Help with new build!

[nickstewartroc]

Alright, so i have a 67 200, with a 69' head, CI 2bbl to 1 adapter, with a 2150 on top (1.21) got the 264/264 112* cam, and a DS2 distro, however, I can't seem to get it to idle! No matter what i do to the mix or idle screws, I can't get it to idle! If I keep the rpms around 1100 its fine, but that's holding the throttle open somewhat, and not relying on the carb itself. It seems to be running way to lean. Any thing you guys can think of? Thanks!
Nick

 

[rocklord]

First thing to check for is vacuum leaks. Could be either of the gaskets on the adapter.

 

[rbohm]

8) i agrre with checking for vacuum leaks. there are three places to look;

1: the gasket between the carb and the adapter

2: the gasket between the carb adapter and the intake adapter

3: between the intake adapter and the log. ant of those three gaskets can cause a vacuum leak. the likely culprit is probably going to be the gasket between the log and the intake adapter as that one usually gets overlooked.

 

[MPGmustang]

I would first check the timing... idle is timing and carb working properly together.
1) with a timing light, set it to 8* with the vacuum line unhooked and plugged, best if the idle is higher than 1100 and lower than 1500 rpm.
2) once sent, change the idle screw, to roughly 1000 rpm, then worry about the idle mixture. also make sure the choke is fully open when adjusting the carb. before you set the final idle speed, you want it 1/2 turn away from too rich, you will hear a difference in idle when u set it.
3) once you have it idling decently, go and change the timing to desired (proabably around 10-12*) and when u do, remember to bump the idle up, disconnect the vacuum from DS2, and plug the vac line with a pencil while u set timing.



it's strange that you're having a hard time setting the idle lower than 1k, my 264/274 110 is also difficult to idle less than 1k, it barely idles round 900 right now, it just seems weak, also I have noticed it idles better when there is load to the engine, like witht he AC on it can idle stronger @ a lower rpm, it's strange but only when it pig rich will it do that, then I see my mpg drop to the low teens.

 

[CZLN6]

Howdy Nick and All:

When you say, "won't idle" do you mean that the engine won't reduce rpms to the 700 rpm range? or, that the engine won't run if rpms drop below 1100? And, Is this engine with an auto trans or manual? Factory initial timing is 6 btc with a manual trans, 12 with an auto trans. MPGs suggestion may be better with your cam and set-up.

Can I assume that you have all linkages adjusted to allow the butterflys to close completely? throttle linkage? fast idle cam?

Can I assume that you checked the butterfly valves to assure that they are straight?

What is the condition the 2150 carb? rebuilt? NOS? or???

Double checking the initial advance and for vacuum leaks is a great place to start looking.

Keep us posted on your progress.

Adios, David

 

[nickstewartroc]

First, thanks everyone for your help! and second, in a reply to rbohm
when you say three gaskets , i have two

my setup is:

Carb
1/4in spacer gasket thing that came with rebuilt kit
adapter
gasket
log


Am I missing a gasket?

 

[MPGmustang]

even though you have a gasket between every thing there can still be a leak, best way to find out is spray some starter fluid or brake cleaner near teh gasket area's, if the engine rev's up then you have a leak, best way to fix is thin RTV on both sides of gasket.

 

[JackFish]

Even with a 1bbl carb mine idles around 1000rpm, and then it drops to around 750-800 in drive with the foot on the brake. It's good.

 

[MPGmustang]

Jack, that's because I think it likes load to bring it down that low...

I don't know how to explain it except what I have observerd... maybe some one can offer a better explanation...
Example:
Idle @ 950rpm, okay,
try idle to 650-750, car stalls, with it running rich or lean with different timings too on top of the rich/lean trials... just sputters and dies (seams weak)

reset to 950rpm idle
turn on AC, idle down to 650-750 rpm, strong and still smooth no stutter... little lope but sounds good...

Either way, I'm not impressed with this cam, and from others voicing out I think it comes down to CSC... but that's my opinion.