Idle Speed

[mojavered]

I just changed out my gaskets on my intake, RPM Performer to Indy heads.  There is no heat crossover on the heads, but the intake has the port for one.  The gaskets I used have the slot there as well.  So, I just changed the intake gaskets and added a fuel pressure regulator.  I have a vacuum leak (I think) or something as there is a slight whistle.  I want to check and was thinking of spraying some B12 Chemtool carb cleaner around intake and carb base to see if there is a change in idle.  It should decrease in rpm?  Right?  Is it or will it be noticeable enough to detect?  Thanks!

[Cooter]

If there is a vacuum leak, and you hit it with the carb cleaner, it should smooth out and rev UP...

[mojavered]

Is there something that would drop the idle?  It seems that speeding the idle up would be harder to notice than a drop...not sure though?

[Cooter]

No, You will know it when you've found the leak.,.The "Whistle" will stop and the engine will rev up..

[MEK-Dangerfield]

No, You will know it when you've found the leak.,.The "Whistle" will stop and the engine will rev up..

I thought the idle would drop.   

[Cooter]

A vacuum leak is a lean condition provided everything else is working properly....You introduce more fuel to the lean condition, the engine revs up..

[Aussie Challenger]

A vacuum leak is a lean condition provided everything else is working properly....You introduce more fuel to the lean condition, the engine revs up..

  Carby cleaner is combustable.

[72cudamaan]

  x2

[MEK-Dangerfield]

A vacuum leak is a lean condition provided everything else is working properly....You introduce more fuel to the lean condition, the engine revs up..

Cooter,

   This will teach me to post early in the morning.   

In the past, I sprayed water around my carb, thus the drop in idle. I totally glossed over that he was using carb cleaner.   

[mojavered]

I have an intake leak !  Idle went up around the intake.  I used some fel-pro gaskets that were way thinner than the ones I pulled off.  Holes all lined up when I dropped intake into place, did not see any gaps and thought they would be fine.  I guess I will hunt some different gaskets down and replace.

[MEK-Dangerfield]

The trouble is you have to believe the heads and intake were machined correctly. I used Gaskasinch on my gaskets for a little insurance.

[mojavered]

I added the some copper permatex, but that was not enough?  Never tried the gasgasinch.  I have seen it at Oreliey's.  Might have to give it a try.

[Aussie Challenger]

Maybe that you will need to check the manifold to head fitment, especially if the head has been machined.

[jimynick]

 :iagree:What Aussie said. Set the intake bare on the heads and look carefully at the resulting joint- should be flush and close. There is a formula to cut the intake to match cut heads, but my sieve of a memory doesn't recall it. Torque to spec, don't just armstrong it. good luck

[mojavered]

My gaskets I had on it were .060" and the ones I put on were only .030".  I ordered some new gaskets and will put them on when I get off work.

I did set on without gaskets and it looked good.  Once gaskets were on, set down with all holes lined up.  Bolts were torqued down to 35 lbs. (aluminum heads, is that the correct torque?)