Winston Wolf Posted June 9, 2010 Author Share Posted June 9, 2010 Well, I got the car back together and running. Had it going first with the Edelbrock on it, as I was still waiting on parts for the Prosystems. Took the car out the other day and it was running like crap. I thought maybe since I put the new fuel pump on and was using the Performer carb that the high (8 psi) fuel pressure was causing the stumbling under acceleration. Got the Holley on tonight and it is doing the same thing. Runs terrible... I thought perhaps it was something to do with the rev limiters on both the distributor and the 6al, so I took the chip out of the box. No difference. Hot set all the valves. No difference, they were pretty close and most were right on. Checked the timing, changed it, nothing. Unhooked the vaccum advance, not it. Looked at my distributor settings, where I wanted them, cap looks new. Tightened the coil connections, nothing. It has never ran like this, so I'm not sure even what to check next. I do not think it is a carburetor issue. Listen to this video and you can clearly hear how it isn't right..... This is modern to light acceleration. Anyways, here are some pics of the new carb....and I would appreciate any ideas on the rough running. Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 9, 2010 Author Share Posted June 9, 2010 PS you need to crank the volume to hear the missing. Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 9, 2010 Author Share Posted June 9, 2010 I think I may try unhooking it from the MSD box and see if that changes anything. If that doesn't work I can try my old distributor and coil. The wires are new this year, I checked them in the dark and did not see any obvious signs of arcing or anything. What has changed: 1.6 rockers on the intake valve Intake manifold Distributor Coil Fuel Pump Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 9, 2010 Share Posted June 9, 2010 What are the dails set for? are you runing a over drive trans? if so what type of bracket are you running? On a Holley the cable mount on the cable needs to be, behind the center of the throttle lever. Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 9, 2010 Author Share Posted June 9, 2010 What are the dails set for? are you runing a over drive trans? if so what type of bracket are you running? On a Holley the cable mount on the cable needs to be, behind the center of the throttle lever. Dials are set for 15 degree mechanical advance all in by 2500. and the # 3 vacuum advance curve, which is 0 deg 4" and 10 deg max at 6". It does not make a difference with the vacuum advance hooked up or not. I am running an OD trans. The bracket is from Bowtieoverdrive.com, made for a 4150 Holley. The bracket is correct and works as it should. I also just had a thought: I had to redo the ends on the spark plug wires to accomodate the HEI style cap. Perhaps my problem is just with a plug wire or the coil wire. May get a new set and replace one side first and test, then the other side. Quote Link to comment Share on other sites More sharing options...
TN454Monte Posted June 9, 2010 Share Posted June 9, 2010 Nice job on the plumbing work on the carb, it looks really well done. Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 9, 2010 Share Posted June 9, 2010 I don't have my book in reach for the dist. I see bowtie changed their bracket setup to look like Holley's setup. You might want to check your line pressure if sounds like the trans is inbetween gears, mine acted like that until I change the line psi to what bowtie overdrive told me. If you are running a bowtie overdrive 700r4 you should have a line psi of 100#. Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 9, 2010 Author Share Posted June 9, 2010 I don't have my book in reach for the dist. I see bowtie changed their bracket setup to look like Holley's setup. You might want to check your line pressure if sounds like the trans is inbetween gears, mine acted like that until I change the line psi to what bowtie overdrive told me. If you are running a bowtie overdrive 700r4 you should have a line psi of 100#. Here is the dist book... Digital E Curve Instructions This is a 200-4r. I don't have any issues with the line pressure, I have plenty. Actually have a gauge installed in the car, so I know. The trans is definetely not between gears, the sound you hear is the engine missing. Quote Link to comment Share on other sites More sharing options...
CrazyDavey Posted June 9, 2010 Share Posted June 9, 2010 Well, I got the car back together and running. Had it going first with the Edelbrock on it, as I was still waiting on parts for the Prosystems. Took the car out the other day and it was running like crap. I thought maybe since I put the new fuel pump on and was using the Performer carb that the high (8 psi) fuel pressure was causing the stumbling under acceleration. Got the Holley on tonight and it is doing the same thing. Runs terrible... I thought perhaps it was something to do with the rev limiters on both the distributor and the 6al, so I took the chip out of the box. No difference. Hot set all the valves. No difference, they were pretty close and most were right on. Checked the timing, changed it, nothing. Unhooked the vaccum advance, not it. Looked at my distributor settings, where I wanted them, cap looks new. Tightened the coil connections, nothing. It has never ran like this, so I'm not sure even what to check next. I do not think it is a carburetor issue. Listen to this video and you can clearly hear how it isn't right..... This is modern to light acceleration. Anyways, here are some pics of the new carb....and I would appreciate any ideas on the rough running. Justin, email that clip to Patrick and let him hear it. He can tell you if it's fuel or ignition...Dave Quote Link to comment Share on other sites More sharing options...
BowtieThunder Posted June 9, 2010 Share Posted June 9, 2010 What is intial timing set at?What is total timing? Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 9, 2010 Share Posted June 9, 2010 Going by the 15° table your base is 10° when the advance starts opening and it reaches 25°. With the vacumn setting 6" you are getting 10° of vacumn advance which is giving you a total of 35° at 2500 rpm's. I'll pop my cap off my digtail e-crvue and share its setting with you and see if it helps you out any. Here is how my is dail #1 is set at 0 and dail #2 is set at 6. The electronic centrifugal advance table I'm using is the 20° advance starting at 5° until 1200 rpm's then it goes up to 25° by 3000 rpm's. Vacumn table im using setting #1 which starts at 0° at 4" of vacumn and goes to 10° at 10" of vacumn. You currently have your first dail set at 5 and the second dail set at 1. It could be the timing coming in to soon try and slide the total back to 3000 rpm's, leave the first dail at 5 and move the second dail to 0 this will still give you 35° total but at 3000 rpm's. Then if that dont work try setting the first dail at 1 and the second dail at 1 the gives you the 2500 rpm's and it keeps the 10° of vacumn but at 10" of vacumn. if that makes sense Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 9, 2010 Author Share Posted June 9, 2010 To eliminate the posibility of it being the advance curve, I unhooked the vacuum advance. I have it set so it is all in by 2500 with a total timing of 34 degrees. Innitial is around 20. The engine doesn't really even run anything under that range, as you can see in the video. I do not think this is related to the advance curve. It is happening at 3500 and 4500 and whatever other RPM I accelerate at. Quote Link to comment Share on other sites More sharing options...
72Monte Posted June 9, 2010 Share Posted June 9, 2010 Do you have a way to check the Air/Fuel mixture? Does it idle smoothly? could it possibly be a lean condition via a vacuum leak? Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 9, 2010 Author Share Posted June 9, 2010 I have a LM2 a/f monitor hooked up in the car. I do not think it is a lean issue, in fact it runs on the rich side per the meter. A vacuum leak is unlikely, the carb only has 2 ports, the large in the back going to my brake booster and the small in the front that was to the vacuum advance, but is now plugged. The intake has one vacuum port that is pluged. All gaskets are new. Again, this seemed to do the same thing with my other (Edelbrock) carb, making me lean towards ignition issues. Quote Link to comment Share on other sites More sharing options...
BowtieThunder Posted June 9, 2010 Share Posted June 9, 2010 Here is what I would do is set everything to 0 so nothing changes set timimng to 38-40* and seee what happens.As far as Vacuum leaks I used 2 brand new gaskets between carb and NOS plate and NO plate ti intake and still had a vacumm leak as it didnt seal.... so dont rule that out unless you pull carb and check it.I dont think 34 degress is enough timing at all IMO Quote Link to comment Share on other sites More sharing options...
stangeba Posted June 9, 2010 Share Posted June 9, 2010 Check the firing order vs plug wires, if two are crossed it won't run right. Quote Link to comment Share on other sites More sharing options...
wallaby Posted June 9, 2010 Share Posted June 9, 2010 I'm trying to get an idea. Does the misfire happen always at 3500 and up, regardless of load? And normally it's ok at speeds under 3500, unless you put a load on it? Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 9, 2010 Author Share Posted June 9, 2010 I double checked that the plug wires are correct already, along with the other obvious stuff. It seems to run fine at low rpm while not in gear. When you rev it up in park and hold a steady rpm, say 2500, it sounds like it MIGHT be running rough, but its hard to tell with the valvetrain rattling and the exhaust. As soon as you go drive it and accelerate, it runs like crap. very hard to accelerate and keep it below 3500 under light accel due to the converter. You can see in the video how soft i am gassing it. So I would say it is prominent under load (light). If i had a vacuum leak, it should be less of a factor in upper rpms i would think. I just picked up some new wires and plugs, so i will start there tonight, then get rid of the 6al, then change coils, then distributors. I will also double check a/f while testing. Quote Link to comment Share on other sites More sharing options...
Cali Z28 Posted June 10, 2010 Share Posted June 10, 2010 What about the distributor being off a tooth? Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 10, 2010 Author Share Posted June 10, 2010 I don't know, but the lack of performance after the last round of upgrades and then further loss with this volley tells me this might be a symptom of the first changes. The cam timing is really bothering me for some reason. I know you degreed the cam, twice and originally you stated that the cam was "off" by 4 degrees out of the box, so you corrected that and then added steeper ratio rockers, which effects valve timings as well. I know its not like unzipping a zipper to modify it, but if it were me, I would go to a straight up cam timing and start there. Too many cam grinders put a very specific advance / retard on their grind so that you can install them dot to dot and get all of the performance that was expected. That's my bit. I agree with you Allan Here is the cam card. It is installed so that the valves open and close at the exact degree the card says on both the intake and exhaust. I would call this "Straight up". The cam is ground with a 4 deg advance into it, but I did not advance it 4 degrees. When the dots are aligned (and they did not perfectly align, but as close as it could be)and the adjuster was set at 0 deg change on the hex adjust the intake valve at .050 was at 22 degrees. I had to retard the cam gear 3.5 deg to get the intake to open at 18.5, which is what cam card call out. I can change my cam timing without pulling the engine apart with the Cloyes cover, but it is installed per the manufacturer.... Do you not agree? And even if the cam was installed a bit advanced or retarded, it wouldn't create the missing I have. Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 10, 2010 Author Share Posted June 10, 2010 What about the distributor being off a tooth? Thanks, but I'm not sure how this would make any difference? I set my distributors up by total timing, and if it was off a tooth you would just have to turn it a little further in one direction to get the timing set right. Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 10, 2010 Share Posted June 10, 2010 If the dist. is off by a tooth it will case a proferance drop. I would make sure #1 is up check the rotor if its pointing towards the drivers head at #1 then it should be good, if not pull the dist up and bearly turn the rotor until it drops in place and is pointing at #1. You can run a engine on the #6 cylinder. Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted June 10, 2010 Author Share Posted June 10, 2010 When you time an engine you hook the light up to the number 1 cylinder. If it was off a cog, you would just have to turn the distributor to get the mark back where you wanted it. The only way it would cause a performance drop is if you didn't time it correctly. I don't have a vaccum can so I can rotate my dist freely. I think what you are talking about is having the distributor in 180 deg off, and that ain't my problem. Quote Link to comment Share on other sites More sharing options...
72Monte Posted June 10, 2010 Share Posted June 10, 2010 A lot of times ignition problems and carburetor problems diagnose similarly....could there be an issue with the carb that was overlooked? Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 10, 2010 Share Posted June 10, 2010 Would the vacumn line for the booster cause it? I'm not sure why the port on the intake wasn't used. Quote Link to comment Share on other sites More sharing options...
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