Valvetrain Set up bad?? Ideas?
12-01-2010, 11:17 PM
#1
Valvetrain Set up bad?? Ideas? Okay so over the summer i built up the top end of my LT1 with p/p heads, crane springs, scorpion 1.6 rockers, and a cc305 cam. My friend at the local machine shop helped me do most of the install (hes also the one that did the heads). Okay so me and one of my Ltx buddy's here in Michigan were talking about how loud my valvetrain is and we were trying to diagnose it...well when my machine friend helped me measure for pushrod length he measure for a 7.00" length rod...well after we got them and started to set lash we realized the lock on the rocker would bottom out before lash was set so he just had me order lash caps...well me and my Ltx buddy were talking and he said he has never heard of a 7.00" length rod being used on an Ltx car..and when i asked my machine shop friend he said having the geometry of the valvetrain lower is safe on the motor and it will last longer. Well i think he was giving me a load of crock sh*t. And since this i have readjusted lash a few times and it never gets quieter (sounds like a rod knock, i can hear it over my exhaust and i have lt headers through a 3" y-pipe with a dynomax bullet dumped right after). I have a few questions for some true Ltx builders. Are my pushrods to short? If they are do you think they are robbing me of HP? Also do you think my scorpion rockers are not good? Should i have gone with comp pro mags? Any help would be greatly appreciated guys! Thanks in advance!
Nick Kerns
Nick Kerns
12-01-2010, 11:22 PM
#2
There are several things that affect pushrod length, including deck height (both block and heads), head choice (stock casting or aftermarket) and head gasket thickness. Unless you've taken some serious material out somewhere (it doesn't sound like it) then your pushrods are WAY too short.
To put it into perspective, I have a zero-decked block, healthy milled heads (-52cc), and an .028" gasket and I use a 7.10" rod (which is still a bit on the short side). It is true that a shorter pushrod is a bit better than being too long, but that applies for about .05" of an inch.
How exactly did he measure for the right length?
To put it into perspective, I have a zero-decked block, healthy milled heads (-52cc), and an .028" gasket and I use a 7.10" rod (which is still a bit on the short side). It is true that a shorter pushrod is a bit better than being too long, but that applies for about .05" of an inch.
How exactly did he measure for the right length?
12-01-2010, 11:29 PM
#3
There are several things that affect pushrod length, including deck height (both block and heads), head choice (stock casting or aftermarket) and head gasket thickness. Unless you've taken some serious material out somewhere (it doesn't sound like it) then your pushrods are WAY too short.
To put it into perspective, I have a zero-decked block, healthy milled heads (-52cc), and an .028" gasket and I use a 7.10" rod (which is still a bit on the short side). It is true that a shorter pushrod is a bit better than being too long, but that applies for about .05" of an inch.
How exactly did he measure for the right length?
To put it into perspective, I have a zero-decked block, healthy milled heads (-52cc), and an .028" gasket and I use a 7.10" rod (which is still a bit on the short side). It is true that a shorter pushrod is a bit better than being too long, but that applies for about .05" of an inch.
How exactly did he measure for the right length?
Thanks for the help!
12-01-2010, 11:49 PM
#5
Haha i think im figuring this out lol...thanks again for your help...i think im going to upgrade my cam to the ai 226/234 and get the correct length rods over the winter...btw man i love your car!! i cant wait till i build a 383 for my car.
12-02-2010, 12:31 PM
#6
There are several things that affect pushrod length, including deck height (both block and heads), head choice (stock casting or aftermarket) and head gasket thickness. Unless you've taken some serious material out somewhere (it doesn't sound like it) then your pushrods are WAY too short.
To put it into perspective, I have a zero-decked block, healthy milled heads (-52cc), and an .028" gasket and I use a 7.10" rod (which is still a bit on the short side). It is true that a shorter pushrod is a bit better than being too long, but that applies for about .05" of an inch.
How exactly did he measure for the right length?
To put it into perspective, I have a zero-decked block, healthy milled heads (-52cc), and an .028" gasket and I use a 7.10" rod (which is still a bit on the short side). It is true that a shorter pushrod is a bit better than being too long, but that applies for about .05" of an inch.
How exactly did he measure for the right length?
12-02-2010, 12:48 PM
#7
Why don't you pull the valve cover and a rocker arm, cover the valve tip in magic marker, tighten the rocker down, spin the motor over once or twice and take a picture of the tip after that so we can see.
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12-02-2010, 03:43 PM
#10
Would haveing guideplates installed on the head w/o them being milled down for them do anything?...also im using the stock rocker arm studs...?
I have ls7 lifters too...
I have ls7 lifters too...
Last edited by Purple94Z28; 12-02-2010 at 04:23 PM.
12-02-2010, 04:23 PM
#15
12-02-2010, 04:24 PM
#16
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lol maybe he meant studs, rocker studs. And if you are using the stock 3/8 studs (maybe to late now) if i was you i would have went with 7/16 studs with 1.6 rockers. By the way i'm running the scorpions rockers and love them, cant here them for the life of me.
12-02-2010, 04:32 PM
#17
12-02-2010, 05:14 PM
#20
