97formula17

Im hoping someone here can help me or at least tell me what im doing wrong. Im in the middle of my build and im completely stuck at this point. First I'll start with what I have. Its a 1997 lt1. I started with a t56 swap, then I figured while I was in there just go ahead swap in a hot cam. Then I figured while I was doing the cam, I should go ahead and do roller rockers and lifters and so on and so on. So now I have my car all buttoned up and have no idea where to go next. I also did the 24x conversion. I have the jet dstuner, I know its not the most desirable but I had bought it prior to learning about the 24x conversion. So I've been playing with the tune trying my hardest to figure it out. As I was cranking the car, a loud knock developed. Pulled the driver side valve cover off and I now have a beautiful bent pushrod, which was suppose to be hardened. It is the intake on cylinder 1. the knock was the Rocker being pushed off the side of the valve tip. Before I put the motor in the car i check all the clearances and spun it over like crazy with a pull handle trying to get it to fail before I put it into the car. I set the preload just like i read. As far as parts go: Gm hot cam, LS7 lifters, jegs (probably the problem right there) hardened push rods stock length, 1.7 scorpion roller rockers, and crane dual valve springs. the Rollers lined up right over the top of the valve. I didn't have any bind of rough spots or anything. The motor spun over beautifully. And i didn't pump up the lifters either, just soaked them in some oil before installation. And lastly if someone can direct me to somebody who can send me a tune so i can get to a dyno that would be awesome. I tried my best to tune it myself, but im in way over my head. Thanks in advance for your time.

96capricemgr

iTrader: (1)

describe how you set the preload.

97formula17

I tightened the polylocks down until I felt tension from the polylock while looking for drag from the pushrod. After that went 1/2 of a turn. With the wrench holding the polylock I tightened up the allen bolt.

Ed Wright

iTrader: (1)

If the rocker went off one side, off the valve stem tip, you either did not use self-centering rockers or no/wrong guide plates. The problem is not the push rods.

97formula17

I used nsa rockers with the trickflow guideplates. I can upload a picture of the push rod and rocker if need be.

96capricemgr

iTrader: (1)

Did you feel drag then go half a turn?

97formula17

Felt the drag then went another half turn.

96capricemgr

iTrader: (1)

I would start by relashing them right.

97formula17

Do I follow the same the same procedure? Ive already spun the motor over and pumped the lifters. Should I wait a few days or will they be fine?

96capricemgr

iTrader: (1)

The looking for drag on the pushrod is where you screwed up, by the time there is drag you are much too tight.
Just spin the pushrod down till it hit the rocker then go half a turn.

97formula17

Got it. Now all I need is a base tune so I can atleast get it running. Do you have any ideas where I can go or a member on here I can talk to?

cardo0

Got what?

Bent p-rod can be from too loose or too tight or too small spring that reaches full compression or falling off the vlv tip from bad alignment.

Too loose if adjusted while lifter on the lobe and not base circle. Do u know what the base circle is and how to find it? Once on the base circle then tighten until it drags is good - then make your adjustment. Anyone that understands how a hydraulic lifter works can see the p-rod cup is not depressed if u can still roll the p-rod back and forth with your fingers. If u can roll the p-rod with a little drag then all the up and down slack is removed - then make your adjustment. Once that cup is depressed into the spring the p-rod is secured and cannot roll or move back and forth with your fingers. GM says u can adjust up to 1 full turn so as it starts to drag is far from 1 full turn as u will/can see/demonstrate for yourself. But leaving too much slack and allowing the lifter/p-rod to separate will bend p-rods - meaning p-rod was not at zero lash.

So i suspect your problem is not the drag method (read any shop manual and they use it) but adjusted while not on the base circle or too weak/small spring that collapsed.
Or maybe even bad alignment with those guide plates.

cardo

97formula17

Yes I know what the base circle of the cam is. Im not a moron. I set the engine at tdc starting at 1...thats with both valves closed. My springs arent too small as they can handle the lift of a hot cam even with the 1.7's. The crane dual springs can handle the same as the comp beehives if im not mistaken. I posted this because I did everything the exact way I read how to (and not just from this site) and still had a bent pushrod. Im going to order anew pushrod and relash everything. And as far the guideplates being set wrong, they only go on one way. They even have the word "UP" stamped in the top. I appreciate the advice but what I meant by I got it was that I got that I must not have lashed them quite right so I am going to redo it once I get a new pushrod.

cardo0

Sorry, i didnt mean to be patronizing. But anyone regardless of experience or knowledge can become unintentional distracted and lash the wrong set of lifters. Just wanted to make u aware of the possibilities.
Heck even the p-rods could be too weak for your vlv train - springs, cam lift and rpm. Hardened p-rod are case hardened not any stronger compressive wise than stock p-rods.
I didnt want to aggravate someone that is honestly looking for help as camaraderie helps us all here. And we all own these performance cars for the fun of it not the aggravation.

Just wanted to help,
cardo