BD240 pushrod/rocker adjuster interchange


IHC in the early to mid-fifties.

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Post Wed Jul 07, 2021 2:02 pm

BD240 pushrod/rocker adjuster interchange

The engine in my S120 (BD240 straight valve head) has been long overdue for a valve adjustment and I found some great forum threads covering the topic. I've been driving the truck a little more lately after finishing some front end repairs, but have noticed diminished power and a weak cylinder #4. A compression test yielded acceptable numbers, so last evening a friend and I pulled the valve cover to inspect and wound up adjusting valves. #4 exhaust rocker was WAY out of adjustment and shows signs of wear in the cup of the pushrod and the spherical end of the rocker adjuster.

I made the adjustment (0.025" hot) to all the valves and the misfire is gone, full power seems to be restored. However I know I need a pushrod and rocker adjuster soon. My dad has an IH 6cyl parts engine from a Farmall 706 gas tractor. Would anyone know if the valvetrain parts would interchange? Pulling a pushrod is no small task as all the cylinder head bolts must be removed to remove the rocker shaft.

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Post Wed Jul 07, 2021 2:28 pm

Re: BD240 pushrod/rocker adjuster interchange

You could try taking pictures of both rocker systems and compare. Maybe a simple tape-measure or better a Vernier caliper would be more accurate.
Removing the rockers is a quick and simple task. You could remove the rockers from the parts engine for a comparison. You might like to compare the push-rods, for length, from each engine.
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Post Wed Jul 07, 2021 3:37 pm

Re: BD240 pushrod/rocker adjuster interchange

Do you have a straight valve or tilt valve? Does your push rod #4 ? valve have a roll tater?
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Post Wed Jul 07, 2021 7:14 pm

Re: BD240 pushrod/rocker adjuster interchange

If you aren't in a rush to tear down the tractor, I can probably dig out the parts book for the 706 early next week and let you know if the part numbers for rockers are the same. My guess is that they are, but that's just a guess. With a straight valve BD, you might want to check the specs again for valve adjustment. The BD tilt valve engines had valve lash of .024-.026, engine hot and idling. The straight valve SD's however were .018 to .020. I think the straight valve setting would be the same for the SD's and early BD's, rather than the tilt valve spec.

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Post Wed Jul 07, 2021 8:49 pm

Re: BD240 pushrod/rocker adjuster interchange

Paul,
Good call on the lash spec. I definitely set it for a tilt valve head, not the straight valve.

My rocker arms actually look just fine, it's the adjuster and push rod that are damaged. I would guess that the adjusters are interchangeable from the 706 engine, just not sure about the push rods.

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Post Thu Jul 08, 2021 8:41 am

Deleted post , wrong size
Last edited by kevin on Sun Jul 11, 2021 7:49 am, edited 2 times in total.
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Post Thu Jul 08, 2021 12:05 pm

Re: BD240 pushrod/rocker adjuster interchange

you can pull a push rod without removing the rocker shaft,

you make sure valve is closed cam lobe is pointing down,

unscrew adjuster all the way and slide rocker over against locator spring,

push rod should come right out
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Post Sat Jul 10, 2021 5:22 pm

Re: BD240 pushrod/rocker adjuster interchange

I went to the LIBRARY section on this site, and went to the MT-97 parts catalog on John Hansen's page.

The rocker arm adjustment screw is part number 16067 DA.

Then I went to the CNH/CaseIH farm tractor parts lookup website. Went to the ENGINE section for the Farmall 460 gas engine.

The rocker arm adjustment screw is part number 16067 DA.

While I was there, I checked APPLICATIONS. This rocker arm adjustment screw is common to all the "letter-series" [A, B, C, H, and M] Farmall tractors as well. So it was used from 1939 until well into the 1970s, at the very least.

I'm gonna do the same search on the pushrod as well shortly.
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Post Sat Jul 10, 2021 6:01 pm

Re: BD240 pushrod/rocker adjuster interchange

The MT-97 shows the pushrod as IH part number 69733R11.

The ag engine doesn't cross over to this number, or vise-versa.

But I found a TON of specs on this part, under NSN 2805-00-374-9399:

Technical Data | NSN 2805-00-374-9399
Characteristic Specifications
MATERIAL STEEL
END HARDNESS RATING 57.0 ROCKWELL C MINIMUM AND 63.0 ROCKWELL C MAXIMUM
END CASEHARDENING INDICATOR CASEHARDENED
BODY OUTSIDE DIAMETER 0.375 INCHES NOMINAL
OVERALL LENGTH 11.969 INCHES NOMINAL
STYLE DESIGNATOR K6 SPHERICAL, UNDERCUT OPTIONAL FLAT FIRST END
CHAMFER ANGLE IN DEG K12 CUP W/SHOULDER AND CHAMFER SECOND END
SHOULDER LENGTH 77.5 SECOND END
CHAMFER LENGTH 0.063 INCHES NOMINAL SECOND END
UNDERCUT DIAMETER 0.281 INCHES NOMINAL SECOND END 0.365 INCHES MINIMUM AND
UNDERCUT WIDTH 0.370 INCHES MAXIMUM FIRST END 0.109 INCHES MINIMUM AND
END LENGTH 0.125 INCHES MAXIMUM FIRST END 0.3085 INCHES MINIMUM AND 0.3165 INCHES MAXIMUM FIRST END
END LARGEST DIAMETER 0.344 INCHES NOMINAL SECOND END 0.382 INCHES MINIMUM AND 0.386 INCHES MAXIMUM FIRST END
FLAT DIAMETER 0.500 INCHES NOMINAL SECOND END
END SPHERICAL RADIUS 0.150 INCHES NOMINAL FIRST END 0.191 INCHES MINIMUM AND 0.193 INCHES MAXIMUM FIRST END 0.1865 INCHES MINIMUM AND
SPHERICAL RADIUS DEPTH 0.1885 INCHES MAXIMUM SECOND END
BODY TYPE 0.209 INCHES NOMINAL SECOND END
III FSC APPLICATION DATA TUBULAR
THE MANUFACTURERS DATA GASOLINE ENGINE,NONAIRCRAFT
MANUFACTURERS CODE 71772
DESIGN CONTROL REFERENCE I18-1872

Apparently, this pushrod had a military usage. But it exclusive to the straight-valve SD and BD engines.
Since this spec shows a cup end [at the rocker arm], I don't trust that Melling part number at O'Reilly.
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Post Mon Jul 12, 2021 12:19 pm

Re: BD240 pushrod/rocker adjuster interchange

The Mellings part number from O'Reilly definitely looks like it has a ball on each end. The listing must be a mistake as my engine has a cup on the upper end.

Thanks for the interchange for the rocker adjuster. It confirms my suspicion that it's interchangeable, but I guess I'll just have to pull a pushrod from the Farmall 706 engine to compare pushrod lengths. I'll keep you all posted with my findings.

Thanks bedrockjon for the advice on pulling the pushrod. I don't know why I never thought to slide the rocker arm sideways against the spring, that's definitely how I'll pull them to compare. That will save a ton of unnecessary work!
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