I agree with ya...starting to think not related to distributor. But this possible blown power valve has my attention.

I've only had the car for a couple of weeks, and when I picked it up....it idled fine....been to the track once and dont know of any major backfire....but if you read one of my initial posts....I was experiencing alot of hesitation and engine miss under load (just off the line) and the engine would not get above 5000 rpm. Just in park....I can rev to 6000+ no problem. Thats why I changed out the plugs/wires/cap & rotor....just to get those components out of the equation.

We checked the timing at the track which was at 28 and moved that to 34....and although I dont think advancing the timing is at fault....thats the first time I noticed a problem with idle....really had to keep on the throttle a bit just to get it back on the trailer.

So if it were a blown power valve....how best to test this since I cant get it to idle below 1800?

Still sounds like a vacuum leak, maybe base plate. I'd try another carb. Also, if it has a stock dampner it may have slipped inner ring to outer ring making the degree markings irrelevant, if thats the case your actual timing could be anywhere.

Well I sprayed carb cleaner all around the intake and carb base plate and did not stall the RPM any....so I'm assuming no leak in those areas.

The damper is an ATI Super Damper. Dont have access to another carb to test....might check around.

A good friend of mine who is a mechanic is stopping by tonight....see what he thinks. I think I will have him check the timing and we will set up the vacuum gage and try to get a reading as we adjust below 1800 RPM.

Still could be the power valve in the carb....so trying to figure out how to test that without just taking it out and inspecting.

If you have a blown powervalve you would know it. It will be running extremely fat.

Update:

My buddy stopped by....and we adjusted timing a bit...he worked on the air/fuel mixture on the carb. Idleing much better although still seems to be running a bit rich....meaning when you "crack" the throttle she bogs just a split second.....like the engine is loaded with fuel.

I still suspect the power valve in the carb....it maybe leaking some and adding more fuel in during idle.....which you have to open the air up to get to run...which obviously keeps you at a higher idle or she dies because of the excess fuel.......my thinking.

Next steps:

Going to purchase a temp gun to check the exhaust temps on each cylinder just to see if we have anything funny going on. Those guns have become really resonable in price and a quick way to check individule cylinder issues.

My buddy is going to make some calls today and see if we can get our hands on another carb just to throw on to verify we have a carb issue......it may be time to do a rebuild kit.

Track is open tonight...so may take it up to test under load.

Still digging.....but making progress.

Carb
 

It would take MAYBE?1 Minute to pull the Bowls off the Carb and Check the Power Valve???
DID I MISS SOMETHING?Is the Carb Mounted somewhere,where you cant get to the BOWLS???
Later
G 8)

Re: Carb
 

Yea....looking at the drawings....does not look to be a hard thing to get to at all....just not sure I would know if its bad once I got there....unless its very obvious....just no experience with it.

p/v
 

Pull the Bowl off,turn the Plate on end that the Power valve is Down.Put some type of Thin Liquid(Carb Cleaner,Brake Kleen)in the Threaded hole that the Valve Screws into,if it runs Threw,the Diapham is Bad!
Or you can use a Vac.Pump.They actually make a P/Valve tester.But,you can usually see if they are Blow!
Hope this HELPS?
Later
G 8)

Re: p/v
 

Ok....I pulled the primary bowl and metering block off and guess what??.....the dang power valve has a plug in it......

So help me understand the reasoning behind that move??......I guess for racing applications....which this is a bracket engine.

Atleast I know now that its not a blown power valve.....but not sure what this means about the idle issue....

Thoughts?

see my reply in your other thread asking about the point of plugging the pv.