Quadrajet setup?

[allflatblack]

Hey guys,
My ’69 has an ’83 350 in it that has never run very well and I took my time to get to looking at it. This weekend I finally decided to tune it up after checking the ignition timing and finding out that the vacuum advance had gone bad. I replaced all of the ignition components and timed it at 4 degrees with the advance plugged. Ran much better, but not great, terrible random idle. The engine was equipped with a Carter AFB spread bore carb on a riser and as I began to try to tune it out, I noticed that the pilots really did nothing. Looking inside the carb while running revealed gas just pouring out of one side of the carb into the right side primary. This carb needed a rebuild. A few weeks before, a friend had been at a swap meet and seen a rebuilt quadrajet for the same year engine for cheap. He picked it up for me, new in box. This was easier than rebuilding the ratty old carter and I had it and a new gasket on the shelf.
The truck would always start right up with the carter, and ran but poorly. I installed the very nice looking quadrajet, hooked up the large base port to the PCV and a smaller port to the ignition advance and capped off all of the others, including the rear brake booster. I shot some gas down the throat and went to start it. Nothing. Even after multiple cranking episodes, nothing. Not even a pop. As if I somehow disconnected the ignition. I immediately ordered a Q-jet tuning book from Amazon, but am surprised that nothing at all happened when cranking, even at WOT, closed throttle.
Is there any initial setup procedure that anyone can see would not even let the engine even think of starting? Screwdriver in chokeflap, accelerator pumps shooting plenty of fuel. Maybe I flooded it. But I cranked until it was uncomfortable.
Thanks for any advice. I will double check that a freak ignition failure has not occurred tonight.

[geezer#99]

You should have left the carter on it. All it needed was a fuel regulator set at 5 psi.
You got fuel to the quadrajet.
You got air.
You need more timing.
Loosen the distributor and advance it 1/2 inch ccw.
Leave it loose enough to be easily turned as someone cranks the motor for you.
You might need to advance or retard it a bit while cranking to get it to start.
Don't pump the accelerator more than a couple times.
Hold the throttle open slightly while cranking and it should fire up.
When it does, tighten down the distributor and keep it running long enough to warm it up.
Then adjust your idle and mix screws.
Then check and adjust your timing.
Try timing at 12 degrees initial to start with.

[allflatblack]

Thanks man, that makes a lot of sense.

[geezer#99]

Maybe burn us off some pics if you have time.
Someone might see something amiss.

[MagmaJct]

My truck only produces 10" of vacuum at idle in drive. I think it's somewhere around 12" - 15" in neutral. Engine runs fine otherwise.

The engine has a Carter AFB that works well, once the engine's warm. Starting and keeping it running's a ***** when cold. I tried a Q-Jet, and it would not idle right. Fuel was being discharged from the main jets. Turns out, Q-Jets NEED GOOD vacuum at idle to function properly. If the vacuum is too low, the Q-Jet won't idle.

If you try to increase the idle speed by opening up the throttles, more air will flow past the boost venturies and pull fuel from the mains, destroying your air/fuel ratio.

Check your vacuum at idle!

Regards,
Mike

[Wrenchbender Ret]

Make shure you are getting spark at the plugs. Check the plugs for black carbon. A flooding condition with the gas we get now can build up carbon on the plugs & keep them from fireing. I know it was running before you changed carbs but something has happened. With gas getting in the manifold it should start. It might have a huge vacuum leak. Is the large vacuum outlet in the rear of the carb being used or plugged?

[allflatblack]

Guys, sorry for the long wait to reply, I have been too busy to look at the truck.
I advanced the distributor about .5" and it fired right up. I waited for it to warm up and then set the timing at around 8 degrees with the vac advance plugged. I then tuned the pilots for highest vacuum at a reasonable idle (around 18 psi).
the truck starts right up and purrs beautifully! It drives like an old chevy now! I'll wait for some daylight and put a few miles on her and listen for any pinging, maybe advance the timing a bit more and tune the pilots after I have a few more mile on it.

thanks for your help!

John

[GASoline71]

What are pilots? Do you mean idle mixture screws? The only time I've head "pilot" was when rejetting dirt bike carbs.

Gary

[allflatblack]

Idle mixture/ pilot jets.

I work mostly on vintage British bikes and these things get mixed together.

[Ironangel]

They're actually the same difference. Pilot circuits are the "idle circuits"...I knew exactly what you meant and what you were adjusting. My KZ-1000 has four, my Chevy's only have two...And this one has the best of both worlds!

[allflatblack]

Serious!

[Ironangel]

No, it's a prank picture of my bike carbs sitting on top of of a Holly...Dont see many Brit bikes on the road anymore. Guy down the street has a Bonneville buried in his garage I've been trying to buy from him...He's too old to ride now but wont come off that bike! heres a pic of my 79-80 KZ-1000 I restored and still race it once in a while. I like to show those late model $30+K V-Twins how slow they go...

[allflatblack]

Very cool, I bought the truck to haul bikes. I race a CB350 in AHRMA.
The british race cars of the day often ran a single AMAL carb for each cylinder. A tuning nightmare, but I bet it was responsive!

[Ironangel]

Glad to see you got that Quadrajet dialed in. I run Quadrajet's on both my 72 C-10's. They are in my opinion, the best carb out there, very forgiving and tuneable once you get an understanding of their various circuits. I like them because one carb is capable of a brawd range of duty. I have one on a small block 350 that pulls a 10,000 pound trailer and still gets 10 mpg. Another on a BB 408ci that spins up 6000 rpm with zero hesitation from stomping on it from a stop and right through the secondaries to pull like a train! Cliff Ruggles and his book helped out immensely in understanding the Quadrajets, he literally wrote the book on Quadrajets. Whats cool about him is he answers his own phone and will talk your leg off discussing carbs and set ups. http://www.cliffshighperformance.com/buy_book_2.html