Well I'm still troubleshooting my falling on it's face issue with my motor. I changed the water pump out with the one that was on my other engine (383) and popped it on there and at first it seemed like it was making more fuel in the filter than the old one but after my test drive and my problem still persisted I noticed that the filter would fill up with fuel about 2/3's of the way, then it would suck it down and I could see the inlet to the filter where it was almost completely empty and looked like the inlet line was just spitting as if it were trying to pump some fuel in there but maybe sucking air or something???? I don't know but this doesn't look right to me.

I did find that after I had set my static timing (with no vacuum connected) to 10' and I had previously checked the total timing without the vacuum line connected and that's why I was only getting 26' total. I checked it tonight with the vacuum line connected and I was at 42' so I backed it down to 33' total timing with the vacuum advance line connected and that ended me up at 4' static timing at idle so I left it there. All this was before my test drive. Took it out and still fell flat on it's face any time I put it under a load and try to gas it. Part throttle on primaries runs smooth no problems but try to push it over a little bit and it starts to miss and backfire etc. through the carb.

This whole fuel filter thing really bothers me, and kind of makes me wonder if the sock in the fuel tank may be obstructing proper fuel flow but what bothers me is that it did not do this with the original engine in the car with the Edelbrock 600 carb. It ran smooth and ran out good when I nailed it. The only difference is my engine, carburetor and distributor.

I think tomorrow I will try and put the 600 carburetor on it and if that doesn't work, I did go ahead and purchase 8 of the 3/4" reach spark plugs (Autolite 3924's) and I'll try and throw those in too and see if I'm just not burning the mixture because of the short reach plugs. If that doesn't work then I don't know what to do next other than maybe try my other distributor but I don't think that's it?????? As usual open for suggestions.....?????

Geez I can't believe I did that, I said water pump because I was thinking about someone elses post about their water pump.......LOL I meant FUEL PUMP!!!

if the fuel sock is suspected you might try blowing the fuel line back in the direction of the tank... not too much pressure though you don't want to blow the sock apart. the sock isn't that fine of a mesh though so i'd think if it was bad you'd find constant debris in the fuel filter.

as far as timing goes, most SBC's i've ever had seemed to like 10-12* initial.

here's a quicky thing to check... pop the dist cap & rotor and inspect the advance weights/springs. rotate the dist shaft with your fingers and confirm it snaps back immediately when released. if it doesn't pull & clean the distributor and check for wear, shaft oscillation, gummed up advance mechanism etc...


not sure if i'm helping or not, but i'm tryin' ;)

:cool:I will try those things too tomorrow John. I appreciate the help. I thought about blowing back through the line and I will be careful not to put too much pressure on it but just enough to get some bubbles in the tank and clear any possible obstruction. I think I will go ahead and replace the little piece of fuel line (and clamps) from the aluminum line to the pump also to make sure that we're not sucking air right there also. Didn't think about checking the weights on the distributor though. The advance seems to be working pretty well from what I'm seeing on the light but will check anyway. If I go back to 10' advance that will put me up around 40' advance with the vacuum line connected. Do you think I should just set it to 10/12' and leave it only as mechanical advance??? I don't think this is what's causing my flat falling on the face problem but it could have an affect on getting top performance after I get it running right anyway, I guess I can make that decision later.

Anyway, thanks for the suggestions. I'll keep posting my progress for whoever is interested and see what other feedback I get.:cool:

Check to see what the mechanical adds and when. I prefer a vacuum advance for street driving (assumes you are using ported vacuum line) as it gives the best performance on the street.

You have air in the line which should pass through the carb and be vented when the motor is running. It sounds like the float levels are set too low in your carb as the problem you are addressing sounds like a fuel supply problem (running lean). You have to actually take the top off of the carb to see where the fuel level is as there are no sight plugs to verify level (which is another plus for the Holley carb).

Big Dave

if the vacuum advance is advancing too much it can be limited by using a stop... look here for info on that: http://www.novas.net/forums/showthread.php?t=4093

:DWell I didn't have much time to work on the car today as I had to catch up on my mowing before we get rained on again. Let it go for too long because I've been working on the Nova and then kept raining when I needed to mow so had to get'r done today. I did manage to find some time thought and I opted to go ahead and put the correct reach spark plugs in first and try that before swapping carbs and/or ignitions. On test drive I still had some misfiring at load and when getting on it, but it was not nearly as bad as it was so this made a definate improvement. The results of this are leading me to believe that my problem may be ignition related now. The engine is the same short block as what the car had when I bought it, the only differences are the heads, intake, carb and distributor. The distributor I'm using came out of a 79 pickup and I think the guy was having some trouble with it when he had it but he had tested everything and said it was all good. I'm going to check a few things out on it tonight and see if maybe I have a weak coil that is not standing up under a load because putting the right plugs in seemed to help quite a bit so maybe it is ignition after all. Film at 11:00................
Oh by the way, I did blow out the fuel line and it seemed to be ok, will look at the rotor and the advance weights when checking out the distributor. We're having fun now.............OH Boy!:D

:D We're having fun now.............OH Boy!:D



hehehe... ain't that the point of it all ??? ;)


JR

:sad: Well I thought I had it figured out but still no joy. I checked out the distributor last night and the advance weights snap back promptly like they are supposed to, the pickup coil had 825 ohms like it was supposed to, the coil seems to be ok with 16k ohms between primary and secondary, troubleshooting guide I found said it should be between 6k-30k, but I did have a burn mark on the rotor bug (just a small one on the little finger that contacts the coil secondary) and the metal strip was a little loose and I could move it slightly and it was giving me eroneous readings on the meter. I thought well that could surely do it and I had a new one on hand so I replaced it. That didn't work.

So this morning I changed the carbs out and put the old 600cfm back on it and that didn't change anything either. I thought since changing the plugs out seemed to help the situation some that it may be ignition but it does seem like it is just starving for more fuel. I set the float levels on the 750 the other day when I changed out the spring and the squirter to the factory settings recommended in the book that Phillip provided me with. They are at 7/16" the the top plate upside down from the top of the floats to the gasket which is the shutoff setting and 1" when you flip it over and the floats are hanging per the owners manual. I'm thinking I will go ahead and raise the float level and let it run a little higher level.

I went ahead and reset the timing back to 10' and this is what I have now. Static timing 10'. Static + Mechanical = 27' Static + Mechanical + Vacuum = 42' Now I could probably advance the timing a little more but I really don't want to be running more than 10' at idle and I think there's enough timing there to make the engine run fine. I can see the mark moving when I give it gas just fine so I don't think that is an issue. What I didn't do was see at what RPM it starts to move. I guess I could check that, but kind of hard when you're doing this by yourself. I guess I could put a tach under the hood and watch it.

Anyway this is really dupin' me. I watched the fuel filter again too at idle and it was full at first then after it ran for a while it stayed full for a while then all of the sudden as if a valve opened it started to drain down in the filter and then it stayed low just like it was doing with the other carb. I don't understand why it does that. I always thought that it would stay at least 2/3's full and when the needle and seat opened up more fuel would go in and the pump kept pumping into the fuel filter to keep it full too but it doesn't seem to be doing that. I took the other fuel pump of the other day and put in on here and they both seem to be doing it so I don't think it's the pump. I guess it's just normal operation???? but sure seems funny to me. Anyone care to explain how the mechanical fuel pump cycle operates and why this is happening? Is there a shutoff/check valve in the pump that stops the flow when there's back pressure from the carb?

I have heard that it's possible that a coil can read out as if it's good but still be bad and that when a coil is weak it can cause this type of problem like crapping out and misfiring when under a load. I could try another coil that's a pretty easy swap out just for G.P. but I don't think I need to put my other distributor in. I don't think the module is bad because they usually go and you have a no spark condition. I don't know but I'm getting frustrated because I've put a lot of work into this and I know this combo will run good once I find this issue.
HELP!!!!!!!!! :sad:

Well I've tried another coil, cap, rotor, carburetor, adjusted float level for higher level, changed squirter, step up springs, checked Mech Advance, adjusted timing, tried 2 different (stock) fuel pumps and still have a stumbling falling down problem when you put the engine under a load. It seems sometimes it will clear up and start to pull but it wants to backfire, miss, crap out when you try to accelerate too quickly. I'm out of ideas unless it truly is a fuel pressure problem but I just don't understand how I could suddenly develop a fuel pressure problem unless these bigger heads, intake and carb truly need a lot more fuel pressure than a stock pump can deliver. Here's a short little video of what my fuel filter looks like at idle, the lighting sucks but if you look closely you can see it sputtering and gurgling and barely see any fuel in the filter except down at the very bottom corner of the filter on the right. http://http://i518.photobucket.com/albums/u347/dellerbe_photos/th_ac584efc.jpg (http://[URL=http://s518.photobucket.com/albums/u347/dellerbe_photos/?action=view&current=ac584efc.flv]http://i518.photobucket.com/albums/u347/dellerbe_photos/th_ac584efc.jpg[/URL)]
http://http://i518.photobucket.com/albums/u347/dellerbe_photos/th_ac584efc.jpg (http://s518.photobucket.com/albums/u347/dellerbe_photos/?action=view&current=ac584efc.flv)

I don't have a fuel pressure gauge hooked up into the system yet it's just the pump and the carb so can't tell what kind of pressure it has. I'm basically stumped at this point. All I can do is keep throwing parts at it unless someone has a better idea.

Never seen fuel that low before and the motor still run. Usually they are at leat two thirds full to filled completly.

Big Dave

Just for laughs take your fuel filler cap off to vent the gas tank. If air can not get in gas will not come out. This should be an easy test.

Big Dave

That's a very good idea. I will try that tomorrow, I'm spent for the day today.

I'm going to take your suggestion and open the gas tank cap and make sure it's venting properly. I need to replace the sending unit anyway it's giving erroneous readings, only reads 1/2 tanks when it's full so I will be dropping the tank soon and putting a new sock on it very soon anyway. Maybe I'll find some clues there, but what really troubles me is the car ran fine with the stock heads, a regular performer intake, the 600 Edelbrock carb and the old points distributor and coil. Oh well, thanks for the help Dave, I really appreciate it.

Hey Dale, reading your 3 threads i thought that the info you provided in them that they might need to be together for anyone trying to help get the whole picture... so i "Merged" them together... i hope you don't mind i'm just hoping to be helping...


i'm pretty stumped on this one, i sure hope it gets resolved for ya Bud ;)


Johnny

Dale,

you mentioned that you are using "stock" fuel pumps right?? You might want to replace those "stock" units with a Holley or Edelbrock one. It seems that you are basically starving the motor of fuel. On my 71, I had a stock unit and it was reacting the same way yours is so I replaced it with a Holley and the problem went away.


Hope this helps..

Yes that's a good suggestion. I've been considering trying that but at $115 a pop for a new fuel pump, I was kind of hoping to be able to prove it first before spending the dough but kind of hard to prove that without increasing the fuel pressure. I have an old Holley Blue I could put on it but I hate how noisy they are and don't really want to mess with running another wire back to the tank and mounting it up etc. Maybe I'll just make the plunge and go ahead and get the Holley pump. I suppose with these larger heads (195cc and 2.055 Intake valves) and the large plenum intake of a Victor Junior with the 1" spacer too boot it could be really demanding some serious fuel pressure to get enough in there to compensate for all the air I'm able to put in it to get a decent mix. Thanks for your input.

The filter should have more fuel than that in it, but it won't be full. What size fuel line is coming from the tank? And if the rubber lines anywhere on the suction side are hard and/or cracked it will cause a fuel delivery problem by sucking air into the lines. Not necessarily a leak just less fuel delivery.

Yeah, that's what I thought too, it will be full and then all of the sudden it will start to suck down and then does't want to fill back up. It has a 3/8 aluminum line coming from the tank which should be more than adequate. I'll check the tubing back at the tank and make sure I don't have any cracked lines or loose connection that may be sucking air. I was going to try Dave's suggestion about craking the cap to make sure I'm not having a vent issue but the damn filter would not go empty this morning......LOL. I'm heading out now to play a little more and see what else if anything I can find before I go spend another $100+ on a Holley fuel pump. I really just don't want to run the electric because then I have to put on the regulator, the gauge, blah, blah, blah. I'll check the lines again though, thanks for the input.

Also rubber hose will turn into black goo with alcohol in the gas (mandated 10% or more nation wide starting June first). It has to be nylon lined braided hose as the regular braided hose you buy is natural gum rubber (it will disolve in alcohol).

Big Dave

I stand corrected. My fuel lines coming from the tank are NOT 3/8" as I thought. Upon closer inspection they are only 5/16" including the line into the tank. The bad thing about 6 cylinder cars is everything is minimal. I did find 2 pieces of rubber tubing and they both did have dry cracks in them. I pulled them off and blew through them and sure enough you could blow air even with the end plugged, so that for sure is at least part of the problem. I replaced the hose in both spots, but I only had 3/8" hose not 5/16" so I double clamped the 3/8" for now hoping it will hold and not have any leaks. I'm checking with my auto parts store now to see if they have any 3/8" aluminum tubing that I can go ahead and replace that 5/16" stuff. There is 3/8" from the fuel pump to the carb but 5/16" from the pump all the way back to the tank. We'll try to get this supply line straightened out first. Thanks again!

Hmmm. Didn't know that either Big Dave. Thanks for the tip on the hose.

The 5/16" line will feed a lot of fuel. Replace the rubber lines (the new hose sold is fine) with some 5/16" hose and give it a try before running new hard lines all the way from the tank to the pump.

Ok well I don't have any 5/16" line so used 3/8" for now and double clamped but didn't solve problem. I'll leave the 5/16" rigids in place for now if you think they'll provide adequate supply for now, but I'll get some 5/16" rubber hose tomorrow and replace my little splices. The 3/8" didn't solve the gurgling problem the filter is still looking pretty low and gurgling so either my 3/8" is not sealing up good on the 5/16" line or maybe I have a restriction in the line. I'm going to just go ahead and drop the tank tonight I think and take a look at everything up close back there. I need to replace the sender anyway so I'll just go ahead and get one on order and the good news is it looks like the tank is pretty easy to drop on these babies. We'll see...............

There is a short hose on the top of the tank that can not be accessed without dropping it.

Well I didn't see any short hose coming from the top of the tank. Mine has a solid steel line coming from the sending unit over to the passengers side corner of the tank where there is a short piece of hose there joining the main fuel line and then again about 1/2 way up the frame another little short piece of hose (good place for an inline fuel filter) and then the 2nd section of rigid line going up to the fuel pump. The end of the sending unit had a 5/16" suction line that was seriously necked down to where there was only about an 1/8" or maybe 3/16" opening, I didn't like that at all so took out my handy dandy tubing cutter and cut that little dandee off so now there is a regular 5/16" opening to draw through. There was no sock on the end of sending unit pickup tube and I blew through the line and there were no obstructions. I went ahead and put it back together the way it was because the tank was very clean inside and I saw no debris (shook it around and tilted it to see if the sock was laying in the tank but didn't see it in there so may not have been one in the first place) and I do have a good filter to catch anything before it goes to the engine anyway, and actually my sending unit appeared to be working ok so may have had a bad ground between gauge seems to be working better now. Anyway, so while I have the tank down I'm going to do a little corrosion control up in the tank area as I spied a little rust under there that needs some attention but will put it back together and make sure I blow all the lines out, I got some 5/16" nylon lined fuel line to replace all the vent lines, and splices on the rigid lines and will probably go with a High Volume Fuel Pump and see what happens then. Wish me luck boys!!!!!:clonk:

You didn't mention finding a build sheet so I assume there wasn't one on top of the gas tank (a place that they are commonly found since the guy has to size the gas line to the motor, by having the default L-6 set-up I guess he had no build sheet for your car).

Big Dave

Nope no build sheet. I do have the original protecto plate and warranty paperwork, registration and owner's manual though. I don't know if it matters much since the car has been converted to a V8 and has a different Tranny now and I found that the rearend is from a 69 Nova and not this 71 at least that's what the PA rearend code tells me. But it's still kind of neat to actually have the original protecto plate and all and it probably must add "some" value to the car's history anyway.

Well after repairing several leaks in my gas tank and doing a little corrosion control work up under that area I got the New Holley 110 gph mech. fuel pump on the car and got the tank back up on it and just had enough time to run her into town (3 miles) and run her through the car was real quick and go top off with some fuel. Didn't really get to get into it too much but I could tell it still is not quite running like it should be but it does seem better than it was. So little by little I seem to be getting some progress, but we're still not there yet. Tomorrow I should have some time to play with it some more and will try some timing adjustments and see if I can get 34' mech advance and see how it likes it there. Maybe it just wants some more timing I don't know, but I'm going to keep an eye on that fuel filter thing too and see how the new pump makes a difference on that. Surely I will get this thing figured out eventually. :yes:

don't EVER call me Shirley !!! :eek:


good luck to ya ;)

Yeah, but you wouldn't say that to TINY now would ya!!! HUH HUH HUH???:noway:

SURE i would !!! :rolleyes:

doncha know EVERYONE'S a ToughGuy.... ON THE PHONE !!! ;)


yuk yuk yuk ;)