Thread: ok i got my little 283 running again...

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as you can see... well it farts and pops and sometimes dies...
1965-67 283 chevy sb bored .60 over..
did have 76 cc heads... nothing special.. completely stock
did have stock cam... intake was holley contender intake with a basic holley 600 cfm carb... electronic choke vacc. sec.
did have junkyard 700r4 richmond 4:10 gears in rear 8.5 10 bolt from 79 el camino, hei distributer, flamethrower coil & module


i recently went on a parts spree.. .got me a new tci street fighter tranny 700r4... (old one cracked) auburn gear posi. lunati voodoo cam.. 1400-5800 rpm... 262 duration 468" lift , 1.5 aluminum roller rockers , gm performance vortec heads, holley red fuel pump... 7psi.. gear drive, edelbrock performer intake, still the same 600 holley carb..


got everything runnin and it was all soundin good... then first test drive when i give it any gas at all at slow speeds ... or when i romp on it at faster engine speeds it like completely misses... then when im gradually slowing down for a stop then when i get stopped, then it will die unless i throttle it.. i dont have access to a timing light .. so i dont know what that is... also when stopped (mainly noticed) when power breaking it.. it has ABSOLYTLY NO power.. unless i can throttle it but even then it takes forever to get to even 2500 rpm... (while powerbreaking) i didnt have this problem with the old setup.. because it could light them up in an instant.. but any suggestions??? anyone??

first off i would get access to a timing light sounds like an issue there but it also maybe fuel but check timing first

Could be vac leak??

Hard to say without a little more info. Connect a timing light to it and find out where that is. If nothing else, at least you'll know what you have the timing set at. To check for a vac leak, you can start the engine and take a small propane torch, turn the gas on (don't light it) and run the nozzle around the base of the carb and intake, if the rpm's pick up while doing this you have found a vac leak where the nozzle is pointed.

Now as for more info...After adding the new parts did you make any adjustments to the carb? Was the bottom end re-built when you were adding the new cam, heads etc? If so, how was the motor, and the cam for that matter, broke in? One last thing I would suggest for now, is that you do a compression check...especially if the bottom end wasn't rebuilt.

Good Luck,
Dutch

Originally Posted by Firechicken

Hard to say without a little more info. Connect a timing light to it and find out where that is. If nothing else, at least you'll know what you have the timing set at. To check for a vac leak, you can start the engine and take a small propane torch, turn the gas on (don't light it) and run the nozzle around the base of the carb and intake, if the rpm's pick up while doing this you have found a vac leak where the nozzle is pointed.

Now as for more info...After adding the new parts did you make any adjustments to the carb? Was the bottom end re-built when you were adding the new cam, heads etc? If so, how was the motor, and the cam for that matter, broke in? One last thing I would suggest for now, is that you do a compression check...especially if the bottom end wasn't rebuilt.

Good Luck,
Dutch

You don't need a torch to check for vacuum leaks.
Just use a can of carb cleaner or break-clean and it will do the same thing and is a little safer also.

ok ill check it sometime.. but no the bottom end of the engine was fine and i didnt change anything.. carb wasnt touched... and cam and heads are broken in... the engine smooths out about 1900-up.. thats if you dont get on it ... at all.. so thats how ive been getting around.. the stall is also the stock 700r4 one..

Originally Posted by erik erikson

You don't need a torch to check for vacuum leaks.
Just use a can of carb cleaner or break-clean and it will do the same thing and is a little safer also.

Oh I know...I just don't like the mess

Originally Posted by tim_bo16

ok ill check it sometime.. but no the bottom end of the engine was fine and i didnt change anything.. carb wasnt touched... and cam and heads are broken in... the engine smooths out about 1900-up.. thats if you dont get on it ... at all.. so thats how ive been getting around.. the stall is also the stock 700r4 one..

Ok, so the carb needs to be tuned to the new setup. Stick a vac guage on it and tune the carb (edit: after the timing is set). Vac guages are invaluable tools in my opinion. Others may disagree with me on that; but, like I said it is my opinion.

Also since the bottom end wasn't touched I really recommend performing a compression and bleed down test. Since the top end is all new and the bottom end is not, your older rings may not be able to handle the new pressure and you may be losing your power right there through the bottom end.

One last thought about all of this....how old is the gas you are using?

the gas is 91 pump... just filled it on wednesday.... and the truck probably has about 6000 miles on it .. so i wouldnt be the rings would it???

Originally Posted by tim_bo16

but no the bottom end of the engine was fine and i didnt change anything..

Originally Posted by tim_bo16

the gas is 91 pump... just filled it on wednesday.... and the truck probably has about 6000 miles on it .. so i wouldnt be the rings would it???

Ok....so I am a little confused I guess. I got the impression that the bottom end wasn't touched....so now I have to ask, was the bottom end rebuilt about 6,000 miles ago and the heads/cam/ignition etc. are brand new and this problem started once you fired it up? Or is it that the heads/cam/ignition etc. all have about 6,000 miles and the motor ran fine at first but it is now running rough?

ooppsss.. yeah sorry.. the motor was a fresh rebuild *about* 6000 miles ago... it ran fine and all no problems.. just recently i just wanted more go fast parts.. so i did and now is my problem... sorry my bad about that one

also.. just wondering... would i have to "down" jet my carb... because it almost seems like it is running rich... but it doesnt really make sense to do that because i didnt touch the carb.. (turn anything up or down) from the stock setup to now...

When you change the cam/heads/intake manifold etc. you change the carb tune that is needed by the engine. That's why I was saying before that you need to set the timing with a light and then tune the carb. A vacuum gauge and a tach makes it really easy to tune the carb's idle circuit without guesswork. It will also help you find out if you have a vacuum leak or not.

I would think just based on what you have done to the engine that it is not running to rich; but instead running to lean, especially since you haven't tuned the carb yet...

Dutch

Originally Posted by Firechicken

When you change the cam/heads/intake manifold etc. you change the carb tune that is needed by the engine. That's why I was saying before that you need to set the timing with a light and then tune the carb. A vacuum gauge and a tach makes it really easy to tune the carb's idle circuit without guesswork. It will also help you find out if you have a vacuum leak or not.

I would think just based on what you have done to the engine that it is not running to rich; but instead running to lean, especially since you haven't tuned the carb yet...

Dutch

I don't think a 600 Holley on a 283 would run lean un-less some really droped the jet size down.

Originally Posted by erik erikson

I don't think a 600 Holley on a 283 would run lean un-less some really droped the jet size down.

Yeah you may be right. Only thing I was thinking was that since the carb had been previously tuned (I am assuming to the lean best setting) for the stock heads, intake, cam etc. and then, without adjustment, dropped on to the motor with a bunch of new go fast parts in it, the idle circuit may be to lean....but hell, I've been wrong before...

Vac leak or if it's an older Holley a blown power valve.