pontiacdog

I'm assembling my 305 TPI engine and I want to ask your opinion if I adjusted the valves and lifters correctly after a valve job.
I'm posting just in case I did something so horribly wrong the whole thing will fall apart when I start it. I heard people use some specific patterns with the valves which I knew nothing about so that made me nervous if I did it correctly.

Basically I just moved from one valve to the next one instead of having a specific pattern. For each valve I rotated the engine by hand until the pushrod was definitely as low as it would go and then I rotated some more to make sure it was on the base circle of the cam.
Then I simply installed the rocker arm, torqued until there was no slop anywhere and gave it an extra 1/2 turn.
I repeated this 16 times and called it a day.

AlkyIROC

That's a long slow process of doing it but whatever works for you.

That's the only part of it that's not 100% accurate depending on how you read it. It should read that you tightened the rocker until there was no looseness in pushrod was gone then tightened the rocker an additional 1/2 turn.

The downside of going valve to valve is that you need to make sure each valve is actually on the base circle of the cam and not in overlap. When one valve for a cylinder is all the way down, you can adjust the other.

pontiacdog

Is there any way to check that I've done this correctly?
When doing it this was actually my biggest problem. I never really knew when the valve was on the base circle and I just went with my gut feeling.

vetteoz

iTrader: (13)

Faster method

Put No 1 cylinder at TDC on the balancer (check with distributor ),
then do both valves on No 1 cylinder.
Without touching crank do
Drivers side ;No 3 exhaust (4th valve) No 5 intake (6th valve) & No 7 intake
Passenger side; No 2 Intake (2nd valve) , No 4 Exh (4th valve) ,No 8 Exh. (last valve)
Then rotate the engine one complete turn until the TDC mark comes back up on the mark again.

Do what's left
Drivers side ;No 3 Int No 5 Exh and No 7 Exh
Passenger side; No 2 Exh No 4 Int. Both No 6 valves and No 8 Int

AlkyIROC

That's the way I do my engine except I have a 4/7 swap cam so the pattern is a little different. Using the timing mark as a reference, you'll either be on #1 or #6 TDC. Half the valves will be on the base circle each time and you only need to rotate the engine one full revolution.

For simple instructions

#1 TDC
INT 1, 2, 5, 7
EXH 1, 3, 4, 8

#6 TDC
INT 3, 4, 6, 8
EXH 2, 5, 6, 7

Works every time no matter what type of cam or grind you have. The valve you are adjusting is always on the base circle.

pontiacdog

What happens if some of the valves are set slightly off from the base circle of the cam?

lonestar7

iTrader: (1)

The lash on those valves will be too tight. Depending on how far off the cam lobe when adjusted, it can cause the valve to be open too long, possible low compression, brunt exhaust valves, bent push rods.

pontiacdog

Okay, thanks.

I still don't quite understand how you can check that the valve is set perfectly on the base circle.
Is there some kind of timing mark somewhere, or is it just that the lowest point of the pushrod is always on the base circle? I mean I installed the rocker when the pushrod wasn't going any lower.

Please excuse my stupidity.

jagdprcp

The process that you used was ok. It jsut took a bit longer than the standard way. The only thing that you might have done incorrectly was when you said:
The correct process is to tighten until the pushrod was barely able to spin with your fingers and then tighten 1/2 turn more.

If you did indeed tighten until it would not move at all then your valves are too tight.

Skeeeter

86LG4Bird

iTrader: (1)

If you "tighten until the pushrod was barely able to spin with your fingers", you've already gone past zero lash.
That won't work in all cases; you got lucky with tight lifters that didn't bleed down and going only 1/2 turn past there.
The correct way is to tighten only until there is no play, just where there's no longer any side to side slop in the rocker or pushrod. You will still be able to spin the pushrod easily. Then give it the 1/2 turn (typical for factory lifters) preload.

AlkyIROC

It's hard to describe the proper amount of play or slop in the pushrod when at zero lash but the description 86LG4Bird gives is the closest you're going to get.

If you try to adjust until you can't spin the pushrod, it will never happen until the plunger in the lifter bottoms out. Even after finding zero lash then adjusting 1/2 turn more. If you wait a few minutes, you'll be able to spin the pushrod again. This is how a hydraulic lifter works and is normal. Adjustment is done, don't try tightening up more.

pontiacdog

Should I loosen them up a little?
Mostly I paid attention to the rocker instead of rolling the pushrod, I did the 1/2 turn at the exact point when the rocker wouldn't jiggle around at all.

When I was done and rotated the engine, it seems the rockers somehow loosened themselves to a point where they work just fine but you can jiggle them a bit if you grab them.

Ransford2987

Here's something for your reference. It's difficult sometimes to exactly convey something specific in a few sentences. If you think you've done it incorrectly, then give it another go. Or just do it anyway, to make sure it's right. This video is somewhere between the "no spin" and "no lift" of the push rod to identify zero lash, so make sure you understand that. Also, this video is mostly so you can see where the lifter is at the low point, not necessarily how to do it. I would go with how vette or alky said to do it.