Unusual Symptoms???

[67 B-body]

I agree the surging idle and lazy rough revs sounds like vac leak. The slow return to idle sounds like ign advance to high. I cant have it leaking to the lifter vallley though... I doesn't employ the valley pan type intake gasket. I use a valley cover, and two individual intake gaskets. I'll post a pic of it too.. I did however get the idle mixture to seem like it didn't need to go any richer. I could hit the acc pump arm and not have a rev up associated with this action. Only thing is, that I had to run the screws out around 5 full turns to get it this way!
Fuel is 93 octane with octane boost added. I know, I know.... not high enough. It should still act normaly but might / probably will have detination under load. I haven't made it to the airport yet to buy some better stuff. I don't have a local gas stop to buy Turbo blue or Cam 2.
OK, Gotta go get ready to head out.

Thanks for all the help!

 

[SUPERSTOCKRACER]

im still banking on a lean condition. i had a intake gasket leak between intake runner and lifter valley. i have seen heads and or blocks surfaced so much that the intake doesnt set low enough for the passages to line up right. everything you talk about just sounds like a vacuum leak somewere to me. leaks at the intake manifold gasket are hard to locate with carb cleaner method. only takes a few minutes to pull the intake and look at gasket to see if its been fitting together ok.

only thing with that is if there was a vacuum leak, and he revs it, the idle 1st would be high and take forever to come down. and yes it would be a very bad lean condition but i dont think thats his problem.

 

[fugly]

5 turns out- another indicator of lean.....not to be mean but I have found the Unifight distributors to be useless- that may be part or all of the problem

 

[67 B-body]

but its not lean at 5 turns out. I agree that it's strange to have them out that far to prevent a lean condition, but once they are out and lean is gone,,,,, it should operate in a non-lean condition. I dont know,,, this thing is realy pissin me off with all the fancy stuff I have used for the build!
40 year old worn stock cast iron heads and miss matched intake and carb stock cast pistons, engine builds run better than this thing!!! I used a stock electronic dist mith a mopar ign module on my Ol' 69RR and it never gave me trouble!

 

[Endangered Species]

I'm grasping at straws here.... Just going back to the basics.

Question; when you have it set say 30 deg will the car start or does it pop back through the carb?
When you have the timing say at 40 deg does the car start or does it want to kick back?

Are you sure the distributor is not 1 tooth off?

You said the carb was used.... (just asking) did you clean it our real good. I use carb cleaner and a stripped wire tie (from a bread bag) and make sure all passages are clean them blow it out. Also make sure the air bleeds on top of the carbs are clean and very important make sure the idle passage (just above the butterfly) is clean. If you have a large cam you may have to drill a small hole in the butter fly right in front of that idle passage.

The last thing I would do would be to leak the motor down and see if there are any internal leaks somewhere. (valve not seating, blown head gasket, etc etc) Leak down tester is worth it's weight in gold.

 

[67 B-body]

It just cranks and sometimes spits out carb at anything less than about 25 deg advance. The timing can't be out 1 tooth on the dist, I can rotate it 90deg in both directions. I took the carb front bowl and metering plate off and ran a small wire through passages and carb cleaner to them as well. That's when I could actualy get responce from the idle mixture screws.

 

[fugly]

The idle mixture screws are a VOLUME control- they should be around 2.5 turns out properly jetted- putting extra turns simply adds more volume and masks the lean mix- the mixture is established by the jets and idle bleeds

 

[67 B-body]

I believe the jets affect part throttle to WOT. As long as the throttle blades are closed down to an idle position, the fuel being supplied should only be coming from the idle circuit which is fed from the passage directly connected through the metering plate and is intersected virticaly up to the air bleed brass plug. This brass plug can be removed and screw in air bleeds if required. This is supposed to allow you to tailor the amount of air along with fuel to achieve the correct raio at idle. Next is the fuel transfer slot that allows fuel during part throttle and aids in maintaning the correct air fuel ratio during acceleration in which the main jets become the primary source of fuel.
This is at least how I understand the curcuitry of a Holley carb... my ears and eyes are open for a different explination of how it all works.....
I will be pulling the intake and carb next weekend when I return from a work trip. I will also be inspecting pushrods, spark plugs, current valve lash again.... there has to be something way off with this thing! I will also be changing the distributer and complete rebuild of the carb...

 

[Endangered Species]

Poping through the carb to me indicates timing being retarded. Which you already know. Are you sure the springs and weights are not bound up? (just asking). When #1 piston is on TDC is the rotor pointing to the #1 terminal? And are the timing marks on the balancer at 0? again grasping at straws.

As far as the carb, pull both sides apart, run the wire in all the port (both sides) again the air bleeds on top of the carb can control idle.. also like I said open the primary butterflys, where they meet the bore you will see a slot or a hole ... that is your idle bleed. spray it with carb cleaner then run your wire in there and make sure it's open. If that is pluged it won't idle worth a crap.

 

[67 B-body]

Poping through the carb to me indicates timing being retarded. Which you already know. Are you sure the springs and weights are not bound up? (just asking). When #1 piston is on TDC is the rotor pointing to the #1 terminal? And are the timing marks on the balancer at 0? again grasping at straws.

As far as the carb, pull both sides apart, run the wire in all the port (both sides) again the air bleeds on top of the carb can control idle.. also like I said open the primary butterflys, where they meet the bore you will see a slot or a hole ... that is your idle bleed. spray it with carb cleaner then run your wire in there and make sure it's open. If that is pluged it won't idle worth a crap.

I have ran it to TDC then verified the 0 mark on the balancer already. That's why I took the timing cover off because it does act like retarded ign timing but things seem to line up on balancer. I thought maybe cam timing was off, so I took it all apart and reassembled double checking cam timing! During carb rebuild everything will be cleaned! I'm. Getting pi%$ed off though! New heads should have good valve seats, new intakes shouldnt leak, new gaskets should seal! RRRRGGGG!

 

[Endangered Species]

This is the crap that makes you hate cars.... LOL... Hey it's probably good to get away from it for a few days. It will be something so stupid that was over looked.
When you get back to work on it keep us updated.

 

[fugly]

My bad on the mixture screws....for some reason I got this mixed up with a similar thread using an Eddy carb.......but I still think it's lean

 

[MoparBill]

Did you use a degree wheel to check cam timing?

 

[67 B-body]

Did you use a degree wheel to check cam timing?

I have not done that yet, just verified that it lines up with the crank. I just made a new degree wheel on autocad and laminated it Thursday at work.
The only trouble is I would have to guess on the exact location for install. The cam measured out fine using my guages, but I dont know the recomended install in degrees. The cam was used for a season in a bracket car, and I got it with the block. It meets the lift exactly that I wanted "as I measured" for this build, and is a solid which I have always liked so I used it.
I also have the exact brand/model timing set and bushing for the dowl pin "3 bolt cam". It should be OK, and certainly be close enough to run fairly well. Sure theres a chance that I could get a 1/2 or so deg closer than it is now if I knew the exact location that the manufacture recomends, but gees ow,, it should still run fine as is! I will be checking though to see exactly where its at next week. I cant help but thinking it would have to be pretty far off to have such poor running as it is now, and like I said before I even removed the timing set and re-installed tripple checking the marks.
I had custom length pushrods made, and I will be checking them to make sure nothings goofy or bent. I dont think I have any issues their because the lash didnt change the two times I checked all 16 of them!

 

[67 B-body]

Well, my new parts are at my house awaiting my arrival.
I bought a new log fuel filter, new Mallory ign module, new carb kit. Hopefully next week I can get things in shape and working well!

 

[Endangered Species]

Let us know how you make out.

 

[67 B-body]

Let us know how you make out.

I sure will...
I expect the ign timing will be much more solid, and perhaps I got some fibers of foam from the fuel cell or crap from the new fuel lines through the system causing the carb to act up, so the additional filter should take care of that potential. It will hook right to the AN fitting on my carbs dual inlet line and the braided supply line from the regulator with the AN fitting will thread right onto the filter.

Wish me luck!!!

 

[67 B-body]

UPDATE:
I rebuilt the carb, added the filter and installed my Mallory dist with the new module. My base timing can be adjusted to a normal setting now! Idle mixture is back to a normal setting too,,, about 2 1/2 turns out and everything is good. I worked a bit on the tottal advance adjustments in the dist, limiting it down from the 50deg tottal is was at from the factory. I ended up limiting it a little too much in the process, but was able to bump up the base timing to 19deg and have my tottal fall in at 38deg. I'll probably tune this in a bit more bringing the base down to about 17 and adjusting the tottal to maintane the 38deg.
I do have some more to figure out though... The rev up is a bit slow, and the rev down takes much too long! With the compression I'm running it should fall to idle pretty damn fast! At least I made progress on this thing! I'm starting to feel much better now!
I did notice I had some bad plugs, and through cleaning them up a bit, I was able to get it firing on all 8. Now with that said, I think they might be in need of replacing and could provide a little better performance and I'll see where things fall from their.
Perhaps I can start fine tunning things like valve lash, jetting for WOT performance etc etc.
I first need to buy a new shifter cable because my header got into a fight with it while I wasn't looking and melted it for me! Damn exhaust!!!!
Thats it for now.......

 

[Endangered Species]

I'm glad your making progress. I'm stumped with the RPM slow reving and returning. That could be carb or it could be timing.
As for the shifter cable... wrap it with heat reflective tape.. (check with Jegs). We had the same problem and the tape solved it.

 

[moparpoor]

Glad to hear things are on the right track.You can beat your head on the wall chasing bull **** some times.Did you ever change your fuel.You will need to change it to fine tune even idle will change.