adjusting valves on Lehman 120

[KDA]

I have a Lehman 120 and I would like to check the valve lash. I have the manual and I have searched the topic on TF. I took the rocker cover off the engine but I couldn't figure out which was the intake valve and which was the exhaust valve. I assume that the arrangement is the same for all 6 cylinders.
Suggestions?

 

[Rob]

I suggest that you contact Brian @ American Diesel. I’m sure that he will give you the CORRECT information in so far as identifying the valves and the recommended tolerances. It’s not a hard job to preform, and hopefully you’ll like the sound of the newly adjusted valves.

 

[Larry M]

Here’s a how to adjust the valves on a Ford Lehman 6 cylinder SP135.

https://www.trawlerforum.com/forums/s6/lehman-sp135-adjusting-engine-valves-3291.html

 

[Pete Meisinger]

pm me, I can send you a copy of the appropriate pages from the Manual. It is really pretty simple both to understand and to accomplish. It is nice to have a book in front of you while you do it.

pete

 

[catalinajack]

I have a Lehman 120 and I would like to check the valve lash. I have the manual and I have searched the topic on TF. I took the rocker cover off the engine but I couldn't figure out which was the intake valve and which was the exhaust valve. I assume that the arrangement is the same for all 6 cylinders.
Suggestions?

I just went through this, that is, even though having the manual I wasn't able to be certain of the procedure. I am certain now. I put together a paper on how to do it. Once you do it you will wonder how it was so daunting beforehand. Once caution: per Brian Smith, the heads must be re-retorqued before adjusting the valves on a FL120. On a FL135, just the opposite, do not touch the heads. The reason is the type of head bolts that were used. See below. Note that the rocker assembly must be loosened to get at one of the head bolts. One other piece of advice: do not use a cheap torque wrench. A wrench with a flexing needle is what I am talking about.

Valve Setting Procedure for Ford Lehman 120/135

Intake Valve Lash (120) - .012
Exhaust Valve Lash (120) - .015

Intake Valve Lash (135) - .015
Exhaust Valve Lash (135) - .015

Valve Sequence from Front of Motor:

Valve 1 – Exhaust
Valve 2 – Intake
Valve 3 – Exhaust
Valve 4 – Intake
Valve 5 – Intake
Valve 6 – Exhaust
Valve 7 – Exhaust
Valve 8 – Intake
Valve 9 – Intake
Valve 10 – Exhaust
Valve 11 – Intake
Valve 12 – Exhaust

To Set Valves:

Rock Cylinder 6, Set Cylinder 1
Rock Cylinder 2, Set Cylinder 5
Rock Cylinder 4, Set Cylinder 3
Rock Cylinder 1, Set Cylinder 6
Rock Cylinder 5, Set Cylinder 2
Rock Cylinder 3, Set Cylinder 4

Rocking Procedure:

Using a breaker bar and a 15/16 socket installed on the center bolt of the flywheel pulley, rotate the engine clockwise until the No.6 cylinder exhaust valve fully opens and the intake valve begins to close. The springs of both are at their highest at this point. Rock in both directions until both are not moving up or down. Then set the intake and exhaust valve lash on Cylinder No. 1.

Then rock 2, 4, 1, 5, and 3 in order. This will happen as the engine is continued to be rotated clockwise.

Note 1: The cylinder head on a Lehman 120 must be re-torqued (110 ft.-pounds) before setting the valve lash. On a Lehman 135 the head must NOT be re-torqued.

Note 2: The rocker arm assembly must be loosened and the last rocker retainer slid off the tube in order to access head bolt No. 22. The fuel return line is in the way.

 

[Nomad Willy]

Can the FL be adjusted hot?

 

[KDA]

Catalina Jack, thank you for your reply. The order of the valves from front to back was what I was looking for. It appears that the first 3 cylinders is a mirror image of the last 3.
Since I am going to use your information to adjust the valves on my engine, could I get you to confirm the order of the valves again, from front to back?

 

[catalinajack]

The numbering if the valves start from cylinder #1 at the front of the engine. Cylinder #6 is at the exhaust elbow end.

Catalina Jack, thank you for your reply. The order of the valves from front to back was what I was looking for. It appears that the first 3 cylinders is a mirror image of the last 3.
Since I am going to use your information to adjust the valves on my engine, could I get you to confirm the order of the valves again, from front to back?

 

[KDA]

Catalina Jack, thank you for your help. I will take a crack at this tomorrow

 

[catalinajack]

I adjusted warm, not cold, not hot. All of my valves except one had lash of less than .005. Yet, I ran them that way for 5,500 miles doing the Great Loop. The engines ran just fine. My point is that, in my opinion, these engines are a bit forgiving so I do not angst over the temp at which the valves are adjusted. Hence, warm, splitting the distance. And, Brian Smith was emphatic about re-torquing the heads. He recommends the heads and valves every 500 hours. That seems a bit frequent but after having done it once, I will probably follow his 500 hour advice. It really is that easy. You might want to consider replacing the cork valve cover gaskets if they are old and brittle. Now that job is truly a pain. If the old gaskets were glued in place you will need a powered wire weel to clean the mating surfaces down to bare metal. I used an air-powered cut-off tool. Good luck.

Can the FL be adjusted hot?

 

[syjos]

Make sure the stop solenoid/fuel valve is closed and secured before turning the engine.

 

[Chuck16]

The information posted here (above) for the Ford Lehman 120 is incorrect in that it is backwards. The lash is .012 for exhaust and .015 for the intake. I know it seems backwards but this is verified with Brian at American Diesel.

Chuck

 

[psneeld]

The information posted here (above) for the Ford Lehman 120 is incorrect in that it is backwards. The lash is .012 for exhaust and .015 for the intake. I know it seems backwards but this is verified with Brian at American Diesel.

Chuck

I too believe that is correct...see the "sticky" thread in the power systems section discussing valves... about what is correct and why even though it seems backwards...it was confirmed many times from different sources.