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New Cam/Heads - Won't idle - Feel like a dumbass

Started by cougs, May 26, 2014, 09:02:09 PM

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cougs

Gang,
After this, I may need to retire from working on my Charger.  :rotz: I recently finally completed installing a VooDoo Cam and a pair of stealth heads on my stock 383.  First, let me say that I am a somewhat novice mechanic.  The engine has the stock specs and ran like a top with the 906 heads and stock cam before I started this crazy project. 

So before I start, you guys need to know this .................When I installed the cam, I accidentally lined up the cam gear "0" mark with the crank keyway's "0" mark.  :brickwall: I didn't see the corresponding "0" on the crank gear when using the "straight up" keyway (this is a 4 deg ret/adv timing set).  So at first, I had the cam installed at maybe 20 degrees advanced   :'(  To say the least, It didn't run well during cam break-in.  I broke in the cam for 13 minutes or so before I had to shut it down.   :brickwall:  I didn't hear any parts colliding and it did run, so hopefully this was a blonde moment for me and I didn't cause any damage......maybe!!!!!!!!!!!  Other than the potential of having a valve hit a piston, can running an engine like this for 13 minutes cause any other damage???????????   :brickwall: :brickwall: :brickwall: :brickwall: :brickwall: :brickwall:

I realized my mistake the next morning, dug through the front of the engine, corrected the timing set and put it all together.  Today, after completing the cam break in from last week, the engine cruises and accelerates fine but runs terribly at anything below 1,500 RPM.  Keep in mind this is a mild cam and should be only somewhat noticeable.  It sounds like it has a terrible miss and it idles very rich (almost black smoke).  Timing is set to somewhere at 12 degrees BTC and it doesn't smooth out going either way.  Idle screw adjustment doesn't help.  I NEED IDEAS.

Also I have what sounds like a passenger side exhaust leak OR a noisy valve/lifter tick.  It seems like the exhaust rocker arm on #6 has a bit too much play.  I don't know if this is causing the tick.

Here's what I've checked:

1. Compression test: (cylinder #2 is at 135 psi, 5 cylinders at 140-145 psi, 2 cylinders at 150-155 psi)  This range scares me.  Is the low cylinder bad enough to cause this?
2. Firing order: It's right
3. Timing/idle screws: don't help
4. Distributor has points and they appear fine.
5. Pulled valve covers and observed rocker arm action during cranking.  No obvious wiped cam lobes.  Again, the car accelerates/cruises. 

HELP!
1968 Charger 383/727  Restored to Stock!

myk

Maybe a massive vacuum leak?  Did the car idle at all during the break-in?

cougs

Car didn't idle during break in but it did take some cranking at first to get it started. I had to fiddle with the dist so it would run.  I didn't realize at the time my error on the time chain.  I did have to break it in in two sessions.  The rockers appear to have good travel so I think the lobes are ok.  I thought about a vacuum leak but it runs rich at idle :shruggy:
1968 Charger 383/727  Restored to Stock!

fy469rtse

I'm with Myk on this , it's how we all learn, don't feel dumb
Start a check list, no open vacuum ports of carby
Carby tightened down, ? Gasket under base to seal
Obvious one is you've changed the heads, did you try the intake bare to see how it sat , it would be my first guess
I would start with the intake sealing properly and carburettor base,
Another good upgrade will be get rid of that distributor and go with a firecore set up,
Are you absolutely sure you have timing right, look up the thread on indexing cams ( dialling in properly ) I had one recently with the timing marks lined up was 14 degrees out, got some one nearby to help out?
You will need a few things to do it properly
Just read a few times until it makes sense the thread on indexing your cam properly

cougs

I didn't put the intake on bare to see how it sat.  I used the paper gaskets on both sides of the valley pan with gasket sealant on all surfaces.  What's the best way to check for a vacuum leak without spraying the engine with solvents?

I'll double check the timing again but it seems to run best where it's at.

I forgot to mention that I did disengage the choke.

1968 Charger 383/727  Restored to Stock!

heyoldguy

Start again. Take everything back off. Inspect every part. Reassemble everything correctly. If the heads were installed OOTB, have someone who knows what they are doing  check them over. I get heads here all the time that are supposed to be bolt on that have warped surfaces, tight guides, out of round valves and hard seats that have as much as 90% leakdown because of poor OOTB quality. Check fit up as others have described here. Time the cam properly. You have a big investment there, do it properly, we've all been through the same thing.

69dodge383

Quote from: heyoldguy on May 27, 2014, 08:41:10 AM
Start again. Take everything back off. Inspect every part. Reassemble everything correctly. If the heads were installed OOTB, have someone who knows what they are doing  check them over. I get heads here all the time that are supposed to be bolt on that have warped surfaces, tight guides, out of round valves and hard seats that have as much as 90% leakdown because of poor OOTB quality. Check fit up as others have described here. Time the cam properly. You have a big investment there, do it properly, we've all been through the same thing.

The only way to go.
You could have several problems here and attempts to fix them may not only waste your time but make you keep banging your head  :brickwall:
Start over, Do it right the first time and never look back.  :coolgleamA:
The way I bought it
1969 Dodge Charger SE
383 Magnum
727
3.23 open 8 3/4 - 489
PS/MB

The way it is
1969 Dodge Charger "The Duke"
440HP '72
10.5:1 Mopar Pistons @.030 (446 c.i.)
Edelbrock Performer Heads
Hughes Solid Lifter Cam 278/283 245/250 .597. 613 108
7Qt Oil Pan
Victor Intake
Demon 850 Carb
TTI Headers 2" Primaries
727 Manual Valve Body
9" Dynamic Converter
4.10 Sure Grip 8 3/4 - 489
3" Dual Super 44
Coys 18x9 20x10.5  Cragar 15x8 15x10

Lunger

 Had a problem with this when I went to a big solid cam. If your sure you have the cam installed correct, then continue the read. I didn't see what carb you had. If its a holley you may have blown the power valves. If you have them protected ,check you manifold vacuum, the power valves may be open all the time, there is a rating on them.  I use to have a Holley on mine , it would run rich , never idle, turn the idle screw nothing then all of a sudden rev like crazy. my manifold vacuum with that big cam was about 5.0 to 6 in. of vacuum, at idle. I could never get the holley to work. Finally broke down bought a deamon , bolted it on perfect out of the box idle , just had to change the power valves.
BULL OF THE WOODS

cougs

Quote from: Lunger on May 27, 2014, 01:02:01 PM
Had a problem with this when I went to a big solid cam. If your sure you have the cam installed correct, then continue the read. I didn't see what carb you had. If its a holley you may have blown the power valves. If you have them protected ,check you manifold vacuum, the power valves may be open all the time, there is a rating on them.  I use to have a Holley on mine , it would run rich , never idle, turn the idle screw nothing then all of a sudden rev like crazy. my manifold vacuum with that big cam was about 5.0 to 6 in. of vacuum, at idle. I could never get the holley to work. Finally broke down bought a deamon , bolted it on perfect out of the box idle , just had to change the power valves.

The carb is the original Carter AVS.  I hadn't thought about damage to the carb yet.  I did have a couple nasty backfires through the carb when starting it up the first time.  What could I have damaged in the carb?  I tried hitting the carb to maybe unstuck a float which has happened to be before but it didn't help.

Seriously, I may pull this SOB out and just have it rebuilt by a shop I'm so fed up with it.   :icon_smile_angry:
1968 Charger 383/727  Restored to Stock!

fy469rtse

nah,
dont get fed up with it , some thing you have done is whats caused this , dont get frustrated and give up , just time to back track ,
reverse the steps and do again,
ive seen carburettors leak because they were over tightened, have you got the power booster vacuum hose connected on the back, vacuum leak ?
aftermarket cams are sometimes the problem, needs to be dialled in with a degree wheel to be done properly
start with the last things done and post photos so we are looking at what your doing, we may see something
take the intake off , remove the gaskets and sit it back on to see it sits correctly,it could need a slight machine to correct misalign with mating surface to heads , wat gaskets did you use for intake , some are more forgiving then others 

cougs

I'm checking for a vacuum leak tonight.  If nothing turns up, I'm tearing it back down again. 
1968 Charger 383/727  Restored to Stock!

cougs

Ran out of time last night but I hooked up a vacuum gauge and it alternates, err vibrates, between 8-13 inches.  The needle is all over the place.  Valve issue????
1968 Charger 383/727  Restored to Stock!

c00nhunterjoe


cougs

Quote from: c00nhunterjoe on May 29, 2014, 05:26:26 PM
Sounds like you bent some valves....

That's my biggest fear at this point.  We will find out soon
1968 Charger 383/727  Restored to Stock!

c00nhunterjoe


cougs

Quote from: c00nhunterjoe on May 29, 2014, 06:27:12 PM
Bring each cylinder to tdc and air them up.

I did a compression test earlier and had a range of 135-150.  Will airing up the cylinders tell me something else?

What else besides a bad valve could make the vacuum gauge bounce like this?
1968 Charger 383/727  Restored to Stock!

XH29N0G

Quote from: cougs on May 29, 2014, 07:04:10 PM
Quote from: c00nhunterjoe on May 29, 2014, 06:27:12 PM
Bring each cylinder to tdc and air them up.

I did a compression test earlier and had a range of 135-150.  Will airing up the cylinders tell me something else?

What else besides a bad valve could make the vacuum gauge bounce like this?

Wish I knew the answer.  Does the bounce correspond to firing of a particular cylinder (maybe check with a timing light).  I also wonder if a leak on one side or in one place where the manifold meets the head could cause this type of behavior.
Who in their right mind would say

"The science should not stand in the way of this."? 

Science is just observation and hypothesis.  Policy stands in the way.........

Or maybe it protects us. 

I suppose it depends on the specific case.....

cougs

From what I've read a vacuum leak would show as a low but steady reading when measuring from an intake port.  Fluctuating needle is either timing or a valve.  But again, just what I've read.   
1968 Charger 383/727  Restored to Stock!

Mebsuta

I have regular 383 HP in my RR.  Went for a ride once, got home and car would not idle well.  Did all the compression tests (145-150 all around), manifold vacuum (low and bouncing around).  Messed around with it, then switched back to a known good carburetor and just like that, idling happily at 700 rpm with 16 inches of manifold vacuum.  

I have thought about changing cams too out of curiosity, but after playing with Desktop Dyno for a while, they all gain at 5000 rpm at the expense of low end, or are those extreme cams that need high pressure springs and flatten lobes.  I always figured aftermarket heads with bigger valves and greater intake port volume would cost low end too, so I just stuck with the iron heads.  

cougs

So, after changing the carb to an Edelbrock Thunder Series and fine tuning the mixture and timing, the idle is "improved".  The thing accelerates like a scalded cat.  Happy with the performance, but not so much the idle.  I went to a slightly more radical cam though.  I'll start a new topic about some other concerns concerns.
1968 Charger 383/727  Restored to Stock!

69wannabe

Never give up man!!! The only way to learn is to screw things up a few times or in my case several times!!  ;D I actually had to pull a 440 out and clean out three grease rags I left under the intake valley pan while we were swapping the intake from dual quads back to a single four barrel. It made one trip up the road and back before one of the rags wrapped itself around the back three lobes of the cam and the other two were sucked up around the oil pump screen. No wonder the oil pressure was low!! LOL!! It looked like someone knitted a blue sweater in the oil pan. Got all the rags and fuzz balls blew out of the block and oil galleries and had to put some new bearings on the crank and he actually wanted a new cam anyway so it was a great time to up grade. Got it back together and believe it or not it ran great without the extra rags inside of it!! :icon_smile_big: Keep picking at it and you will get it where you want it. Takes time and patience!!