3900 rwd

[mbirt]

I've thought of that, maybe use some lock tight...and the using a flat tapped Cam isn't a terrible idea. you're leaving some on the table but it's gonna make more then stock.

I'm not interested in using the early generation hydraulic flat tappet cam as-is, I just want to use it as a cheap, easy to find core to have Delta or another grinder create a hydraulic roller cam to my specs for less than half the price of an off the shelf aftermarket hydraulic roller cam. I think the LZ9 has a lot of untapped potential as a 3/4 LS engine. Those who have come before us have probably bit off more they can chew when it comes to extensively modifying the bottom end, while I just want to see if the LS-based cylinder head can show % power gains with only a cam and spring change similar to the LS engines.

[1QUICKHATCH]

you could use a 3x00 cam (with spacers) and get a regrind, but it is hard to say how well it would hold up for racing. my 3x00 regrind cost me about $180 Cdn. about 5-6 years ago. have you called around to any of the larger performance cam company's ?

what is your compleate budget for the engine?

[mbirt]

you could use a 3x00 cam (with spacers) and get a regrind, but it is hard to say how well it would hold up for racing. my 3x00 regrind cost me about $180 Cdn. about 5-6 years ago. have you called around to any of the larger performance cam company's ?

what is your compleate budget for the engine?

My budget for the entire racecar is $2017, excluding tires and some safety items. My goal for the long block was to spend < $200 on the junkyard engine, $40 for 12 LS6 valve springs (already acquired), and <$150 for the cam regrind. Buying bearing spacers and a 1994-1999 HR core cam for regrind is a poor value proposition compared spending the same money for a better clutch or better axles. A pre 1994 flat tappet core with my own lathe work to build up the bearing journals might be worth it, however. I'm yet to call anyone other than Delta. I think my hollow cam regrind request is fairly low risk (.037" base circle reduction for my lift target) and shouldn't require any welding.

I'm working in China right now and spent some time yesterday trying to find a core cam from a Buick. It looks like they transitioned to assembled cams here around 2003 or 2004.

[trash boat]

https://wot-tech.com/race-camshaft.html I'd probably use this Cam with spacers... it says "race" but in a 3900 should work good on the street

[Guest]

My budget for the entire racecar is $2017, excluding tires and some safety items. My goal for the long block was to spend < $200 on the junkyard engine, $40 for 12 LS6 valve springs (already acquired), and <$150 for the cam regrind..

You don't have to swap the cam in order to get the engine to run. It will run on the stock cam. With the vvt actuator not recieving a signal from the computer, the cam will be locked in the advanced position and still runs and makes decent power

I might be confused and if I am please disregard but you plan on swapping in a flat tappet cam? A reground flat tappet?

If you can't put in a ROLLER Comp cam from WOT tech or a factory 3400 roller cam, then I wouldn't do a cam swap. You can then use that money towards something else like a larger throttle body and adapter. going to a flat tappet is going backwards.

[mbirt]

My standalone ECM will have no problem controlling the VVT, but, at the amount of overlap I want in my cam design, I won't be able to use much phaser swing before crashing valves into pistons. GM made it pretty obvious that this engine uses VVT to drive internal EGR and implemented it to replace the external EGR loop. It's not a performance VVT system--it's a cheap, low warranty risk replacement of a troublesome external system.

I'm just looking for the cheapest core solid cam to have reground to my LZ9 hydraulic roller specs. I know that the angled flat tappet lobes will destroy the roller lifters and I'd never run the flat tappet cam's original lobes with roller lifters.

I like your idea about running the stock cam for a while. Dyno time won't be in my budget, so I might as well see what I can make with my own stepped long tube headers, 10.8:1 compression, maybe a custom UIM, E85, and my standalone ECM.

[Guest]

since claim that the vvt is for emissions, and you are building a GRM car, I wouldn't even worry about the standalone controlling the vvt. It won't be used during the performance aspects that the GRm challenge puts your car through.

Also I would't worry about having a 3400 or solid core cam reground to the vvt cam specs. The stock 3400 cam and lx9 3.5 cam have darn near the same specs as the 3900 vvt cam. They are very close.


stock 3400 cam specs according to this link

http://www.grandamgt.com/forum/showthread.php?t=81977

And 3900 vvt cam specs.

Duration at .050.
Int 194
Exh 195

Lift
Int .272
Exh .286

Cam events @ .050
Int opens 12 ATDC
Int closes 26 ABDC

Exh opens 38 BBDC
Exh closes 23 BTDC

The two cams are so close its not worth regrinding the 3400 cam or finding a solid core 3x00 cam to regrind for the amount of money you will spend. Just run a factory 3400 or 3500 cam, the 3.9 rockers are 1.7 ratio.

You will eliminate the vvt cam and just have to use spacers, or machine up some rings to attach/slip over the 3400 cam journals to fit the 3900 block.

I say save your money on a regrind and put it towards something else.

[niceguy]

Any updates on the 3900 progress?

[trash boat]

[trash boat]

It's on boys...just realized its been two years since I started this thread lol

[trash boat]

I picked up an rx-8 6 speed, going to make an adapter also has anyone considered these pistons? http://www.jegs.com/i/Clevite/695/2243540/10002/-1 seem like I'd just need to get them fly cut. I also picked up some ls9 springs, Cam soon

[trash boat]

Picked up a 3500 intake and ordered a speedway motors adapter. We'll see if I can't mount this Mazda trans

[neophile_17]

It's good to see progress being made! Very interested in seeing how easy it would be to mount that RX8 trans. That trans. is going to be cheap to come by for the next couple years if my pull-a-part visits are any indication. Keep up the good work!

[trash boat]

It's good to see progress being made! Very interested in seeing how easy it would be to mount that RX8 trans. That trans. is going to be cheap to come by for the next couple years if my pull-a-part visits are any indication. Keep up the good work!

That's where I got mine, and the front suspension...the rear is also a pick and save special, 300sx diff, 4X4 Chevy truck axles, spindles struts and lower control arms are Malibu Max with uplander hubs.

[trash boat]