273 intake on a 318

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rigrunner

rigrunner

rigrunner
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Put a factory 4 barrel intake off a 273 onto a 73 model 318 2 barrel engine w/ a 600 edelbrock carb, the first and last cylinder on the passenger side are not getting gas. Plugs are firing but are dry causing a miss on two cylinders. Used the 2 brl intake gasket to install. Intake and carb sat for a few years, so rebuilt carb. any ideas on how to fix this problem or what to check would be appreciated.
 
rigrunner said:
Put a factory 4 barrel intake off a 273 onto a 73 model 318 2 barrel engine w/ a 600 edelbrock carb, the first and last cylinder on the passenger side are not getting gas. Plugs are firing but are dry causing a miss on two cylinders. Used the 2 brl intake gasket to install. Intake and carb sat for a few years, so rebuilt carb. any ideas on how to fix this problem or what to check would be appreciated.
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If the other cylinders are getting gas, so are those. You need to check for other problems. How is the ignition system?
 
Check the two spark plug wires to see if they are getting spark-pull each wire one at a time, off the plug have some turn the ignition and see if you can see spark. Are the spark plug wires new? What about the distributor cap.

Dave
 
rigrunner said:
Put a factory 4 barrel intake off a 273 onto a 73 model 318 2 barrel engine w/ a 600 edelbrock carb, the first and last cylinder on the passenger side are not getting gas. Plugs are firing but are dry causing a miss on two cylinders. Used the 2 brl intake gasket to install. Intake and carb sat for a few years, so rebuilt carb. any ideas on how to fix this problem or what to check would be appreciated.
Click to expand...

I thought the bolt angles on the 273 intake wouldnt allow this?
 
car ran fine the day before i switched intake, i pulled the plugs out and they were a little black but they didnt smell like gas at all. the ignition system is new. is there a chance of a blockage or gasket slip, or carb jets not putting out enough gas on that side to feed all cylinders? sprayed starting fluid around intake, found no vacuum leaks. could i have fowled the plugs? not looking forward to pulling intake back off.
 
273 intake came off a 318 engine, it is the late model 273, everything bolted right up.
 
there's simply no way what you describe can have anything to do with the fact that you have a 273 manifold on a 318.
even the intakes with the different bolt angle have the exact same port runner size and spacing.
I have 273 heads on my 318 with a 318 manifold. I only went with the 273 heads because they are closed chambered. if you like I can go out and take photos of a 273 head next to one from a 318.
your issue has to be something else.
 
intake works, the cylinders arent firing and plugs dont smell like gas at all. if they are getting gas and not firing, shouldnt they at least be wet and/or smell like gas? thanks for all the help...trying to get it ready before christmas!
 
I agree, it can't be caused by the intake. Since this started with the intake swap I'd look at simple things, like are the plug wires on the correct plugs & in the cap in the correct order.
 
Maybe a mouse or something crawled into the intake while it was off or something got into the head and is blocking the valves. Did you do the swap indoors or? Maybe a valve isn't open on thos cylinders. Is something blocking the valve from opening? Cam alright?
 
Are the 318 heads the small port ones? If so then you should have no trouble at all. If they are the bigger ported heads you might have a vacuum leak inside the block, This happend to a buddy of mine, the heads were leaking into the block, did you use steel or paper gaskets?
 
No there are a few 318's that have a bigger port and then with this fella putting a 273 intake on it could happen. My case was the exact opposite, we put a 318 intake on a 273 heads had a couple leaks.

I have to look up which heads are different but there are/were some not the same.
 
he mentioned it was a '73 318 so small ports, the bigger ports came quite a bit later. my '78 had the small ports also. I think they went to the bigger ports in the '80's, basically they're 360 heads.
 
can it be the intake or carb has something clogging it up? it sat in a box for a couple of years. i rebuilt the carb. and if so, can i clean the intake w/o taking it back off like running a coat hanger through it or vacuum it out? i am asking questions from the road, hoping to work on it in the morning, thanks for all your help.
 
I would be amazed if you found anything in the intake runner. the engine running would have sucked anything in a runner that wasn't really really stuck in there. my guess is, it's in the carburetor. did you do anything inside it? if the jets are too lean the farthest cylinders from the carb will starve. this would be exaggerated if one side were plugged up. I would go through the carb if you haven't already.
 
is the factory manual fuel pump enough to power the larger carb versus the factory 2 brl carb?
 
if the carb is only 600cfm, it definitely will handle it unless there is something wrong with it.
 
I'm assuming you're using the '66-7 single plane manifold? If so, Try dribbling a tiny stream of gasoline in the carb on the side that has the problem. If it smooths out, you have an idle circuit on that side that's partially clogged. I make a primer can out of an old plastic oil bottle by drilling a tiny hole in the cap. You can use a squirt can also but it's a little harder to control volume. Just keep a fire extinguisher handy in the odd chance you have a backfire or bad plug wire somewhere.
Thanks, Mark
 
Those manifolds are single plane. I don't see how one side could be affected. I think your carb is messed up.

Do you have access to a different carb to try, just to check if thats the problem?

That 600 Edelbrock should work fine with the factory jetting.
 
thanks for all the replies. turned out to be a vacuum leak. now it i can get the trans kickdown working
 
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