Camaro_freak

iTrader: (1)

So my project of building a forged 383 for boost is nearing completion, and last night I tried firing it for the first time. It cranks fine, but was misfiring badly and wouldn't stay running. I don't have everything reinstalled yet since I don't want to undo everything again if it has to come back out of the car for some reason. So here are the things I haven't done yet:

- No coolant. Only planning to run for 30 seconds or so
- Harmonic balancer/pulley not installed
- No alternator, power steering pump, or AC hooked up
- No AIR pump
- Open manifolds, cats and y-pipe not installed

The car has been sitting for over a year with old gas in it, so not sure if that could be an issue. Also, for a baseline tune, I simply started with the 350 CI speed density tune and only changed the displacement setting for the 383. I thought this would be close enough to get it running, but perhaps not. Also, the 58 mm throttle body may need adjustment for idle since it's never been run on this car. Any thoughts or suggestions?

ahritchie

iTrader: (1)

What are the specs on the build?

Camaro_freak

iTrader: (1)

Engine is built for boost by an STS turbo, planning to eventually run around 12 psi boost. CR is ~9.6:1.

-Block bored .030" over, splayed 4 bolt mains
-Lunati sledgehammer 3.75" crank
-Eagle forged H-beam 5.7" rods, ARP 7/16" bolts
-Eagle 4 bolt main caps
-ARP main studs
-SRP -16cc dish forged pistons
-AFR 210cc competition ported "Eliminator" heads, 65cc chamber
-Comp Cams 1.6 ultra pro mag rockers
-BTR LTX springs
-AI billet custom cam (I don't remember the specs offhand, but I want to say .556 both intake and exhaust, 116 LSA)
-Ported LT4 intake manifold
-Professional Products 58mm throttle body
-Stock LT1 timing set
-Stock exhaust manifolds, slight porting at inlets

The engine was almost completely assembled by me, except for the heads which had a 5 angle valve job and assembled by AES.

ahritchie

iTrader: (1)

Yeah, I think you need a decent mail order baseline tune to start with at least, maybe put some fresh gas in it too....that is a far from stock setup, that's a lot of money to spend on an engine to skimp on something like proper tune first.

myltwon

iTrader: (1)

what injectors?

Also I would double check valve adjustment

Camaro_freak

iTrader: (1)

I've been doing all the tuning myself, so I just need to get it running to dial it in. I decided to ditch the 1.5 bar tune (for now at least) and go back to an older 1 bar speed density tune as my baseline, adjusted to 383 CI of course. Just fewer variables to worry about.

I also put my old throttle body back on, just to simplify things and get it closer to the original engine for now.

I'm pretty confident the valve adjustment is correct. I haven't checked to make sure spark is at all cylinders yet. I will put some fresher gas in also and try again.

Camaro_freak

iTrader: (1)

I loaded a more basic tune tonight and it fired right up and kept running. Problem now is that there's a tranny issue. I have the driveshaft just hanging out the back of the tranny to prevent fluid leaking out, but in park THE DRIVESHAFT STARTED TURNING!!! I heard and felt it clunking around so I had to shut it down. This is a used FLT level 5 4L60E tranny I bought from a member on this board. I will call FLT tomorrow about it.

bufmatmuslepants

iTrader: (3)

It sounds like you know what you are doing, and that you are not running it long, but I'd be wary of flooding it with fuel, diluting your oil, and wiping a bearing or not seating the rings properly if your tune is way off. I know it's $200, but that's an expensive build to gamble on. Even if you got a baseline mail order and dial it in yourself, I would just be careful.

Camaro_freak

iTrader: (1)

Thanks for the advice, I definitely don't want to trash the engine. I don't think it's running excessively rich though, since the idle is now reasonably smooth and not backfiring or anything.

I discovered the tranny was not actually in park even though the shifter was, so that's taken care of. I re-started the engine this morning and posted a short vid on youtube:


Seems to be running okay from what I can tell. Good enough to put it all back together anyway.