Doing my first ever aluminum head swap and measuring push rods.

[rjrobin2002]

Doing my first aluminum head swap on a 96 roller 351 block and never measured for push rods before.

I got the heads, rockers, and a adjustable push rod.

I was thinking of throwing 2 tacks on one of the original used hydraulic lifters to make it solid for the test. Any reason this wouldn't work?

 

[ntsqd]

You really need the lifter that you're going to actually use because there's no way of knowing exactly where the cup will be in the lifter. Should also be using checking springs on that cylinder's valves.

 

[rjrobin2002]

You really need the lifter that you're going to actually use because there's no way of knowing exactly where the cup will be in the lifter. Should also be using checking springs on that cylinder's valves.

I was trying to get by without putting tester springs in, but I guess I can if it's mandatory. I don't have a valve spring compressor, but know I could rent one.

 

[.94 OR]

Get a tool that you can change springs with the heads on the engine.
https://www.amazon.com/dp/B0BHQTDZGZ/?tag=classicbroncos-20

Then make a tool to hold the valves up when you pull the springs. Old spark plug with an air chuck welded in.

 

[ntsqd]

I've even seen nylon rope fed in thru the spark-plug hole and then the piston run up to TDC to hold the valves up. No idea how well that works, but I've seen it done so they must have figured it out somehow!

 

[Broncobowsher]

Overthinking it...

Are the lifters new and you can still cycle the plunger easy? If so, you are set.
Measure the plunger stroke, use that lifter and just bottom out the plunger. When done, remove about half the plunger stroke off the measured length of the pushrod. When you get pushrods they come in standard lengths. Just find one that is going to work with the stroke of the lifter. Might be a little longer or a little shorter, your rocker arm check will tell you which way is more favorable. Don't need a solid lifter (sure it is easier if you do, no math), don't need checker valve springs (although great if checking valve to piston clearance).

 

[ntsqd]

I guess I should have asked if you are just trying to get a length that merely works OK, or are you intending to set up the rocker geometry correctly?
Can buy push-rods in any desired length (within reason) from people like Smith Bros.

 

[rjrobin2002]

Overthinking it...

Are the lifters new and you can still cycle the plunger easy? If so, you are set.
Measure the plunger stroke, use that lifter and just bottom out the plunger. When done, remove about half the plunger stroke off the measured length of the pushrod. When you get pushrods they come in standard lengths. Just find one that is going to work with the stroke of the lifter. Might be a little longer or a little shorter, your rocker arm check will tell you which way is more favorable. Don't need a solid lifter (sure it is easier if you do, no math), don't need checker valve springs (although great if checking valve to piston clearance).

Does a hydraulic lifter run partially compressed when they are used with adjustable roller rockers? I've never thought about it and just run factory ford heads and non adjustable rockers in the past.

I'm gonna put one of the original length 351 push rods in and check the pattern, I guess I could get lucky and it be centered.

I should know tomorrow.

 

[EPB72]

Does a hydraulic lifter run partially compressed when they are used with adjustable roller rockers? I've never thought about it and just run factory ford heads and non adjustable rockers in the past.

I'm gonna put one of the original length 351 push rods in and check the pattern, I guess I could get lucky and it be centered.

I should know tomorrow.

Depends on the lifter , usually the manufacture would provide that info ..
Some could be 0 preload . no oil in lifter and plunger can start to depress with very little effort so zero lash takes a little light touch.
seems most are zero lash and about .060 preload{ some will give you a range } on plunger which is in most cases about 3/4 turn of the adjuster after zero lash is reached,

FWIW on stock engine roller or flat tappet seen many that that have 1-2 turns past zero lash , when I tear them down for what ever repair I always check and record this data .. not necessary but something I've always done.. seen 2.5 turns on a 5.8l with only 25k on it from the factory

 

[Viperwolf1]

Pedestal mount rocker heads are 5/16"-18 thread. That's 18 turns per inch of bolt. One turn would be 1"/18, or .056". 3/4 of a turn would be about .042".

 

[Broncobowsher]

Pedestal mount rocker heads are 5/16"-18 thread. That's 18 turns per inch of bolt. One turn would be 1"/18, or .056". 3/4 of a turn would be about .042".

But you have rocker ratio as well. But the ratio needs doctoring. 2.6/1.6 since the pivot point is now the valve tip. The output is the total length. Input is the adjuster.

 

[rjrobin2002]

Depends on the lifter , usually the manufacture would provide that info ..
Some could be 0 preload . no oil in lifter and plunger can start to depress with very little effort so zero lash takes a little light touch.
seems most are zero lash and about .060 preload{ some will give you a range } on plunger which is in most cases about 3/4 turn of the adjuster after zero lash is reached,

FWIW on stock engine roller or flat tappet seen many that that have 1-2 turns past zero lash , when I tear them down for what ever repair I always check and record this data .. not necessary but something I've always done.. seen 2.5 turns on a 5.8l with only 25k on it from the factory

So on all the video's they show adjusting to zero lash, turn 1/2" more, then torque the center Allen head poly lock nut to like 20lbs when valve is closed.

What affect would 1 or 2 turns preload have on the top of the valve wear pattern when using the dry erase marker?

I understand how a shorter or longer push rod will make the roller pattern move.

 

[EPB72]

So on all the video's they show adjusting to zero lash, turn 1/2" more, then torque the center Allen head poly lock nut to like 20lbs when valve is closed.

What affect would 1 or 2 turns preload have on the top of the valve wear pattern when using the dry erase marker?

I understand how a shorter or longer push rod will make the roller pattern move.

Lets clarify your heads have screw in studs with guide plates and poly locks,, and are not pedestal mounted rockers?
so if 3/8 stud then 1/2- 3/4 turn generally puts the preload where needed , still lifter manufacture should have recommended spec,....if you error on less preload you might have some lifter tick, tightening them up may quiet them down , ..

the comment on 1-2 turns was on vehicles that are non-adjustable ,pedestal type, and the preload range can very on vehicles that daily drivers ,,

 

[rjrobin2002]

Lets clarify your heads have screw in studs with guide plates and poly locks,, and are not pedestal mounted rockers?
so if 3/8 stud then 1/2- 3/4 turn generally puts the preload where needed , still lifter manufacture should have recommended spec,....if you error on less preload you might have some lifter tick, tightening them up may quiet them down , ..

the comment on 1-2 turns was on vehicles that are non-adjustable ,pedestal type, and the preload range can very on vehicles that daily drivers ,,

Gotcha, that makes sense now.