Delta 88 1966 with 425 engine.

After noticing a noise I removed the valve covers and find out that one rocker arm is getting no oil. The rocker arm pivot is already worn a bit (missing 2.2 mm), what makes the valve does not open all the way.

Push rod is clean, lifter seems to be okay from what I could see with an endoscope through push rod canal.

Engine oil level okay, looks clean (about 400 miles after change).

What can be the problem? Do I have to take off intake to go to lifter?



Worn pivot

measuring worn thickness

measuring original thickness

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Yes the intake must be removed. Problem could be lifter related or a blockage in the oil galley which is quite rare if the engine is generally clean.

Can you tell if both lifters are not oiling or just one?

Keep the lifters in order so they go back on the same lobe if they are reused. The lifters can sometimes be disassembled, cleaned and reused. Don't swap internal lifter parts from one to another.
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I have seen this type of wear pattern on many of the lifter fulcrums over the years.
I'd suggest simply bolting the rocker arm back together and then use a drill to prime the engine via the distributor hole.
Confirm if oil is flowing up to the rocker in question or not. If oil is flowing then simply replace the rocker arm pivot and be on your way.

If no oil is reaching the rocker then removal of the intake and investigating the lifter is probably the next step.

 

It's just only one that does not oil.
When rebuilding a year ago, whe noticed a lot of trash in oil gallery. Block has been cleaned, then rebuilding including disassembling, cleaning and reusing lifters/

I think there has been some dirt left what now has been stucked in lifteroil opening.

 

I already know this rocker arm gets no oil. All are wet, only this perticular one is not, whad couses the wear pattern.

What do you yhink of putting some break-clener from above on top of lifter, wait for a while and after tht do the priming test?

 

Did you verify that the small hole in the rocker above the pushrod is clear?

 

Yep, hole is clear, even as pushrod itself.

 

Trying Brakleen should be ok. IMO, the lifter will probably need to come apart. Curious, which rocker is this?

 

I wouldn't spray brakeclean into a sealed up engine. You will wash away the oil protection of your cam and lifter and likely seize it or cause additional wear. If the pushrod is clear you can spray through it, then you have to pull the intake and that one lifter to check why.

 

Pull off the intake and then the pushrod and lifter so you can see if oil comes out the hole in the lifter bore that supplies the lifter.

 

Cilinder no. 7, the last one in the row, I think the intake.

 

Thanks all for your advice, I better take the intke off and take out the lifter. I keep in touch!

 

The last one in the row leads my thought toward the oil galley being plugged. It may be worth pulling the distributor galley plug with the orifice to oil the distributor gear and confirm that it is clear. If the distributor oil galley orifice is plugged it won't give any warning.

 

Oil gallery plug has a small hole in it. I will check if the hole is clean!


Thanks!

 

What is the current status of this problem?

 

Sorry, but personal circumstances are preventing the repair for a while. I'll keep you informed

 

So it was a blockage in the oil channel. With new bearing shells, valve seats, etc., it's now running like a charm again.

 

Good to hear that you found and fixed the problem!