383 240Z is dog slow....confused?

[TheNeedForZ]

What can be done to the torque converter? Do they lose fluid or efficiency over time?

[Graeme]

I would totally suss the carby first before moving on to other issues. It sounds like the whole inards of the carb need a good clean out. Finish the other qjet , put it on and let us know if it is better.

 

Always pays to eliminate possible causes bit by bit.

Grae

[Guest tony78_280z]

Oh yeah!! Whenver possible, one project at a time! Trust us!!!!

[grumpyvette]

before doing anything else you need to do a compression check and

read this old post

OK you just bought a 383 VETTE ENGINE..OR DID YOU????

HOW do you know its NOT a 307, or a 350 the guy sold you? sure it runs ok... but is it really a 383????

 

since a SBC 383 engine is BUILT FROM almost any 4" bore block by installing a 3.75" stroke crank and matching pistons and rods, the casting numbers will provide very little if any useful info! and you CAN,T depend on whether its internally or EXTERNALLY BALLANCED because BOTH type cranks,ballancers and flywheels could have been used in assembling a sbc 383)

youll need to measure the bore and stroke, or at least the voluum of a cylinder to get the displacement, of the engine, now the correct way would be to disassemble the engine, but you can get a very good idea as to the displacement

 

with a simple test.

remove the rockers from cylinder #1 and disconnect the battery[/color]

pull the #1 spark plug and put the timing mark at TDC, using a 5/8 socket and breaker bar on the crank nut, use a screw in air hose adapter to replace the spark plug from your compression tester(dont attache the gauge) just the hose and adapter(*YOU MUST USE THE TYPE THAT HAS NO VALVE OR OBSTRUCTION TO AIR OR OIL FLOW IN EITHER DIRECTION WHEN THE GAUGE IS NOT ATTACHED)

have your buddy help by placing the hose in a quart of oil and turn the engine to BDC , letting it suck oil into the cylinder thru the hose, now slowly turn it untill your back at TDC,letting it blow air and oil back out, at this point the cylinders combustion chamber voluum and the hose are full of oil, NOW do it a second time, this will fill the cylinder WITHOUT AIR,but this time as the piston starts to compress the oil out of the cylinder,as you move from BDC to TDC let it squirt into a clean and empty container untill you reach TDC, a 350 will squirt out approximately 717 cc of oil, a 383 will squirt out approximately 784 cc of oil

your local grocery store will have measuring cups/bowls

marked in BOTH liters and ounces, the 100ML, 200ml ECT are REALLY CCs (look to pay well under $10) so your looking for about 784ML or 7 3/4 of the way to 800 ml on the measuring bowl for a 383 but a 350 will just push a bit over 715 ml of oil

 

after finding the voluum, remove the adapter and leave the plug out, turn the engine over several times, to force the oil out BEFORE replacing the rockers, then replace the rockers and with the plug STILL OUT spin the engine on the starter several times to blow excess oil from the cylinder, only then can you replace the plug, and yeah, its measy and loud, and the cylinder will smoke for a minute untill the plug cleans itself! but its way less work than tearing the engine down to check!!