3.9L LZ9 engine internal upgrade & performance?

[mrtohil]

Actually I am trying to keep the VVT function. And I'm planning on installing this engine (with the 6spd F40 trans) in a Beretta.

[ericjon262]

So, I take it that you're going to ditch the VVT aspect of the LZ9? any particular reason why? I'm really liking this build. any plans to put the motor in a car?

[Nightingale]

i just went with the conversion bearings from cncguy to use gen3 cams. He uses the wider sbc bearings in his adapters plus you can get custom grinds easier this way.

[mrtohil]

Quick question. Has anyone figured out if the cam bearings can be swapped out with something better? Similar to how you can swap 3.1L cam bearings with Chevy V8 cam bearings, but the V8 ones are better since they have more surface area. I know that the first cam bearing will need to be stock due to the size and oiling holes. But cam bearings two through four look normal.

[mrtohil]

Hello everyone. Working again on this thing...hopefully to the finish. We'll see what new experiences happen this quarter. Did I miss anything while I was gone?

[carbon]

Sorry the format of that table bothered me...

Lift____________[0.100]_[0.200]_[0.300]_[0.400]_[0.500]_[0.600]_[0.700]_Avg CFM_Max CFM
Session 1(int)____62.4___128.6___186.8___218.9___232.1___238.5___NA______177.8___238.5
Session 1(exh)____52.6___100.0___138.2___150.1___154.7___155.8___156.5___129.5___156.5

Session 2(int)____67.1___131.9___191.1___236.0___250.0___257.3___261.1___199.2___261.1
Session 2(exh)____52.6___101.3___134.1___155.7___166.6___170.3___172.0___136.0___172.0

Session 3(int)____59.7___115.3___169.0___217.6___253.3___273.8___257.9___192.4___273.8
Session 3(exh)____53.4___102.0___136.9___157.5___165.5___169.6___172.0___136.7___172.0

Session 4(int)____63.3___125.4___187.2___238.7___263.7___265.1___266.2___201.4___266.2
Session 4(exh)____53.6___105.3___145.7___163.4___168.9___171.1___172.4___140.1___172.4

[mrtohil]

Just curious if anyone knows the specs for the stock valve spring. The specs I'm looking for are Seat Pressure, Open Pressure, Coil Bind and Spring Rate.
I found the installed height of 1.8in. Thanks ahead of time.

[mrtohil]

Ha! Yeah, don't what to tell you there. I also thought that that reading was weird. Especially how it falls off quickly after 0.600. To be quite honest with you I was a little nervous at the end of this session and what it meant. I think that ridge I mentioned before was really messing with my flow.

[robertisaar]

Intake readings for sessions 3:

@ 0.600" lift = 273.80
@ 0.700" lift = 257.90

In all other sessions, your readings at 0.700" lift were higher (albiet slightly) than the readings at 0.600" lift.

THIS!

[bszopi]

Intake readings for sessions 3:

@ 0.600" lift = 273.80
@ 0.700" lift = 257.90

In all other sessions, your readings at 0.700" lift were higher (albiet slightly) than the readings at 0.600" lift.

[mrtohil]

I'm sorry robertisaar, I can't seem to understand what you're asking/stating. Please clarify for me.

[bszopi]

Where are the pics...?

EDIT: Nevermind... http://s296.photobucket.com/albums/mm174/mrtohil/LZ9/

[mrtohil]

The next step for me now is to check valve to valve clearance and valve to piston clearance. I also have to check what the new valve spring installed height will be and if there wil be any issues with coil bind.
I am currently working to fitting LS1 roller rockers onto the head. I've posted pics of what they look like mock installed. There are four problems with fitting LS1 rockers these heads...but the end result I think is well worth it.
The first is that I needed to find rockers that were not shaft attached. As some as you know, SBC valvetrain is pretty simple. And the setup is simple. The valves are all in a line, non splayed. Also, the intake and exhaust valves are in the same place for every cylinder. So, most aftermarket rockers are mated together in pairs or by bank. This does not work here. LZ9 valves are splayed and on top of that, two cylinders have the valve placement swapped. So I was able to find independent roller rockers.
Second, the mounting pedestals for the rockers are different, but the same. LZ9 rocker pedestals have a wide, almost gem cut look to them. And each pedestal has an aligning tongue, which matched a groove in the head. SBC pedestals look like a tube with a base on it. These aftermarket units have metal bar the aligns them properly to the valve tip. Also, the new rockers are substantially thicker on the pedestal mounting area, both on the sides and for and aft. So, my teachers were able to find someone to machine the top of the original pedestals to match the aftermarket ones, while still retaining the alignment tongue.
Third, inside each pedestal, where the mounting bolt goes through is a little treaded area. This basically screws the pedestal to the rocker. Which is fine if you're using the same mounting hardware. But that is not possible. The mounting bolt for is different for SBC. What's interesting is the bolt thread size and pitch are the same, but the shoulder at the top of the bolt is what's different. So I found better replacements with some allen bolts which are stronger and are the appropriate length. But the threaded section inside the pedestal was not allowing full proper contact of the pedestal to the head. Allowing the rocker to feel loose. Loose bolt and aluminum don't mix well. So I drilled each internal threaded section out. Now there is full contact everywhere on the pedestal and rocker. And the rocker bolts down correctly.
Fourth, I test fit the rockers on different positions on the head. There were no issue with clearance until one. There is one position on each head where the valves are splayed close enough and just foreword and aft of each other to have one rocker body rub against the fulcrum of the other. I believe I'm going to have to grind off a little off the fulcrum to provide clearance.
This can be a fifth, but it will also depend if you have the longer valves like I do. And if rocker to valve tip contact position is important to you. I will have to shim each pedestal differently(if required) to move the rocker upward to have the tip roller be in the proper valve stem tip position.
That's it for now. Hope you like the latest pics and info.

[robertisaar]

i mean, look at the reading .100 less... and then flow was lost?

[mrtohil]

Yeah, i actually lost it everywhere until 0.500.