Ijust fired up the ol lt1 the other day for the first time since the build. it knocked a rocker off and the others where kind of chattering lightly. anyone know the exact sped on tighting them with a feeler gauge. i did the old fashioned way.

 

You should be adjusting to 0-lash, then 1/4 turn of preload.

WD

 

I'm with him. I took mine to 0 lash, but i took mine to 1/2 turn. Been that way for 23,000 miles now. I know the feeling though. I adjusted mine on my truck when i was like 15 cuz i was a god mechanic then....only to find out like 9 or 10 of them came off...lol.....

 

You must not be doing the adjustment correctly, use these procedures.

WD

Hydraulic Lifter Pre-Load Adjustment

What is Hydraulic Lifter Preload? Mechanical cam designs require a running clearance or valve lash; hydraulic lifters are just the opposite. When the rocker arm assembly is properly adjusted, the pushrod must take up all the clearance and descend into the hydraulic lifter, causing the pushrod seat to move down by .020 to .060. The distance that the pushrod seat moves down away from the retaining lock is the Lifter Preload. The hydraulic mechanism requires this precise amount of preload for it to do its job properly.

What happens if the amount of Hydraulic Lifter Preload is wrong? If clearance exists between the pushrod and the seat in the hydraulic lifter, after the rocker arm assembly has been adjusted, you will have no lifter preload. In this case the valve train will be noisy when the engine is running. All of the hydraulic force produced by the lifter will be exerted against the lifters retaining lock, and this could cause the lock to fail.

If the opposite occurs and the pushrod descends too far (more than .060?), then you have excessive lifter preload. In theory, a hydraulic lifter can pump up whatever preload you put into it, therefore with excessive preload, as the engine RPM and oil pressure increases, the hydraulic mechanism will pump-up the pushrod seat. This will cause the valve to be open longer and lift higher. This will decrease the cylinder pressure, lowering the performance of the engine. If the preload is excessive it may cause backfiring from the engine. How to correct this situation will be explained in the next sections.

Methods to Adjust for Proper Hydraulic Lifter Preload
Hydraulic Lifters Can Be Adjusted at Any Engine Temperature Since hydraulic lifters can compensate for thermal expansion of the engine, the adjusting can be done with the engine cold; hot adjustment is not necessary. Adjusting Hydraulic Lifters for Proper Preload: In order to adjust the preload the lifter must be properly located on the base circle or Heel of the lobe. At this position the valve is closed and there is no lift taking place. You will need to watch the movement of the valves to determine which lifter is properly positioned for adjusting.

1. Hand rotate the engine in its normal direction of rotation and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinders “intake” rocker arm. (Why? Because when the exhaust valve is just beginning to open, the intake lifter will be on the base circle of the lobe, the correct position for adjusting the intake.)

2. Back off the intake rocker arm adjuster and remove any tension from the pushrod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do so. (If you are installing brand new lifters they will be in the neutral position when they come in the box.)

3. Now spin the intake pushrod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning of the pushrod, you are at Zero Lash. Turn the adjusting nut down one quarter (1/4), or one half turn (1/2) from that point. Lock the adjuster into position. The intake is now adjusted properly. Most high performance applications use ¼ turn.

4. Continue to hand turn the engine, watching that same intake. It will go to full open and then begin to close. When that intake is almost closed, stop and adjust the “exhaust” rocker arm on that particular cylinder. (Again, when we see the intake almost closed, we are sure that exhaust lifter is on the base circle of the lobe.) Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.

5. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.

Do Hydraulic Lifters Need to be Primed with Oil? Many people mistakenly believe that hydraulic lifters must be soaked in oil overnight and be hand pumped up with a pushrod before installing into a new engine, this is not necessary. In fact, this could cause the lifter to act as a solid and prevent obtaining proper preload.

 

If you are set on using a feeler gauge then about .020 cold at TDC on each cylinder. As they get oil and warm upit should take up the slack. If you want to do it the right way with each cylinder at TDC you should spin the pushrod as you tighten until you get drag and then a 1/4 to 1/2 turn. Make sure you lock the nuts or use poly locks depending on what you have.

 

I guess my instructions above fell short??? Possibly not detail enough.

WD

 

Hey at least you tried.

 

You have hydraulic lifters. You only use feeler gauges to adjust lash on solid/mechanical lifters.

Follow The Engineer's post, and you'll be set.

 

wow! you are supposed to lash rocker arms...wtf! why didn't anyone tell me definitely good instructions.

 

Mine was touchy with the 1.6's..I had to use 1/4 turns..

Here is a easy way to hit them all..

 

i did adjust the lash. and i adjusted them to spec. i knew what is recommended wouldnt be exact but i figured it would be close enough boefore i could adjust them with the car running. im not 15 or an idiot for that matter but i believe that the rocker that came off probably wasnt seated on the pivot point well to begin with and when it did align after the start it was probably way too loose and come off. simple fix, no big deal, i was jsut asking if anyone new what was exact on them or if lash adjustment wasnt good enough but obviously it is. thanks for the help and to the engineer, that was a very good and detailed write up.

 

LOL, no they didn't fall short and they were plenty detailed. I didn't know you were the only one allowed to give advice on here and figured the OP didn't want to read a book so I provided cliff notes