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Rocker arm adjustment question

Posted: November 6, 2017, 11:58 am
by Gnant
Over the weekend I put in new lifters, push rods and rocker arms on my straight 6. I don't know if its a 240 or 300. VIN says 240 but the late date code on the block has me thinking it may be a 300.

Here is my problem. The nuts on the rocker arms keep backing off. The new rocker arms came with two nuts and the paper inside the box states: "The two nuts packaged are for early (3/8") and late (5/16") applications."

My rocker studs take the smaller nut. And the small nuts provided aren't oblong like the bigger ones for the early motors.

Do I just tighten them all the way down? Is it that simple? I was going through the process of finding TDC, finding zero lash and then adding about a half a turn. Ran great but after just a minute or two of idling, several started backing up.

When I took the old ones off, they nuts were tight, and once loosened, they just came off by hand. They weren't tapered. So I am thinking these aren't adjustable and I just run them all the way in.

Any help is appreciated. Thanks.

Re: Rocker arm adjustment question

Posted: November 6, 2017, 10:12 pm
by unibody madness
I Think by your explanation that you have an adjustment nut, and a lock nut, since they are not tapered. You adjust the inner to where you want it, hold it with one wrench and tighten the locking nut while holding the adjuster steady
. It will take a few tries before you get the knack of holding the adjuster tight enough that it will not affect your adjustment while tightening the locking nut. the tapered adjusters are far superior in my opinion.

Re: Rocker arm adjustment question

Posted: December 31, 2017, 11:32 pm
by Truckrat
One other bit of information I will need when I put my 300 back together!

Re: Rocker arm adjustment question

Posted: January 1, 2018, 7:46 am
by ThinLizzy13
Gnant wrote:I don't know if its a 240 or 300. VIN says 240 but the late date code on the block has me thinking it may be a 300.
240 stroke is roughly 3 1/4” (3.18”) and a 300’s is 4” (3.98”).

Per my Ford 66 shop manual (should be the same for 65)

Sorry in advance about the poor image quality...
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It looks like you rotate the engine like you would when setting lash, but instead of measuring the lash you're just tightening the nut 3/4 turn once the rocker to pushrod slack has been eliminated.

Hope this helps.

Re: Rocker arm adjustment question

Posted: February 11, 2018, 6:03 pm
by ThinLizzy13
You ever get this sorted out?