Rocker valve adjustment

kitesurfer

kitesurfer

Well-Known Forum User
After starting the car last weekend I decided to check the rocker clearances. All checked and set and the engine sounds very sweet. But, inlet valve on number 4 cylinder is markedly higher on the adjusting stud which just scratching the back of my mind as to why. Couldn't see any wear...just plain odd! Any ideas anyone?
 

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Ok & thanks....action required. Concerned now!!
First step very careful inspection. Probably need some more help on this. I have some manuals to study first. Huge sucess in having the car starting and running so smoothly last weekend then I'm hit with two issues...this and a possible alternator failure.....the joys of classic cars!!
 
Just checked the manuals. I think its a missing lash pad as from memory all I can see is the 2 valve collets. Hopefully someone just forgot to replace it rather than it floating around the engine :eek:
 
Yeah you shouldn't be able to see the collets or the valve stem.
It may be lying about on the top of the head, if not it'll be in the sump.
Thing to check out is if there's a problem with the valve opening and closing fully.
 
i had a lash pad jump out once and it was located on top of the oil pump housing where it must have fallen down the timing chest.
only found it once the pump was removed.
 
Jimbo said:
i had a lash pad jump out once and it was located on top of the oil pump housing where it must have fallen down the timing chest.
only found it once the pump was removed.
Click to expand...

Found it!!!!!!!
Lash pad lying near a spring. Feeling much happier now :)
 

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Rob Gaskin said:
Well done, so who adjusted the clearance and thought it ok to run it???

As Mike said, it could have been catastrophic.

:thumbs:
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Another classic case with this car and why I am taking a lot more time to check things out. Silly things such as hose clips loose and crankshaft pulley bolts missing etc. It feels as if the car was thrown together in haste for whatever reason. I'm now focusing on the brakes as a priority with emphasis on the rear brakes. Replacing both cylinders as I've already discovered one leaking. This is not the end of the world as I'm really pleased the car is so solid and original. No rush as the end of April is my target to have her back on the road!! :)
 
Will also keep an eye on the valve. Hopefully some engine run time will sort it if there's a tendancy for it to stick. Compression test was good. Dont really want to take the head off at this stage when the engine is sounding so smooth. Keep my ears out for a slight misfire!!
 
just check this one thing.
when my uncle rebuilt the engine in my datsun he used normal 10/40 engine oil to lubricate the parts as he assembled it but once assembled the engine sat around for years before being turned over.
even though he did an oil change when the engine made it into the car the old oil used to assemble the engine was still stuck to the valve train and actually caused the valves to gum up and get stuck meaning the valve was stuck down even with no pressure from the cam. this resulted in the lash pads falling out causing horrendous tapping noise.
this resulted in a top end rebuild because the valves had to be removed to clear off the cruddy old oil and check for any damage.
turn the engine over by hand and just check the valves are returning properly just in case something similar may be happening.
 
You got me thinking Jimbo. Maybe I should take a little more care with the cars I've brought over. The silver car hasn't been used for 32 years and the oil was a bit odd. I have changed the oil now but I did run the engine with what appeared to be chip fat. Seams OK now though so I could of been lucky.
 
Jimbo said:
just check this one thing.
when my uncle rebuilt the engine in my datsun he used normal 10/40 engine oil to lubricate the parts as he assembled it but once assembled the engine sat around for years before being turned over.
even though he did an oil change when the engine made it into the car the old oil used to assemble the engine was still stuck to the valve train and actually caused the valves to gum up and get stuck meaning the valve was stuck down even with no pressure from the cam. this resulted in the lash pads falling out causing horrendous tapping noise.
this resulted in a top end rebuild because the valves had to be removed to clear off the cruddy old oil and check for any damage.
turn the engine over by hand and just check the valves are returning properly just in case something similar may be happening.
Click to expand...

Wise words & thanks. I'll check tomorrow morning.
 
I've had a lashpad come off from a cold start for no apparent reason. After reading old threads on USA forums I levered down the spring, replaced the lashpad and carried on.

kitesurfer, I assume you know there is a book "How to rebuild your nissan and datsun ohc engine"
 
Pads don't drop out on their own
It might be worth investigating a little further as to why the lash pad came out in the first place, a well adjusted engine, in good condition, run under normal tolerances should never drop a pad.

Things that's could cause a dropped pad
Loose valve seat
Bent/damaged valve
Damaged or corroded valve guide
Broken or badly worn spring(s)
Heavily coked engine
Poorly adjusted or loose valve (very poorly and very loose)
Foreign object inducted and stuck under the valve (momentary)

A compression or a leak down test is your best friend here
 
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