nuteguy
Well-Known Member
Also, I was hoping to stay away from roller rockers. I don't see a need for them in my application since I am looking at a hot street car which might one day (hopefully) see a strip.
Pushrods
- Thread starter nuteguy
- Start date
nuteguy
Well-Known Member
I'm running the cam that came with Edelbrock's top end kit. Its nothing crazy. Here is the card:
http://www.edelbrock.com/automotive/mc/camshafts/locator.php?part_number=7194&submit=go
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On that card, which I actually just noticed, is the only place anything is mentioned about adjustable pushrods or rocker arms (Footnote 1)
http://www.edelbrock.com/automotive/mc/camshafts/locator.php?part_number=7194&submit=go
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On that card, which I actually just noticed, is the only place anything is mentioned about adjustable pushrods or rocker arms (Footnote 1)
Rocketman
Well-Known Member
Yeah I still have mine that came with the kit. I let a Comp Cam guy (David McCarver I think) talk me into the cam, rockers, and pushrods. Some pictures of that build are in my gallery if you want to take a look.
nuteguy
Well-Known Member
My cam is already in and degreed. Getting a whole new cam is out of the question for me.
moper
Well-Known Member
Nute - I noticed you're in CT. Where?
nuteguy
Well-Known Member
An update:
I got hold of some Crane Cams adjustable roller rockers and pushrods. They are now installed and ready to go. I initially adjusted lash by finding zero lash (where I could not move the pushrod up and down at all) and then went a half a turn past that. After speaking with the engine builder who did my machine work for me, he recommended finding the bottom of the lifter and then backing off a half a turn. That way at higher rpms when the lifter does not have enough time to preload, it does not collapse itself and create a lot of lash. I adjusted following his advice yesterday. The lifters still have some travel and I can still spin the pushrods even though it was pretty difficult. I did have on oily gloves and there was oil on the pushrods themselves.
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Also, I should note that I test fit stock pushrods and rocker arms and they seemed to work perfectly fine in terms of clearances and angles. Granted I'm no professional engine builder but I didn't see anything critically wrong with them.
I got hold of some Crane Cams adjustable roller rockers and pushrods. They are now installed and ready to go. I initially adjusted lash by finding zero lash (where I could not move the pushrod up and down at all) and then went a half a turn past that. After speaking with the engine builder who did my machine work for me, he recommended finding the bottom of the lifter and then backing off a half a turn. That way at higher rpms when the lifter does not have enough time to preload, it does not collapse itself and create a lot of lash. I adjusted following his advice yesterday. The lifters still have some travel and I can still spin the pushrods even though it was pretty difficult. I did have on oily gloves and there was oil on the pushrods themselves.
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Also, I should note that I test fit stock pushrods and rocker arms and they seemed to work perfectly fine in terms of clearances and angles. Granted I'm no professional engine builder but I didn't see anything critically wrong with them.
BLK 68 R/T
Well-Known Member
While true that you adjust lifter preload on the base circle of the cam or heel, you should not be backing off the adjuster 1/2 turn. While on the base circle of the cam back the adjuster off enough to get a feeler gauge in between the valve stem and the rocker arm, the feeler gauge should be whatever the recommended preload is for the lifter. Then turn the adjuster in just until the pushrod will not rotate by running your fingers across it. Remove the feeler gauge, count the turns on the adjuster until the rocker arm contacts the valve stem, now turn the adjuster exactly that same amount again to set the lifter preload.
383man
Well-Known Member
I feel for you as you have to many hands in the kettle which has to be confusing you. It sounds like your saying your eng builder is telling you to collaspe the lifter and run the plunger all the way down to the botom and then back it off a half turn ?? I hope thats not what he is telling you but the way I read it thats what it sounds like. Which you dont want to do as if the lifter pumps up more you wil surely bend valves.
All you need to do is put the cam on the base of the cam where the valve is closed. Then adjust either and adjustable pushrod or and adjustable rocker to zero clearance where the pushrod does not push the lifter plunger down at all. You just want the pushrod to sit in the lifter cup but not push it down any and adjust until there is zero clearance. Then you can adjust the rocker or pushrod to push the lifter plunger down to the amount of preload you want. Which if you go about 3/4 of a turn you should be fine. You want the lifter plunger close to the top so if you race it and the lifter pumps up it cant pump up far and cause any eng damage but you want it down some so it can adjust to zero lash and not be noisey. Most guys who race with hydraulic cams run them at close to zero preload but 3/4 turn turn down after zero lash should be fine. Your cam is not all that big and you should be able to run it with the adjustable rockers or stock rockers with little trouble.
We run the MP .557 cam in my sons 400 with the Eddy heads and we use Crane ductile iron adjustable rockers and once we got the pushrod lenth everything else lined up good. We did not have to make any other changes to it and its been running and raced since 2004. I know I am just another hand in your pot but this is really getting blown up to much and must be just confusing you more and more. Ron
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Here is the setup on my sons 400 with us using the Crane adjustable ductile rockers on the Eddy RPM heads. Ron
Great reply, Ron. Saved me from writing it....thanks.
383man
Well-Known Member
451Mopar
Well-Known Member
For pre-load, I just check the adjusters threads per inch (TPI), then find zero lash and turn the adjuster the required amount (based on the TPI) to get the lifter pre-load.
Usually a 3/8" adjuster is 24 TPI and a 7/16 adjuster is 20 TPI. So one turn of the adjuster is 1/24" (or 1/20" for the 7/16" adjuster.) In decimal that is 0.04167" per turn (or 0.050" per turn on the 20 tpi adjuster.)
Most standard Hydraulic lifters I have used (not the race or performance ones) list a range of 0.020" to 0.060" of lifter pre-load, so with a 24 TPI adjuster, one turn past zero pre-load get you near center of the pre-load range.
Usually a 3/8" adjuster is 24 TPI and a 7/16 adjuster is 20 TPI. So one turn of the adjuster is 1/24" (or 1/20" for the 7/16" adjuster.) In decimal that is 0.04167" per turn (or 0.050" per turn on the 20 tpi adjuster.)
Most standard Hydraulic lifters I have used (not the race or performance ones) list a range of 0.020" to 0.060" of lifter pre-load, so with a 24 TPI adjuster, one turn past zero pre-load get you near center of the pre-load range.
BBishere2
Well-Known Member
Here's a link to an old Hot Rod Magazine 440 build using the Edelbrock Performer RPM heads, a Comp Cams hydraulic flat tappett cam and stock rocker arms - I didn't find any mention of custom push rods. This may have been an oversight - or they dropped in the stock ones(?)....
http://www.hotrod.com/how-to/engine/1412-how-you-can-build-a-stout-537hp-street-440/
http://www.hotrod.com/how-to/engine/1412-how-you-can-build-a-stout-537hp-street-440/
moper
Well-Known Member
nute - Ron is right. You Do NOT want to back away from the lifter bottomed out. If that's what the builder said you need to talk to him more. What he's asking will hang the valves open - almost 100% guaranteed. Best bet is what you initially did: zero lash or preload, then go another 1/4-1/2 turn. Less is better for a fresh engine start and cam break in.
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