DaleMX

iTrader: (4)

When setting the preload on the lifter should the lifter be on the base circle or can it be up on the lobe?

JPR

Set it up on the base circle of the cam, anything more than 2 turns preload, buy shorter PR's. These LS1 motors get a bit clattery with less than 1.75 turns into the preload.
Good luck!
Joe.

1dirtyZ

iTrader: (1)

don't adjustable rockers require 3/4 turn of preload?

JPR

Stock preload is 2.5 turns down to 22 ft lbs. I have found that 2 turns ensures a quiet valve train, anything less sounds like a sewing machine to me. We have 35 sets of heads out there with -0- complaints of noisy valve operation so I am sticking with my theroy. On the other hand, I set up the LT1 LT4 adjustable rockers at 3/4 to 1 full turn which is less than an LS1 preload with basicly the same lifter for quiet operation, I haven't figured that one out yet, I am guessing that it's the difference between a 1.5 stock rocker vs a 1.7 stock ratio. I am just going with what works.
Joe.

<small>[ August 18, 2002, 09:50 AM: Message edited by: JPR ]</small>

ScottyG

Time for a stupid question:

When you say "2 turns preload", does that mean 2 full turns of the rocker bolt after the point of zero lash?

I'll be swapping my cam this week.....

1dirtyZ

iTrader: (1)

another question, are we talking stock rockers or after market?

DarkHorse_LS1

So, is JPR saying that a clacking valvetrain might need the rocker arm bolts tightened up more?

JPR

Dale, my rule of thumb is, if I have to use a CM push rod, I will only use them in A4 cars, I use stock PR's in stick cars only so if a gear is either missed or over the engine is over reved, your chances of bending valves are that much lessened and I would rather bend pushrods than valves IMHO. I don't mill enough off my S2 or S1 heads to constitute using a shorter PR to begin with on my packages. S1 (10.3) is from a stock cam to a 218 cam, and my S2's (10.5) heads are a TR 224/.561/112 cam.

1 DirtyZ,
stock rockers or aftermarket, pre load is pre load, it's all cam base circle sensitive.

Dark Horse,
I am not saying that the rockers have to be torqued more than 22 lbs, the PR's just have to be matched specifically to the base circle of each cam, every aftermarket cam is different.

Joe.

ScottyG

Wow...my question must be stupider than I thought.... not even worthy of a reply eh, Joe? <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />

JPR

Sorry Scott,
I am busy answering all these question and I over looked yours, and yes, 2 full turns in after the rocker contact to the PR.

ScottyG

Thanks Joe.

Yes, I've read the posts about what you guys are up to. Sounds like you've got a lot going on.

The 382 shortblock price is sweet!

DaleMX

iTrader: (4)

Thanks Joe, While were at it let me ask this. Is one pushrod better than the other. I'm looking to replace my stock rods with some chromemolly rods and am wondering about the differences between crane, comp, etc... Any help is appreciated.
Dale

1dirtyZ

iTrader: (1)

thanks for the reply jpr,
but not disagree with what you said or show any disrespect or anything , but 2 turns on roller rockers (crane) comes out to 0.157", isn't that too much?
or by aftermarket you meant the slp's?
i could use all the info i could get , cause i'm a sufferer of the "sewing machine" syndrome. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />