5.3litre

iTrader: (6)

I'm fixin to remove my heads on my ls7 project to send them to get milled.
I'm gonna step up to a bigger cam while i have the heads off too. I'm still gonna use the stock rockers. My question is, when i get the heads back and bolted on. Can i just simply put the rockers back on and torque them down?Or do i need to do it in some kinda valve or cylinder sequence? I read sumin about havin to manually turn the engine over by hand to make sure the valves are shut in the head?

DaveX

It's best to torque them down when the respective lifter is on the base circle. I usually just turn it over by hand (with the plugs out) and do a visual on each one to make sure it's on the base circle before torquing.

5.3litre

iTrader: (6)

What do you mean by base circle? Would this mean the pushrod is at its lowest point?

SOMbitch

iTrader: (8)

Search the vettenuts post here. Some just go to 22ft.lb but he gives the best way IMO... A good write up....

Old SStroker

You are going to measure for the correct pushrod length with the new cam, correct? The new cam will have a smaller base circle if it has more lift, so best pushrod length will change.

You should check with you cam designer for the amount of lifter preload he suggests. After you measure the pushrod length with your new cam and milled heads installed you can order the correct length and get them in a couple of days. While you are at it, ask your cam guy which pushrods to use, by brand, diameter and wall thickness (or part number).

Good luck.

Jon

5.3litre

iTrader: (6)

I searched. Can't find it

Thanks. I'm dealing with Ragin racing and we have already discussed these things.

Also guys i have another question. I have done 1 cam swap before but the engine had the heads on it. I'm gonna be swapping cams w/o the heads on this time and i was wandering if this changes anything? What extra things am i gonna have to/not have to do since the heads are off. Thanks

Ericbigmac83

iTrader: (19)

Tighten to 22lbs, spin motor. tighten to 22lbs again


Having the heads out only makes it easier. no real changes, don't have to worry about the lifters dropping tho since you can just remove them

5.3litre

iTrader: (6)

Ok, but what if a particular lifter/pushrod are sitting to high? Won't you run the risk of breaking the rocker arm bolt off in the head or stripping the threads?

Ericbigmac83

iTrader: (19)

nope, you're good

vettenuts

iTrader: (4)

Here is the GM procedure for the LS1, can't guarantee its the same for the LS7 but I would think it would be as the bolt preloading logic is the same.

5.3litre

iTrader: (6)

alright thanks for the info

Beaflag VonRathburg

iTrader: (176)

Having the plugs out will make it a ton easier on turning the engine over. It will just bleed all of the compression out of the plug holes instead of maintaining it in the cylinders.

5.3litre

iTrader: (6)

Is the intake valve on each cylinder the one toward the front of the engine or toward the tranny?

vettenuts

iTrader: (4)

The exhaust is closest to the exhaust port is the best way to figure it out. On driver's (LS1) the intake is first working back, on passenger it is opposite. Heads are identical, but face opposite directions.

5.3litre

iTrader: (6)

alright. thanks for your help

topher455

iTrader: (6)

Also try to make sure the tip of the rocker stays centered on the valve (left to right) when you are tightening the rocker. I've seen people just reef the bolt down and pull it into place and it makes me cringe. It is aluminum you are tightening into so a little prevention is worth...