1 Tappet adjuster screw almost at max adjustment

[Adski]

Hey guys
Just installed new Pistons, cylinders and heads onto my 1600 square engine
Wasn't planning on a full rebuild just a freshen up. Rings had clearly had it so had the heads. So I replaced all of the above.
I looked carefully into the engine when the cylinders were off and saw nothing out of the ordinary looking.
However I've just put the cylinders and heads on and have come to adjusting the valve clearances and the Middle rocker arm on cylinder 2 seems much looser than the rest. I can adjust the screw in enough to rectify the problem, but I'm wondering why this would be. No other arms are this loose on either side. I even tried s new rocker assembly. No change.
I've checked the push rod and it seems fine. I've looked down the tube at the lifter cup and it seems fine.
If I can adjust the screw enough to set the tappets correctly will it be ok? Or do I pull the heads and cylinders off and look further for the problem.
Cheers.

[blues90]

did you compare that push rod with the others as far as the length goes?

[Adski]

[blues90]

As long as you are certain you have the crank shaft set in the proper position when adjusting the valves and the push rods are the exact same length then I ask what are these heads you got are they good ones because I have no idea . I would check the valve stem height and see if they are the same.

[Adski]

i actually did place a straight edge across all the springs and retainers with no pressure on them and they appeared to be straight.

If it was a cam shaft / lifter issue, would it cause a problem on the opposite side in the same valve?

[rockerarm]

Hi. Did this symptom happen prior to replacing the cylinders and heads?
Some simple tests would include holding a straight edge across the valve tips and see if they are all at a similar height. Next remove the four pushrods and assure they are the same length. If the two checks do not show anything suspicious, I believe you may have an issue inside the engine. You stated you swapped out the entire rocker arm assy, so I believe you have eliminated nearly everything that is easily accessible.
Long time ago, I was working on a type 1 engine that every week the valve on only one valve would be excessively loose. I performed the same as I stated and determined the lifter was at fault. Interesting as the opposing valve (lifter, pushrod, etc) had zero issues. Being in Los Angeles, and having access to many speed parts, I obtained a few aluminum pushrods without one of the tips in. I set the rocker arm on the offending valve to approx. two threads above the jam nut, determined my new pushrod length, cut it, and installed it. This engine hit on all four cylinders and would have to adjust the valves every other weekend for her. When out of adjustment, fabed up another pushrod and began the same ritual. The oil was changed more often as I knew there was more metal particles in the oil. After a year or so the motor was dis-assembled and one lifter was a half an inch shorter on the end that contacts the camshaft. This bug was only used around town and was not something to rely on for a long duration.
Hope this helps, Bill.

Remember this is a diagnostic tool and not top tier advice on repairing engines. (glad I got that out)

[Adski]

Hey Bill,

Thanks for the reply.
This engine was out of another square back that I was restoring. I never drove it, but I tuned it up when in the other car and ran it and it seemed to run fine. I don't recall having the issue previously - however it was probably 2 years ago, so i'm not 100%. I do remember having to replace one of the adjusting screws because the thread on it was cactus and couldn't be adjusted.
Wow, sounds like you went to some length to avoid opening up the engine and replacing the lifters! Well done!
I visually checked mine and they looked ok, but I could have missed something. Wish I'd taken photos! I'll know for next time.

The engine is still out of the car on a stand and tinware hasn't been replaced yet. So theoretically I could quite easily remove the heads and cylinders to check inside. Only annoying thing would be sourcing another paper gasket because I used a smear of copper gasket seal and i'd probably need to clean that off before re-installing?
Also, is it safe to just remove one cylinder head without loosening the other side?

[blues90]

Thing is on the lifters they need to rotate since there are 4 lifters per side and only 4 cam lobes . If they don't rotate what happens is the lifter wears on one side of the large head and if that's the case it will only affect to one push rod since the other side lifter may very well rotate . The lifters seem to wear far more than the can shaft lobes.

Yes you can pull one head but you can't see the lifter heads that meet the cam lobes . The only way to be certain is measure the lift you get on the other head that uses the same cam lobe . Yet as you said it's just the one valve so it does sound like the one lifter is not rotating as it should. Sounds to me like you need to open the case .

[Adski]

Thanks Blues!

So, to measure the lift, do I measure the travel of how far the tappet arm (?) moves in and out?
I haven't done that, although would be good to check to see what the difference is. Would I find what is acceptable wear for this measurement in a bentley? Or would I have to measure the actual lifter, rather than 'lift'? (If that question makes sense?

Thanks again!

[blues90]

[ally5443]

I'm having the same issue on no3 , did you find a solution?