Alright here's the deal. I went to help my friend put some 1.6 rr's (self-alighning from federal mogul) on his 94 T/A along with LT4 springs (all with stock cam). When adjusting the rocker arms, we torqued them down just to the point where there's no more play in the pushrod, then from there about 1/2 a turn and then they should be fine right?? Well at that setting, the rocker arms kept slipping off the spring, so we torqued them down another 1/4 turn or so or just the point where they wouldnt slip off the spring and felt about the same as the stock ones did when trying to wiggle them. We did this and turned the crank accordingly so each piston was at TDC when working on that cylinder. When the time came to fire up the car, 2 pushrods broke and the rest got bent. (but at least no valves were bent or dropped) So we're like ok, well the rocker arms must have been too tight to break pushrods.

He has the car towed to his mechanic as we ran out of time to do this again because of college and work. They put new stock pushrods in along with the 1.6's, and surprise!!, he broke/bent several pushrods when he went to start it up. So now the mechanic tells us that LT1's can't use roller rockers and that you need the stock stamped style to work. So now, the mechanic put the original 1.5's back on and left the LT4 springs in, and the car is running fine (with yet another set of pushrods).

So I guess my question here is: shouldn't LT1's accept roller rockers? It seems many here are running roller rockers just fine on otherwise basically stock valvetrains. What went wrong with this whole, should have been a 2 hour job turned into days? Is it true LT1's can't accept roller rockers or is this BS? Sorry for the long post, but I need to know what the deal is with rocker arms. thanks


Jason

 

Are you sure that they are self-aligning?? They do have the little guides where the roller meets the valve stem right, that is what keeps the rocker arm from coming off the valve.

 

LT1s can and do run roller rockers with no problem. Your mechanic does not know what he is talking about.

If the rockers would not stay put on the valves, then you probably have the non self-aligning variety. The way to check is to look at the part where it rides on the valve. The self-aligning ones will have two ridges that stick up either side of the roller. These ridges sit to either side of the valve and keep the rocker in place. Look at one of the stock rockers, and you'll see what I'm talking about. If the rockers don't have the ridges, then you either have to get some that are self-aligning, or buy guideplates and install them. The guideplates have "fingers" on them that hold the pushrods, so that the rockers stay centered over the valves. Use the guideplates ONLY if you have non-self-aligning rockers. You souldn't use self-aligning rockers and guideplates together.

You should also check the the springs you are using really do have enough range for the setup. If they are binding (open all the way so that the coils contact one another), then you would get the problems you describe. Are you sure they are LT4 springs?

I have Comp Pro Magnum non self-aligning roller rockers with guideplates. I run a cam that is much larger than stock with no problems.

 

Hey llafro what did you run at the track with your setup?

 

Maybe you somehow had the wrong roller rockers.

Not familiar with a Federal Mogul 1.6 roller rocker.

 

Thanks for the suggestions. I haven't talked to Chris lately about this as both of us have been busy (hence me not responding until now). I'm about 100% sure the springs he got are the LT4 springs (got as a set from paceperformance) just from the fact that the LT4's are harder to compress then the stockers. As for the self-aligning thing, I thought they had that, but was never positive on it, especially having torque them down so much so they'd stay on the spring. It looks to me like he's gonna have to get different rocker arms that are actually self-aligning. I'll let you know what happens.

Jason

 

just buy some guideplates instead of new rockers.

 

Did Chris ever figure out anything? I talked to him last week about the whole situation on the phone, I saw he called me the other night but haven't had a chance to call him back. The whole thing sounds really strange. I think i suprised him when I was talking about how much the head/cam swap is he was asking about. If it bent/broke pushrods, I'm pretty sure it had to bend some valves, but i told him a leak down test would have to be done to know for sure.

Jason

 

Chris had the car towed to a shop, and they said his valves were fine and there's no need to replace them, so his hopes of "having to do a rebuild" are lost. This is also the same shop that said LT1's can't use roller rockers.

Right now the car is up and running fine with the LT4 springs and the original 1.5's. He still has to talk to his uncle at federal mogul about ordering different rocker arms. Yes he could go with guideplates if he wanted, but I think he's looking to return these 1.6's and get some ones that are actually self-aligning. I'm not sure really though, he's broke right now so who knows what will happen if he can't get a refund on those 1.6's.

BTW, nice setup in your T/A. Who built your 406?

Jason

 

That's great to hear that he didn't bend any valves, I'm sure that's a relief for him.
I built my 406, I was going to take it to the track today but I have a transmission leak so it's gonna have to wait.

 

No, he was actually disappointed he didn't bend a valve as it would have been a good excuse to rebuild the motor.

Jason

 

I thought the only Aftermarket/OEM Self-Aligning 1.6 rr's made are from:

GM Performance Parts
Crane Gold(same as above)
CompCams

???
Ive heard of Scorpion and never heard that Federal Mogul made a set.

 

I honestly don't know. The rockers could have been made by a company Federal Mogul owns or something. I thought the same thing when he told me he got them. Either way, he got them for $130 from his uncle who gave him some sort of discount.

Jason