HELP!!!!

RPMustang

Active member
Ok, we have the C.I. aluminum new head on my son’s 66 coupe. We bolted on the intake and hooked up the Autolite 2100 carb.

When we try to start it I pump the throttle lever twice, then turn the key and it starts right up, revs to about 4000rpm, and immediately stalls out. :banghead:

If I physically hold the choke totally shut, I can keep it running, but again, it “idles” at 4000 rpm!
By totally shut I MEAN totally shut. If I allow the choke to open even the tiniest bit, the car immediately stalls out.

Also, if I slowly open the throttle while my son turns the key, it will eventually start & run, but again, it won’t run below about 4000 rpm. Any lower on the throttle and it won’t run at all.

ANY ideas guys? I really want/need to get this car running again.

Thanks
Lance Robaldo
 
I'm thinking vacuum leak. Any time you do something major like that you have the possibility of a leak. The fact you need to keep the choke closed is shows air is getting in somewhere else. I just put a 250 2V head on my car and expect something similar when I turn the key. Had to make my own gasket for the intake. :roll:

Ron
 
Agreed - because there's a vacuum leak between the valves and throttle plates, the carb isn't getting a proper signal to send fuel, and the thing is leaning out to the point of stalling.

Regarding the rocker arms: did you ask Mike about running nonadjustable rockers on the aluminum head? I don't know if there is a different geometry where you would need different sized pushrods, but I think everyone else with this head is running adjustable rockers.

Personally, I already had the roller rockers on my log head, so I just moved them over.
 
snip >--"Regarding the rocker arms: did you ask Mike about running nonadjustable rockers on the aluminum head?"

I went ahead and put on adjustable rocker arms & ball/cup style pushrods. I was then able to properly set the lash on all the valves.

As far as the carb issue, I think everyone is pretty much in agreement that there's an air/vacuum leak in the system.
I'm pretty comfortable with the carb seal to the intake, but I'm not nearly so confident in the seal between the intake & the head.

So my working theory right now is that I must have a fairly large leak between the intake manifold and the head.

I've already pulled the manifold and am going to make some new gaskets for it to see if I can get it sealed up better.

Lance.
 
This probably isn't the problem, but you have plugged all of the extra vacuum port openings on the intake manifold, right?
 
Unless I'm horribly mistaken (and this is totally possible), there's only one vacuum port on the C.I. intake manifold and it's located on the top of the #6 runner.

Yes, it's plugged.

I had it running to the PVC valve initially, but after experienceing these problems, I decided to just plug it until the issues are resolved, that way I have less potential issues to deal with.

Lance.
 
Sounds like your ecceleration pump is working, with the surge and then dying, but it sounds like you are not drawing any fuel through the venturies are idle circuit, I know nothing about the carb you are using though.
 
What about vacuum sources on the carb (sorry, just trying to help and I have NO idea about the 2100s). One time, my ex was driving a car of mine, it backfired and never ran right after. The backfire caused the vacuum cap at the back of the carb to burst. I found it a long time and a lot of $$s later but.....it put a leak in there I couldn't find. Doesn't Mike make gaskets for your set up? Mine is an 250 2V so I have no choice in the matter right now other than making one. No sealer on the gasket right?

As we ALL know, this would be real easy if you were right down the street :roll: It would also be a bigger problem if we didn't have each other's help/advice! 8)

Ron
 
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