[mdacton]

sbc how can you tell if intake is leaking from the valley? besides taking it apart

 

[IANIL8]

The easiest two ways...First and cheapest carb cleaning/brake cleaner while it's running spray around the intake normally it will idle up when you find the leak. Second and most effective is a smoke machine things are amazing.


God Bless

 

[mdacton]

its nothing on the outside leaking, I think its leaking from the lifter valley but not 100% sure

 

[Autorotica]

Propane works... Bra Kleen will not if its not flammable


Chris

 

[ordinary builder]

underside is one of the most difficult...

some have used a long probe tube stuck in thru one of the slots in pushrod area and point upwards under the manifold towards the ports..

but must be carefull, because too much carb cleaner / brake spray can in fact ignite inside block / valley and then you will have a GIANT leak..( explosion)...

many use a special sniffer similar to what is employed in air conditioning leak detection...

no shortcuts..you have to pay the bucks....!!!!

 

[Ten5TireRacer]

Find a repair shop near you with a smoke machine, seal any exit areas, and pump it through the valve cover until you see smoke.
The stuff dissipates almost immediately, and won't effect anything. Some times it takes a while for the smoke to fill an area and find a way to escape, but there really isn't much better of a way to find if there is a leak easier than that

 

[trmnatr]

Cover the carburetor with your hands and see if it dies or keeps running

 

[gordrc51]

I had one that was leaking on the underside of intake. Pulled breather out and pcv and check if crankcase builds vacuum with both plugged.

 

[mdacton]

I can block the carb off and kill it. but with 2 diff carbs sames issues all seem vac related wont respond to tuning idle adjustments etc.

almost wants to run on when shut off etc.

Im going to just pull it off and check, hate to do that without knowing for sure

 

[haberkorn]

Pressurize the engine with 3-5 pounds of air and spray around with water mixed with dish soap.