Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 27-11-2011, 22:05   #16
Registered User

Join Date: Jul 2011
Location: Australia NSW south coast
Posts: 633
Re: Blow-by Causing Oil Leaks

The problem with the breather to the intake is if the engine is tired and pumping a bit of oil this oil fed into the intake becomes a fuel. The added boost of more fuel and a bit of piston sealing during the compression stroke by adding oil to the cyls produces more pressure in the cyls so more bypass when the cyl fires which makes more pressure in the crank case which sprays more oil into the intake ....... A runaway diesel on a suicide mission, a common small diesel pick up truck problem.
If you use an oil catch tin and drain it regularly then it should be ok. Feeding it into the exhaust would also require a catch tin to stop the vacuum created in the crankcase from sucking all the oil out.
Either way, get an oil catch tin first, into the exhaust just makes a little more smoke if there's a bit of oil with the fumes but into the intake you are feeding all that rubbish back through the engine. possible issues are carbon behind the intake valves and building up a heavy layer of rubbish all through the intake track.
Either way will give you a reprieve for a while but it's not a long term fix.

T1 Terry
__________________

__________________
T1 Terry is offline   Reply With Quote
Old 29-11-2011, 10:26   #17
Registered User
 
duefocena's Avatar

Join Date: Aug 2010
Location: Newport Beach, CA.
Boat: TPI Lagoon Catamaran 42'
Posts: 234
Images: 1
Found a tube from the manifold to the crankcase. Manual says it is an oil pressure regulator? Anyone familiar with adjusting,rebuilding or replacing this?
__________________

__________________
duefocena is offline   Reply With Quote
Old 29-11-2011, 19:08   #18
Registered User
 
Vyndance's Avatar

Join Date: Mar 2010
Location: Ventura, CA
Boat: 48 Californian
Posts: 195
Images: 12
Re: Blow-by Causing Oil Leaks

What do you see when you pull the dipstick and the oil fill with the motor running?
__________________
Vyndance is offline   Reply With Quote
Old 29-11-2011, 21:57   #19
Moderator
 
sailorchic34's Avatar

Cruisers Forum Supporter

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 4,815
Re: Blow-by Causing Oil Leaks

For the air breather / vent in the valve cover, there are several methods that work. running a vent hose from the valve cover to the intake air filter, running the hose to a port on the intake manifold, (most new engines are done this was as no unfiltered air gets into the engine, You can also just install a small air filter on the outlet. Seen some on LBC's (little British cars once in a while). Or the dip tube with a catch pot would work too. The Dip tube was old school engine design back before oh 1965 ish

The pressure buildup inside the engine is normal and is why ALL engines have a ventilated crankcase. Odds are your rings and everything else is fine.

Unless the oil pressure is low, under 25-30 psig, I would not adjust it. Adjusting the oil pressure is done at the oil pressure bypass valve.
__________________
sailorchic34 is offline   Reply With Quote
Old 29-11-2011, 22:42   #20
Registered User
 
duefocena's Avatar

Join Date: Aug 2010
Location: Newport Beach, CA.
Boat: TPI Lagoon Catamaran 42'
Posts: 234
Images: 1
Re: Blow-by Causing Oil Leaks

Thanks Chic,
I'm still confused as to how this engine has run for the last seven years without a breather.
When I pulled the rocker cover I found a baffle with a filter behind it. There is a threaded hole with a plug in it. ( in the service manual it shows the plug).
I can pull the plug, afix a tube and put the tube in a can to catch any oil that gets past the baffle and gauze filter but what about the fumes?
The warnings above not to run it to the intake (runaway diesel?), scare the pants off me.
__________________
duefocena is offline   Reply With Quote
Old 30-11-2011, 09:24   #21
Moderator
 
sailorchic34's Avatar

Cruisers Forum Supporter

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 4,815
Re: Blow-by Causing Oil Leaks

Hum..while it could be possible to increase engine speed, maybe, if the rings were really worn, I don't see the runaway diesel thing being a serious problem. After all yanmar and others run the crankcase vent to the intake manifold. There are no instances of runaway dieseling caused by the crankcase vent, in boats that I'm aware of.

Runaway dieseling happens mainly in trucks on long steep mountain descents. Even there its rare. On a boat its not going to really happen. (its really hard to find a wave long enough...)

Oh engines will run fine without a breather/vent. But it will cause oil leaks or excessive oil use via the valve stems.
__________________
sailorchic34 is offline   Reply With Quote
Old 30-11-2011, 09:36   #22
Registered User
 
duefocena's Avatar

Join Date: Aug 2010
Location: Newport Beach, CA.
Boat: TPI Lagoon Catamaran 42'
Posts: 234
Images: 1
Re: Blow-by Causing Oil Leaks

We catamaraners have to "back down" on big waves all the time....... There's been times I've wished I had a "Jake brake".

I'm going to take your advice and run it to th intake. Can't believe 4 Perkins mechanics have't been able to tell me how it breathes.

Thanks for your help Sailor
__________________
duefocena is offline   Reply With Quote
Old 30-11-2011, 11:06   #23
Senior Cruiser

Cruisers Forum Supporter

Join Date: Dec 2006
Location: Seattle
Boat: Cal 40
Posts: 2,401
Images: 7
Re: Blow-by Causing Oil Leaks

Quote:
Originally Posted by sailorchic34 View Post
Hum..while it could be possible to increase engine speed, maybe, if the rings were really worn, I don't see the runaway diesel thing being a serious problem. After all yanmar and others run the crankcase vent to the intake manifold. There are no instances of runaway dieseling caused by the crankcase vent, in boats that I'm aware of.

Runaway dieseling happens mainly in trucks on long steep mountain descents. Even there its rare. On a boat its not going to really happen. (its really hard to find a wave long enough...)

Oh engines will run fine without a breather/vent. But it will cause oil leaks or excessive oil use via the valve stems.
There was a story in a local mag about a guy with a new for him boat that was going into runaway. Mostly he praised the mechanic that came out on Sunday, but the end result was the mechanic drained the excessive oil that the new owner had put into the crankcase.

John
__________________
cal40john is offline   Reply With Quote
Old 02-12-2011, 17:56   #24
Registered User
 
Jesse's Avatar

Join Date: Apr 2008
Location: Oro Bay Puget Sound
Boat: Irwin sloop
Posts: 374
Re: Blow-by Causing Oil Leaks

Your post #20 seems to be the logical aproach to solving the problem. It will show you how much blowby you are dealing with and help you decide whether to route it to the intake manifold or not.
__________________
Jesse is offline   Reply With Quote
Old 02-12-2011, 18:35   #25
Registered User

Join Date: Jul 2006
Posts: 3,949
Re: Blow-by Causing Oil Leaks

Wait a minute--weren't you finding that all the oil in the crankcase was gone after running hard for a few hours? Nothing showing on the dipstick. Where was it going? Or maybe I have missed part of this story somewhere.
__________________
Kettlewell Cruising
Kettlewell is offline   Reply With Quote
Old 02-12-2011, 18:40   #26
Registered User

Join Date: Oct 2009
Location: CLOD in OH
Posts: 257
Re: Blow-by Causing Oil Leaks

Running it to the intake will also create a slight suction, and the eng will burn up the fumes you are worried about.
__________________
Paydirt
Mark Zarley is offline   Reply With Quote
Old 02-12-2011, 18:47   #27
Registered User

Join Date: Jul 2011
Location: Australia NSW south coast
Posts: 633
Re: Blow-by Causing Oil Leaks

Quote:
Originally Posted by Jesse View Post
Your post #20 seems to be the logical aproach to solving the problem. It will show you how much blowby you are dealing with and help you decide whether to route it to the intake manifold or not.
+1, even a coke bottle with a hole in the side of the neck and another hose from there to the air cleaner. this will tell you just how muck blowby there is.

"Found a tube from the manifold to the crankcase. Manual says it is an oil pressure regulator? Anyone familiar with adjusting,rebuilding or replacing this?"
With that hose/pipe to the inlet manifold, if it's easy to remove take it off and see if it's blocked. There could be like a PVC valve in there and what they mean is a crankcase pressure regulator. These PCV valves simply block up with carbon rubbish after a while, petrol/thinners/carby cleaner will wash the rubbish out fairly quickly.
If this is what's wrong Id still connect up the breather from the tappet cover to the aircleaner, lets fresh air flush the nasties out of the crankcase.

As far as the big hill or wave causing run away, motoring against a strong current or wind is virtually a never ending hill.

T1 Terry
__________________
T1 Terry is offline   Reply With Quote
Old 02-12-2011, 19:02   #28
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,371
Re: Blow-by Causing Oil Leaks

I believe those little Perkins were built by a european manufacturer and relabeled... I forget who built them, but they dont seem to have the rep the traditional perkins have... so who knows, maybe theydesigned with no vent. It's a good question though... how does an engine get crankcase pressure in there but not burn oil. Maybe it's designed to run with the pressure....? (bad idea for oil leaks!)
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 04-12-2011, 18:38   #29
Registered User
 
Jesse's Avatar

Join Date: Apr 2008
Location: Oro Bay Puget Sound
Boat: Irwin sloop
Posts: 374
Re: Blow-by Causing Oil Leaks

Progress update?
__________________
Jesse is offline   Reply With Quote
Old 06-12-2011, 05:23   #30
Registered User
 
brakauskas's Avatar

Join Date: May 2010
Posts: 167
I have some of the same problems with blow by in the intake but I am also registering high oil pressure. I have a lot of leaks at both crankcase seals that I will also be replacing. I have a chance to replace the high oil pressure relief valve so hopefully that is my fix. I have a Perkins 4-108 and every mechanic I talk to tells me to just live with it. They say Perkins are oilers.
__________________

__________________
brakauskas is offline   Reply With Quote
Reply

Tags
oil leak

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
Oil Leaks from 4.108 Timing Plate Rob H Engines and Propulsion Systems 11 09-11-2011 08:42
Bad Oil Pressure Gauge cburger Construction, Maintenance & Refit 8 08-10-2011 06:17
Why Two Oil Dipsticks on Perkins 4-108 ? dancamp009 Engines and Propulsion Systems 16 22-08-2011 07:45
Reporting an Oil Slick knottybuoyz Rules of the Road, Regulations & Red Tape 33 15-08-2011 17:01
How Do I Change My Oil ? flatlander Engines and Propulsion Systems 25 12-07-2011 17:05



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 17:10.


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.