Blew my exhaust maifold gasket

[DBG]

Well, I blew my exhaust manifold gasket last night.

It's the very front one. I can see where it's turning black on the side of it so I guess I'll get to wrench on my new car sooner than I thought.

It's really not loud, but I can hear and notice it, so it's gotta be fixed.

It will also give me a chance to clean it up and maybe paint it while it's off.

Is there any tricks or things I should look out for?

Thanks
Chuck

 

[player1up]

ugh, So common with a stock skinny exhaust. If you are going to take it apart you might want to true up the manifold to head surface....
See this post.
http://www.forabodiesonly.com/mopar/showthread.php?t=33620
and this one from slantsix.org
http://www.slantsix.org/articles/manifold-install/types-mounting.htm

I also used the high temp orange rtv silicone to add some sealing power to it.
Things to be aware of:
Don't over tighten the nuts, it's real easy to do and it wont gain you anything (might actually crack the manifold because it wont slide)
The manifold is meant to "slide" along the head surface as it heats and cools.
Super duper ...aussie, remflex.... gasket wont help if your manifold is too far off. I'm using a fel-pro gasket after the remflex blew out (from over-tightening, 2 heat cycles and it had been pushed out the side of #1 cyl)
Oh yeah, the manifold pair is HEAVY, no seriously, it's a hernia waiting to happen.
Oh and the little triangular washers can be a bear to put back on the studs without a magnetic stick or taping them to a socket.

 

[DBG]

Thanks for all of th tips. I broke the first stud I touched. The one closest to the thermostat, so I had to replace that.

I used a NAPA gasket as I heard they were good ones. Other than the broken stud which I got out with some heat and vise grips everything went OK.

My old gasket blew out right on the very front cylinder.

After I got it all together I noticed that my air cleaner wasn't letting enough air through. So I went with a small Mr. Gasket air breather and I can't believe the difference!!!!

I also tightened my carb up that had almost EVERY nut and screw loose....LOL

I did a MPG with my OLD air cleaner and without touching anything. (Just the way I bought it) I got 16.6 MPG.

I'm going to do another one now that it is breathing better. I can actually tell it is running stronger after tightening everything up.

Thanks again
buds
Chuck

 

[player1up]

Glad to hear it went well :cheers: Slants will run with all kinds of things wrong...I found 3 loose head bolts a bent pushrod and 2 loose rocker arm bolts and mine was getting about 13mpg.. I only get about 15-16 now with the 2bbl carb but I drive.... um... briskly

 

[vynn3]

After I got it all together I noticed that my air cleaner wasn't letting enough air through.

The air FILTER or the air CLEANER? And how do you know it "wasn't letting enough air through"? Was the filter just dirty, or are you judging the design of the air cleaner assembly itself?

So I went with a small Mr. Gasket air breather and I can't believe the difference!!!!

Do you mean an open element air cleaner? If so, I'm not familiar with the older style air cleaners from '65, but the difference you might be "feeling" is the now unmuffled sounds of the intake tract. Lot's of guys make this simple change at some point in their hot rodding careers and swear they can feel a difference in performance (myself included, many, many moons ago), but realistically, it just means HOT air has an easier time getting into the carb, which is less dense, and isn't good for power. But they sure SOUND good, don't they?

You probably did MUCH more for driveability and power by tightening down your carb, thereby sealing a vacuum leak. There's nothing wrong with an open element air cleaner, but to make more power, you'd be better off attaching ductwork to your old air cleaner (assuming it was the snorkle type) that vents COLD air to the carb near the front of the car. Also, later model snorkle type air cleaners (70 and up?) usually have a flapper and a tube that vents hot air from the exhaust manifold when the engine is cold. This helps MPG by bringing the engine to operating temperature quicker. You could see an improvement if you get a properly working later model air cleaner system installed. It just won't LOOK as cool... ;)

Just my $.02. Good luck!

 

[DBG]

I had the stock type air cleaner on it. The air cleaner doesn't have a snorkel. It draws air from the bottom of the air cleaner.

It has a clean filter in it, but it always seemed like it wasn't getting enough air. It might have just been me, or tightening up the carb, but I know it's running a ton better.

I'll report the gas mileage when I fill up again. I was talking about the total design on the breather itself. It has very little room for air to come from under the breather. There's no way to add anything to it that would help get more air into it.

You are correct that tightening up the carb probably did the most good, but I also have tried both air cleaners now and I can tell a difference when the open air cleaner is on.

I'm 50 so I'm past the stage of just liking the sound better. LOL We use to turn our air cleaner's top upside down on chevy's with a quadrajet to hear that "Dooo Waaaaa" sound when we would kick it down around 30-40 MPH.

I'm looking forward to my next MPG check.

Thanks for all of the help.
Chuck

 

[vynn3]

We use to turn our air cleaner's top upside down on chevy's with a quadrajet to hear that "Dooo Waaaaa" sound when we would kick it down around 30-40 MPH.

Y'know, I like EFI for maximum efficiency, and I'd have it on every car I own if I could afford it and tune it. But NOTHING beats the sound of a big, nasty pair of secondaries opening at full throttle. Even on a Chebbie. ;)

Best of luck!