Ford Lehman hours

[Larry M]

1600 to 1800 rpms based on sea state.

 

[bfloyd4445]

1600 to 1800 rpms based on sea state.

Thanks. The reason for the question was i read at Bomac's website that they recomend cruising be done at 2000 to 2200 rpm which seemed high from what forum posters had indicated.
I'd like to see a torq curve on this engine

They also recomend replaceing the transmission oil cooler every two three years and to change the heat exchanger every five years. Do you do that? That should be a question for another thread huh?

 

[Larry M]

UOTE=Floyd;126553]Thanks. The reason for the question was i read at Bomac's website that they recommend cruising be done at 2000 to 2200 rpm which seemed high from what forum posters had indicated.
I'd like to see a torq curve on this engine

They also recommend replacing the transmission oil cooler every two three years and to change the heat exchanger every five years. Do you do that? That should be a question for another thread huh?[/QUOTE]

Floyd: Pretty much all the routine maintenance we do is based on hours not time. 2000 to 2200 rpms for cruising? What's the link for Bomac that has their recommendations?

 

[Marin]

They also recomend replaceing the transmission oil cooler every two three years and to change the heat exchanger every five years. Do you do that? That should be a question for another thread huh?

The rpm band that is most suitable for the Dorset engine, according to people we know in the UK who spent a good part of their career servicing, repairing, and overhauling them is 1500-1800. This is why the engine was such a miserable failure as a truck engine. High rpm and constantly changing rpm under high loads killed it fast. And it's why the engine proved so good in relatively low load, constant rpm service like generators, cranes, pumps, and combines.

If you use the cupro-nickel oil and transmission heat exchangers, American Diesel recommends these be changed every 2,000 hours IIRC. The main heat exchanger should go a long, long time, at least if it's cupro nickel.

The main heat exchangers (curpro nickel) on our engines are the ones the engines were fitted with in 1973. The oil and transmission exchangers were all replaced by us during the first few years we had the boat.

 

[bfloyd4445]

UOTE=Floyd;126553]Thanks. The reason for the question was i read at Bomac's website that they recommend cruising be done at 2000 to 2200 rpm which seemed high from what forum posters had indicated.
I'd like to see a torq curve on this engine

They also recommend replacing the transmission oil cooler every two three years and to change the heat exchanger every five years. Do you do that? That should be a question for another thread huh?

Floyd: Pretty much all the routine maintenance we do is based on hours not time. 2000 to 2200 rpms for cruising? What's the link for Bomac that has their recommendations?[/QUOTE]>>>

In the owners manual is lists the max rpm as 2500
Lehman 120 Operators Manual - Operation & Maintenance

Bomac's LF page
Bomac Marine- Ford Lehman Engines Parts, Remanufacture and Service

I can't find where i read 2000-2200 yesterday

another poster mentioned his engine gets hot at 2000rpm and the manual says thats caused by the wrong prop

Britt

 

[SomeSailor]

We cruise mostly at 1750-1850 range. Certainly nothing over 2000 for more than a few minutes to clear things out.

 

[Larry M]

Floyd: Pretty much all the routine maintenance we do is based on hours not time. 2000 to 2200 rpms for cruising? What's the link for Bomac that has their recommendations?

>>>

In the owners manual is lists the max rpm as 2500
Lehman 120 Operators Manual - Operation & Maintenance

We have the SP135 and WOT loaded is also 2500 rpms

Bomac's LF page
Bomac Marine- Ford Lehman Engines Parts, Remanufacture and Service

I have that link. BOMAC has given us good service in the past and they answer their emails.

I can't find where i read 2000-2200 yesterday


another poster mentioned his engine gets hot at 2000rpm and the manual says thats caused by the wrong prop

The wrong prop, could be but it could also be a cooling system issue.

Britt[/QUOTE]

Running at 2200 rpms gets us hull speed (~8.4 knots) plus we are burning about twice the fuel if we run at 1700 rpms/~7 knots. I think you'll find with most FL's, either the 120 or 135s, the operators run between 1600 - 1850 rpms.

 

[bfloyd4445]

>>>

Britt

Running at 2200 rpms gets us hull speed (~8.4 knots) plus we are burning about twice the fuel if we run at 1700 rpms/~7 knots. I think you'll find with most FL's, either the 120 or 135s, the operators run between 1600 - 1850 rpms.[/QUOTE]

1.4knt increase dosent seem worth the effort to me and if you were trying to outrun a storm its not likely to make a diference

Thats what i had thought untill i read the 2-2200 as cruiseing rpm. My old Ford tractor is set at max 2000 and 1650 to 1800 is the recomended working rpm which makes sense.

The FL owners manual lists peak torq of 280 at 1600 and its been my experiance engines seem to rum very eficient at around this rpm.

But thanks for the info. I am learning lots about these engines and so far i havent seen any negatives with them

 

[bfloyd4445]

We cruise mostly at 1750-1850 range. Certainly nothing over 2000 for more than a few minutes to clear things out.

do you ever use a fuel additive? I always use them in all my engines since they went to that new formulated diesel fuel. Engines run very clean with one of these aditives and they keep the upper valve train, injectors and pump better lubricated. One of the problems with the new fuel was that it didnt lubricate as well as the old disel fuel did causing wear in the engine, pump, injectors

 

[Rusty]

We have about 5,800 hours on our engines. We run about 1600-1650 rpm. That's good for 8-8.3 knots. The previous owners had most of the exhaust system replaced. We've not done any significant work on the engines. Regular maintenance and oil changes. No problems so far.

We have been using ValvTect fuel for the last couple of years and have not been using additional additives.

 

[LA Wannabe]

I'm gonna have that done. The boat went on a trip to Catalina Island Sunday and is expected back tueday. The sticker on the oil filter shows it haveing been changed in november of 12. There are detailed records on this boat going back to 1999 and before that it only had one owner which is documented.
A posting in the simgle vs. twins thread got me thinking about the real life of one of these engines. I have a 1975 ford tractor with a similiar engine in it that i drove for 1/4 mile with no oil in it five years ago cause i changed the oil and my neighbor distracted me before i tightened the drain plug and it fell out. I was out brush hogging when i noticed the oil light so i drove back to the farm rthen discovered no plug. Well the tractor runs as good as ever still burns leaks not a drop and no smoke. Its the only tractor i have so it gets quite a bit of use.
I think if the Lehman is built like my tractor it will live a long long time.
Thanks for the information

Britt

In regards to the 1975 Ford tractor incident'
LOL, now that's testament with a bit of "been there, done that" and "how do ya like me now" attitude! I love it!
Thanks Britt!

 

[Andy G]

A slight thread hijack. What's the theory behind opening up the engine to full revs every now and again. My original operating manual notes that at high revs the engine has a tendency to blow blue smoke, unburned diesel.I can't see how that would clear the tubes so to speak. There again I am no mechanic.

 

[bfloyd4445]

In regards to the 1975 Ford tractor incident'
LOL, now that's testament with a bit of "been there, done that" and "how do ya like me now" attitude! I love it!
Thanks Britt!

your wlcome and thanks.
But aint nuttin but a true story. I am one of those guys that has to have everything perfect and has little tolerence for the, 'thats good enough" attitude. But the truth is we all make mistakes like with my poor old tractor and thats what a good engineer designs into his creations. He knows people screw up so he designs a widget that will compensate for those screw ups as much as possible. However, i wish to make it clear that this does not include over building. Over built referrs to a widget that is made much stronger than meeded just to be sure resulting in higher intial cost. That my friend is poor engineering resulting in a clunker. The FL has not proven to be a clunker like the indian sqaure four, etc. but a solid eficient power system.
there is so much out there that is simply produced to get your $$$ with no thought to longevity that one can't help but appreciate widgets like these FL-D power systems.

 

[bfloyd4445]

A slight thread hijack. What's the theory behind opening up the engine to full revs every now and again. My original operating manual notes that at high revs the engine has a tendency to blow blue smoke, unburned diesel.I can't see how that would clear the tubes so to speak. There again I am no mechanic.

Black smoke is unburned diesel fuel blue smoke is motor oil i believe. Anyone know for sure?

 

[Marin]

Black smoke is unburned diesel fuel blue smoke is motor oil i believe. Anyone know for sure?

That is generally correct although I don't think the black smoke is actually unburned fuel. I think it is the result of poor combustion due to too rich a mixture/too much fuel. So perhaps "poorly burned fuel" is a better discription. Rick B could answer this more accurately.

 

[bfloyd4445]

That is generally correct although I don't think the black smoke is actually unburned fuel. I think it is the result of poor combustion due to too rich a mixture/too much fuel. So perhaps "poorly burned fuel" is a better discription. Rick B could answer this more accurately.

Poor combustion results from low compression or lack of air or to much fuel in the mixture. To much air dosent result in black smoke but to much fuel does. If the fuel is burnt then the smoke is light colored not black so black smoke must be wasted fuel, hench unburned fuel.

 

[Marin]

If it was actually unburned fuel it wouldn't be smoke. It would be fuel.

When an old-generation diesel like the FL120 is started cold, the temperature in the combustion chambers is too low to properly ignite all the fuel that's fed into them. So the unburned fuel goes out the exhaust as just that--- unburned fuel--- and it makes a sheen on the water behind the boat. As you know fuel and oil are like blood--- it doesn't take much to look like a lot. So the sheen can be pretty big back there, particulary in the winter.

Once the combustion cylinder temperatures start coming up the combustion becomes more even and all the fuel injected into the cylinder is ignited. At this point unburned fuel is no longer expelled from the cylinders to go out with the exhaust and the sheen goes away.

That's a whole different deal than black smoke. To my way of thinking you don't get smoke unless you burn something. The fact that the smoke is black means the fuel is getting burned, but not efficiently.

Again, I'm not an expert on this so if I'm off base perhaps someone who is like Rick or Tom (Sunchaser) can correct me.

 

[bfloyd4445]

If it was actually unburned fuel it wouldn't be smoke. It would be fuel.

When an old-generation diesel like the FL120 is started cold, the temperature in the combustion chambers is too low to properly ignite all the fuel that's fed into them. So the unburned fuel goes out the exhaust as just that--- unburned fuel--- and it makes a sheen on the water behind the boat. As you know fuel and oil are like blood--- it doesn't take much to look like a lot. So the sheen can be pretty big back there, particulary in the winter.

Once the combustion cylinder temperatures start coming up the combustion becomes more even and all the fuel injected into the cylinder is ignited. At this point unburned fuel is no longer expelled from the cylinders to go out with the exhaust and the sheen goes away.

That's a whole different deal than black smoke. To my way of thinking you don't get smoke unless you burn something. The fact that the smoke is black means the fuel is getting burned, but not efficiently.

Again, I'm not an expert on this so if I'm off base perhaps someone who is like Rick or Tom (Sunchaser) can correct me.

most people consider smoke as a discoloration of the air by some foreign substance be it vaporized diesel fuel or wood products. Smoke is a collection of tiny solid, liquid and gas particles like vaporized diesel fuel caused by incomplete combustion.

 

[bfloyd4445]

A slight thread hijack. What's the theory behind opening up the engine to full revs every now and again. My original operating manual notes that at high revs the engine has a tendency to blow blue smoke, unburned diesel.I can't see how that would clear the tubes so to speak. There again I am no mechanic.

I think the idea is that at high rpm the carbon deposits don't have time to cool so they get hotter and hotter till they vaporize and cause blue smoke. I am a firm believer in fuel additives as a result of years of messing with engines. Some are gimmicks but some do improve lubricity of fuel and remove engine deposits. With modern reformulated D fuel i religiously use affitives, PS from Napa or Amzoil's additi8ve. There is a lab report posted at powerstroke.org listing several of them and what the test results were for each. The bearing scour results were an eye opener.

 

[Dave_E]

Old thread, let’s update it. 1977 (43 years old) with 4500 hours. Smoky startup and goes away after warmed up. 1800rpm... runs all day like a kitten.

 

[FF]

Gas or diesel the fuel must be vaporized to burn , it enters the combustion chamber only atomized.

If atomized fuel is subject to combustion , it becomes Buckey Balls.

These, carbon balls float on the surface. of water.

 

[diver dave]

Gas or diesel the fuel must be vaporized to burn , it enters the combustion chamber only atomized.

If atomized fuel is subject to combustion , it becomes Buckey Balls.

These, carbon balls float on the surface. of water.

Yes, thus the inefficient burning of a cold carbed motor. I think a hot intake manifold at least helps further atomization from that drippy idle jet.

 

[Choices]

92, roughly 6000 hrs. Zero problems.