atc3434

iTrader: (4)

So, I completed my swap to non-CC components in my 86 Sport Coupe. Started right up, check for leaks, got everything ready for tuning. Set my base time to 11* BTDC, running the vacuum adv from the front drivers side port on the carb. (I've read that some perfer manifold vacuum when an aggressive cam is used, but carb vacuum should be ok for my application, right?) Without a vacuum gauge, I can only get so close on the "perfect" idle mix, I just continued to lean things down till I started to loose rpm, then went back in aprx a 1/4 turn on the air bleeds, seems to start and idle fine, doesn't load up, holds steady, etc.

Went for a drive to see where things are at, the first thing I noticed is my TV cable, while connected in the correct location, must not be generating as much pull as it used to with the CC-Qjet, my shifts are really early, and downshifts are not easily obtained. The car has a pretty wicked shift kit, it'll still bark 1-2 if I manually shift it. So, what can I do to add tension to the cable? It would seem I could pull a little more cable through the linkage (it has the round, hook style OEM setup) and clamp it off further down, would that be an effective solution?

Second thing I noticed, the bottom end is defintely more responsive than the Q-jet, but not quite right, a full hit at anything under 1500rpm results in a bog then go situation, but a quick punch to 1/2 or 3/4 throttle yeilds the best results - is this indicative of too much pump shot?

Crusing, the car runs fine. I've gotta get a TCC switch rigged, because I'm not sure, but there might be slight lean surge, that'll come out more once I can lock up 4th gear.

WOT, the car falls off, you can really hear it pulling air, but it feels wicked lean. It does pull to 5000rpm, but defintely not as well as the CC Q-jet. I've had an intermittent fuel starvation problem with this car before, and I was experiencing that when it was hot with the new carb, but even cold, it feels awful lean. (I know, get a fuel pressure gauge on it and find out whats actually going on, its in the works, just haven't been able to do that yet. I'd certianly take your thoughts and suggestion on that matter as well...)

Question is, would my mild 305 require more secondary jetting that the stock Edelbrock jets? (Carb is all setup w/ the stock, 1406 calibration.) What about the primary metering rods, go richer in the power staging? I have no experience with this style carb, but I have heard the 1406 is calibrated pretty lean, anybody care to make a rod/jet suggestion? I'd love to hear them.

battyice

Sounds like your accelerator pump shot is insufficient, trying moving the linkage to a different hole. The bottom hole delivers the smallest pump shot, the two above it larger, with the top one delivering the largest shot.

As for the transmission linkage, you will probably need something like this: http://store.summitracing.com/egnsea...DS=1&N=700+115

You need to verify that you have proper fuel pressure before you start tuning the carb, Edelbrocks seem to like 5.5-6.0 psi. If the fuel pressure checks out good, pick up an Edelbrock calibration kit and experiment with rich/lean settings to see what yields the best performance. You should also see how much vacuum your car produces at an idle and see if you need a different metering rod push-up spring.

From personal experience, the 1407 on my camaro was very lean out of the box and required larger jets to run properly.

//<86TA>\\

iTrader: (14)

hey, good to see you've got things together. definitely put the accelerator pump to the top hole, try that if it get better you are on the right track. put a heavier set of step-up springs in it. check to make sure that the tv is actually being puller all the way out at WOT, i never had the stock throttle/tv bracket on my car so i don't know what its like. changing the rods is easy, look at the page in the tuning manual for the 1406 and i thought there were a few richer settings that you can achieve with just a rod change. as for the secondaries, go a step or two richer and see what happens,

Tobias05

bump your accelerator nozzle up to a .33 and your step-up springs to the color correlating to highest vacuum, purple or white i believe.

you need to correct your tv problem, or you will melt your trans in no time. ask me how i know. that throttle cable corrector lever will help put things back into proper geometry. you will have to play with the settings, but must have it set for a double downshift in 4th gear, even if it causes later light throttle shifts.

what are you running for ignition? mechanical and vacuum advance timing set at?

atc3434

iTrader: (4)

So, here is some updating. After some more driving, the car is really, really flat with the secondaries open. Off the secondaries, it wasn't bad, still soft off dead idle, but good snap from 1200rpm on up. But oh man, the secondaries are worthless at this point. Basically, anything over 2/3's throttle, you just get more noise, absolutely no power difference from 2/3's throttle on up. Definetly feels very very lean, it doesn't ever run out of fuel (previous problem w/ Q-Jet was different, it would die completely, you'd have to release the throttle a few seconds to let the bowls refill - I atributed this to a horrendously crimped fuel line which I fixed w/ the swap), but just doesn't seem to provide enough fuel to support the adt'l airflow from the secondary side.

So, figured I'd start simple with tuning, I went to the .73/.42 rods (stock was .75/.47) just to see where that would put me. Well, it improved bottom and mid pull, anything over 2/3's throttle is still dead. I think some adt'l pump shot will bring the low end response right in where I want it, I'm not expecting tire shredding on throttle wacking on the mild cammed 305, I'll be satisifed if it'll just stand up quick and get right up on the secondaries where it wants to run.

Now, for the secondaries, I'm concerned. I know this carb is lean stock, but I'm not just kinda lean up top, I'm dead anywhere on the secondaries. I can go from the stock .95 to a .101 jet, is it really going to make enough of a difference? I know, just go out and try it, I need daylight before I try yanking the carb top off. Any reason, by the way, not to do that with the carb still on the motor. I know, don't drop any screws in, but is it practical to try and change the secondary jets with the carb on the motor, or just better to pull the carb? Does it seem likely I could really need that much more fuel than the stock calibration, or am I more likely looking at a different problem? 86TA, this was your carb, what secondary jetting where you running, and with what combo?

I'm gonna work on the springs once I get WOT on the secondaries dialed in, That shouldn't be to hard to find a good transition spot, I'll want a vacuum gauge to set that anyways, which I haven't yet aquired. I'm more worried about the gapping bog at this point.

Tobias - where does one aquire this tv cable adjuster you mention? I wouldn't mind late upshifts one bit. And yes, I'm aware of the potential damage of a poorly adjusted TV cable, I've been just holding second gear for most of my testing, not shifting on the power, etc.

Ignition is a Summit HEI, base timing (no vacuum) is 11*BTDC. I don't have a dial back, so I'm not sure what my curve looks like, I'm running a 1 light and 1 medium spring for the mechanical advance, and of course vacuum for cruise. Perhaps it could tolerate some more advance, I haven't got a single ping out of it, even when I got it hot and was really pushing the lean condition on some high load setting. Appreciate your thoughts guys.

Tobias05

http://store.summitracing.com/partde...50+4294908216+

i hear summit HEI's have 16* mechanical, so add that to your 11 initial, and you've got 27 degrees. a little low, shoot for 32. I'd probably go with 2 medium springs as well.

FWIW: I am running a reman HEI, MSD cap/rotor, Superconductors, 50K volt coil. using the crane hei kit with 800-3200 curve, 20 degrees mechanical and 16 degrees initial. vacuum advance(manifold) is limited to 15 degrees, with 31 degrees at idle at 700-800 RPM.

shoot for something like that.

hope i can help ya out!

atc3434

iTrader: (4)

More updates - I was able to take a drive just now with the car, its much cooler out, response was much better across the board. Surprisingly, the car was pulling on the secondaries, and not to terribly bad. Still felt soft, but much much better than before. I'm sure the rod change helped too, the throttle response is now better than where I was at with my Q-Jet. So, now I'm thinking I really may have a fuel starvation problem, ontop of some lean secondary jetting. The carb is right on the manifold, just a gasket, no spacer. Could things be getting too hot, causing a boiling type condition with fuel? Appreciate your thoughts.

Tobias - I'm gonna bump to 16* initial to see what I get. Maybe I'll rent a dial-back and figure it all out.

Tobias05

oh, i'd get one of these too to help with the hot carburetor. I am running one as well.

//<86TA>\\

iTrader: (14)

i was running the largest secondary jets i had, which i think were the jets out of my 750. check the choke adjustment, the secondaries will not open when the choke is on, even slightly, so if the choke never really comes off the secondaries will not work, you can play with the linkage and see what i mean with the car off, just look and see how things work. i have to go but i will be back later, need to cook

that corrector bracket for the tv cable it already on the carb, no need to buy another.

IIRC, the secondary jet is smaller than the primairy in the stock calibration. bump it up a bit and see what happens.

atc3434

iTrader: (4)

I have visually confirmed secondary operation, and I know what the car sounds like going onto them. I'm going with a fat jet on the secondaries, we'll see what happens.

battyice

What type of fuel pump are you using? Like I said before, Edelbrock carbs are fussy about fuel pressure.

How much vacuum does your engine pull when idling in gear?

atc3434

iTrader: (4)

Update: Got home from work, had exactly 1 hour before band rehersal, so I figured I'd see if I could pull the carb and get the main jets changed. I was able to do with just a touch of time to spare. Went from a .095 main jet to a .101.

Wow.

Its now on par with its performance with the Q-jet, maybe just slightly less on top still. Defintely no longer lean, my buddy says just the faintest puff of black smoke when it really climbs up on the secondaries. If Tobias is correct at the SUM-850001R HEI only runs up to 16* of mechanical adv, I've got a lot left on the table there with only 10* of base timing, I'm going to try about 16-18* and see if I can get away with it.

86TA - can you confirm what the total mechanical advance that HEI will provide, I can't find any conclusive info on Summit's website.

Tobias05

mechanical advance depends on the weights/springs, ie one type of dizzy is gonna vary from the next.

i dug up this article from scottland about his summit hei. its a few years old, and the pictures aren't there anymore, but there's a lot of good info in this thread.

https://www.thirdgen.org/forums/tech...t-working.html

//<86TA>\\

iTrader: (14)

the dizzy came with a little pink piece of paper that had the baseline calibration on it, but it said nothing of the total, i would have included it but it walked away on me and i cant find it. you could always just put the lightest springs in, thats what i was running. then just bump the timing up a degree or two at a time and see what happens when driving, just listen for pinging/detonation

atc3434

iTrader: (4)

Update, again.

Wow 2x! I rechecked the timing, I was actually only at 2*BTDC, I think I may have set the adv with the rpms at about 1000rpm before, which was probably giving me some mechanical. So, I set my idle at 600rpm w/ no vacuum adv and dialed up 14* of initial timing. Its like a new car. This little 305 runs. Hooked up the vacuum adv back up, reset my idles, and went racing on a Friday night. There were cars that used to beat me before than I now beat with ease. There was one 05 Grand Prix GTP that used to be real even with me, now I can pull 2 cars before I'm into second gear, and he doesn't make any ground back up from there. The car has never had so much bottom end power, and even pulls better up top. It'll easily roast the tires now, where as with the Q-jet I never made real good power. Stalling on the converter with my old launch technique results in wild wheelspin, its making way more power. So I'm happy.

The bad news is towards the end of the night I had made a run at another car, and checked my mirror just as I finished second, big cloud of smoke. Pulled right over, I was blowing oil onto the drivers side header from the rear of the head. So, I guess I'll be digging deeper into the engine after all. Maybe just an improperly tightend head bolt(s), I'd really rather not pull the head. It'll only do it if its real warm, and under heavy load/rpm. Doesn't do it at all cruising or highway driving, I can't repeat the condition free-revving, but it will defintely do it if you've got it warm enough, under a good load. We'll see what happens, I'm gonna pick up a torque wrench and verify my head is properly torqued, there was plenty of other things not tightend with this motor, it wouldn't surprise me. Again, any thoughts are appreciated, I'll get back to the tuning once I clear this up, I've still got to clear up my boiling fuel issue, which I think I've traced to a fuel line running in contact with the lower radiator hose...

//<86TA>\\

iTrader: (14)

well its great to hear that its working for you, about the leaky head, are you sure its not the valve cover?

the hot sopt on the fuel line is probably where is enters the engine compartment under the a/c heater box, its real clost there, maybe wrap it with an insulating material, do you have headers or manifolds?

atc3434

iTrader: (4)

Yea, I'm sure its the head, the valve cover is completely dry, it looks like it only does it when its real warm and under heavy load, other than that it does not leak at all. I actually have driven the car the last two days and have not been able to repeat the condition, so its not clear how severe things are. I'll probably race it again this Friday, and we'll see what happens.

For the fuel, there are two hot spots, right by the fuel pump there is a hardline that goes up from the pump to the carb, and it is actually pressing firmly against the lower radiator hose. Then again at the top of the motor the coolant hose to the heater core is pressing firmly against the fuel hardline. So, I think with some re-routing, and may a carb spacer I can solve my hot fuel problems. If the car is cool I don't have any trouble, soon as I get the coolant nice and hot, I can't pull at WOT for more than about 5 seconds. Which is sad because the car is really running well across the rpm range. Once I get good fuel I'll put some timing tape on and figure out what my total is, I think the 305's still got more to give up on the topend.

Tobias05

Torque check those head bolts, then pick up some hedder wrap for your fuel lines, and that spacer i pointed out. MSD sells a timing tape kit for like 3 bucks, has about 10 different sizes on it. been using it for months, still there.

glad to hear you're having better luck with your edelbrock than i did! keep it up.

five7kid

iTrader: (14)

The chances of oil leaking from a head gasket are somewhere between zero and nil.

Valve cover and intake leaks will disguise themselves as "head gasket" leaks. Head gaskets will leak compression between cylinders, and perhaps into the coolant system, but not oil to the external.

atc3434

iTrader: (4)

I know the heads don't contain a high pressure oil galley that would leak to the outside, I'm still exploring options. I find it hard to beleive that it really is the head as well, there isn't any uneven-ness in the motor, there isn't any indication of coolant in the oil either. An intake leak is a possiblity, I can say for certain it is dry along the outside edge of the valve cover, and its only wet down by cylinder #4, looks like it sprayed out onto the header, there is a slight discoloration there. I know there is an oil pressure port somewhere on the drivers side, that may be worth investigation.

F-Body Demon

iTrader: (1)

I had a similar issue. Was blowing oil out of the dipstick onto the manifold. So if your not running a PCV or its messed up that could be it. Only happened when I goosed it too. Just tryin to help, not sure what side your dipper is on. I think 85/86 was the switch wasnt it? Not sure.

atc3434

iTrader: (4)

Dip stick is on the passengers side. I have a breather in the passengers side cover, and the carb vacuum to the drivers side cover, so I'm not sure what the deal is, crankcase should be vented ok.

SpitotRs305

what kind of valve cover gaskets are you using? cork? crome valve cover?

atc3434

iTrader: (4)

Honestly, I'm not sure, I just bought the car last fall, and have not yet had the valvecovers off. I should know soon enough, if it gives me a big oildown like that again I'll be tearing in as deep as I need to go. I actually just bought a house w/ a nice big 2 car garage and will be moving in at the beginning of Sept, so this winter I may either do the heads/valvetrain/more cam on the 305, or more likely go right up to a 350. We'll see.