Idle problems, Replacing 440 cam without pulling motor?

[dailydriver]

I have a 66 Charger with a giant race cam, Holley carb, headers. Motor was built by the previous owner, not sure exactly the specs of the cam, but my mechanic tells me it is a "bottom of the page" cam, about as big as they get, and it has the appropriate stall converter. Having some trouble with getting the car to idle in without setting the idle speed super high. We've been adjusting the secondaries on the carb and the (stock) distributor trying to get it to settle down, but struggling. Car wants to stall out in gear unless idle is set super high. So we are starting to look at the idea of just going with a less aggressive cam.

My mechanic thinks we can probably do it without taking the engine out, by just removing the radiator (want to replace it anyway) and the grill, but I wanted to post to find out for sure. Anyone have any experience with doing this on a 66 charger with a 440. I'm wondering if the engine will need to be jacked up a bit? Or if there is enough room?

Also interested in tips for getting the car to idle better without changing the cam. Someone suggested drilling tiny holes in the butterfly of the secondaries. The car actually ran better with the secondaries closed for the past two years or so, but the idle speed was still super high.

I'm way less technical than most of you guys, so I appreciate the wisdom.

 

[RemCharger]

Can change cam without pulling grill
Try tightening up the mech advance in distributor
Very careful tuning .
make certain theres no vacuum leaks. Holley I'm assuming.

 

[biomedtechguy]

Very careful tuning .
make certain theres no vacuum leaks.

..and is the distributor vacuum advance? If so, use it. You may have to limit total timing by using a mechanical "disc" available from Don at FBO Ignition aka "4 seconds flat". Instead of me getting into it and getting it half right, ¼ confusing, and ¼ wrong, I suggest calling or emailing Don and see what he says. I am a huge advocate for having the absolute BEST ignition system you can afford on your car, and for you and my forum friends what I'm thinking is the advance set up to help at idle may result in a lower idle speed than:

setting the idle speed super high

by making the engine more efficient at idle, thereby keeping it from stalling. Once you crack the throttle open, it should run like normal.
Talk to Don,
http://www.4secondsflat.com/Ignition.html
or look at what I'm replacing my FBO Ignition system with, because it is even more flexible where timing is concerned:
https://progressionignition.com/
This way your engine will be running at its best, and you won't have to worry about breaking in a new cam and lifters, and all that entails.

 

[qkcuda]

I just put a new cam in mine. Mine was complicated by the fact I had factory A/C which I did not want to disconnect, so I had to lift the condenser out of the way. The cam will come out with just the rad removed. I think I took out the two outer bolts on either side of the grill support, just to give me a little wiggle room, but I did not have to remove the grill.

 

[qkcuda]

Here is another picture. I did end up removing the center section of the grill, because the previous owner had only put three of the six bolts in it. I think it gave me a little better access but was not really necessary.

 

[PurpleBeeper]

You can swap the cam with the engine in the car as mentioned. Drilling holes in the primary butterflies allows more air at idle while allowing the throttle blades to be closed & covering up the transfer slot (good thing). Does it really stink like gas at idle?

 

[PRHeads]

I’d see if you could find out exactly what the cam is, and then decide if that cam makes any sense for what you want to do with the car.
With some bigger, more race oriented cams, having to click it into neutral at stop lights isn’t that uncommon.

I’d also suggest doing a cranking compression test to see if the motor is somewhat “over cammed”.
Big cams and low cranking compression numbers can make for fairly dissatisfying/disappointing street combos.

 

[pnora]

Sounds like you have a massive vacuum leak or a plugged up carb.

 

[diesel_lv]

or look at what I'm replacing my FBO Ignition system with, because it is even more flexible where timing is concerned:
https://progressionignition.com/

About time a company did this. I have a timing module in my hardtail Harley. Its not wireless, but can be plugged into computer and make multiple curves. My jet boat w a blowthru turbo carb conversion uses an MSD box that again can make multiple curves. This is a great idea. Please post up when you do it and how well it works.

 

[66Satellite47]

To OP, what's excessively high idle speed you are experiencing? Not sure what "bottom of the page" cam means. Sounds like the mechanic doesn't know a hell of a lot. A big cam can want more idle speed. My big drag cams liked about 1000 RPM. But that's still a reasonable level.

Edit: BTW, you should be able to easily replace the cam by removing the radiator and the grill.

 

[biomedtechguy]

About time a company did this.

They literally took a concept from my dreams and made it reality!
I actually saw a home brewed version of this out of state at some big Mopar event. I don't recall but I think it was at the 'Nats a couple 3 years ago in Ohio.
The guy had a few different modules, CPUs, and whatnot cobbled together here and there in his car, under the hood, and sporadically worked with a notebook style computer. He showed me how he had full control over everything re ignition and timing, but it was clunky, the notebook made and broke communications, and although the concept was solid, the execution was reminiscent of Gilligan's Isle...
For all I know this him and represents the refined product of his concept/execution. Or someone stole the idea from him.
OR...
Someone is reading my mind while I sleep!

 

[diesel_lv]

They literally took a concept from my dreams and made it reality!
I actually saw a home brewed version of this out of state at some big Mopar event. I don't recall but I think it was at the 'Nats a couple 3 years ago in Ohio.
The guy had a few different modules, CPUs, and whatnot cobbled together here and there in his car, under the hood, and sporadically worked with a notebook style computer. He showed me how he had full control over everything re ignition and timing, but it was clunky, the notebook made and broke communications, and although the concept was solid, the execution was reminiscent of Gilligan's Isle...
For all I know this him and represents the refined product of his concept/execution. Or someone stole the idea from him.
OR...
Someone is reading my mind while I sleep!

This has been around for 20 yrs, just not wireless or BT and not this small for cars. I hook up a data cord to my very tiny, in nose cone, Harley module. Let's me set up to 20 points and naturally curves between points. Works w vacuum also. It's made by dynatec. The MSD on the boat has been around for over 10 yrs, It's for converting from FI to carburetor. It has same features and also adjusts vacuum advance and boost retard. The idea and functionality has been around for yrs. Just these guys put it "in" the distributor and allow BT hookup for on the fly adjusting.

 

[Sweet5ltr]

If it were me, I'd purchase a Wideband 02 gauge kit for $150, it will make tuning & troubleshooting much easier for a street car.

Other than that, #4 in this article likely has some relevance to your situation, break out the drill bits. https://www.hotrod.com/articles/tuning-holley-carb-made-easy/

 

[IQ52]

Really big cam huh? What kind of initial ignition timing are you running? How much mechanical advance do you have?

 

[diesel_lv]

Not sure what "bottom of the page" cam means. Sounds like the mechanic doesn't know a hell of a lot

Bottom of the page cam is a generic term for very aggressive, low vacuum, lopey cam, as they were listed in magazines from least aggressive to most, top to bottom.

 

[diesel_lv]

Low vacuum cams can usually be helped by using manifold vacuum at the distributor. Set initial timing around 18°, then adjust vacuum pot on distributor w Allen wrench in hole to 30-32° timing at idle. I know it's a can of worms on this. But with very aggressive cams, it works and allows you to keep rpm down. As above, it's in the 4seconds flat page, it does work. If you call, be prepared, he's very difficult to talk with though.

 

[biomedtechguy]

Just for clarity, I'm NOT the OP, I'm not having problems with my idle on my 6bbl (not anymore at least), I DO have a dual wideband O2 sensor system.
I had suggested to the OP that maybe an ignition system from Don at FBO (www.foursecondsflat.com) that allows for a more aggressive advance at idle, vacuum advance, and limit on total mechanical advance would help. It helped me. I am moving to the Progression Ignition, because it's exactly what I always wanted.

This has been around for 20 yrs, just not wireless or BT and not this small for cars. I hook up a data cord to my very tiny, in nose cone, Harley module. Let's me set up to 20 points and naturally curves between points. Works w vacuum also. It's made by dynatec. The MSD on the boat has been around for over 10 yrs, It's for converting from FI to carburetor. It has same features and also adjusts vacuum advance and boost retard. The idea and functionality has been around for yrs. Just these guys put it "in" the distributor and allow BT hookup for on the fly adjusting.

I didn't know that, but it's such a great concept, I knew I couldn't be the only one thinking that, I just wasn't aware of it being a reality, other than the "one off" homemade setup I saw, and the Progression unit.

 

[biomedtechguy]

Low vacuum cams can usually be helped by using manifold vacuum at the distributor. Set initial timing around 18°, then adjust vacuum pot on distributor w Allen wrench in hole to 30-32° timing at idle. I know it's a can of worms on this. But with very aggressive cams, it works and allows you to keep rpm down. As above, it's in the 4seconds flat page, it does work. If you call, be prepared, he's very difficult to talk with though.

AGREED!

 

[biomedtechguy]

Other than that, #4 in this article likely has some relevance to your situation, break out the drill bits. https://www.hotrod.com/articles/tuning-holley-carb-made-easy/

I was able to resolve this with the Promax replacement metering block for my center carb.

 

[66Satellite47]

If it were me, I'd purchase a Wideband 02 gauge kit for $150, it will make tuning & troubleshooting much easier for a street car.

Other than that, #4 in this article likely has some relevance to your situation, break out the drill bits. https://www.hotrod.com/articles/tuning-holley-carb-made-easy/[/

Don't use drill bits! With my first 6bbl setup I followed the DC recommendations for drill sizing the end carb metering plates. Chased a miss for quite a while. Eventually inspected the drilled meter plates with a magnifying glass. Tiny swirl marks were evident. Got new stock plates, boom problem solved. Learned the correct method is to use reamers, not drill bits, no swirl.