rep Power: 8
JimsCAL is on a distinguished road
Sounds like you tried all the usual suspects. I agree with sailing dog that you may have a partial obstruction in the #2 cylinder passages. Have you tried back flushing? Forcing water in the direction opposite the normal flow may dislodge whatever is resticting the flow.
Reply With Quote Share with Facebook
  #8  
Old 06-25-2007
Gene T's Avatar
Senior Member
 
Join Date: May 2006
Location: Left Coast USA
Posts: 666
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
Gene T is on a distinguished road
The Volvo cooling system is bizarre. At least it was on my MD7a. The whole cooling system relies on an even distribution through multiple parallel water passages. One or more get plugged and you have localized overheating. I had an flash over condition, my description, at higher load the engine temp would increase until the water in the block would flash to steam, cold water would then rush in and the temp gage would drop to cold. This cycle would repeat over and over. The problem was the two water passages in the front of the head down into the block were plugged. I could get access by pulling the freeze plugs and routing them out with a wire while flushing with a hose. It was quite a bit of work and there was a lot of rust in there. The good news it when it was done the engine ran at a nice and even temp.

One other problem could be the thermostat housing. If the bypass hole rusts enough that it gets too big there won't be enough pressure behind the thermostat to allow proper flow through the engine at high load. I ended up adding a restriction to my circuit to make up for the rusted out housing. Had to play with it a bit to get the right size. Too small and the engine runs too cold. You really need to draw out the cooling system through the engine to understand how it is supposed to work.

Another problem with these engines varies with how they sit in the boat. If you leave the water feed open the water level in the engine will be at the same level as on the outside of the hull, which could mean critical water passages could be in moist air and not under water which is worst case for rusting shut. This is a good reason to shut your intake valve when leaving the boat for long periods of time.

Flushing with acid will not unplug passages if they are completely plugged.
Reply With Quote Share with Facebook
  #9  
Old 06-26-2007
Junior Member
 
Join Date: Jun 2007
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
technolaser is on a distinguished road
Thanks to everyone for the replies. I will give a flushing solution like Rydlyme a try when I can lay my hands on it. Otherwise I'll just go easy on the revs and see how it goes.

Thanks guys.
Reply With Quote Share with Facebook
  #10  
Old 06-26-2007
Senior Member
 
Join Date: Jun 2004
Location: Malaysia
Posts: 314
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
haffiman37 is on a distinguished road
There is unfortunately only one way if the 'easy' ones (back-flushing through drains) fails: Off with BOTH heads, check and clean ALL passages. You'll be surpriced!
Leaking injector will normally lead to more black smoke than usual, but not overheat.
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
overheating kubota mrkeith Gear & Maintenance 36 05-29-2007 09:39 AM
Engine Overheating on Helms 30 rendezvous Gear & Maintenance 17 08-02-2006 05:18 PM
Overheating Perkins 4-108 Eleanna Gear & Maintenance 13 07-24-2006 06:59 AM
Volvo MD11C Overheating takwita Gear & Maintenance 2 05-16-2004 05:47 AM
Perkins 4.108 overheating singingdrum Gear & Maintenance 2 04-22-2003 07:19 AM


All times are GMT -4. The time now is 05:11 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.