Clogged intake manifold

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spdart

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I pulled the stock iron 2bbl intake manifold off of my 73 318 LA engine and found the exhaust gas crossover clogged. I used a pressure washer to blow a bunch of stuff out but am tempted to remove the plate on the bottom to get better access. The plate is attached with what looks like two large rivets that I could drill out but don't want to do something I'll regret because I don't know any better. Has anyone removed this plate before and how did you reattach it?
 
Removing the plate won't do you any good. It's a heat shield to keep lifter valley oil from burning on the hot crossover. I wouldn't worry about it since everybody else's crossover is blocked with crud as well. The only difference is that you have had yours off and know about it.
 
Grumpus is right. That's just a heat sheild to prevent the oil from "Coking" and falling back into the engine.

Just keep chisiling away and soaking with carb cleaner. If your car is stock you'll want it cleaned out as the heat crossover also heats up the choke stove and insures that the choke is opened in a timely manner.
 
Hot-tanking the intake will clean out the cross-over passage and it takes time to dissolve the deposits. I've had it done many years ago and there was some residual deposits left behind. Besides having the choke come off faster, having a hot spot under the carburetor will give you better fuel economy and low-speed response.


Intake Manifold Heat
 
the rivets are spiraled and will screw out if you use a chisel to spin them. then just drive them back in with some locktite
 
I'd say don't remove that plate. I went ahead and jammed drills, punches, coat hangers and whatever else worked to get out all that oily hard carbon in my crossover. I didn't stop until it was perfect, and I used degreaser. It's a *****, but you'll feel good in the morning knowing it's clean.
 
i removed mine to clean and it wasnt that hard. i believe i tapped them and turned and pulled them out with vice grips.
 
Thanks all for the input. I used my gas powered pressure washer to clean it out initially and was amazed at how much crap was in there. The hard deposits are left now and am doing the poking and scraping thing to get that cleaned out. The heads are coming off next since the matching exhaust passages are completely blocked.
 
daredevil said:
i removed mine to clean and it wasnt that hard. i believe i tapped them and turned and pulled them out with vice grips.
Click to expand...
Same method used on mine, but I paid to get it done. My machine shop charged me $25 to pop off the cover, clean the crud out, tap new threads and use regular bolts to resecure the cover.
 
clifftt said:
Same method used on mine, but I paid to get it done. My machine shop charged me $25 to pop off the cover, clean the crud out, tap new threads and use regular bolts to resecure the cover.
Click to expand...

But oddly there's nothing under the cover but the bottom of the manifold. :read2:
 
when I feel the need to remove that shield i simply cut a slot in the top of the rivet using a zip cutter and then I hit it with one of those hammer driven impact drivers with a tight fitting slot screwdriver bit.Comes right out! THe you can get in there with a wire wheel and get it really clean.
 
when I feel the need to remove that shield i simply cut a slot in the top of the rivet using a zip cutter and then I hit it with one of those hammer driven impact drivers with a tight fitting slot screwdriver bit.Comes right out! THe you can get in there with a wire wheel and get it really clean.
 
when I feel the need to remove that shield i simply cut a slot in the top of the rivet using a zip cutter and then I hit it with one of those hammer driven impact drivers with a tight fitting slot screwdriver bit.Comes right out! THe you can get in there with a wire wheel and get it really clean.
 
when I feel the need to remove that shield i simply cut a slot in the top of the rivet using a zip cutter and then I hit it with one of those hammer driven impact drivers with a tight fitting slot screwdriver bit.Comes right out! THe you can get in there with a wire wheel and get it really clean.
 
when I feel the need to remove that shield i simply cut a slot in the top of the rivet using a zip cutter and then I hit it with one of those hammer driven impact drivers with a tight fitting slot screwdriver bit.Comes right out! THe you can get in there with a wire wheel and get it really clean.
 
needsaresto said:
when I feel the need to remove that shield i simply cut a slot in the top of the rivet using a zip cutter and then I hit it with one of those hammer driven impact drivers with a tight fitting slot screwdriver bit.Comes right out! THe you can get in there with a wire wheel and get it really clean.
Click to expand...

i think we got it
 
Why would you un-block it, and lose HP? I purposely block them off; denser gas mixture.
 
ramcharger said:
But oddly there's nothing under the cover but the bottom of the manifold. :read2:
Click to expand...
True the bottom of the manifold is there, but there's also the air passage running under the center of the plenum which heats the air-fuel mixture. I know its best to block off for add'l power, but my car is about driveability and I'd prefer to have it warm up sooner rather than later ... she's just a cruiser, not a racer.
 
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