Need MAJOR help with tune up

groovy · 09-22-2004, 04:22 PM

I have a 1977 2.7 that has been giving me major problems. I bought the car in boxes and i have been attempting to put it all together. heres the list of what the engine has. im shure some of the details are pointless, but I will list them anyways. Balanced crank
balanced clutch
ported flow test
65-68? aluminum crankcase
s grind cam
solid rockers
headers w/glasspacks
40 ida 3c carbs
velocity stacks
9.8:1 compression
msd 6AL ignition
msd blaster 2 coil
and the guy that started the rebuild built a billet distributor housing that uses mercedes electronic ignition guts.

After messing with it a while and not having any luck i took it to a mechanic that tuned this car before the rebuild and coming back i noticed that the drivers side would slightly and constantly pop and then it would pop loudly every so often. So being the perfecionist that i am i just couldnt live with it. So I messed with it myself and now its really bad.
Now the car has a hard time starting and if I ever get it running it wont idle below 1000 rpm and the driverside blows out black smoke bad and has a black liquid that i cant tell if its sooty gas or oil.
The regulator was set at 3.0 and i changed it to 3.5 and i checked the float level with that PMO gauge (the drivers side was so low they didnt even come up on the gauge) I also pulled off the driver carb to see if it was leaking and now the accelerator pumps dont pump anymore and i checked them before i set the float level and the worked fine, and i can hear that the pass. side working.

PLEASE HELP with any idea that you might have even if its a dumb idea because i know ive used up all my dumb ideas, and ill tell you i dont know much about porsches I spend most of my time working on street rods.

tab tanner · 09-22-2004, 04:58 PM

I sent you a P.M.

1974carrera · 1974carrera's Garage

Groovy,

1) Was the engine also in boxes or was it assembled...has it run corectly at all since you've had it?
2) When it was popping, do you know if it was popping through the carbs or the exhaust?
3) Can you list the vaious jet sizes currently in the carbs...air corrections, main, idle and emulsion tubes...and are the jets the same for each choke?

groovy · 09-22-2004, 05:43 PM

Well i dont know what a p.m. is but after typing it i got one of those dumb idea to check the dipstick and i noticed that it was low and i checked the exaust on the driver side and noticed that it is still wet so i guess thats not a good thing but that mechanic did a compression test and said the rings were not fully seated but there was no major leaks, so i dont know what i did. The car sat a few months before i got enough time to work on it again do you think that the oil could have seeped throught the not fully seated rings and its still trying to burn it off.

groovy · 09-22-2004, 05:53 PM

well 1974 carrera
1)the engine mostly together i just put the ignition together, bolted on the carbs, made the exahust, hooked up the tranny, ect.
2) i cant remember where the poping sound came from.
3) I was going to check the air corrections, main, idle and emulsion tubes but i just figured that the guy who was building this car had already changed that stuff because this guy knew these cars he just ran out of time required to finish it
this may seem like a stupid question but how do you check what size all those things are?

Rondinone · 09-22-2004, 06:03 PM

If it's backfiring from the exhaust, and there's black smoke, you are probably running rich.

I would also get a timing light, and use it to verify that all your cylinders have ignition.

groovy · 09-22-2004, 06:13 PM

ill try sat. when i have time to adjust the carb and yes all cylinders have spark ive checked that quite a few times (when i ran out of ideas) and ive checked my timing more times than i want to admit