I'm building a 5.9L engine,
It's had the block deck milled, aftermarket heads, cam and rockers. Does 6.750 or 6.800 pushrod length sound reasonable?
That's about .200 shorter than stock,
Thanks.
G-Man
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I'm building a 5.9L engine,
It's had the block deck milled, aftermarket heads, cam and rockers. Does 6.750 or 6.800 pushrod length sound reasonable?
That's about .200 shorter than stock,
Thanks.
G-Man
Sounds like a guesstimate.
You need a checker pushrod.
That is a guestimate, with a pushrod checker.
I would like to go even shorter, but the rockers wont let me,
Just asking if that length has been used in other combos.
G-Man
Check your valve train geometry....Period
:biggthumpup:
Thanks SynRG for the video.
Great video....Now that I'm running Jesel shaft rockers I'll know how to measure for push rods.
I liked this one:
I watched a video, read some tech tips, measured twice and cut once.
Still no matter what i can't get the geometry correct, i can make the pushrod checker so short that the rocker bottoms out on the stud and still the pattern is on the exhaust side of the valve stem i believe i have the wrong rocker arms.
Does anybody have a set of 1.7 rockers for sale?
G-Man
Did you use your valve springs with the pushrod length checker or a light pressure spring that is recommended to be used when measuring for pushrod length? If you use regular valve springs its easy to start compressing the lifter and skewing your measurements. From what I have read and how mine are personally set up they like very little pre-load to prevent them from pumping up at high rpm.
What heads?
What rockers?
Yes, checking springs.
EQ CH318B heads, unknown rockers, 1.7 ratio.
We can end this thread now.
G-Man
Great info for Mopar geometry (and fix):
http://www.b3racingengines.com/techcorner.asp
Thanks Joe, that was very helpful.
Gwyn
You need to make your lifter solid . Remove the internals of your lifter and make a shim out of a bolt and nut , I used a 5/16 x 1" hex bolt from my header . Adjust the nut so when you drop the cup onto the lifter . The cup meets where the bottom of the snap ring groove is , as if it was installed . Now you can check for push rod length.
Attachment 14838
I too am interested in this thread and the outcome of the findings. When we built my engine 5 yrs ago, it needed shorter than stock pushrods. I have Crower SS 1.7 ratio rockers, (made for our engines) And a Comp cam straight from them. I was just searching comp's website, but did not see where it said anything about the "base circle" being smaller/larger or the same as stock. Correct me if I am wrong, but if the base circle is larger wouldn't that necessitate the use of shorter pushrods? And, vice-versa?
Never mind the what's this and what's that .a solid lifter with a pushrod checking tool and the correct roller tip pattern accross the valve tip ,is all that matters . When ever anything is changed in the valvetrain this set up should be followed. Oh by the way did you place play dough on top of your pistion to check valve to pistion clearance while the cam is set on its center line? By the way, I had 1/4 " shims made for my rockers to fit correctly . .Attachment 14840