I think you may have an additional issue to check. If it's not a stock dampener, make sure the timing markings are correct. Mine was not, but my machinist/ builder caught it upon installation. He scribed a new mark at the correct TDC point.
I'm a hobbyist. Not a professional. Don't be hatin'!
Update Worked on car all day tried all kind of different setups Checked timing No vac advance Initial 36*. Idle 950-1000. Vac 12-13 Total 55*. 2500 rpm timing maxed out Startor spins engine with no issues with this much timing
Idles in gear 600-700 Vac 8-10
You're basically trying to band-aide having the wrong camshaft. Also, driving it with above 36 degrees full throttle, even if you don't hear audible detonation, you an still creating serious damage to your new engine. If this is the only way it runs, and for some reason you want to try to run it this way, then lock out the advance @ 36degrees (no vacuum, no mechanical advance - just 36 degrees under all conditions like a strip-dedicated car).
However, if you want better performance, better drive-ability, and even some fuel economy improvement replace that cam. If you want some support on that, then you can throw your specs. up here and get 5000 opinions.
Here's what we would need. Again, you previously posted a lot of this information, but it'd be easier for all if it's consolidated.
Vehicle Engine Displacement: 350 (+overbore?) Max RPM redline: Compression ratio: (9.5:1?) Intake Manifold: Carb Size: Torque Convertor Stall: (2200rpm?) Rearend gearing: Transmission: Exhaust header type with primary and collector size: Exhaust size, and w/without H-pipe or X-pipe: Fuel Octane to be used: Main use: Mostly spirited street with some 1/4mile use, mostly 1/4mile, autocross, roadcourse, ? Desired vacuum @ idle: (in-Hg.) Idle characteristics: Smooth, mild lope, very lopey, choppy
Yes I have the 9 way crank gear set. set 2* advance per comp cam techs Spent some time with the engine builders today they don’t see why the high initial timing either Comp tech guy wants me to put stock balancer on to check timing Thinks line is in wrong location This was already checked piston stop and deg wheel to find tdc put balancer on. line rights up with 0 Comp cam is willing to work with me and the machine shop if any damage to engine has happened do to the cam I have to go down their list of things to do and check so they can determine what the problem is on why it wants so much timing Now they have me checking ignition system, distributor I also talked to distributor manufacturer today to see what I can test or check they think it might be a problem with the pickup inside I’m sending them pictures in am that they are requesting of the inside of distributor Bottom line is that if it’s the cam they will refund me and get me a cam that will work But according to both of them it should run with out any problems and with out all that timing
I have to agree with Firebird Mike. Although I'm not an expert on camshafts, you have a camshaft that is more suited to a large displacement or race type engine. The intake manifold and camshaft need a lot of air to work together, either a large displacement engine or a smaller one at a higher RPM. Some camshafts require an idle of 1200 plus just to keep running. There is a tendency for some to install carburetors, manifolds and camshafts that are just too big for their application.
Maybe it's just a distributor snag and a quick fix, I hope it's something simple, but maybe you should list what you have for a foundation and what your intended use is and research what components would be the best to achieve that goal. You've been chasing this for quite some time now, it could be all the components are in good working order but just not suited to your engine.
Yes I have the 9 way crank gear set. set 2* advance per comp cam techs Spent some time with the engine builders today they don’t see why the high initial timing either Comp tech guy wants me to put stock balancer on to check timing Thinks line is in wrong location This was already checked piston stop and deg wheel to find tdc put balancer on. line rights up with 0 Comp cam is willing to work with me and the machine shop if any damage to engine has happened do to the cam I have to go down their list of things to do and check so they can determine what the problem is on why it wants so much timing Now they have me checking ignition system, distributor I also talked to distributor manufacturer today to see what I can test or check they think it might be a problem with the pickup inside I’m sending them pictures in am that they are requesting of the inside of distributor Bottom line is that if it’s the cam they will refund me and get me a cam that will work But according to both of them it should run with out any problems and with out all that timing
Mickey....I have a friend down in Seabrook , who does cams , and dyno stuff, lee Atkinson....
I can get you his email.... email me again....or actually since I have your other email I will reply with his email addy
Alright guys I was looking thru the receipts and the spec of everything that was bought for the build and I ran across something that didn’t make sense The converter I bought I switched one of the numbers and it’s only a 2000 stall now this may or may not be the only issue but it’s something that needs to be changed
My bad for not checking before I installed it
I called in a favor from a guy I now in Chicago big mopar guy has built a bunch of cars and spends time at the tracks he was able to get me in touch With 2 places a big dog who builds and knows torque converters And the performance place they use Which I will mention them at a later date And by the way I’ll be seeing my buddy from Chicago in about 2 months Coming to Houston I’m getting the right torque converter that matches the rpm range of cam, intake, trans type, rear gearing , tire size and for how the car is going to be driven After I get new converter in and the timing setback and all the carb and distributor springs back to normal will see if it idles better when in gear If not the cam comes out and in with something else Thanks for all the input It will be a couple of weeks before it’s all back together Keep everything crossed
I’m getting the right torque converter that matches the rpm range of cam, intake, trans type, rear gearing , tire size and for how the car is going to be driven
Mickey, did you get my forwarded email from Lee ? if not ,here it is : On Aug 25, 2018, at 12:22 AM, L Atkinson <vcxzrewq@yahoo.com> wrote: Bjorn,
I looked at that thread. If it idles best at 30-something degrees initial timing, then the timing chain was installed one-tooth off. Seen that several times.
The cam is too big, and there are other issues, but none of them matter until he gets the timing chain properly installed,
Update Ok I now it’s been awhile but it’s finally all back together Been busy with work and kids in school and yard work So here’s what I have Timing set at 16*. Vac advance not hooked up Total. 38* Advance hooked to manifold vac Distributor advance springs back to stiff ones Step up springs are still the silver ones the strongest Idle Park 950 - 1000 Idle. In gear. 850 - 900 And with the new converter it dose idle in gear now I can sit at a stop sign in gear and not 2 foot it 2700-3000 stall Carb reset Idle air 1 1/5 out Good vac 11 Good oil pressure 30 idle crushing 60 Water temp 180-190 I’m having a hard time keeping the carb on the idle circuit The ldle screw is right at that spot where the primary’s want to start to bleed if I back it off a little the idle drops quite a bit and when my fans kick on it drops the idle even lower I drove it for a while it runs good has decent power The longer i ran it the idle started to go away even in Park it got really low and choppy started to hesitate on take off mild take off Pulled a couple of plugs and they were all black and sooty I need to work on the carb settings more At idle it dose seem to run rich you can smell it in the exhaust Any thoughts
Alright I’ve found some of the problem I took carb off and looked at the bottom I’m not in the idle circuit at all the transfer slots are way over exposed this would explain the black sooty plugs their has to be fuel bleeding in their I can reset the throttle plates over the transfer slots To show the square or the .040 thou mark but now it want idle dose anyone know how to get the idle up with out cranking up the idle screw or cranking the timing way up I’ve heard the Edelbrocks don’t like low vac at idle Less than 12in Has anyone drilled holes in the throttle plate to gain a higher idle Some of the Holly’s have them drilled from factory In the event I change the carb what would be the carb to use I thought about going fuel injection
Well I'm not an expert, but more than one answer to your questions has been your camshaft choice. I'm not saying you cannot tune with this cam and intake manifold, if you insist on using the camshaft and intake you may have to do some modifications. I also, in my non-expert opinion, think you have made the wrong choice with the cam and intake. One thing I see is you have the strongest step-up springs. Vacuum holds the metering rods down and the springs try to lift them. You have 11 inches of vacuum, I would think the springs are lifting the rods and letting more fuel in. Maybe a lighter spring will hold the rods down until you open the throttle and the vacuum drops. I only had 9 inches of vacuum and was able to tune the EPS 800 for my engine. I also had a camshaft and intake that were suited to the bottom end. Don't remember if the carb is new or not but it must be clean, any restriction in the idle air bleeds will cause a rich idle requiring the throttle blades to be open more than normal to let in more air. Drilling the plates and even the idle air bleed restrictors is an option, but hard to reverse. Make sure you have the carb to the limits of cleanliness and adjustability before you get the drill out. Just my opinion, I'm not an expert.
You have a combo that will result in a rough idle at a higher rpm, but you should still be able to idle without fouling the plugs. A higher initial timing will help with a larger camshaft, you have already done that with the 16 initial and vacuum advance on the manifold port.
In your post on 15/08/18 you said you pulled the plugs and they were white. What changes have been made since then?
Assuming the engine is going to stay in the configuration it is presently, what do we think the cause of fuel fouled plugs are? Obviously, too much fuel or too little air. You don't want to open the butterflies any more than the idle circuit.. Before you drill the plates or restrictors to allow more air lets look at what may be causing too much fuel.
There are the most likely causes, no matter what carburetor you have and a few specific to the Edelbrock. Your carburetor is new but even new ones may need cleaning. Float height and drop settings, a float set too high will flood the engine. Needle and seat leak, there may have been a bit of debris in the carb from factory or perhaps some dirt got into the fuel line when it was installed. Check to make sure the seat is clean. Make sure you install a good filter between the pump and the carburetor. Gasket leak, could be a piece of debris is under the gasket causing a leak. Fuel pressure too high, the pressure must be below 6 inches. You have a regulator and a return line, try five inches. Make sure the fuel tank is vented, a clogged vent will increase fuel pressure as the fuel warms. Idle mixture screws set too rich. The idle mixture screws may be set incorrectly in an effort to smooth out a rough idle caused by something other than carburetor settings, such as ignition or valve timing. Fuel pulling over through the main circuit at idle, this could be from too much pressure in the float bowl, too high a float level or the metering rod lifting and reducing restriction at the main jet. Fuel pulling over into the secondary, secondary plate open or the air valve allowing air past the secondary auxiliary system discharge nozzle. Fuel bypassing the accelerator pump check ball. Air filter too small or clogged. Debris blocking the idle air bleeds, restricted air bleeds will cause a rich idle. May also be why you have to keep opening the throttle blades to let in more air. Choke operation, don't know if you have a choke but that is one of the most common causes of flooding.
Ensuring a clean carburetor should be a priority. Even a new carburetor can have debris inside. Last year Holley had their Christmas "Holleydays" sale. I I bought a QFT Q-850. The cavity between the metering blocks and the carburetor body looked like one of those Christmas cards with all the glitter on it. Almost had to wear sunglasses. Needless to say it took a lot of cleaning before I could even start to tune.
If all else fails, you could drill the throttle plates to allow more air in at idle but you shouldn't have to. Last resort stuff. Drilling out the idle air bleeds is another last resort thing. Some of the newer Holley ultra HP carbs have an air bypass that allows air past the plates without drilling. Does the same thing but is adjustable. 1960 Chrysler corp had a Holley four barrel on some Dodges that didn't even have an idle speed adjusting screw. It used the same bypass that the new ultras have. You pulled out the air cleaner stud and adjusted the amount of idle air with the throttle blades completely closed. If (IF) you have exhausted all other avenues you may be able to lean out the idle by drilling holes. You may also increase the idle rpm to an unusable rate.
I have a friend in Sugar land Texas that built up a 455. He bored it out installed a large camshaft, Edelbrock aluminium heads and a big honkin' single plane intake. He wanted to go like snot when he matted the pedal. It did, but, he complained about his clothes stinking like gas everytime he drove the car. I suggested a dual plane manifold but he wanted to keep the large single plane 'race' manifold. He had a large Edelbrock, changed the rods and jets numerous times, changed distributor and timing countless times, adjusted the idle mixture screws until they almost wore out. Then he started to drill the plates. Eventually he took off the 'JUNK" Edelbrock and put on a QFT Q-950. Trouble is his clothes smelled like gas every time he drove it. He changed out the power valve, bought a set of 40 jets and changed them up and down. Now the car sits in his garage where it has been for the last two and a half years because he can't get a good carb. The Q-950 can be adjusted by way of idle feed restrictors and air bleeds but that is just a little over his present understanding of the carburetor he has now. I'm tempted to go down there when he's away on vacation, change out the camshaft and intake, put on a 750 cfm carb and close the hood. It'll still go like stink, but his clothes wont.
I think I've added all I can to this topic, sorry if I couldn't help you any.
Of course these are just my opinions, I'm not an expert.
Good talk that’s good info The timing back on that day was 36 bass timing now I have the right torque converter and I’m able to put timing back where it should be my total is still a little high but I can limit that latter I have had the carb apart twice to check floats and other things I even dropped the floats about an 1/8 inch I can get it to idle but I have to turn idle screw 1 1-2 turns up which is just off the idle circuit Idle air set with vac gauge 10inch Changed step up spring to yellow the off idle flats spot is gone Idles around 950 But I have fuel leaking off the flow boosters just enough that you can see it their Don’t think I haven’t though about ditching this carb and getting a different one seems that they have a lot of issues high maintenance Its new by the way
This should probably be changed to new thread Need help dialing in carb The engine runs and idles fine It runs rich it starts a little hard fuel dripping from flow boosters Most cars you can get in pump gas once turn key and it will start or least fire off If I set the throttle plate where it’s suppose to be the car want start unless you hold the throttle down a little bit and even then it want stay running unless you hold the throttle down a little now if I turn idle screw up 1-11/4 turns it will idle fine but I’m dripping fuel from boosters If you just pump the gas and try to start it it just cranks and no fire The engine needs more air it has plenty of fuel getting in I still have the idle screw in to much it’s better but I’m 1/2 way up the trans slots I’ve tried all the tricks I know and some that I found on the web so tonight I will get the drill out unless someone has some old tricks or know how to correct the issue with out changing to new carb right now I know I know this carb it’s perfect for this engine I’ll say It I thought about going fuel injection but I wanted to keep it mostly time period correct
Good progress. You are correct that the transfer slots being exposed are causing too much fuel. And while you could drill some holes in the throttle plate, which would allow you to turn the idle screws down, you would be treating the symptom, not the root cause. By that I mean, the camshaft selection.
If you were to change the camshaft to say, the XE268, the cylinders would be pulling in more air at idle (and everywhere else really), and you could turn the idle screw down so your not on the edge of exposing the transfer slots. On top of that, you would have a significant increase in torque across the rpm range (average around 20 ft-lbs) and gain peak horsepower. See, in your combo, both these cams have about the same peak (slight edge to your baseline choice, but not until the very top end), but because you've had to advance your camshaft, it's actually making less. Idle with the XE268 will still sound very aggressive (this is still a healthy cam for a 350), but you will gain more vacuum at idle, and it will idle at a lower rpm. And as I recall, comp did offer to allow you to trade out the cam.
You have the ignition timing curve where it should be, the torque convertor more in line with the rest of the setup, and it's running as well as it will with the combination that you have. Time to finally address getting a more appropriate camshaft.
These 2 cams are almost the same the intake valve is different the xe268 opens later and doesn’t stay open as long the intake duration is a little less on the intake valve the exhaust is the same We are actually dynoing a Chevy 350 with that cam in right now After that I may put the 280h cam witch is in my Firebird to see what the difference is This isn’t the first motor I’ve put this cam in However it is the first pontaic motor the motors are built almost the same, the specs are basically the same Unfortunately the Firebird happens to be my personal project Witch seems to have the dreaded black cloud over If their can be issue their will be
Everything is the same with engine build Final timing and I might be able to drop it some more Timing 16* Distributor mech advance 15-16* recurved Vac advance hooked up Vacuum 10-11 I did move the fuel line and insulate it Same elderbrock carb Had to modify carb I started drilling the front butterflies, started small and reset the carb idle screws so transfer slots where set right this was a trail and error As I did this I noticed that the idle was getting better and I was able to adjust the carb and move the timing down Ended up with 1/8 holes idles at 900 Rest of specs above Engine is a very heavy breather and that carb in my opinion can’t handle it And I’m not impressed with this carb I spent lots of time on phone with elderbrock to try to fix it I may change to a efi setup in time Anyway car runs great and sounds great I’m currently chasing a voltage problem with the ignition After running for 30 minutes I lose voltage I have on another post Ignition resistor wire