Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.
I was in the junkyard today and stumbled across a LZ4 in a G6, and I noticed the rocker arms sitting on the bumper, so I grabbed one and brought it home... some of the pics suck, I'll get better ones later...
as far as I can see, the main differences are in the pedestals, not the rocker itself, it also appears as though any competent machinist could make changes to the pedestal of the 3500 rocker to fit the LZ4 rocker.
the LZ4 rocker is also 0.5 oz lighter than the LX9 rocker (5.2 oz vs 5.7)
I have not measured the ratio of either rocker.
going by looks, the LZ4 rocker looks much stronger, this may call for a test fixture and high strength hardware for destructive testing...
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I still don't have new pictures of the parts by themselves, but I did install a rocker on my LX9 3500, and it bolts on no problem with the LX9 pedestal swapped on. I didn't turn the engine over to see how the work through the lift curve, when I get the new engine back from the machine shop, I'll do a more thorough check.
a proper install will likely need new pushrods, and I would recommend valvesprings too as the 3x00 springs suck... On the exhaust valve I installed the rocker on, there was a very noticeable amount of play, over .060". this could work out to be a very cheap and easy mod for the 3x00 engines, as the stock rockers are 1.6:1, and the LZ4 rockers are supposedly 1.7:1
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
the geometry is way off... time to start looking at other options...
photocred Ben @ WOT-Tech.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Can you get a "side view" photo of the candidate and original rockers side by side (or top to bottom) so that we can assess any geometry difference?
They're both roller trunion, right? The only difference is the weight and ratio? It looks like the LZ4 is an investment casting and the LX9 is a stamping.
The LX9 is the 94mm bore non-VVT 3500 and the LZ4 is the 99mm bore VVT 3500?
How much difference is there otherwise between the two sets of heads? Different valve length? Different rocker boss height relative to the deck?
both rockers are almost identical, the LX9 (non VVT) is Stamped, and the LZ4(VVT) is cast. both have a roller trunion, and both trunions are the same diameter and width.
Looks like the LX9 base. when I get my heads back from the machine shop, we'll try this again and see how it looks. I think he took that pic on a 3400 head, so it may work better on my 3500 head.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
