ok i have switched everything needed to go from tbi to carb. but im having some issues here they are maybe someone could help 1.its been almost imposible to time the engine i try to go by the tab and when i think its running the best im at really low RPMs on the tach. i have heard that ideling is suppost to be at arround 8k mine is arround 5k * im running a accel dizzy by the way it came on my 80 305 sbc 2. motor shakes alot i have a fuel pressure gauge on the line and they needle just bounces non stop. * i dont have a fuel pressure regulator i have heard that on 87 and up wit center bolt heads if you witch to carb you must fun hi octane gas like 92 oct is this right? i usually out 87 oct could the gas be causing this problem? and if i want to change the heads to older style non center bolt what do i have to replace other than the heads them selfs thanks in advance
Heads interchange directly, but 305 engines have small cylinder bores so 350 heads can't be used as the valves are too big. Try timing the engine at higher RPM. Run it up to about 2500 RPM and set timing at around 36 or 38 degrees. This should be high enough RPM that you are above the vacuum and mechanical advance in the distributor which could be fouling you up. Can't imagine the fuel octane would be a factor until you get on the highway...maybe some knock-ping on hills. Should run okay in the driveway regardless of octane. Are you using an electric fuel pump or a mechanical? The stock 1987 electric fuel pump could be producing too much fuel pressure for a carburetor.
Do you have the vacuum line pulled from the distributer and plugged when your setting the timing? Is it wired right...check again cause its real easy to screw it up! Is that a points distributor? If it is did you set the plug gap to a points style gap? The gas won't make a difference...all that changed is how it got delivered to the cylinders.
to add to hacker, does it even have a vacuum advance? if the distributor came on the engine, then it's not likely to be the correct one for a carburetor.
As was mentioned, the octane dosn't matter especially on a pretty much stock 305 and at idle... What intake and carb did you swap to? It olmost sound's to me like you may have a vacuume leak with the poor idle quality, timing issues.. Has it been taken apart before? I've seen some sbc's (for some reason it's been mostly 305's too) where the front cover and balancer were not matched so the timing marks meant nothing..basically, a later model cover with earlier balancer or vise versa.If so, find TDC and start over on the timing. Make sure that TDC is in fact 0 on your balancer. If it's not either switch to the right balancer or buy timing tape for it to mark TDC on the balancer and start again.. How did it run with the tbi before you removed it, or did you get it non running? Just a couple thought's.
Says he's runnin' an Accel distributor...could come both ways...right???? (Damn...I can't remember! LoL)
Sounds to me like you have the wrong distributor for what your trying to do. With out the TBI not hooked up the Dist is probably operating in the 'limp home' mode off of the computer. Find an earlier HEI that only has the one plug in up on the side of the distributor cap.
of course they come both ways guys...one made for carbureted engines that has vac adv, one for injected engines that has a plug for computer controlled adv. if it came ON the engine and the engine was a running FI engine when he got it, logic stands that it would not have the vacuum advance on it because advance would have been controlled by the TPS. i've also seen guys swap carbs from electonic to normal and have that problem a million times
Skaja...I don't think Accel made the factory distributor for a Chevy! I ***ume that it was aftermarket, BUT came to him in a 1980 305! Everyone is right in this thread! But were all talking different things. I'm ***uming that the 305 is removed from a donor vehicle and has been stripped clean of all computer controls so that shouldn't be an issue. CHIEF...we need MORE info!!!!
i thought he said it was an 87, then i looked back and realized i got that number from his octane question yeah, more info chief...lol
ok the accell has vac advance it came out of my old motor that was a 1980 305, the motor blew so i got a free 87 camaro thats where this motor came from, like i saod i switched the intake to a edelbrock 87+ so the middle holes would line up, u i put the stock mechanical pump from the old 305 the acell dizzy and i bought a brand new edelbrock 600cfm manual choke, i sprayed carb cleaner around the manifold and the carb to check for va*** leaks and i couldnt find any i tryed timimg the motor wit the vac adv plug and unpluged didnt make too much of a difference
See can you borrow a regular GM HEI and try it. As the guys before stated sounds like a vac issue.. IMHO
i'ld have to say regulate the fuel pressure fist, then look at timing....most 305's ya have to be shootin the gun down from basicly hi-noon....if u are aimim t/gun from other angle, it is probably the wrong marks...like wise, when dizzy was dropped in, it could also be off some teeth, then wired out of syn..... jus some stff to check.....mark
ill check em again tomorrow, and im going to try a stock hei dizzy, any one else got any thought,thanks in advance
Possibly the ring on the balancer has slipped and then you will never get it timed right unless you find top dead center and put a timing tape on it. Also if you dont have a vacuum gauge buy one and check the vacuum and use it to set the idle mixture screws on the carburetor.. Are you sure you didnt get the dizzi in a tooth off from TDC ???? Dave
if this setup worked on the other motor, i doubt something went bad between swaps. maybe a vaac leak or mis-wired.
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