396/375 hp/motor issues

[christopher teed]

Ed,I turned the idle screws out .it didnt change the lean condition or change the results as i had a vacuum gauge hooked up while i turned the screws out.

[Ed Wright]

Originally Posted by christopher teed

Ed,I turned the idle screws out .it didnt change the lean condition or change the results as i had a vacuum gauge hooked up while i turned the screws out.

Changing jets will have very little effect on idle fueling. Sounds like you need some help. Where are you located?

[c612pro]

Actually losing cam lobes does not necessarily affect the lash as the base circle is not really affected. The fact that there is no vacuum at low engine speed indicates possibly having a cam ground off spec, maybe lobe center off, if the vacuum gauge fluctuates wildly that shows a vacuum leak. At least a good look inside the oil filter and the engine should tell you if there is mechanical trouble.

[Adger Smith]

Most of the cams goig flat I've seen do change the lash because the lifter always gets shorter. Put the vac gauge back in the tool box and use it to tune a car with a stock cam. You might need a smaller idle air bleed or check it for Vac leaks if it is lean at idle. If you have a PCV hooked to it like it was a stock car get rid of it or get one that is designed for low vac. Get an O2 sensor on it with some Data logging if you can't figure it out.

[Ed Wright]

Originally Posted by Adger Smith

Most of the cams goig flat I've seen do change the lash because the lifter always gets shorter. Put the vac gauge back in the tool box and use it to tune a car with a stock cam. You might need a smaller idle air bleed or check it for Vac leaks if it is lean at idle. If you have a PCV hooked to it like it was a stock car get rid of it or get one that is designed for low vac. Get an O2 sensor on it with some Data logging if you can't figure it out.

There ya go.

[njk53]

Make sure your headers are not leaking. We picked up a miss with an engine fresh off of the dyno and it turned out to be a leaky header gasket.

[Billy Nees]

Originally Posted by Adger Smith

You might need a smaller idle air bleed or check it for Vac leaks if it is lean at idle.

Not to oversimplify things but do you have a plugged idle air bleed?

[Mike Taylor 3601]

What Billy said,did you hear engine on dyno ?Has carb had fuel sitting in it since dyno?
Had BBC that was working on one time,idling sounded like carb or valve lash too tight,idled sound like was on 6cyl. all that was good,with idling tried to get feeler gauge in between rocker/valve would'nt go,shut off lash would check right, long story short tore down found lobes just strarting to go.

If have temp gun may shoot ex and find if one cyl. colder than others,no vac @ idle I would guess you are getting comp. back in intake,ethier valves being held open some reason ,bad lobes? bent valves?

Mike Taylor 3601

[Ed Wright]

Plugged air bleeds make them richer, not leaner.