440 tuning issues

[doublekrossd]

I originally posted in general tech, I think it's better suited here...

First off, I understand heat and humidity will effect what I'm doing... Ok so, I have a seemingly never ending project trying to tune my motor. Some (ok a lot) of the parts may not be perfectly matched but it's what I got.

basics- I have a 440 bored .30 with flat tops, stock stroke
Indy Little EZ's @ max wedge ports matched to Indy single plane intake
comp 23-227-4 has .525 lift, 1.5 Harland sharps
Carb is a custom built (not for this car) C&M 1080cfm holley made from a 4150 body
All MSD ignition box, coil, wires, distributor. running about 15* @ idle and 34-35* all in by 3000 rpms.
No vacuum ports on the motor, just one plugged port on the carb spacer

Problem #1 is the kickdown, which I'm getting closer on but coincides with problem #2.

Problem #2 under hard acceleration in 2nd or 3rd gear around 2500rpms up to about 4000rpms, the engine will pop out of the exhaust and sounds horrible. when I get on it from a stop it runs up pretty good and only rarely pops. It's almost like it needs a little more timing (or maybe too much?) but I'm not sure how far I can safely push it without detonation. I cant hear the motor spark knock due to the exhaust dumping out at the front of the rear wheels. Plugs are all fairly new, wires are all new and checked for resistance. I guess I'm not sure what to check next as I don't get too many chances to go "run" the car due to bored local cops, loud exhaust, and shitty Michigan roads.

Problem #3 it builds a good amount of crankcase pressure. I have 2 breathers, one on each valve cover and they both blow a little oil vapor, nothing bad, but if I get on the motor hard a couple times and come back home, I notice the dipstick is pushed a little out of its hole. Weird huh?

any of you experts got an idea? Big thanks in advance!

 

[Lionized]

I'm pretty sure you're running rich. Do a lean drop and try it out.

 

[doublekrossd]

What's a lean drop?

 

[gtxno1]

Are you sure you are not popping out of the Intake if so you are lean

 

[Lionized]

What's a lean drop?

After re-reading your OP I'm kinda thinking you're over-carbed (probably jets). A lean drop will simply give you better idle/off idle quality. You mention this is a "custom" build but not for your engine. This could be your problem. Exhaust backfires tell me you're running rich.

 

[khryslerkid]

What do your plugs look like?

 

[doublekrossd]

Yes 100% out of the exhaust.
Plugs look ok, not black but not white.

 

[doublekrossd]

From what I'm learning I've go a few issues here

Not enough compression
Not enough cam / duration
Too much in the heads and intake and not enough motor
Also sounds like a got a bit of a ring problem. When the heads were off, cylinders looked great so we left it alone till I can save a bit more money and make the big bottom end.

I'm gonna try a 800 DP Holley in the morning that's a much more mild carb

 

[Mike67]

DK I know you are having some tuning issues and have yet to get everything working in harmony but I have a question about the cam. I have the exact kit to install in my motor once I finish up some suspension upgrades...what are your thoughts on it? Potential? I have a similar set up my cr is probably a little higher than yours & I'm running rpm heads...I'm thinking of selling the kit and going to a bigger roller but funding that dream is a little ways out...just trying to decide...
Thanks

 

[PurpleBeeper]

There's at least a possibility that you've got an exhaust valve hanging open....maybe bent or some carbon buildup on the seat. If your carb swap doesn't do the trick, maybe run a compression check?

 

[SlinktRR]

#1 set your throttle valve (using the kickdown) to be slightly open at idle. Then make sure that the lever for the throttle valve goes all the way open with the accelerator to the floor. This is your starting point, you can adjust sensitivity from there while driving.

#2 The carb is pretty big for street but workable. Under hard acceleration at 2500 rpm in 2nd or 3rd, your 727 should downshift. Check kickdown...has to be all the way open at WOT to start, then you can adjust how sensitive you want the kickdown to be from there. It will depend on whether you have shift kit, high rpm governor, personal taste or driving habits, etc.

I dont think its jetting if it runs fine in 1st from a dead stop through the gears but its possible. I would look at timing, accelerator pump shot, power valve. No vacuum advance? The carb may just be getting poor vacuum signal at tip-in because its a wee bit massive for street duty. Try the 800 cfm

#3 - try using a simple PCV setup on one valve cover plumbed to the carb vacuum port and a breather on the other, which you can plumb to the air cleaner or just vent.

 

[doublekrossd]

DK I know you are having some tuning issues and have yet to get everything working in harmony but I have a question about the cam. I have the exact kit to install in my motor once I finish up some suspension upgrades...what are your thoughts on it? Potential? I have a similar set up my cr is probably a little higher than yours & I'm running rpm heads...I'm thinking of selling the kit and going to a bigger roller but funding that dream is a little ways out...just trying to decide...
Thanks

I don't think that's the right cam for my application or yours. The duration, from what I'm told is way to low/short. That can was put in my motor with stock 452 heads and a tunnel ram, it worked good, i wanted better so I installed the indy heads and to be honest, probably lost some power due to the low compression and not being able to get velocities up where they need to be on the intake side of the heads. If you still have an opportunity to change it, I would. My entire bottom end will be coming apart as soon as car show season is over

 

[doublekrossd]

Ok, so I got the new 800 Holley on and tuned in. At firs car didn't wanna drive hardly at all, back in the garage. Put some more timing in it. Im about 16* at idle and 36* I think, but realized my light is shitty, so who knows. Feels like it could take a little more, still starts super easy and fast and loves to go. Got just a little hesitation at first but then goes like mad.

Kickdown is finally working! Not great yet, but its close. Doesn't like to get into 3rd gear till about 50-55 mph. But it works and that's a step in the right direction.

With a bit more timing, who knows if my light is right, it should clear up the hesitation right?

 

[Lionized]

Ok, so I got the new 800 Holley on and tuned in. At firs car didn't wanna drive hardly at all, back in the garage. Put some more timing in it. Im about 16* at idle and 36* I think, but realized my light is shitty, so who knows. Feels like it could take a little more, still starts super easy and fast and loves to go. Got just a little hesitation at first but then goes like mad.

Kickdown is finally working! Not great yet, but its close. Doesn't like to get into 3rd gear till about 50-55 mph. But it works and that's a step in the right direction.

With a bit more timing, who knows if my light is right, it should clear up the hesitation right?

Yup.
Go through that carb...make sure it's clean. Check your timing with an ensurable light (one you know works). 16* - 18* advanced should be correct but make sure it's bang on.

 

[miller]

Kickdown is finally working! Not great yet, but its close.

Kickdown...base setting at WOT (lol, again) should be, kickdown linkage FULL back, then slightly off...a little play.
Timing...hesitation can also be caused if the advance is hanging. Just saying make sure it's working free. (Sometimes it needs a drop of oil.)

 

[SlinktRR]

I use 20 degrees initial because that's what my engine likes. Put a vacuum gauge on the carb and time for max vacuum at your chosen idle speed. It sounds like you are close.

Well done on the kickdown. Now you can adjust the throttle valve pressure to your liking by adjusting the kickdown slightly more closed at full throttle. I used to be manual trans or nothing but I absolutely love a 727 with a shift kit, it is a lot of fun.