let me start out with saying i haven't done this in a while... however plenty times in the past. Question: I recently did head gaskets on my SBC and while i was at it found true TDC (with a piston stop). I just put her back together and started adjusting the lifters. I took the lash out of the lifters that you adjust on #1tdc (#6 valves were rocking), gave each lifter 1 full turn to preload. Then I turned the motor over to #6tdc and did the remaining lifters. When I rotated back to #1tdc they had lash again? what did i f up?
You must have been setting them on a cylinder that was at split overlap,you were 180 degrees out on the crank. Set them again, starting with one that has slack at TDC, that's firing position.
start with # 1 at TDC of the firing stoke (#6 rocking as you said). adust #1...then rotate 90 degrees of the crank,do # 8 ..... rotate 90 degrees , do #4.....keep going through them all in order of 3-6-5-7-2
I always start with #1, rotate the crank until the intake is open and adjust the exhaust. rotate again till #1 exhaust is open and adjust #1 intake. Then move on to #3 and down the line on that bank then do the same thing with 2 4 6 and 8. I only preload 1/2 turn myself.
When I have the intake off I use the following procedure. Position the lifter to be adjusted at full lift. Turn the crank 180 degrees. Turn the adjuster nut down until the pushrod seat is about .060" below it's retaining ring. I then place my 'tool' in the gap between the seat and the retaining ring and loosen the valve adj nut until the 'tool' is trapped. I then tighten the adj nut until the 'tool' just comes loose. Go to the next valve and repeat. The 'tool' is a length of .041" SS safety wire with about an 1/8" leg bent 90 degrees at one end. If you can see the individual cam lobes you can avoid having to turn the crank so much. Adj the valve when the lobe is directly away from the lifter.
i guess i'm not on the base circle somehow? Doesn't make sense. Especially because i'm pretty sure i'm dead accurate on TDC at this point.. I also verified #1 and #6 tdc's by watching the rocking valves.. guess i'll be pulling the valve covers again tonight.. Could it be that the plungers just aren't returning, just a thought? the motor did sit overnight and there was still some minor play so i guess this discounts this idea.. Something to note is that the play is not excesive. Essentially feels like just before i put the extra turn in to preload.
ray-jay.. that's a great idea.. i'd really like to avoid repulling the intake if possible though so i'll be doing it at the rockers..
I don't think you can do my procedure without the intake being off. You have to be able to see the pushrod seat.
yup.. i'll just have to go with the 1/2 turn to 1 turn of preload... I'll definitely use yours next time though.
Just do it with the motor running. A bit messy but effective. I used to have a valve cover that I cut a slot in just above all the adj nuts.
With the valve covers off, turn crank until intake valve on #1 closes, then keep rotating until the timing mark is in position. Then adjust both valves on #1. Do the same again for each cylinder per the firing order. You can double check them after its running as suggested...
When building a new motor this lets you fire the motor and go directly to 2500 rpm for cam breakin. I used to have an engine test stand and after I installed the oil pan I transferred the short block to the test stand and used it as the engine stand. I would finish****embing the engine and hooking up all the elec, cooling and fueling bits all in one go. Then fire that mother up and break in the cam for 45 mins at 2500 + rpm. Come back in the next day drain the water, remove the ex manifolds and retorque the heads. Reinstall the ex manifolds and mufflers, fire that mother up again and hot lash the valves and the motor was ready to install and drive away. I may have never become a believer in retorqueing iron heads if not for the test stand. It made it simple to do compared to bending over fenders, access to getting the ex off, etc. I ALWAYS found that the loosening torque on the head bolts would be all over the map. Some would still have full torque and some would feel like they didn't have 10 ft lbs.
i totally believe it.. my 90k*****ty SBC doesn't warant that kind of attention though .. thanks for all your advice though.
This is the way I have done it many times with no problems.. No.1 firing position, adjust exhaust valves 1-3-4-8 intake valves 1-2-5-7 No 6 firing position - exhaust 2-5-6-7 intake 3-4-6-8
that was the exact procedure i did.. i'll try again tonight... wierd.. both that and the method going thru tdc in firing order...
ok - i'm dumb.. i pulled the valve covers last night. There was no lash to speak of. I had my buddy stop by who had put a motor together more recently than i have and i guess i was expecting the rockers to tighten up as well. The fact is that the pushrods did have a decent amount of drag when you try to spin them, it's just that if you try to tweek the rockers a bit you could budge them a bit... i guess as always i was just totally overthinking it... Thanks all for your info and support...
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