Injectors on Ford Lehman 120 replacement

[AnnapolisJim]

How difficult is it to remove and install injectors in a Ford Lehman 120 engine? I would like to remove mine and have them cleaned/adjusted at a local injector shop. Also after they are installed, how do you bleed the fuel lines at the injector?

 

[Marin]

While I've not done it it's pretty easy. I believe there have been discussions about this on the forum in the past so a search of the archives should get you these discussions.

Whether or not you need to bleed the injectors seems to depend on the disposition of your engine. We never have to bleed our injectors after a fuel filter change on our two FL120s. We bleed the two filters on the rear of the engine and the injection pump but we've never bled the injectors themselves. The engines always start right up.

However, there have been folks on the Grand Banks owners forum who say they need to bleed their injectors as well, to get their FL120(s) to start.

Don't know how readable this is but here is the section from the FL120 operator's manual on how to remove the injectors. Surprisingly, the Ford shop manual for this engine doesn't describe removing the injectors, at least not anywhere I could find. It just says to do it in those operations where it's necessary. I guess it assumes the shop people all know how to do it.

 

[AnnapolisJim]

Marin--Many thanks for the info. I have the manual and, as you point out, it does not look too difficult to do. My engines have approx 2500 hrs and someone said I should have the injectors rebuilt/replaced. But both engines run fine besides a little smoke when I start them cold. Do I fix them if they are not broken? Decisions Decisions.

Many thanks.

 

[Capt.Bill11]

In most cases redoing the injectors does little to help with the smoking on a Lehman. Especially if it's running well otherwise.

 

[Marin]

If an FL120 doesn't smoke (blue) on cold start startup there's something wrong with it. It's the nature of the beast.

If the smoke doesn't go away after a few minutes as the engine warms up and finishes burning off the lube oil that's seeped down past the valve stems while it's been sitting, there is also something wrong with it.

 

[Capt.Bill11]

If an FL120 doesn't smoke (blue) on cold start startup there's something wrong with it. It's the nature of the beast.

If the smoke doesn't go away after a few minutes as the engine warms up and finishes burning off the lube oil that's seeped down past the valve stems while it's been sitting, there is also something wrong with it.

Perhaps. But at least with a Lehman you have a couple thousand hours or more to figure it out. :lol:

 

[Xsbank]

Expensive repair if it ain't broken. I mailed mine to a fine gent in Wisconsin who sent me a set of rebuilt ones for $25 each. That was worth doing but he's retired now. Little difference except a slightly smoother idle. Not for $100 a pop, or whatever it is now, thank you.

 

[av8r]

It is easy to remove and replace the injectors, and you do not need to bleed them if your batteries are in good shape. 30-45 seconds of cranking at half throttle should be fine.
Some of us think it is faster to remove the rocker shaft to remove the injectors (me) and some of us think it is a waste of time to remove the rockers (xsbank).
Adjusting the valves had more effect on smoothing out the idle than changing the injectors did, and resetting the injector pump timing to factory specs smoothed things out even more.

 

[AnnapolisJim]

Thanks to all of you for your sound advice. This is my first time using this forum and it is great getting your responses. My vote it to leave the injectors alone until they really need attention.

Thanks to all.

 

[RT Firefly]

Greetings,
Mr. AJ. I may have missed you. If so, welcome aboard. I think your final post (#9 above) is a wise decision OR if it ain't broke, fix it until it is...

 

[kchace]

There are some engines that need (and some manuals specify) injector service at regular intervals, Lehmans are not one of those. In my opinion some mechanics who are not particularly familiar with Lehmans may needlessly recommend injector work. The bottom line is that absent an obvious injector type issue, a Lehman can go thousands of hours without any need for injector service.

Ken

 

[Biwitched]

Thanks for everyone’s help on this injector or fuel problem we appreciate it

 

[FF]

Modern chemistry is cheap and might be a help.

My injector guy sez its worth a shot to clean injectors in place .

An hour of running is usually enough to realize any difference , if there will be a difference.


Stanadyne Performance Formula Diesel Fuel Injector Cleaner ...

 

[Pete Meisinger]

Not at all a difficult job. The most difficult part is getting the bleed off/overflow tube out of the engine. It MUST come out, it is a twisted tube with a hollow nut at each injector. Just kind of a pain to get out and replace.

The injectors themselves come out pretty easy. There is a pry bar type of tool which helps but I didn't use one. Be certain you get the "crush" washers out of the holes and be certain to install new ones. Plug the empty holes with a rag as you work on the others, keeps dirt and old crushed washers out.

The valve cover gasket is reusable unless it is broken or really sad looking.

Rebuilding will run you about a hundred each. There are no new ones available. Have your shop guy save you the worst of the mechanical injector part. They are fun to play with and makes it easy to see why the engine was misbehaving.

Plan on a couple hours out and a couple back in. Not a bad idea to adjust the valves while the injectors are out. No compression makes turning the engine very easy.

DO It, don't be scared

pete

 

[catalinajack]

If you decide to adjust the valves, a good idea, on a FL120 the heads must be retorqued first. If the gaskets are trashed, consider installing studs in the block rather than using those 1/2- inch slotted bolts to tighten down the valve cover. Doing so will allow you to silicone glue the gasket to the valve cover and then slip it over the studs. Then tighten the nuts. That way there is no risk of the new gasket slipping off the mating surface. You can get the studs from McMaster-Carr. If anyone is interested I can look up the part number from my order.

Not at all a difficult job. The most difficult part is getting the bleed off/overflow tube out of the engine. It MUST come out, it is a twisted tube with a hollow nut at each injector. Just kind of a pain to get out and replace.

The injectors themselves come out pretty easy. There is a pry bar type of tool which helps but I didn't use one. Be certain you get the "crush" washers out of the holes and be certain to install new ones. Plug the empty holes with a rag as you work on the others, keeps dirt and old crushed washers out.

The valve cover gasket is reusable unless it is broken or really sad looking.

Rebuilding will run you about a hundred each. There are no new ones available. Have your shop guy save you the worst of the mechanical injector part. They are fun to play with and makes it easy to see why the engine was misbehaving.

Plan on a couple hours out and a couple back in. Not a bad idea to adjust the valves while the injectors are out. No compression makes turning the engine very easy.

DO It, don't be scared

pete

 

[jgtrucking]

If you decide to adjust the valves, a good idea, on a FL120 the heads must be retorqued first. If the gaskets are trashed, consider installing studs in the block rather than using those 1/2- inch slotted bolts to tighten down the valve cover. Doing so will allow you to silicone glue the gasket to the valve cover and then slip it over the studs. Then tighten the nuts. That way there is no risk of the new gasket slipping off the mating surface. You can get the studs from McMaster-Carr. If anyone is interested I can look up the part number from my order.

I have adjusted many valves, but this spring will be the first on my fl's. I have never seen anything about retorquing head bolts, on an in-service engine. Nor do i remember it from the scan of the procedure about a year ago. I do know it says to do it at operating temp, but ive been assured you can let her cool a bit more for mechanic's comfort without hurting the process.
That said, i am curious where the re-torquing of the head bolts comes from? I don't know everything, so i might well have missed this...

 

[psneeld]

I have adjusted many valves, but this spring will be the first on my fl's. I have never seen anything about retorquing head bolts, on an in-service engine. Nor do i remember it from the scan of the procedure about a year ago. I do know it says to do it at operating temp, but ive been assured you can let her cool a bit more for mechanic's comfort without hurting the process.
That said, i am curious where the re-torquing of the head bolts comes from? I don't know everything, so i might well have missed this...

There is advice all over the map about servicing Lehmans. Some believe what one man said (even though some of it changed over the years even from his mouth) is gospel, even if it doesn't follow conventional wisdom. Some follow 1950's oil recommendations despite info suggesting newer oils may have or not.....have beneficial properties.

I think retorqing the head is important at different phases of the engine life and maintenance. But every time you check or adjust the valves?

If I worried about head bolt torque that often, I would be looking for alternatives to those bolts or a new engine. Valves being out of adjustment may be for all sorts of reasons.

Some people apply rules of thumb without looking at the big picture of how things out of metal either work or don't.

 

[SteveK]

How difficult is it to remove and install injectors in a Ford Lehman 120 engine? I would like to remove mine and have them cleaned/adjusted at a local injector shop. Also after they are installed, how do you bleed the fuel lines at the injector?

In the library (top right of web page) I have uploaded a service manual and now an operators manual (once upload is approved). The job is easy, just takes longer to do than expected first time, plan on the day.

 

[catalinajack]

psneeld, yes, there are all kinds of advice on servicing Lehman diesels. I got mine from Brian at American Diesel. He recommends adjusting the valves every 1,000 hours. He also counsels that retourquing the heads should be done before adjusting the valves on a FL120. However, on a FL135, the heads do not get touched, different type of head bolt. If in doubt call Brian. I did.

As for 1950's oil recommendations, now that does not make any sense. Oil formulations have changed dramatically in the last 60 years. However, the engines haven't changed so the advice on retourquing the heads remains as valid today as it was yesterday.

There is advice all over the map about servicing Lehmans. Some believe what one man said (even though some of it changed over the years even from his mouth) is gospel, even if it doesn't follow conventional wisdom. Some follow 1950's oil recommendations despite info suggesting newer oils may have or not.....have beneficial properties.

I think retorqing the head is important at different phases of the engine life and maintenance. But every time you check or adjust the valves?

If I worried about head bolt torque that often, I would be looking for alternatives to those bolts or a new engine. Valves being out of adjustment may be for all sorts of reasons.

Some people apply rules of thumb without looking at the big picture of how things out of metal either work or don't.

 

[Comodave]

I took a seminar from Bob Smith. We did the valves but did not retorque the head.

 

[jgtrucking]

psneeld, yes, there are all kinds of advice on servicing Lehman diesels. I got mine from Brian at American Diesel. He recommends adjusting the valves every 1,000 hours. He also counsels that retourquing the heads should be done before adjusting the valves on a FL120. However, on a FL135, the heads do not get touched, different type of head bolt. If in doubt call Brian. I did.

As for 1950's oil recommendations, now that does not make any sense. Oil formulations have changed dramatically in the last 60 years. However, the engines haven't changed so the advice on retourquing the heads remains as valid today as it was yesterday.

Yea i'll call him next week, need a couple things anyway. Maybe these things have a history of backing off? Flys in the face of years with on-highway diesel service. And if it is the case to do it, maybe related to the head gasket material. I admit i currious why Bob smith, the guy who marinized the thing would not say to do it but now Brian does. But there is always something to learn

 

[SteveK]

I took a seminar from Bob Smith. We did the valves but did not retorque the head.

Seems even the Smiths have different opinions.
Having torqued the heads before valve adjust there was room to so and not all werevthe same. Now done no need gor 1000 hours.

 

[Comodave]

Ok, first given is that I am not a mechanic, but I sort of remember that torquing the head bolts on a 120 causes the bolts to stretch so they have to be replaced each time. I think that was what Bob said in the seminar. But bear in mind that was on a 120 and I don’t have 120s so maybe I wasn’t paying complete attention about torquing the head on 120s.

 

[SteveK]

Dave many schools of thought. No worries.

 

[Comodave]

Dave many schools of thought. No worries.

I didn’t think anything bad, just trying to remember what Bob said. It has been 5+ years since I took the seminar and sometimes CRS disease kicks in...

 

[SteveK]

I didn’t think anything bad, just trying to remember what Bob said. It has been 5+ years since I took the seminar and sometimes CRS disease kicks in...

Crap. I must have CRS cause i cannot remember what it means.

 

[Comodave]

Can’t remember stuff or some other word...

 

[catalinajack]

Dave, that does not mean that it shouldn't be done at the recommended intervals. It only means that it wasn't part of the seminar. There's only so much that can be done in a seminar in the allotted time. Please, folks, don't take my word for it, call Brian at American Diesel. If anyone does so, kindly report back. Or, don't do the heads and risk warpage. The fact is I consulted with Brian in person at his place of business in Kilmarnock, VA when picking up a new pair of exhaust elbows. He specifically mentioned head warpage. By the way, retorquing the heads is not difficult. You will already have the valve cover off to adjust the valves so it's just a simple matter of backing off each head bolt and tightening to spec using a good torque wrench. Takes maybe one half hour. Just follow the sequence in the manual.

I took a seminar from Bob Smith. We did the valves but did not retorque the head.

 

[BruceK]

My 120s were retorqued by my mechanic,around 2200 hours, he said they came up quite a bit. Studs were not replaced, tightening pattern was consulted,all was well afterwards. Pretty sure it`s 135s you must not retorque.

 

[Comodave]

Dave, that does not mean that it shouldn't be done at the recommended intervals. It only means that it wasn't part of the seminar. There's only so much that can be done in a seminar in the allotted time. Please, folks, don't take my word for it, call Brian at American Diesel. If anyone does so, kindly report back. Or, don't do the heads and risk warpage. The fact is I consulted with Brian in person at his place of business in Kilmarnock, VA when picking up a new pair of exhaust elbows. He specifically mentioned head warpage. By the way, retorquing the heads is not difficult. You will already have the valve cover off to adjust the valves so it's just a simple matter of backing off each head bolt and tightening to spec using a good torque wrench. Takes maybe one half hour. Just follow the sequence in the manual.

I didn’t say that it was not done on account of lack of time. Bob never said to retorque heads at that time. Maybe he felt it wasn’t needed, who knows. If Brian says to do it then I would do it. But I am pretty sure Bob said to replace the bolts and not to retorque the old ones.