Starting Battery Size (Ford Lehman 120)

[Bob Cofer]

That is correct. The boat was originally equipped with a "charge divider" which, I assume, was a couple of diodes through which the alternator was connected to both batteries at the selector switch. And then the batteries were combined when the ignition button was pressed for starting. This "charge divider" was removed by PO for some reason and the alternator was only connected to one bank. By re-configuring I hope to get twice the house bank in the same foot print and an isolated starter battery. I will also fix the problem of the 2nd bank not being charged by the alternator.

Now I see the reason. Gotta love those PO’s.

 

[SailorGoneBad]

That is a very interesting comment. Part of my battery re-configuration project is to replace about 44 feet of battery cable. I'll be using 1/0 boat cable replacing original 1AWG welding wire.

 

[SailorGoneBad]

Did not mean to imply anything nefarious about my PO. He was a good custodian of this old boat. I suspect the old diodes failed and wiring around the worked well enough for his purposes. Dedicated and relatively cheap stater battery makes sense to me as it frees up both 4Ds (soon to be 4 Trojan 6 volt gulf cart batteries) for the house.

This is still not a huge bank but, at least for now, I only have a 53 amp alternator to charge it back up anyway.

 

[Westiculo]

Our boat came with an 8D dedicated to the genset only (!?!) and four 8Ds that served as both housebank and main SP135 starters. All diesels—genset and Lehmans—now start with a single Group 31 AGM. It’s topped off via a Balmar Duo Charge. Should it crap out, a flip of battery switch ties in the 1,250-AH housebank. So far, not a hiccup with this arrangement.

I have the same setup. 1x G31 for all starting jobs and a good size house bank to parallel as necessary. Not overdone, not underdone, juuuuust right.

 

[SeaBreeze]

I just went through a similar exercise a few weeks ago on our Marine Trader 34 with a FL 120. When we bought the boat it came with 2 8D batteries. I dreaded getting those beasts out of the subfloor engine room but bit the bullet. I used a block and tackle to get them up to floor level. To ensure I would never have to do that again I replaced the 8D's with 4 Duracell 6v 215 ah golf cart batteries from Sam's Club. Our boat doesn't have a dedicated start battery and has worked well that way. Wired the four batteries in series and parallel yielding a 12v 430ah bank. The bank can be split with a selector switch. We also have a G31 dedicated battery for the genny. The genny battery can be switched to start the engine in an emergency. This set up is working very well. If I find I need more amp hours, I'll add two more 6v batteries. I got the 4 GC batteries on sale for $70 each.

 

[Pete Meisinger]

A group 27 will work but most use a single grp 31. That is if it is truly a dedicated start battery. If it is called upon for house duties you need several deep cycle batteries.

If you don't have an isolator switch or a crossover switch to give the starting battery some help if you have an issue such as running out of fuel and needing the starter to prime the injector pump then you should carry jumper cables.

The secondary filters and the injector pump can both be primed with the lift pump manually. Since the Racors are on the suction end you will need to prime them with a separate priming pump or other fuel source if they are run dry.

pete

 

[jleonard]

I had a single group 31 1000 cca in my old Dodge/Cummins pickup.
I had the truck 10 years as my commuter and it started every day even in below zero weather.
I would occasionally start it on below zero days without using the grid heater. The Cummins didn’t like that much but there was more than enough battery power.

 

[BruceK]

"if they are not dead from running the refrigerator"

Ser 31 are great start batts but die rapidly when run flat.

True deep cycle batts hate to be run flat , but survive the abuse a bit better.

If just 2 batts are for combined house and start work, 2 deep cycle 8D will have enough plate area to start most engines even down below 50% SOC.

Have you thought of installing a SOC meter ?

Not a bad idea.
When I first got the boat, at anchor I would set the battery switch to 1 or 2, keeping one fresh for starting. I ended up with one fairly dead batt, and decided it was better to draw on both and not overdraw one.
I keep an eye on other indicators, and never end up with overdrawn batts. The system seems less than ideal, but used carefully it works. If all goes south there`s the genset and its now dedicated battery, but that`s never happened since our first cruise with old batts. The PO had a fridge running on that batt,I soon terminated that.

 

[alormaria]

In the summer anything will start a 120 Lehman.

 

[syjos]

In the summer anything will start a 120 Lehman.

It's the winter starting where I need 2 group 31's for the Lehman. I keep the engine room at 50 degrees all winter but still takes longer to start.

I have a 200 pound flywheel on my Lehman and it takes a bit of cranking for it to pick up enough speed for it to start.

 

[dhays]

It's the winter starting where I need 2 group 31's for the Lehman. I keep the engine room at 50 degrees all winter but still takes longer to start.

I have a 200 pound flywheel on my Lehman and it takes a bit of cranking for it to pick up enough speed for it to start.

I'm surprised that even in winter it takes the two batteries, but I would say your experience would be good info for the OP.

 

[syjos]

I'm surprised that even in winter it takes the two batteries, but I would say your experience would be good info for the OP.

If I had the original 87 pound flywheel, 1 G31 starting battery would suffice.

Several years ago, Chevron stopped selling Delo 100 30 weight, which is the recommended oil for the L 120. I now use Delo 100 40 weight which does not help with starting in winter

The engine turns real slow at first and picks up speed after a couple revolutions until it starts.

I've thought of switching to the 87 pound flywheel but it entails a longer shaft or moving the engine rearward. The PO installed it thinking smoother engine. He would have saved a lot of time and money with better engine mounts. It's slightly smoother at idle but still needs to idle at 750 rpm.

When I replaced the motor mounts with softer mounts and installed a Federal Flexible Shaft Coupling, the 120's idle smoothed significantly. Still idle at 750 rpm.

 

[rslifkin]

Oil-wise, I'd suggest going to a 15W-40 or 10W-30 diesel oil. There's no good reason to run straight weight instead of a good multi grade at this point (possibly excepting in a Detroit). And it'll be much easier to start cold with the multi grade (plus easier on the engine as it'll build pressure faster).

 

[syjos]

Oil-wise, I'd suggest going to a 15W-40 or 10W-30 diesel oil. There's no good reason to run straight weight instead of a good multi grade at this point (possibly excepting in a Detroit). And it'll be much easier to start cold with the multi grade (plus easier on the engine as it'll build pressure faster).

Multi weight and detergent oils are not recommended for Lehman 120.

 

[rslifkin]

Anyone who says not to use a detergent oil in any engine is living in the 1930s. There is absolutely no reason to EVER use a non detergent oil in an engine with an even remotely modern lube system (as in pressurized with a filter). Non detergent oils just let junk build up everywhere instead of keeping it suspended so it can get filtered out.

And there were absolutely good reasons in the past for staying away from multi grade oils in a lot of engines. The viscosity improvers used would tend to shear, leaving the oil thinner than desired. The technology for those has come a long way, so it's much less of a concern than it used to be. Using a 15W-40 should give plenty of safety margin in an engine designed for a straight 30.

 

[syjos]

Anyone who says not to use a detergent oil in any engine is living in the 1930s. There is absolutely no reason to EVER use a non detergent oil in an engine with an even remotely modern lube system (as in pressurized with a filter). Non detergent oils just let junk build up everywhere instead of keeping it suspended so it can get filtered out.

And there were absolutely good reasons in the past for staying away from multi grade oils in a lot of engines. The viscosity improvers used would tend to shear, leaving the oil thinner than desired. The technology for those has come a long way, so it's much less of a concern than it used to be. Using a 15W-40 should give plenty of safety margin in an engine designed for a straight 30.

If that's true, why is non detergent oil still marketed?

A client poured Delo 400 multiweight into his Lehman 120 when he was unable to find Delo 100 nondetergent.

That summer, his engine developed oil leaks around the seals and a few gaskets.

He contacted AD and Bob Smith told him that seals and gaskets shrink with what is in detergent multigrade oils, causing leaks. Bob advised my client to switch back to Delo 100 30 weight immediately but said the leaks would take a while to stop.

It took 2 1/2 years for the seals to stop leaking and up to 3 years for some of the gaskets.

Detroit's and some Perkins suffer the same fate.

 

[rslifkin]

The leak thing with detergent vs non detergent can be a problem in an old engine. The detergent oil doesn't damage the seals, but if the seals are a bit worn, once all of the little bits of gunk get cleaned out, they'll leak (because the gunk was the only thing keeping the oil in). Personally, I'd say it's better to let the stuff get cleaned up and fix whatever leaks appear. Kinda like fixing a cooling system where the pressure cap has gone bad and isn't holding pressure. Once it's fixed, you're likely to find some "new" leaks that were previously masked by the lack of pressure.

And non detergent oil is still sold because it's cheap to make and there are some uses for it, they're just fairly limited at this point.

 

[psneeld]

from a later 1988 Ford Lehman operator's manual (edition 8) yes for 2720 models...

 

[syjos]

The 1978 120 Lehman manual recommends single weight oil API classification CC, CD or Series 3, all obsolete. For 32 to 90 degrees 30 weight. Over 90 degrees 40 weight.

 

[syjos]

The leak thing with detergent vs non detergent can be a problem in an old engine. The detergent oil doesn't damage the seals, but if the seals are a bit worn, once all of the little bits of gunk get cleaned out, they'll leak (because the gunk was the only thing keeping the oil in). Personally, I'd say it's better to let the stuff get cleaned up and fix whatever leaks appear. Kinda like fixing a cooling system where the pressure cap has gone bad and isn't holding pressure. Once it's fixed, you're likely to find some "new" leaks that were previously masked by the lack of pressure.

And non detergent oil is still sold because it's cheap to make and there are some uses for it, they're just fairly limited at this point.

PO used Delo 100 30 weight since the boat was new in 1976. I continued using the same when we bought Sandpiper in 2000 with 3,200 hours. Until Delo 100 30 weight was discontinued a few years ago. I've been using Delo 100 40 weight since with no issues other than slow cranking in winter. Currently at around 6,300 hours.

I do not wish to take a chance with a multi or detergent oil.

 

[dhays]

There was a thread on the use of single weight vs multi weight oils in Lehman engines here on TF a handful of years ago. That that are interested may want to look it up.

 

[syjos]

There was a thread on the use of single weight vs multi weight oils in Lehman engines here on TF a handful of years ago. That that are interested may want to look it up.

Thanks Dave,

I searched for it when the issue popped up on the post. No hits.

I follow the advice given to me by three individuals who assisted and educated me about older British diesel engines.

Bob Smith, no explanation required.

Norm Dribble the engine department supervisor at Doc Freemans. He was the PNW Lehman expert. He held sold out Lehman 120 classes twice a year for nearly 30 years until his death.

Jim Danielson the marine propulsion expert at Pacific Detroit Diesel in Seattle. Perkins marine engine was part of or distributed by Detroit Diesel in the 90's.

All three experts advised single weight, non detergent oil in older design Lehman Ford or Perkins diesel engines and certain Detroits. With the frequency of oil and filter changes on marine engines, using non detergent oils was not an issue.

 

[BruceK]

Multi weight and detergent oils are not recommended for Lehman 120.

Did they exist when the 120 first came along? I`ve been using 15-40 for 10 years with no apparent ill effects in either of 2 engines. Several mechanics have implicitly disagreed with the non recommendation.

 

[catalinajack]

Not recommended in a Lehman? By whom and why? Absolutely makes no sense. And please don't tell me Bob Smith. He was an engine guy, not a petroleum engineer.

Multi weight and detergent oils are not recommended for Lehman 120.

 

[psneeld]

At some point multi weights WERE recommended as OK for some Lehmans by the manufacturer....see post 48.


Not sure what made different models of the Lehmans that different from one another (same time frame) that multis were OK in some and not others.....


Other than the updated manuals ) ...of which there are many variations....


Even through the years Bob Smith's opinions changed, now his son also concedes different opinions for some things....Bomac who rebuilds Lehman says different things....etc...etc...


The best evidence is Lehman owners who have been doing things different from each other for decades. They seem to have the same results as the experts.... success despite the differences.



For the most part most of these "absolute musts" that so many TFer passionately post here...as long as some conditions are met, JUST DON'T MATTER....

 

[jleonard]

I use 15-40 in mine. After talking with Bob Smith for a while one time, he finally admitted that was ok.
I use that in my Westerbeke gen set also.

 

[rslifkin]

PO used Delo 100 30 weight since the boat was new in 1976. I continued using the same when we bought Sandpiper in 2000 with 3,200 hours. Until Delo 100 30 weight was discontinued a few years ago. I've been using Delo 100 40 weight since with no issues other than slow cranking in winter. Currently at around 6,300 hours.

I do not wish to take a chance with a multi or detergent oil.

With that many hours of non detergent, yes, I'd be a bit concerned about switching unless you wanted to drop the oil pan and pull the valve cover to clean things up first. That's a lot of potential crud to dislodge. And I'd also expect a lot of seals to need replacement.

 

[syjos]

With that many hours of non detergent, yes, I'd be a bit concerned about switching unless you wanted to drop the oil pan and pull the valve cover to clean things up first. That's a lot of potential crud to dislodge. And I'd also expect a lot of seals to need replacement.

Gotta stick with what's been working.

 

[rgano]

I have SP225s in my boat. It came with 2 4Ds for starting. It has built in fiberglass battery boxes so when I replaced them I stayed with the 4Ds just because it was easy. The group 31s should start a 120 easily. Personally I would go with 2 31s so as to have a backup if the battery shorts out or just dies. I would have them set up in 2 banks so that only one was online at a time and the other one as a offline spare.

What he said!

 

[OldDan1943]

Avalanche,
You actually need a refer in Alaska...

Reefer? Maybe a traveling salesman and it was on sale?

For my Cummins 380, Cummins manual recommends 15-40. Sounds like a plan to me.