Few months back I swapped my heads and rockers went from E7s with 1.7 rockers to trick flows with 1.6 rockers. I'm now trying to figure out pushrod length the only problem is I have everything torqued down with hydraulic lifters in the motor. Do I have to tear the top end off again just to get a solid lifter in there or is there a way for me to get an accurate reading setup as is? With the current setup and a 6.750 length pushrod I get a centered line that's a little on the fatter side
jays90foxbody
Yes you can measure them with hydraulic lifters. It is best if you can measure them with no oil in the oil pan that way you do not have to wait for the lifters to bleed down, but if there is already oil, once you spin the motor over to TDC wait for at least 60 seconds, I recommend 2 minutes, to let the lifter bleed back down for a proper and accurate measurement.
I had a few stock lifters that wouldn't bleed down, so I used them to check pushrod length. Afterwards I disassembled and cleaned them... but for a while I had a nice solid lifters to work with.
I don't know why you would want the lifter to bleed down. That seems to be the exact opposite of proper advice, unless you subtract the lifter collapse amount from the pushrod length you find with the check rods.
It seems to me you really want the lifter at operating height. It also seems the very last thing you want is to center with the lifter in an abnormal plunger height, and not even know what the state of collapse is when you check (which is what a bled down lifter would be doing).
This is the whole reason behind check springs. Check springs don't collapse the lifter. They let it sit extended.
So you have some people who do this at maximum lifter height by using a weak check spring or a modified "solid" lifter, which means the lifter is pumped up normally, and some doing the measurement with the lifter at an abnormal plunger height you should never see in operation.
Since I planned on running mine at very slight lifter preload, I put a brass slug in a lifter that set the push rod cup at the planned height. But that is just me. I could be all wrong, and you really want to use a 800lb spring or a dry lifter with normal springs and pick a pushrod with the lifter collapsed, instead of check springs or solidized lifters and the lifter at operating height.
It seems to me you really want the lifter at operating height. It also seems the very last thing you want is to center with the lifter in an abnormal plunger height, and not even know what the state of collapse is when you check (which is what a bled down lifter would be doing).
This is the whole reason behind check springs. Check springs don't collapse the lifter. They let it sit extended.
So you have some people who do this at maximum lifter height by using a weak check spring or a modified "solid" lifter, which means the lifter is pumped up normally, and some doing the measurement with the lifter at an abnormal plunger height you should never see in operation.
Since I planned on running mine at very slight lifter preload, I put a brass slug in a lifter that set the push rod cup at the planned height. But that is just me. I could be all wrong, and you really want to use a 800lb spring or a dry lifter with normal springs and pick a pushrod with the lifter collapsed, instead of check springs or solidized lifters and the lifter at operating height.
I took and old lifter, used a cutoff wheel to grind through the lifter flat into the plunger on both sides, laid a bead in there and ground them flat again - solid lifter for checking things like this........
There are many ways to find the correct push rod length. This is a video that really explains it and shows it well.
The video is for a solid lifter engine. For a hydraulic lifter engine, add 0.050" to the measurement you come up with using this method.
Dan
https://www.youtube.com/watch?v=o5is9BsH5OU&feature=em-upload_owner
The video is for a solid lifter engine. For a hydraulic lifter engine, add 0.050" to the measurement you come up with using this method.
Dan
https://www.youtube.com/watch?v=o5is9BsH5OU&feature=em-upload_owner
.....and you will notice he is using very light weight check springs.
This is so he does ****NOT**** collapse or bleed down the lifter if it is a hydraulic.
The minute the lifter collapses, you will start getting the wrong length.
This is so he does ****NOT**** collapse or bleed down the lifter if it is a hydraulic.
The minute the lifter collapses, you will start getting the wrong length.
If you collapse the lifter while measuring you will find out real quick you bought pushrods that are way to long. You do not want to collapse the lifter
I would use a solid lifter except for the fact that I've already torqued things down and I don't want to pull one head and have to trash a head gasket. If the motors been sitting and only been turned by hand what kind of state are the lifters in? Bled down? I've found lighter springs to use I'm gunna pull the springs on one valve and use them
I found this tool on summit http://m.summitracing.com/parts/pro-66789 it seems like it would help a lot with the whole geometry aspect of it never was very good at math. Know of an reason why it would only be listed for Chevys is there a different angle between valve and rocker than in the SBF?
Because when you assemble your engine, proper valvetrain adjustment requires you to pre-load the hydraulic lifter. The .050" accounts for that pre-load.
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
