Mak

So, I've got my Edlebrock intake manifold off. After removing it, I found the crossover plug on the left side was loose (no doubt causing the engine rattle I've been chasing)... the right side plug is so tight I haven't been able to remove it at all (definitely not ratting!) So, my dilemma is whether to try and get the loose one to not rattle... or remove the other one and leave them both out. My car is a year-round, weekly driver... but being in California, more hot weather than cold weather. Also, any tips on removing the side that's stuck?

oldcutlass

You may have less trouble repairing the loose one.

Mak

I sprayed the stuck plug with penetrating oil... I won't have another chance to work on it until Sunday, now. From what I've read here, plugging the crossover isn't really necessary on street cars. That being said, my car has always run great... I only pulled the manifold off because of a coolant leak. I'm hoping removing the crossover plugs wont cause any noticeable decrease in overall performance (I certainly wouldn't miss that rattle, though)

Mak

Okay, I'm planning on attacking the stuck crossover plug with a slide-hammer tonight when I get home from work.
Anyone have any advise or reasons why I shouldn't remove them???

bigoldscruiser

As long as you are still running a carb, removing the plugs should be fine. You're choke will even work again if you set it up. I had the same problem when I changed to FI. Before long, there was this rattle. When pulling the intake, I found both plugs loose and rolling around in the manifold. I pulled them out, shaved them down to fit and hammered them into the heads. I had to keep them because of the FI. All has been well since.

I assume you are going to drill a hole and insert a course threaded lag or similar to attach to the slide-hammer. That should work. If the first one pulls out without removing the plug, go bigger. Good luck

Olds64

I have an Edelbrock intake that I didn't install the plugs in. I've heard you can block the exhaust corssover ports by wrapping the intake manifold gasket with an aluminum sheet cut from a soad can.

I think your idea of using a slide hammer will work. Good luck.

Toyaholic

I've been told the Olds BLUB-BLUB exhaust sound will be more noticable without the plugs.


I have the L69 intake and run with the block off plates turned closed. Should I also use plugs? I live in the South and replacing the factory choke with a manual.

Mak

I've heard of the soda can trick, too. But my question is if there is really any actual benefit to blocking the crossover on a daily driver? So far it sounds like there's not.

Fun71

Can you just leave the one stuck plug in? With one plug out there may be enough exhaust heat to warm the carb and for the choke to work properly.

Mak

I have an Edelbrock carb w/ electric choke... so that's not an issue. I wonder if leaving one in & one out would cause a problem?

mike's88

I've thought about this, and since any metallic plug will eventually become a heat transfer, especially aluminum, does it really matter whether they are blocked or not? I've transfered my q-jet to an elec choke, so it really won't matter, except for heating the mixture, which the factory did any way. IMHO the cars ran pretty damm well with that set up.

Olds64

I agree that blocking the exhaust cross over wouldn't make much of a difference. Concievably, I guess you plug that exhaust cross over so the air fuel mixture coming through the carb stays cooler going into the engine. If the air is cooler that means it is denser as well. However, it gets so darn hot under the hood near my engine I don't think it would make a difference.

Mak

Well, after an hour with a slide-hammer... I guess one side is gonna stay plugged. I can see the faint outline around the plug, but it won't budge. Funny, the other side was loose and just pulled right out.

Toyaholic

Aren't the plugs lead?

Olds64

Did you try saturating the plug with PB Blaster?

DoubleV

1) Tap plug and intall a bolt

2) Attach chain to end of bolt

3) Attach other end of chain to a car

4) Secure intake manifold

5) Take car for a one inch cruise

droldsmorland

You can run with one plug in it will essentially do the same thing. If I was you I would not run with out the crossover plugged off (on at least one side).
I live where its cold half of the year and I still had hot soak issues until I installed the crossovers. I welded mine into the iron intake. You can do the same with aluminum intake just use an aluminum plug and find a good welder & Machine shop.
Dont forget to remove the stove thermo flap in the exhaust manifold too, then weld up those holes.
Several reasons to leave it in. Denser colder air intake charge, no hot soak issues such as boil over or lock, no discoloration on the intake (paint bake off for the painted ones).

Mak

Intake is back on. I ended up with the drivers side plug removed, the passenger side plug still in... the exhaust flapper was removed long ago. I think it should be fine since the exhaust won't be diverted through the intake crossover anyway. I hope to have it running & back on the road tomorrow.