I am putting my engine back together after replacing headgaskets. Car has 1.7:1 "Ford racing" Crane cams roller rockers on it. Don't laugh at me, I'm used to working on OHC engines... How do you set valvelash correctly? I THOUGHT lash was 0, but i've read otherplaces you need to have a certain amount of lash. Any help would be greatly appreciated. I will be ready to set lash tomorrow!
Valve lash adjustment?
- Thread starter Cman88
- Start date
Here is a set of instructions I learned off of years ago, they work very well. I tend to only try to go 1/2 turn, gives a little more room for error if you over rev it and it will make a little more power.
http://www.cranecams.com/pdf/453e.pdf
http://www.cranecams.com/pdf/453e.pdf
TheBocSez
New Member
Are those stud mount rockers? If so, I used the same method, works fine. I went 3/4 to keep things quite. At 1/2 I had a few that still tapped a little.
With pedestal mount rockers the only thing that you can really do is shimming them.
Here is the procedure as it was told to me. It worked for me.
Assemble the pushrods and loosely bolt down the rocker arms for cylinder #1
Rotate the until you are at TDC for cylinder #1 and verify that both of the lifters are on the base circle of the cam. At this point both the intake and exhaust valves will be closed.
Tighten the rocker bolt down until there is no play between the pushrod and the end of the rocker. I tightened mine down until I couldn't rock the rocker back and forth from the pushrod to the valve stem. You don't want to get it tight yet just take the play out of it. Get out your torque wrench and tighten the rocker bolt down to between 18 and 25 ft-lbs or torque but you want the bolt to turn more than a 1/4 turn but less than 3/4 turn to achieve the torque value. If you get to specified torque value before a 1/4 turn then your pushrods are too short and you don't have the proper preload. If it takes more than a 3/4 turn then your pushrods are too long and you have too much preload. If they are a little to long it can be a production variance in the heads or rockers that can be corrected with shims. If they pushrods are too short then there isn't much you can do except get longer pushrods.
Do the same for each cylinder and they should be good to go. I have gone back and checked them after a few heat cycles just to check them.
Here is the procedure as it was told to me. It worked for me.
Assemble the pushrods and loosely bolt down the rocker arms for cylinder #1
Rotate the until you are at TDC for cylinder #1 and verify that both of the lifters are on the base circle of the cam. At this point both the intake and exhaust valves will be closed.
Tighten the rocker bolt down until there is no play between the pushrod and the end of the rocker. I tightened mine down until I couldn't rock the rocker back and forth from the pushrod to the valve stem. You don't want to get it tight yet just take the play out of it. Get out your torque wrench and tighten the rocker bolt down to between 18 and 25 ft-lbs or torque but you want the bolt to turn more than a 1/4 turn but less than 3/4 turn to achieve the torque value. If you get to specified torque value before a 1/4 turn then your pushrods are too short and you don't have the proper preload. If it takes more than a 3/4 turn then your pushrods are too long and you have too much preload. If they are a little to long it can be a production variance in the heads or rockers that can be corrected with shims. If they pushrods are too short then there isn't much you can do except get longer pushrods.
Do the same for each cylinder and they should be good to go. I have gone back and checked them after a few heat cycles just to check them.
Alright, cool. Since the cam remained stock and there was no change made to the lifters or pushrods, I would assume it should go back together with no adjustments needed. This is, of course, assuming the previous owner installed these parts correctly to begin with... which we know isn't the case.. I'll keep you posted.
RYC CUKR said:
They all came out just fine. I used 23ftlbs and had no problems. I saw in your posting though that you had things backwards... Less then a 1/4 turn would indicate too LONG of a pushrod... More then 3/4 of a turn would mean they are too SHORT..
I just need to go put on the valvecovers, crank pulley, water pump pulley and the upper intake and this whole project is done. Hopefully it works.Similar threads
