larger magnum cam...longer pushrod??
#814348
09/25/10 09:33 PM
09/25/10 09:33 PM
|
Joined: Aug 2003
Posts: 4,673
On the parachute mount
n20mstr
OP
master
|
OP
master
Joined: Aug 2003
Posts: 4,673
On the parachute mount
|
since the stock vavletrain is non adjustable...if i put a bigger cam in a magnum smallblock, will it need alonger pushrod??
....BAD A$$ STREET CAR.....
|
|
|
Re: larger magnum cam...longer pushrod??
[Re: n20mstr]
#814349
09/25/10 10:18 PM
09/25/10 10:18 PM
|
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
joedust451
super gas
|
super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
|
Quote:
since the stock vavletrain is non adjustable...if i put a bigger cam in a magnum smallblock, will it need alonger pushrod??
Shouldn't. You can always gets adj. rockers fairly cheap, are you planning on changing springs? You really should to match the cam so you don't float the valves,just be awhare the factory bolts are small & could break if spring pressure gets too high. Are these factory magnum heads?
|
|
|
Re: larger magnum cam...longer pushrod??
[Re: joedust451]
#814350
09/25/10 10:22 PM
09/25/10 10:22 PM
|
Joined: Aug 2003
Posts: 4,673
On the parachute mount
n20mstr
OP
master
|
OP
master
Joined: Aug 2003
Posts: 4,673
On the parachute mount
|
all stock valvetrain, yes changed the springs, now if the cam is larger than the base circle is smaller....is it normal for there to be a little "lash: in there, gets taken up when the engine is started again and the lifters pump up that lil extra???
ALSO i lost one of the stock keepers, cant find it any where...any one got just one?? stick in an envelope and mail to me?? lol boy do i feel dumb
....BAD A$$ STREET CAR.....
|
|
|
Re: larger magnum cam...longer pushrod??
[Re: n20mstr]
#814351
09/26/10 12:26 AM
09/26/10 12:26 AM
|
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
joedust451
super gas
|
super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
|
Quote:
all stock valvetrain, yes changed the springs, now if the cam is larger than the base circle is smaller....is it normal for there to be a little "lash: in there, gets taken up when the engine is started again and the lifters pump up that lil extra???
ALSO i lost one of the stock keepers, cant find it any where...any one got just one?? stick in an envelope and mail to me?? lol boy do i feel dumb
Yeah, ide say the base circle should be that different that it couldn't make up the difference, i had my stock cam re-ground from bullet cams, i'm sure they trimed down the base circle a tad.
Maybe Patrick will have what you need, hopefully he sees this & chims in, or you can PM him, i'm sure he will help you out. 
|
|
|
Re: larger magnum cam...longer pushrod??
[Re: n20mstr]
#814352
09/26/10 12:31 PM
09/26/10 12:31 PM
|
Joined: Oct 2007
Posts: 4,206
New York
polyspheric
master
|
master
Joined: Oct 2007
Posts: 4,206
New York
|
1. this has nothing to do with duration, so a new cam may require nothing at all.
2. higher life doesn't always mean a reduced base circle, a non-welded regrind always has a reduced base circle
3. base circle reduction needs more length: 1/2 the reduction
4. more lift needs less length: 1/2 the lift increase
5. final result depends on how the cam is ground and the rocker ratio
Boffin Emeritus
|
|
|
Re: larger magnum cam...longer pushrod??
[Re: polyspheric]
#814353
09/26/10 08:49 PM
09/26/10 08:49 PM
|
Joined: Aug 2003
Posts: 4,673
On the parachute mount
n20mstr
OP
master
|
OP
master
Joined: Aug 2003
Posts: 4,673
On the parachute mount
|
Well i stuck a feeler gauge in there, and .025 get the rocker nice and tight, A little math, 6.925 + .025 + looks like the Hughes 7.050 pushrods will work great....lets hope the stock rockers last a lil while...the cam is from Scott brown and its 580 lift , mopar perf springs
....BAD A$$ STREET CAR.....
|
|
|
Re: larger magnum cam...longer pushrod??
[Re: StrkrDart69]
#814355
09/26/10 10:55 PM
09/26/10 10:55 PM
|
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
joedust451
super gas
|
super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
|
Quote:
With that much lift I hope you had the valve seal to retainer distance checked. Magnums do not have alot of retainer to seal clearance over .500 lift. I would purchase adjustable rockers, and use an adjustable pushrod checker to find out what length pushrod you need. Remember to check the rocker wear pattern on the valve stem tip.  
 , if you didn't have the guides cut down i don't think .580 lift will work.
|
|
|
Re: larger magnum cam...longer pushrod??
[Re: joedust451]
#814356
09/27/10 09:55 AM
09/27/10 09:55 AM
|
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
|
Quote:
Quote:
all stock valvetrain, yes changed the springs, now if the cam is larger than the base circle is smaller....is it normal for there to be a little "lash: in there, gets taken up when the engine is started again and the lifters pump up that lil extra???
ALSO i lost one of the stock keepers, cant find it any where...any one got just one?? stick in an envelope and mail to me?? lol boy do i feel dumb
Yeah, ide say the base circle should be that different that it couldn't make up the difference, i had my stock cam re-ground from bullet cams, i'm sure they trimed down the base circle a tad.
Maybe Patrick will have what you need, hopefully he sees this & chims in, or you can PM him, i'm sure he will help you out.
if it's a regrind, that's how they get more lift, reduce the base circle, so there is a possibility to need longer pushrods. if you do, these are nice and cheap:
http://www.summitracing.com/parts/CCA-7828-16/
dependng on who's specs you believe, they're .018-.036" longer than stock magnums...
sorry, don't have a spare keeper....maybe try get one from a junkyard, or maybe hotroddave40, or rockauto lists sealed power VK216 for the magnums...
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
|
|
|
Re: larger magnum cam...longer pushrod??
[Re: n20mstr]
#814357
09/27/10 10:06 AM
09/27/10 10:06 AM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
Well i stuck a feeler gauge in there, and .025 get the rocker nice and tight, A little math, 6.925 + .025 + looks like the Hughes 7.050 pushrods will work great....lets hope the stock rockers last a lil while...the cam is from Scott brown and its 580 lift , mopar perf springs
Check the MP springs before you use them... I bought a
set that were good to .640 lift(according to MP) and
tested at 63# at 2" seat pressure
|
|
|
|
|
