Six Pack POURING Gas in the Motor-What's Up?

[moparpoor]

Make sure the metering block gaskets are correct. I just ran into this problem after someone else rebuilt some carbs.

It had this gasket installed and it was filling the motor with gas.

It needed this gasket.

I damn near pulled my hair out trying to figure out why it was so rich.

They actually used to make another gasket yet.It is almost exactly the same gasket as lower pic.Just has the small hole above power valve cutout deleated.This was usually found on the mechanical sixpack.

 

[RS23VOA]

One of my cars had these plugs removed and the screws were backed out too far. I screwed them all the way in and backed them out about one turn and my problem was solved. They were so rich you could see gas running in while it was idling. It took me forever to figure it out.

 

[62MAX]

They actually used to make another gasket yet.It is almost exactly the same gasket as lower pic.Just has the small hole above power valve cutout deleated.This was usually found on the mechanical sixpack.

Both the above are four barrel gaskets,incorrect for a 6pk.These are the only correct 6pk gaskets,top,center carb,bottom,ends carbs.If you have raw fuel in the engine it can only come from a bad needle/seat or O ring or high float level,or high fuel pressure,nothing else.

 

[PurpleBeeper]

That's a hideously small amount of vacuum....even for that cam. Here is the correct procedure for choosing a power valve, straight from Holley.

http://www.holley.com/data/TechService/Technical/power_valves.pdf

Notice it says to divide the vacuum reading in half, and choose the closest power valve to that number. Obviously, you cannot do that. I suspect you have other issues. Can you see fuel dripping down any of the carburetor throats? If so, you have something much worse than a simple blown power valve.

I am not sure I understand your modification. You say you drilled the metering block holes behind the power valve? What does this accomplish supposedly? Although I have limited experience with six packs, carburetors have been one of my specialties for a very long time. The power valve circuit is a pretty smart one. It knows what to do as long as it's clean.

Hey Rusty,

1. Metering Block/Plate holes: I just read it in an old technical article....honestly, I don't know much about tuning carbs. All I'ver ever done that worked was use the lightest outboard springs I could get and increase the center carb squirt to eliminate any "bog" off the line. Like I said, drilling the center & outboard metering plates was something I read 20 years ago. I'm have the new stock outer metering plates & plan on replacing the power valve again with the check valve fix, checking/replacing the center carb gaskets. I'll probably leave the 50cc pump unless I start blowing black smoke off the line or fouling plugs.

2. Low Vaccuum: Yep, VERY low.. even with the 4 bbl. I've got on it now PLUS a smaller cam I installed (Comp Cams XE274H 274/286 488/491) + new timing chaing. I'm only getting maybe 5-6" of vaccuum at idle. I suspect an intake leak.... the heads were milled (amount?) & the block was milled (.040"?) by two seperate machine shops many years ago. I was told "the block was very uneven and we had to take off a lot to square the decks". At one point I couldn't even bolt up an intake and "guessed" to take .020" off the 4 bbl. and six pack intakes since I didn't want to remove the heads. It got better, but I still think this might be my low vaccuum problem.

How can I mill my intakes exactly what I need to seal correctly? How can I make sure all the angles are correct/flush? My new machinist mentioned that if I overshoot the milling I can always use the paper six pack intake gaskets with the bathtub gasket (no room to use them now)

 

[62MAX]

Hey Rusty,

1. Metering Block/Plate holes: I just read it in an old technical article....honestly, I don't know much about tuning carbs. All I'ver ever done that worked was use the lightest outboard springs I could get and increase the center carb squirt to eliminate any "bog" off the line. Like I said, drilling the center & outboard metering plates was something I read 20 years ago. I'm have the new stock outer metering plates & plan on replacing the power valve again with the check valve fix, checking/replacing the center carb gaskets. I'll probably leave the 50cc pump unless I start blowing black smoke off the line or fouling plugs.

2. Low Vaccuum: Yep, VERY low.. even with the 4 bbl. I've got on it now PLUS a smaller cam I installed (Comp Cams XE274H 274/286 488/491) + new timing chaing. I'm only getting maybe 5-6" of vaccuum at idle. I suspect an intake leak.... the heads were milled (amount?) & the block was milled (.040"?) by two seperate machine shops many years ago. I was told "the block was very uneven and we had to take off a lot to square the decks". At one point I couldn't even bolt up an intake and "guessed" to take .020" off the 4 bbl. and six pack intakes since I didn't want to remove the heads. It got better, but I still think this might be my low vaccuum problem.

How can I mill my intakes exactly what I need to seal correctly? How can I make sure all the angles are correct/flush? My new machinist mentioned that if I overshoot the milling I can always use the paper six pack intake gaskets with the bathtub gasket (no room to use them now)

Good luck !

 

[RustyRatRod]

Well I wasn't knockin you drillin the meterin blocks, I've just never heard of it. What purpose does it serve?

 

[PurpleBeeper]

Well I wasn't knockin you drillin the meterin blocks, I've just never heard of it. What purpose does it serve?

Hey Rusty, I'm not sure......."maybe" it allows more fuel into the main circuit??? I have no idea honestly.

 

[RustyRatRod]

I did some research on it and I *think* he means enlarging the power valve ports. If he's talkin about drillin new openings (which to me is what it sounded like) I have no clue.

 

[PurpleBeeper]

Not exactly

I did some research on it and I *think* he means enlarging the power valve ports. If he's talkin about drillin new openings (which to me is what it sounded like) I have no clue.

Not exactly.... and excuse me, but I'm going from memory WAY back. On the metering block for the center carb, if you unscrew the power valve and look indide that big threaded power valve hole there a two small holes on either side. I drilled out those holes a little larger. If I'm dreaming here, please stop me.

 

[PurpleBeeper]

Hey Max

Good luck !

Hey Max, I've seen those specifications before that say if you mill the heads or block "X" then you mill intake face of the heads (or intake) "Y".

My problems is that I have no idea how much the heads or block were milled! I don't think any metal was taken off the intake face either. Since one shop did the block and another shop did the heads (both out of business by the way) I have no clue.

Without tearing down the motor.... How do I make sure the intake/head mating surfaces are at the correct angle & line up correctly? Thanks everyone!

 

[Meep-Meep]

Normally you won't be able to get the intake bolts to all line up. That's a sign that the heads were cut too much ad the intake side possibly not cut at all.

 

[PurpleBeeper]

Normally you won't be able to get the intake bolts to all line up. That's a sign that the heads were cut too much ad the intake side possibly not cut at all.

Yep Meep, that is exactly the problem I have. I could not install the intake bolts. The intake bolt holes were at least 1/8" higher up than the bolt holes in the heads. I guessed .020" and cut that much off both my 4 bbl. and six pack intake manifolds. Now I can just barely get the intake bolts in (intake holes still higher up than holes in heads). Forget about tyring to use the paper six-pack intake gaskets..... no way they'll fit in addition to the valley pan.

Now my intakes bolts up (after cutting .020" off the intakes), but I have 4-5" of vaccuum at idle. I suspect I'm leaking vaccuum where the intake bolts to the heads because of the problem I described above.

How can I fix this? How do I make SURE I'm not leaking vaccuum in this area? I've sprayed carb cleaner on top the intake/head mating surface, but I can't really do that underneath the intake. I've re-sealed the intake(s) at least 6 times..... valley pan/indian head only.....valley pan/form-a-gasket..... cut the valley pan & used paper six-pack gaskets & form-a-gasket to seal the top of the motor.....etc, etc.

Maybe the intake IS sealed and I have a vaccuum leak someplace else??? I just suspect this area because I'm sure I have a problem there, I get the same low vaccuum with 4 bbl. or six-pack setup, and I've changed just about everything else I can think of.

 

[RustyRatRod]

Not exactly.... and excuse me, but I'm going from memory WAY back. On the metering block for the center carb, if you unscrew the power valve and look indide that big threaded power valve hole there a two small holes on either side. I drilled out those holes a little larger. If I'm dreaming here, please stop me.

No, you're correct. There are two holes there, on the beveled area, one on each side. I had just never heard of enlarging them. It would simply richen up the shot the power valve gives when it opens.

 

[62MAX]

That modification was recommend for super stock and bracket racing,PVCR was to be opened to .043 and .052,which is actually about .002 larger than stock.

 

[PurpleBeeper]

That modification was recommend for super stock and bracket racing,PVCR was to be opened to .043 and .052,which is actually about .002 larger than stock.

So, no reason that would dump fuel in the motor unless the power valve is blown too? (or too low vaccuum so the power valve is constantly open), etc?

More and more it's sounding like I need to put the carbs back as close to stock as possible (can't really un-drill the center metering block), check my gaskets, check my needle/seats and o-rings, put the special $7 part in the power valve hole, put the stock metering plates back on, check my outboard idle screws, mill my intake some more....... and maybe buy a rabbit's foot for luck..... simple.

Seriously, it sound like I need to start at square 1.

Anyone know how to make SURE my intake/head mating surface is true? Is my best bet just to hand my wallet to a machine shop and have them mill .010" at a time? How can I make sure the angles of the intake/head face are correct?

 

[loneagle]

There is a trick a friend used to use with paper towls and I mean like 4 layers thick he would soak them in oil put them down on service then bolt down were it crushed out oil it was proper degree and were it didn't it wasn't when you remove intake it will show this in the paper towels since top would be crushed bad bottom not so much I'm sure card board would work to measureing its thickness with micromitor but again I'm sure there is more scientific ways to prove this but I don't know them I'm not the engineer I'm just the grease monkey to turn the wrenches as I'm told by those whom know more have more knowledge and done more reading if you don't try you already failed so what's it gonna hurt as far as the other I'm just getting into six packs but as far as all I read yes start at square one then do minor adjustments from there

 

[Bigun426]

Did you set your float level with the engine running?

 

[PurpleBeeper]

Did you set your float level with the engine running?

No, I set my float levels with the engine off.... I use only an electric fuel pump, so does it matter???

 

[62MAX]

Yes it does,you are using fuel whlie the engine is running and have to maintain the recommended level.

 

[RustyRatRod]

Yes it does,you are using fuel whlie the engine is running and have to maintain the recommended level.

This ^^^^^^^^^ While you can set preliminary float levels with the electric pump, you still need to make the final adjustments running.