I recently put my new heads on my 455 and did some repairs on the bottom end (fixed the front 1 bolt main). Now, I floor it, and it either feels like the secondaries are not opening or it chugs a little like fuel is running short. It is a 455, 850 performer q-jet, worked Al SE heads, TA212, and a stg. 1 mechanical fuel pump. Do you all think I might need a 1/2" fuel line? If so, how can I go about this w/o spending crazy $$$? Does someone make a setup that will replace the stock 3/8" that attaches to the top of the gas tank? Is it OK to neck down to the 3/8 at the pump or does that defeat the purpose? Any help would be appreciated. Thank you.
Fuel Line! Well, if I read your setup correctly I would say you will need to add an electric fuel pump and maybe a larger line too. As for necking down at the tank, that will defeat the whole deal of putting in a larger line. If it was me I would install a good electric pump at the tank. That might work with the 3/8" line. If not I would go for a first class fuel system with sump and pump, filter , regulator and line. You spent all kinds of money on heads, cam and such, don't kill it with a junk fuel system. I always like to over kill the fuel and ignition system first thing so I don't have that worry as I add other serious parts. Just my opinion; Jim Netherland
You do NOT need bigger fuel line. (I installed an electric pump by the tank, just as suggested above. With 14 lbs pump pressure through the 3/8 tubing, and a regulator near the carb to knock pressure down to about 6 psi, my fuel pressure guage doesn't show insufficient pressue no matter what RPM I'm at. The only time the needle drops is when the pump isn't running.) Maybe you have carb problems, maybe you have fuel pump problems, maybe it's ignition...or whatever. 3/8 fuel tubing is enough to support WAY more horsepower than you have. Any chance the sending unit's "sock" is plugged? How about rotted hose or pinholed fuel tubing between the tank and pump? Air could leak into the fuel tube or hoses and reduce pump volume.
Hello guys. Thanx for your help, I appreciate it. I have no idea about the sock in the tank. Fuel pressure is my best guess, it is possible that it is not the problem, though. This weekend I will see my brother, who is a much better carb guy that I am. I will double check timing again when I get home from work. Thanx again.
John, want to barrow a mechanical pump? I can check but I think I remember I put in the stage 1 pump some time ago, The engine is just sittin there anyway. If you want to try it I will send it. Also if you think you need a better pump, then maybe you should try the TRIshield pump, its spendy but would handle all the volume you would ever need - without the hassle of a electric pump. You could also barrow my 800Qjet if you want to try both...(my qjet was set-up for the B4B manifold and we did alot of work getting the secondary air valve to open at the correct rate/time.
Line! Sorry some don't agree you might need a new fuel line. Not sure what kind of power you are making with an aluminum headed 455, but I know with my steel head engine, no way I could run with a 3/8" line, stock pickup and stock pump. Surly an aluminum head car should run quicker than the 10.30's @ 127 I run with steel heads and hydraulic cam in my GS. Hope you find the fix. Jim N.
Well, if I stuck aluminum heads on my 455, I surely wouldn't need a 1/2" line to feed the carb. Where do you draw the line? o No:
Stage 1 fuel pump? I personally feel that the Stage 1 fuel pump is the BIGGEST problem you have...:eek2: :error: ...I see some bigger fuel line in your future, and a MUCH better fuel pump for sure!:Brow:
Maybe not a 1/2" fuel line, not really wanting to argue that. The fuel line size (read: volume needed) is directly related to HP. If you can feel the engine lay down in gear, either pressure is TOO LOW, or the volume isn't enough. In this case, prolly both!ou:
Granted I have a stock motor, but when my fuel pump went in the past it would run good until I would floor it and as soon as I got rolling over about 75 it would fall flat on it's face. Then after a second or two it would live again.....and then fall again. Kind of embarassing when you trying to outrun a Corvette.
i had that happen when i had a clogged filter that was just after the pump. but if you have the filter in the qjet, when those get cloged it will just lack power.
Limitations of the stock STG 1 pump is right about 450-475 HP. We have tested, re-tested and verified this repeatedly on the dyno, with half a dozen different pumps, which suck gas out of a can sitting 3 feet away from the pump. And of course, the whole deal is static. I despise electric pumps on anything but race cars, hence the need and desire to have a mechanical pump that would feed anything with a 455 valve cover and a carburator on it. Short of that unit, you may want to try one of TA's pumps, I have no experience with them, but I would guess it has to be better than the stocker. And we regularly replace the fuel line and pickup assembly in anything with more than 475 Hp with our 1/2 pickup and 1/2 line kit. We remove just the front section of the factory lines, and install the 1/2 aeroquip push lock line right thru the frame in the rear, and exit it at the stock location. But, before you go bolting on parts, I strongly suggest that you check your fuel pressure, to see if it is dropping. That will lead you to a solution, without wasting dollars. By the way, our beloved q-jet is the hardest carb to keep fuel in the bowl under marginal fuel delivery situations, due to it's small fuel bowl volume and single inlet.
More good info here! http://www.v8buick.com/showthread.php?s=&threadid=28308&highlight=Billet+Mechanical+Fuel+Pump
Thanx for all the great feedback guys, very appreciated. I am going to check around for prices on aeroquip line & TA's pump. But I will check fuel pressure before I have to spend any money (pregnant wife w/baseball bat).
Pressure is not the most important thing here. It's volume. One pint in 30 seconds is normal. That's what they told me in school 20 yrs. ago anyways.:grin: Just disconnect your fuel line and stick it into a container and have someone turn the starter for 1/2 a minute. After doing this, there should be at least 16 ounces of fuel in it.:Smarty:
tsp 1/2 fuel line Jim any pictures of your 1/2 line set up and cost.Do you change the pick up in the tank?Thanks
i run the stage 1 pump, i have a modified Qjet with stock fuel line, but the reture line is blocked at the pump (i was told that helps) and i run a large metel inline filter just after the pump, the stock filter is removed (this gives the carb some extra volume) and the hole in the filter houseing out is drilled out to 7/16''. there are a few buicks running the stage 1 pump running low 12s high 11s. maybe they are just lucky?? now that i have got my car to hook up right i should be running alot faster so then maybe a will have to inlarge my fuel line??? just my 2 cents
Steve, Yes, we convert the pickup to a 1/2 deal, and I will try and post a couple pictures tonight. JW
I just did the math: :Smarty: I don't know if I could do it again, but 1 pint in 30 seconds works out to be 4 miles per gallon assuming the car is travelling 60 MPH.:bglasses:
