Carb issues

[Tunis68XS29]

Hi,

My first post here but I have been reading a lot of posts here about carbs (flooding etc.) and electrical woes that seems to affect our old rides. My car is a 68 R/T with a newly rebuilt 440 in it. I used an edelbrock 600-ish CFM 4-barrel with sec vacuum from my old engine. I have had some problems with my car which I hope you can help me pinpoint:

When it is hot, like closing in on 212 deg (I have an Autometer temp meter on the dash so I think it is fairly accurate) it will sometimes not start until I have cranked it enough and when it starts, it smells of gas.

When I start it cold it dies if I don't hold it at around 2000 RPM for a minute or so (is this normal?, my first muscle car..)

The throttle response is pretty much nonexistent, When I floor it, it works okay nothing more but when I slowly push down on the pedal it sort of stumbles somewhere in the middle and I notice that the engine isn't really performing as it should.

A friend of mine has a Holley 850 all mechanic that I could borrow from him till I get something that works better if the carb is to blame. If I should go for the Holley, what would be necessary to get it setup correctly for my motor? I run the Mopar Performance Orange Box Ignition with Mopar dist and coil, 727 and 3.23 gears.

Now to an electrical concern, I have tried everything and my car keeps charging at 15 volts, 14.5-14.8 with low or high beams on. Is it safe to drive around with this high charge voltage?
I have eliminated the dash ammeter for safety reasons - 40 year old wiring and an ammeter did sound like a no-brainer to me to get rid of.

This pretty much sums up my problems for this time, there will be more but if it ran excellent all the time it wouldn't be much of a hobby right?

Thank you,

Per

[Ghoste]

The Eddycarters have issues with heat soak and modern fuels so the hot start problem is no surprise.  A insulating spacer may help.
As for the cold start, is there a properly operating choke on it?

[Tunis68XS29]

Thanks for the reply! It has an electric choke on it hooked up, but I havn't changed 'fiddled' with it I just hooked up the wires. I havn't tuned a carb before let alone a choke so I wouldn't know where to start.

Thanks

Per

[W4ATL]

The engine needs to run at "fast idle" when first cranked up cold. The original carbs have a fast idle setting. I am not sure how your carb works, but the on the original carb you press the accelerator pedal all the way to the floor and the idle is set to fast. Once the car is cranked it will run at the fast idle. When you tap the accelerator pedal it will kick down to the normal idle. I usually let mine run at fast idle for about 30 seconds or so.

15 v sounds high to me. Do you have an electric voltage regulator or mechanical? Remove the voltage regulator and if it has a coil on the bottom then it is mechanical. You can adjust the voltage (instructions in service manual and maybe on this site.) If it is electrical then there is no adjustment and you need to trace the wires in the charging circuit. A search of this site can provide you with an electrical diagram. A check of the wiring wouldn't be a bad idea in either case.

[b5blue]

If your intake is aluminum the heat cross over needs to be blocked off at the valley pan...OK to drill a 1/8 hole in the block off to let some heat in. Check and adjust ignition first and get that right before adjusting carb or you will end up chasing your tail. How much and when advance will your dizzy give you?  Are you using vacuum advance? Check the battery very closely as a weak one will want to constantly bleed off amps from the charging system. Have you cleaned the bulk head connections? Always check all grounds for very good clean connections there should be a strap from battery to block and body and one from block to fire wall near or to voltage regulator. Regulator needs to be modern type not old mechanical one for ECU to be getting proper volts. Sounds like your choke needs adjusting too.  

[Tunis68XS29]

Thanks for taking your time with this guys!

I have the electronic voltage regulation. I have tried four different regulators and two different alternators, every combination gave me 14.6 -15 volts at idle without headlights... I measured the resistance in the circuit from battery positive to the regulators ignition post and it was something around 1.5 ohms. I cleaned the bulkhead connectors using some electronic cleaner spray, very effective. I haven't checked the oblivious yet as you pointed out b5blue, the battery. I have thought about it but never tried another battery. I will do that as soon as I have the time.

My friend, who actually knows something about these old cars - unlike me, helped me get the new motor in the car and he set the ignition timing according to the engine builder, 34* deg (total?). We set the timing at around 2200 RPM with the vacuum hose from the intake disconnected from the dist. The hose has been connected to the dist since the timing setup so I guess it uses vacuum advance (?). I have an aluminum intake, the edelbrock performer rpm 440.

About the Holley 850 double pumper, will this carb fix any of my issues? I'm not going to stick with the edelbrock anyway as I purchased my engine with a Holley 780 sec vacuum. It got lost in shipping and hasn't shown up yet. That is why I want to know if it's a good idea to switch to the double pumper now and when my carb shows up put that on instead.

Thanks for your input!

Per

[Tunis68XS29]

Update: We swapped the edelbrock for a freshly rebuilt Carter 4738. The engine pulls very good over 2500 rpm but we can not set up the idle on this thing. When driving and keeping the rpms at around 2000 it runs very "roughly" - the tach dial jumps between 1800 - 2200 and the engine doesn't sound very good. When I let the gas pedal go and it idles down it dies on me. We could not start it - no matter how many times I pumped the gas pedal, without pouring some gas down the carb. So our conclusion was that it was running way to lean on idle but no matter how we turned the idle mixture screws - it died when I let the rpms drop bellow 2000 rpm.

Anyone with good knowledge on these carbs that can help me correctly set up the idle on this?

Thank you!

Per

[68RED4SPEED]

Can a weak fuelpump cause us this problem ? When engine coming up in rpm the problem is gone and it runs better than ever , I think we also have to check fuelpressure and also the amount of fuel when carnking the engine, anyone agree with  my thoughts ? Fuelpump is the only item not replaced at engine, all other stuff is brandnew. Carb is bought and restored in US and is a 1970 440 HP original item .
Sven

[68RED4SPEED]

Carter is now gone and replaced with my Holley 850 double pumper, now the engine purrs like a kitten, the carter is ok if you buy a strip kit but it was easier to take the Holley from my raceengine until Per can has got a own .
Sven

[Charger RT]

where are you taking the voltage reading? If you are still having the issue take 3 readings one at the battery one at the alternator and one in the fuse box and post back the readings.
Tim

[68RED4SPEED]

Per is now on vacation he will be back next week, I dont like electric shit , carbs ok.
Sven

[Charger RT]

hope he is having a good time
Tim

[Tunis68XS29]

Thanks Tim, I had a good vacation. Got the relaxation I needed.

I measured the voltage at the battery, alternator and I have an in-dash voltmeter. At the alt: 14.9-15 V, at battery: 14.8-14.9V, in-dash voltmeter: above closer to 15 than 14.75. It's an analogue voltmeter and quite small so it is difficult to say. I hooked up the voltmeter to the ignition feed going to the circuit board on the original dash, so it should almost be at the fuse box.

Tried my friend's (68RED4SPEED Sven) battery, no difference. His car charges as it should around 13.8 V. I have tried a couple different regulators, nothing seems to matter.

Per

[mhinders]

It could be a problem in the wiring. The alternator is getting the info that the battery is almost empty and tries hard to recharge it.

[Charger RT]

it seems the positive side of the circuit stays pretty constant every where you take readings.

In an earlier post you said the regulator is electronic. Is it the 69 and back style or 70 and newer?

Take a volt reading at the regulator use both meter leads at the regulator.

Do you have good ground straps between engine and body and battery?

I would put the positive volt meter lead on the positive battery cable and move the ground lead around. take a reading with the ground lead on the battery, the firewall, and the engine.
Tim

[Tunis68XS29]

Thanks for the replies!

It has the newer style with two fields at the alternator. Should I measure the voltage over the field terminals on the alternator? I don't know how I would be able to connect the leads at the regulator terminal without cutting some wiring, which I don't wanna do. I took the reading by placing the meters positive lead on the battery and then I moved the negative lead around. It was within 0.03 volts all over the place, from engine to firewall, at least according to my digital multimeter.    Don't know what to do now...

Per

[Charger RT]

we need to get the reading at the regulator. The 12v+ wire going to the regulator and the ground (regultor housing) is what the regulator uses to set voltage. If the regulator housing has a poor ground or the power wire running in has extra resistance the regulator will run the system harder until it sees the right voltage at the regulator and it will be high every where else.

This is a 68 correct? That is what is posted in post 1. How was the regulator converted for the 70 and newer regulator? New harness? Spliced plug? Getting an extra regulator plug and a couple of bullit connectors that fit the plug you can make a jumper harness to put between the regulator and the harness and it can be tested in the added section.
Tim

[Tunis68XS29]

I made a custom harness and I got the voltage down to 14.4 volt at the battery. It was the same at the alternator and somewhat lower at my dash-mounted voltmeter. I don't know how accurate the voltmeter is but I think it is okay. The voltage over the regulator started at 4.5 volt when I started the engine. It dropped down after a couple of minutes and settled at around 3.2 with occasional jumps to 3.5 volts. The voltage at the coil was 9.6-9.7.

Thanks for your help!

Per

[Charger RT]

I assume your readings were on the 2 wires of the regulator? If so that would show how the regulator is charging. The higher the reading the higher the amp output to get correct voltage. Under a normal start up that reading would slowly drop as the battery gets charged after the start up draw.
The 2 wires on the regulator are 1 is 12v+ from a keyed source. The other wire goes to the alternator. The reading I would have liked to see was with the meter hooked to the keyed source wire and the metal case of the regulator. That reading should be what the regulator is tring to charge at.

I'm glad you got it down some. What did you do to it to get it down?
Tim

[Tunis68XS29]

Thanks for your reply Tim!

I removed the original harness that connects to the charging and ignition circuit and installed brand new cables and terminals. I guess I had some resistance in the ignition wire which would let the regulator believe my voltage at the battery was lower than it actually was. I will get a reading at the keyed ignition post in the regulator and the case and report back as soon as I have the time.

Per

[Charger RT]

thats great you found that. Glad you posted where the resistance was found.
The voltage reading at the regulator will show what that regulator is basicly set for. 14.2 volt was what we looked for years ago. Back in the day some of these were set on the high side the cheap aftermarket were worse.
Tim