Is there a way to detect vacume leaks between the Intake Manifold and the Cylinder Head. Engine starts, but runs extremely rough and then dies after about 10 seconds.

Thanks.
Steve

 

you got to be pulling your hair out at this point. Maybe check to see that your valves aren't adjusted too tight. If that's not it , turn the dist. while its running to smooth it out. You could squirt a little oil along the intake gasket area while its running to see if its leaking on top but if its leaking underneath???

 

Hamck, I have no hair left.
At first the valves were too loose. At least they were found loose after a few start attempts. And it won't stay running long enough to turn/adjust the distributor.

Thanks for the response.
Steve

 

in answer to your question, yes.

smoke machine is one way, there are threads on DIY machines from fog machines out there.

others use smoke or propane.

you can also remove the manifold to inspect the gasket area for leaks, sucking oil, etc.

 

Smoke machine? Fog testing? Old farts like myself use carb cleaner in a spray can to test for leaks.....I don't need no STINKING Smoke Machine ( unless its for a Halloween party )

Get some carb cleaner and spray along gasket mating surfaces, sounds like you have a bigger problem......bad valve adjustment, wrong ignition firing order....bad fuel....even with vacuum leaks a motor should run at a high idle speed...good luck

 

Thanks for the ideas.

Steve

 

Much appreciated.
Steve

 

Had the same problem on my L-82. Combination of valve lash to tight and vacuum leaks at intake manifold mating surface to heads. I noticed black soot on the edge of the manifold next to the heads in 2 or 3 spots. Took a feeler gage .001 and started trying to slip in between manifold and gasket. Found 3 big gaps. Decided to pull the manifold and put sealant around all the surfaces. Fixed it.

 

Or.... We have a propane tank with a small hose attachment on it. Crack it open and and test (no mess).

 

I'm with ya Cary.
Will drain, pull, remove manifold and install a gasket set that I know works.

Much appreciate in hearing of your past experience on this.
Steve

 

Thank you sir, but it just doesn't run long enough to see if the propane changes RPM.

That is how you meant the propane checks for intake leaks. No?

Steve

 

Yes indeed Steve...

I've been watching this... and you know sometimes you just have to punt and go back to the basics. Double check everything, chase your wires over, verify you are adjusting the valves correctly and never rule out the simplest things…. and when you get disgusted walk away from it.

Now… the need to turn to adjust the distributor can be eliminated.

If you bump your timing to say 10 degree’s on the mark, then hook up your timing light and turn the distributor until the light comes on and then lock it down! You’ve just eliminated the need for turning it after it runs because it’s at 10 initial.

Now if you want to smoke it... Go find someone with one of the electric cigarette or go buy you one. The smoke in the electric cigarette is provided by PG or ‎Propylene glycol the same stuff that causes the smoke machines to smoke. It'll cost you about 50-60 bucks for a decent Aspire Mini Tank Nautilus and a battery to power it. But go to one of those smoke shops, the workers there love to show off how much smoke they can blow.

You get a fluid mix with 80 percent PG and 20 percent VG (about 8-9 bucks) and you've got your own personal smoke machine.

Then... you put a long vacuum hose on the car and block off what you can. Suck the smoke in (don't inhale Bill) and blow it into the vacuum hose. If there is a leak you'll see the smoke, you may have to repeat this a few times.

Don’t ask me how I know this works please… lol. It does work and we’ve got a video up on our Facebook page where we used this same method to determine the gasket was defective on the throttle body of a 1986.

Electric Cigarettes have pulled three of my employee’s to the non-smokers of the world side… They are amazing, but for me they have a neater use.

Crazy I know.. you can watch this in action on our facebook page video at this link... But you have to like the page to see it. https://www.facebook.com/video.php?v...type=3&theater

Ernie

 

Thanks Ernie!

Heavy gauge wire from the fuse box, going to the correct terminal:


Steve

 

Have you tried hooking up a vacuum gauge to see what is going on inside the engine? You Tube has quite a few examples on how to read the gauge. The gauge should help with the above in finding out if you have a vacuum leak, misadjusted valve or bad cam or lifter. Jerry

 

Are you absolutely certain that you don't have a couple of plug wires switched? Believe me, it happens.

 

I will check that out Jerry. Thanks!

Steve

 

Oh yeah, I understand my friend. You know I do have the lower plug Wire Shields installed;


...and when those two front wires come out from the motor mounts, it is indeed easy to get them on the wrong plug. Just tugging on one for identification wasn't enough for me: I used an ohm meter to verify.

But since you mentioned it, I'll check them again.

Steve

 

After ohm checks and reseating wires to plug and cap, being able to adjust the distributor position to where the engine runs, and then able to use a timing light and adjust timing further, the engine now runs smooth. Not really sure the carburetor had something to do with it, as I did remove it and install a different gasket, but at least I now can use propane gas to leak check the intake manifold. That is what this thread was supposed to be about.

Steve

No Intake leaks!

Did discover that if the stock Valve Cover Hold Down strips aren't used, valve cover leaks will happen.