Six Pack issues and rebuilding by tommyg29

6 minute(s) of a 193 minute read

4-7-2014

Got home from work and decided to remove them....had all three sitting on my workbench in 12 minutes.

Getting better. Now just going to fit some plywood blockoff plates to the secondaries on the manifold, cap off the two fuel outlets and try with just the inboard, but... later... have to attend a funeral first  

4-8-2014

I will link all the pictures to photobucket, but Im far from done here.

Today I spent an hour or so blanking off the secondaries with plywood and took time to clean the manifold up a bit. Tomorrow will cap off the fuel lines and try to start it up with JUST the primary. More pictures to come.

4-9-2014

Ready to try to start it up again tomorrow.

Got my two pack thing ready to go, but first I cleaned up the manifold.

Look carefully and you'll see they are capped, but had to tighten em down a couple times to make them leak free.

I get nervous about leaving the sight plugs off. What Ive been doing to check levels is running the electric pump, and then turning it off, and then removing the site plugs to check. If a little spills out, I figure that should be about right.

I guess a good place to start... each carb level set just barely leaking out.

btw, my squirter seems to work well. In fact it seems like a huge squirt out those little 31/1000 holes.

Will try starting it up tomorrow.

4-10-2014

I looked and it didnt appear to be an open port. There are two screw holes to mount the pod but I used the two screws in them. 

Anyways, just tried starting it up and it ran, when I gave it half throttle, but didnt want to climb above about 2000 rpm, again like it was suffocating, but it did run smoother this time. Still wouldnt idle, and still blowing smoke, but running far better than the other day.

I was originally running 80 jets, and now using 66s. Much closer to stock, but still blowing smoke, and not running   

Maybe go back and try 80s??  

Heres a description of my build from the prior owner:

Tom:

'74 440 block + .030 stock 3.75 stroke (446")

'66 516 casting closed chamber heads

Stock cast crank

Stock LY rods

Closed chamber heads

Basic machine work was done on lower end by someone else, we bought it used. But, it has TRW forged flat tops, Federal bearings, stock replacement rings, etc. A basic rebuild with heavy pistons. Heads have 2.08/1.74 stainless performance valves. I pocket ported and cleaned them up, and gasket matched them, ending up around 245cfm @.550 intake, 175cfm @ .550 exh. Spring seats and guides cut for springs. They were also milled to get a true final compression of 10.5:1. Intake is a factory '70 iron 6bbl that was also port matched and cleaned up as best as I could reach, no plenum mods. Carbs are factory '70 six pack 4sp vacuum carbs, jetted and tuned. Cam is Crane hydraulic H-302-2, 302, .504 lift, 232 @ .050 intake, 312, .528 lift, 242 @ .050 exh. It runs 1 7/8 Hooker headers and MSD 6AL with a Pro Billet dist. 

Chassis dyno results: 378hp @ 5300     470tq @ 3500

It's got 83 of overlap and will have a rough idle and the plugs may get fouled if it's idled a lot or driven lightly all the time. Last I checked it was around there too (170-175 IIRC). The reason the cylinder pressure is what it is is because the intake valve closing event officially seals the cylinder as the piston is moving up the bore. The larger the cam, the later that intake valve closes, so the lower the effective cylinder pressure will be with the same given mechanical static ratio. 

I have a couple hints: Run the highest octane you can get (unleaded 93/94) and don't keep snapping the throttle at idle or pumping too much while it's warming up. It's never going to idle perfectly or smell clean at idle but it's not bad and you could always set it a little faster idle speed to help that. You can also try going with a higher heat range plug too.""

Coolant is still green but need to flush it soon anyway.

Its hard for me to tell what color the smoke was but it seemed light color. Definitely not black though. In fact I dont think its ever blown black, though maybe very light gray.

I really dont think its coolant, and I definitely dont want to think that  

Now, if it blew between cylinders I imagine this would mostly mean a loss of compression? That would make some sense. Yesterday I tried starting it and it turned over a few times and then locked. The battery was at 12.5 volts so I figured maybe dead battery again, so I charged it up overnight to 13.6 volts, and turned it over and it seemed to lock again. I pulled 3 or 4 "easy" plugs just in case this evening before trying again. Didnt observe anything much draining out of any plug holes, but one of the plugs was definitely wet with that I thought was gas. Anyway, then put the plugs back in and tried again and this time it cranked for a few moments and finally spit to life, and after a few more moments it started running somewhat smoothly, but didnt want to go more than about 2000 rpm, and after about 30 seconds I let off and tried to let it idle, but it wanted to quit, so I just let it.  

Guess I should try to check compression this weekend. Obviously I wont be checking on a warm engine, but I will install the gauge and crank it over a few moments each cylinder. Whats the easiest and safest ways to disconnect ignition and cutoff fuel for the check?

And question 2: is the accelerator pump supposed to be squirting immediately and each time the throttle is opened?

I never really observed its operation before but it sure squirts a larger stream than I would have thought.

I guess under normal operation with my mild pump cam, it doesnt squirt its maximum potential amount, and closes off quickly?