measured pushrod lengths

[EVIL]

I just measured for pushrod lengths. I'm using Harland Sharp 1.60 rockers with 2 threads showing and morel roller lifters with a 212 212 cam.

I checked every push rod length and they were all different. Here are the lengths

<------ front of engine
7.958, 7.964, 7.950, 7.998 7.942, 7.960


7.960, 7.930 7.990, 7.945 7.967, 7.956

the biggest difference is between 7.930 to 7.998 with .068 total.

what push rod length should i get that will work for me?
maybe something around a 7.965?

All help is appreciated.

D

 

[pajo]

why dont you get el cheapo push rod lenght checker and find out exactly what you need..?

 

[EVIL]

That is how i got those exact measurements. I'm trying to figure out what one length would be best since buying all the different lengths would be costly.

D

 

[pacecarta]

did you add for preload of .020- .030?
how are you measuring the adjustable , overall tip to tip?

two threads showing where? top above lock nut or bottom of cup underside of rocker

 

[EVIL]

After there was no up and down play i did an extra 1/3 turn.

I had between 2 and 3 threads showing under the rocker where it meets the push rod.

I used digital vernias/calipers and measured tip to tip. I did it 3 times each to be sure and they were all within 1 to 4 thousandths each.

D

 

[pacecarta]

harlands call for one thread showing or one recessed at bottom (only a .100 window)

i would take two turns out of the rockers (up) and order prods .100 longer than the shortest rod and set the preload at 1/2 turn

puts you about 8.050 which is where i find most iron head 212 rollers with morells to be using a .060 gasket,
just putting this out there comp lifters require prods about .150 longer than morell in the 8.200 range depending on gaskets

 

[EVIL]

I appreciate your help but this is directly from the Harland Sharp web site pertaining to our engines

"When setting pushrod length have no more than 3
and no less than 2 threads showing on the bottom side of the rocker, between the
rocker body. This is for proper oiling and correct geometry."

I also have .040 gaskets

 

[pacecarta]

my mistake , mixed up the harland and t+d intructs

setting between 2-3 threads only gives a one turn window or .050

from your measurement you have two bad valve tip heights out of norm with the others ..one recessed valve (7.930) one valve low (7.998) not seated maybe
try tapping the valve at the tallest prod measure (the 7.998) see if it seats better
the other valve (7.930) you could remove and take a little off the tip (.020)

 

[EVIL]

I went ahead and measured all the lifters once in each port and ended up with different sizes which means that the lifters them selves are off a bit.

Then i measured again with the other rocker arm and ended up with up to .050 difference from the first arm.

This tells me the rockers are also off.

All thing are not created equal.

I may start switching the rockers around on the arm to match up rockers with lifters to get a more equal height difference across the board. This is gonna take a while!

D

 

[turbofabricator]

Did you measure valve stem highths? That is usually the biggest reason for differing pushrod lengths. You can also grind/hand file an oiling transfere groove in the rocker arm to ensure there is oil geting through the adjusting screw. I use to do that to all the T&D rockers I installed. There just isn't alot of adjustability when there are annomolies in the valve train. I used a small (read tiny) 1/8" rotary file in a die grinder to make the notch. Basically I would elongate the oil hole up and down about .040" if I had ANY doubt the adjusting screw oil notch wouldn't line up perfectly.

 

[EVIL]

I checked the valve stem heights using a straight edge and there are variances.

Won't these variances effect the clearances between the valves and the pistons?

On a brighter note, after switching around rockers and lifters i've ended up with a low height of 7.950 and a high of 7.974. 7.950 pushrods should work fine.

D

 

[Mike Licht]

Pushrods are not measured tip to tip, they are measured 110* on the radius. What lifters are you using? Most of the rollers seem pretty happy about .040 to .050 preload if you want less noise

 

[EVIL]

I'm using Morel roller lifters.
Thanks for the 110* radius info Mike.

D

Pushrods are not measured tip to tip, they are measured 110* on the radius. What lifters are you using? Most of the rollers seem pretty happy about .040 to .050 preload if you want less noise

 

[smoke20]

mine take 8.200 plus .080 I'm doing a engine now a guy built that only has 2 threads holding on lock nut for adjuster he had 8.000 he needs longer too