cold blooded @#%*$ !

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Ironmike

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Thanks to the forum, my 340 Demon is REALLY running great. After messing with timing, mechanical advance, vacuum advance and idle mixture....she is purring like a tiger. Great throttle response, geat top end and a nice stable 900RPM idle. Not bad for the big purple cam. Should really see a difference this week as a new 4:10 center section will be on my porch tomorrow, to replace the 3:23's.

My issue is the cold start. This thing spits, sputters, bucks and belches until warmed up. Never had a muscle type car do this before....but then again I've never had a cam with this much duration. I do have a manual choke and really have to "finesse" it to get going.
I have about 8 lbs vacuum @ idle and I know Holley puts a 6.5 power valve in the carb.
Do I need to put a 4 in there, or is this just the nature of the beast?
 
You need 1/2 of the vacuum, so 4 would be it.

The Purple cams do idle with a chop and warm up time should be alotted. Choke position should be closed somewhat to help with a smoother idle until warm.

What is the duration?
 
When I had the 508 purple in my 360 I couldn't drive it for at least 5 minutes after a cold start,it just plain didn't like it.
 
Don't know what cam you have but my 360 with the Lunati cam is real cold natured too. I have to finesse it for at least 3 minutes to even be able to take off. If I adjust the idle mixture screws a little rich it helps it not be so cold natured but then it's rich when it's warmed up. BTW: No choke on mine.
 
Yup even the BB hates the cold, barks and farts for a couple minutes before she settles down and quits bitching. (hey kind of sounds like my wife when she has to go outside to start her car in the winter). No choke just raw fuel from the accel. pump.

Terry
 
My 500+ lift truck at start up........

*squirt squirt squirt squirt squirt squirt*
Hehehehehehe vrum........

*squirt squirt squirt squirt squirt squirt*
Hehehehe vrum vrum puh........


*squirt squirt squirt squirt squirt squirt*
Hehehehehe vrum vrum vrum vrum puh vrum puh phih!


*squirt squirt squirt squirt squirt squirt*

And the saga goes on.

Overlap has a way of doing that to engines, LOL.
 
dodgetkboy78 said:
My 500+ lift truck at start up........

*squirt squirt squirt squirt squirt squirt*
Hehehehehehe vrum........

*squirt squirt squirt squirt squirt squirt*
Hehehehe vrum vrum puh........


*squirt squirt squirt squirt squirt squirt*
Hehehehehe vrum vrum vrum vrum puh vrum puh phih!


*squirt squirt squirt squirt squirt squirt*

.
Click to expand...

how does that go again???
 
You can really help your situation with a good ignition system, mopars are some what cold natured or so i thought untill i installed these things, when i had my 451 duster, it would sit a good week at times on the trailer outdoors, it had a 750dp & even a TR with 2 600s, but i ran an MSD Dig. 6 box & elec. pump, even with snow on the ground it would fire off pretty quik & within 20-30 seconds it idle'd sweet, i was running a comp solid cam with 250/256 dur. @ 50, so the cam was alittle aggressive. The key is a good ignition & timing curve.
 
dodgetkboy78 said:
My 500+ lift truck at start up........

*squirt squirt squirt squirt squirt squirt*
Hehehehehehe vrum........

*squirt squirt squirt squirt squirt squirt*
Hehehehe vrum vrum puh........


*squirt squirt squirt squirt squirt squirt*
Hehehehehe vrum vrum vrum vrum puh vrum puh phih!


*squirt squirt squirt squirt squirt squirt*

And the saga goes on.

Overlap has a way of doing that to engines, LOL.
Click to expand...

LOL, glad I wasn't drinking coffee, I'd be smelling it now since it would have went through my nose with that one.

I agree, alot of overlap and of course, a big cam size makes engines cranky.
My big block is a nasty ***** when cold. The longer it runs, the better it performs.
 
i run a t-ram,with 2 450cfm holleys with no chokes.280/290 dual pattern hyd. with a 108 lsa.its a little cold blooded.1 pump and about half a rotation and its running.however i have to kinda give it a little gas now and then for the first 20 second or so before it idles on its own.my initial timing is at 18*i let it run for abut 5 min before driving.
 
I tried running a tunnel on my 318 one day in the fall, it was like 40F, and pretty humid. The throttle mores iced up so bad the throttle was sticking......

LOL, glad I wasn't drinking coffee, I'd be smelling it now since it would have went through my nose with that one.

I agree, alot of overlap and of course, a big cam size makes engines cranky.
My big block is a nasty ***** when cold. The longer it runs, the better it performs.
Click to expand...

Believe it or not, thats with a choke. I think the reciprocating mass of the RB helps, my old neighbor had a radical 273 I built for him, with J heads, and a big OL/DUR cam, the thing seemed like it wouldn't even run with the starter off until the temp got up, LOL.

The worst starting chryslers made tho, had to be the damn slant-6. They flood so easy........
 
Usually with a choke and fast idle cam, they start up and run fine. I have always been able to do this, regardless of cam.

The key is having the proper choke butterfly setting with the correct amount of fast idle setting. This can be tricky sometimes, and I prefer electric chokes over manual, but they can be effective as well.
 
Glad to hear it's not just me. I mean geez, I can't ***** too much...it REALLY runs good ONCE it's warmed up. And it DOES fire up right away...I just can't go anywhere for a few minutes.
Maybe I should play with the choke and fast idle adjusment. Or maybe see if Holley makes an electric choke for the DP. Whaddaya think?
 
The worst starting chryslers made tho, had to be the damn slant-6. They flood so easy........[/quote]

i beg to differ! my slant has no trouble starting in the cold, 40F no problems and i have a .510 lift/246 @ .050 108 LSA cam and a 600 DP no choke... tap the pedal twice and then let it warm up and ur good to go!
 
It's all in the carb you can get a cam way bigger than that to go cold but you have to have a choke and it has to be elec or it will not get enough fuel or if its mech choke it wont be possible to drive cold because you have to vary the amount of choke plate opening as the engine temp increases and its too hard to vary it manually while driving (unless your real good)so if you want it to go cold I would reccomend getting an elec choke and spend some time adjusting it but my two cents is dont waste money on a choke when you dont need to be driving it cold anyways thats hard on the engine I have a elec choke on mine and I got it adjusted pretty good for starting it up and going right away but dont cuz you gotta let all the rotating parts get to the same temp cut the entire choke horn off thats MORE HP anyway spend your money on go fast parts like someone mentioned a ignition box if you dont already have one or a carb spacer

MORE HP = COOLER:munky2:
 
805moparkid said:
The worst starting chryslers made tho, had to be the damn slant-6. They flood so easy........
Click to expand...

i beg to differ! my slant has no trouble starting in the cold, 40F no problems and i have a .510 lift/246 @ .050 108 LSA cam and a 600 DP no choke... tap the pedal twice and then let it warm up and ur good to go![/quote]

You haev a 250* cam and 600DP on a slant?
 
You can try a electric choke but I'll tell you they are a PITA to get adjusted right. And the rate they come off don't always match what your engine needs. Then stop the engine for 5 minutes and the electric choke cools down and are full choke again when the engine don't need it. I have no problem at all working on Holley's and making them run right but I've had 2 with electric chokes and never could get the chokes adjusted just right. I like a manual choke for that reason. I just feel it's easier on things to warm it up for a couple minutes and then go.
 
.510 lift/246 @ .050 108 LSA ......on a slant?man thats a healthy grind. 805moparkid whats the idle rpm once it gets up to temp?
 
340, with any cam- manual choke it, in the winter, all they way. As soon as it fires, pull the choke back, to where just the fast idle is there. Let it warm up.
Get the over -riching choke off, and keep the fast idle. Takes some finessing.
 
Problem is, my non stock engines need 1500+ to keep running when cold, and thats too high of an RPM.

A stock 318 will idle at 700 once all the cylinders are firing.
 
I have dual 600 edelbrocks on a tunnel ram on my 440 in my coronet. The rear carb has an elec choke. That thing pops off after a couple pumps and idles real nice. Its all in the adjustment.
 
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