Trawler Forum

Trawler Forum (http://www.trawlerforum.com/forums/)
-   General Maintenance (http://www.trawlerforum.com/forums/s32/)
-   -   Lehman 120 head retorque (http://www.trawlerforum.com/forums/s32/lehman-120-head-retorque-13209.html)

psneeld 01-07-2014 09:20 AM

Lehman 120 head retorque
 
Over in my Tach Adapter thread I pointed out that I may have a little oil seep around the head gasket too.

I have searched this forum and the web for guidance but have hit a stalemate of views.

While scrutinizing my engine for sources of oil leas...I may have a little oil around the head gasket but notice very little or none flowing down the sides of the engine.

My manuals say "don't" retorque the head...but AM recommends every 500 hrs...and I get conflicting info off the web.

Any definitive guidance source? Something about stretch bolts on the newer engines and if mine was a rebuild in 2009 (PO gave NO additional info or documentation on it and AM has no records of it) I'm worried about a blind retorque while cruising....is there any markings on the bolts?

I'm wondering if I can go another 250hrs till I get home and just pull the head, new gasket and new bolts?

Any thoughts please.

Larry M 01-07-2014 09:44 AM

I'd call Bomac Marine Power Group and ask Greg. They rebuild lots of Ford Lehmans.

Bomac Marine- Ford Lehman Engines, Parts, Tanks, Phaser Generators and Service

Northern Spy 01-07-2014 10:09 AM

Consider this.

Buy, borrow or rent a UV light. Shine it on your engine and see if your oil fluoresces. Some does, some doesn't. If not there are additives you can purchase to add to your oil.

Clean your engine very well with some simple green or the like, getting rid of all the residual oil. Then start it up and use the UV flashlight to check for the actual source of the oil leak(s).

I have a dual wavelength flashlight that has found many a leak on all sorts of equipment using this methodology.

Many of the leaks were not from where I originally thought it was from, and saved me from unnecessarily taking things apart.

RickB 01-07-2014 11:00 AM

Good advice. Dye tracer is a cheap and effective troubleshooting aid.

psneeld 01-07-2014 11:27 AM

thanks guys....

Brooksie 01-07-2014 03:04 PM

If, like the later Perkins, you have stretch bolts, then re-torque (or should I say re-stretch) is not necessary. How to find out if you have the stretch bolts... I'm not sure. The Perkins bolts look entirely different in that they are actually bolts not studs.

elramblito 02-23-2014 06:08 PM

Yesterday my ford Lehman 120 wouldn't stay lit. Been starting every time for two years. Filters have about 60 hours. Ideas?

Xsbank 02-23-2014 07:34 PM

Psneeld, check your lift pump first. As strange as it sounds, the oil leaks out of the gasket on the block and migrates upwards and looks like a head leak. Many are caught by this one. It has a really crappy fit on the block, needs a new gasket and a smear of Permatex.

I'd almost bet a beer on this one.

psneeld 02-23-2014 10:07 PM

Quote:

Originally Posted by Xsbank (Post 215405)
Psneeld, check your lift pump first. As strange as it sounds, the oil leaks out of the gasket on the block and migrates upwards and looks like a head leak. Many are caught by this one. It has a really crappy fit on the block, needs a new gasket and a smear of Permatex.

I'd almost bet a beer on this one.

Seriously????...oil migrating up against gravity over a foot higher??? and not spraying up there??

I'd love to hear from anyone else that's ever seen that one...just goes against my experience.

My leak is out of an injector line seal and migrating down the head gasket line and dripping down the back of the motor....

thanks though...

Xsbank 02-24-2014 01:24 AM

Seriously. Clean up all the oil and put a paper towel or similar around the lift pump. I threatened to bet a beer on it and so you know I am serious. It's something to do with the way the engine vibrates. Check it out first, before you ridicule.

If it's dripping out of your injector seal, why do you think its a head gasket? Just tighten it up.

psneeld 02-24-2014 06:28 AM

I have checked it out...back when I first posted I didn't notice the leak(s) from the injector pipes but as they got a little worse they became ore obvious.

I have tightened them but the seals must be going.

Plus absolutely dry around the lift pump.

Reaearched fuel pump oil leaks and none of the discussions mentioned oil "vibrating" anywhere but down into the pan...just having a hard time believing it will migrate up a block side (wicking not possible as there's nothing to wick up).

The real reason for the post was the uncertainty to retorque the head or not based on lots of confliction info....I certainly didn't want to do it in the middle of a long trip and wind up with major maintenance but I didn't want to ignore it and wind up with major maintenance on a long trip.

I can live with all kinds of oil leaks as long as they are in the right sorts and can be monitored.

FF 02-24-2014 07:34 AM

OIL is cheap, FORGETABOUTIT, and enjoy your cruise.

psneeld 02-24-2014 07:47 AM

Quote:

Originally Posted by FF (Post 215497)
OIL is cheap, FORGETABOUTIT, and enjoy your cruise.

Thanks...see you tomorrow!!!

jleonard 02-24-2014 08:16 AM

I agree with FF....don't worry about a small nuisance leak. Place a piece of an oil diaper to absorb it.
I am also not a big fan of retorquing an old engine.

psneeld 02-24-2014 08:29 AM

Quote:

Originally Posted by jleonard (Post 215504)
I agree with FF....don't worry about a small nuisance leak. Place a piece of an oil diaper to absorb it.
I am also not a big fan of retorquing an old engine.

Pretty much the people I trust on here all say about the same as what is my experience...don't retorque.

I just don't get the conflicting info people report from American Diesel...makes me really wonder.

The engine only has 1000 hrs if the engine is truly a rebuilt as the PO stated..and had some documentation for...sure looked new and he did give me everything from a spare flywheel to injection pump to oil coolers, etc..etc...they had to have come off his trade-in core. Though he did tell me it was a 135 and it's really a 120..no biggie..just another verification of how clueless POs can be.

My big leak was the tach adapter that I pulled and plated over...easy peezy...and if the other leaks all stay small...I was planning on some more major stuff this summer where I sit for 8 months and hope another Sandy doesn't shake me from my slip too early in the season.

So another week in Ft Piece then the 45 day crawl back to NJ...hope you guys wear out winters welcome up there soon so I can return to warm gentle breezes and azaleas blooming....:D....

jleonard 02-24-2014 08:53 AM

Quote:

Originally Posted by psneeld (Post 215511)
he did give me everything from a spare flywheel to injection pump to oil coolers, etc..etc...they had to have come off his trade-in core. :D....

And all this time I thought you had a single engine boat...LOL:dance:

psneeld 02-24-2014 09:39 AM

Quote:

Originally Posted by jleonard (Post 215519)
And all this time I thought you had a single engine boat...LOL:dance:

I do...I also have a nearly functional, single Lehman storage shed....:rofl:

Ski in NC 02-24-2014 11:24 AM

I've re-torqued one 120 Lehman to address a head gasket weep. Put torque wrench on and none moved. A bolt that has been in place for a long time will not move even if tension has degraded.

Next, I marked each bolt position, then one at a time took each out, cleaned bolt and hole threads, lubed, then installed and tightened to specified torque. The marks showed the new position was generally 45deg more rotation than as found. Gasket weep was cured.

I don't know the Ford well enough to recommend (or not recommend) a retorque. It is rare for diesels to have such a recommendation, and even more rare for it to be done.

Simply putting a torque wrench on it and going to spec torque will not do anything unless bolts are very loose. Bolt needs to be marked, loosened and retightened. Good idea to clean the threads too, as dirty or corroded threads will not convert torque (what is measured) to clamping force (what is wanted).

psneeld 02-24-2014 11:34 AM

Quote:

Originally Posted by Ski in NC (Post 215569)
I've re-torqued one 120 Lehman to address a head gasket weep. Put torque wrench on and none moved. A bolt that has been in place for a long time will not move even if tension has degraded.

Next, I marked each bolt position, then one at a time took each out, cleaned bolt and hole threads, lubed, then installed and tightened to specified torque. The marks showed the new position was generally 45deg more rotation than as found. Gasket weep was cured.

I don't know the Ford well enough to recommend (or not recommend) a retorque. It is rare for diesels to have such a recommendation, and even more rare for it to be done.

Simply putting a torque wrench on it and going to spec torque will not do anything unless bolts are very loose. Bolt needs to be marked, loosened and retightened. Good idea to clean the threads too, as dirty or corroded threads will not convert torque (what is measured) to clamping force (what is wanted).

Good advice...similar to what others have advised...

Fortunately I don't think I have a weep from the head gasket and if I do it is really small at this point...so I'm just keeping an eye on things till summer when I can decide whether to just keep monitoring or pull the head and replace the gasket and bolts with new.

RickB 02-24-2014 11:52 AM

Later model Ford manuals state that re-torquing is not required or recommended with the new style head gasket.

As far as lubricating the threads of head bolts ... that is almost guaranteed to to start another anchor thread. Unless the manual says to lubricate, and says what kind of lubricant to use, the amount of bolt stretch obtained with a lubricated thread may be far in excess of what is obtained with a dry thread.

If you reused your old bolts, the reason you got another 45 degrees is because they have already stretched, perhaps beyond their elastic limit. I would not trust them, particularly after being lubed.

But, not knowing the bolt or the specific engine serial and type of head gasket, my concern is purely opinion ... informed opinion but in this particular forum that may not be good enough. Caveat torquer.


All times are GMT -5. The time now is 07:14 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012