Need info on 3900 variants

[34blazer]

It seems that locking the cam out is a large compromise, since the cam grind is meant for the VVT, which as I understand it, is constantly adjusting, not just by RPM and/or load.

Without knowing valve events, I have to take everyone's word on it, opinion or fact. Dynamic EFI will be running the engine so VVT is out. I could devise a crude arduino based device and attempt to use the VVT, but I have to stay sharp on Weapons and Tactics, and other queep that monopolizes most of my study time. So learning to code is out. I wish I had access to a centerless and CNC ID grinder then I would make my own cam bearing spacers lol. Still a ways out so I can dig in my free time. Also, the engine should be here tomorrow.

[Guest]

if you are telling them 3900 engine, they won't have anything for that. no one seems to. I think we need to specify for the 3x00 motors to get them to talk to us.

the valve events were measured by CNC in another thread which I can link to if you want. they were for the vvt in the full advanced default position. Not sure if they are accurate, so you might want to measure yourself on your engine when it arrives. Who knows, maybe cams changed in later model years.

I read something a while back stating that GM increased the journal size, to allow for larger lobe profiles. not sure if thats true, but if so, it means GM planned to put some big cams in this thing at one time or at least have the ability. larger journals but gm kept a tiny lift cam makes no sense but I guess they were purposely limiting hp. with the cam they used, they still could have kept the smaller cam journals, making things much easier for us. DOH why weren't they thinking of the aftermarket? LOL

[34blazer]

I just called the tech line and its going to be a custom billet no matter what, I specified a roller for a 3x00 and they said it can be done(obviously) with larger journals. Starting price for a custom billet is $900, price goes down if ordered in batch.

If I can score some cam bearing spacers for a decent price, and buy the stage 2 roller turbo cam kit from WOT, and keep it under 1K, that wont bust my budget for this year.

The way I see it, cam bearing spacers could be a nightmare to make without a centerless grinder, a lathe would cause too much chatter, even with a rubber band or electrical tape, since the material would be really thin. The ID may be cut with a lathe, but I feel that an ID grinder may be better. So hopefully someone can come up with some cam bearing spacers lol.

[Guest]

Without knowing valve events, I have to take everyone's word on it, opinion or fact. Dynamic EFI will be running the engine so VVT is out. I could devise a crude arduino based device and attempt to use the VVT, but I have to stay sharp on Weapons and Tactics, and other queep that monopolizes most of my study time. So learning to code is out. I wish I had access to a centerless and CNC ID grinder then I would make my own cam bearing spacers lol. Still a ways out so I can dig in my free time. Also, the engine should be here tomorrow.

DIY Autotune sells a device that is specifically for VTT, but it was originally designed around the Miata VVT, which I believe is functionally different than the LZx VVT design. It would be something to look into since the firmware is open source, I believe, and could be made to work.

http://www.diyautotune.com/catalog/vvtuner-c-80.html

[34blazer]

Well, it's here.

Look for a new build thread, dropping this in the Grand National.

[Xnke]

I don't understand the hullabaloo about bearing spacers.

Just make bearings and go on about it, it's not a huge deal. The OEM bearings are aluminum alloy applied to a steel backer ring, the alloy is expensive but available. Look for 850.0-T5, A08500 alloy. Formerly known as SAE750. The bearings are turned on a lathe when they're made, there's no big reason to make some complicated bearing spacer.

That said, you could just call the bearing makers and get some bearings made. Would be easy for WOT-Tech or any other stock supplier to get some SBC bearings made with larger OD's. I've had bearings custom made a single set at a time for engines that did not have stock bearings available.

Just to be complete-what size OD does the new bearing need to be, and will the ID be the same as the standard 3400 roller cam?

[34blazer]

I don't understand the hullabaloo about bearing spacers.

Just make bearings and go on about it, it's not a huge deal. The OEM bearings are aluminum alloy applied to a steel backer ring, the alloy is expensive but available. Look for 850.0-T5, A08500 alloy. Formerly known as SAE750. The bearings are turned on a lathe when they're made, there's no big reason to make some complicated bearing spacer.

That said, you could just call the bearing makers and get some bearings made. Would be easy for WOT-Tech or any other stock supplier to get some SBC bearings made with larger OD's. I've had bearings custom made a single set at a time for engines that did not have stock bearings available.

Just to be complete-what size OD does the new bearing need to be, and will the ID be the same as the standard 3400 roller cam?

I'm AD AF, I don't have the know how or capability to make any cam bearings. LOL. But I'm sure if you were up to the task, there may be some takers if you offered to make some

I've already contacted durabond and they told me no dice, they can't source the material thick enough to build a set to match the specs I gave them. They suggested Clevite, though.

Specs for the LZ9 are in the pushrod section...

http://60degreev6.com/content.php/89-2006-Present-Pushrod-VVT

I found some LX9 specs here...

http://www.g6performance.com/forum/showthread.php?t=264

LZ9:

Front and Rear bore; 2.175-2.177"
Middle bores; 2.155-2.157"

LX9 cam bearing I.D:

1.871-1.872"

cam journal; 1.868-1.869"


I found some cam bearing spacers with bearings installed, ready to be installed into the block, so Im going that route.

Xnke, thanks for sharing! Much Appreciated!

[34blazer]

I'm kicking myself for throwing out all my leftover 3400 stuff, I need a fuel rail now.

[34blazer]

[34blazer]

According to Mars the LZ9 fuel rail test port can be used as a return port. He is using a 255 pump and can maintain 43.5 psi, so that's good news.

The trigger wheel is 58x missing tooth which is not compatible with the buick ignition. Im needing a trigger wheel with 3x, or even spacing to be divisible by 3. Also needing a cam trigger wheel, which I'm trying to devise a way to use the buick reluctor and cam sensor, and modify the oil drive with a dizzy shaft cut down and faced/drilled to mount the reluctor. Timing the cam sensor will need to be exact since there is not much space or adjustability behind the lower intake. I was thinking about trying to make a reluctor wheel with a 30* window to be used on the front of the cam gear as well. Then mount the sensor in the timing cover since VVT will not be used. Out of money for now, though...

[Guest]

no need to modify the test port. get one of these and you will be good. you have to make custom fuel lines anyways.

http://www.summitracing.com/parts/aei-13129/overview/

Not interested in wiring up a 7730? wot sells the crank triggers and can do a base tune for you.

[34blazer]

Yeah already have an adapter to use off the LC2 rail so that's covered. Not wanting to go with a 7730 right now, last resort. I don't want to chop the factory harness and I like the idea of using the SFI6 already installed. Just some thought for now until money starts showing up.

Sent from my XT1080 using Tapatalk

[34blazer]

Are the connecting rod cap bolts and main cap bolts torque to yield?

[Guest]

Yes, which is part of the reason I replaced them in my LX9 with ARP rod bolts.

[34blazer]

Yes, which is part of the reason I replaced them in my LX9 with ARP rod bolts.

Thanks, I wanted to be sure.