My 67 GS400 intake manifild has the exhaust gas passage that directs exhaust gas under the carb. I presume this is to heat the carb/choke quicker. My problem is that the exhaust gases are going directly to the PCV outlet and into the primary venturi. This can't be correct, but I'm not sure what the solution is. My first thought is to get a different carb/manifold gasket that covers the exhaust gas passageway in the manifold. Has anyone run into this and have a solution for me????? Thanks Harvey
Do you have the metal gasket plate that is sandwiched in there? This is supposed to act as a buffer so the exhaust doesn't eat the fiber gasket up and get into the carb.
Adam nailed it...the steel shim gasket is either gone or has eroded. Time to take care of that right away, or the exhaust gas will eat the carb in no time. Devon
Adam and Devon :TU: Thanks! I've looked around at all of my extra parts goodies and can't find one. I did find an old intake with the gasket still attached. I also found an old carb with the gasket attached. That begs the question as to which side of the gasket the metal spacer goes. It would seem from my old carb and old intake they each had it on a different side of the gasket?? Are these metal spacers readily available??? Thanks again guys. It's nice to know that someone seems to always have an answer to most everything! :TU: Harvey
Harvey, the composite gasket goes on the intake (make sure you match it up to the exhaust passage as it's not symmetrical). The steel heat shield goes on between the composite gasket and carb. Devon
Good news! I stopped by my local GM dealership today and he had one in stock. So problem solved. Devon, not to discount your advice, but thinking about the purpose of this plate, it would make more sense to me to have the metal plate on the intake. Thereby keeping the exhaust gases away from the gasket???? o No: Another question, should the metal plate have some type of sealant put on it? Metal to metal doesn't usually make a good seal. Thanks again! Harvey
gaskets There is supposed to be a heat resistant gasket between the intake manifold and the heat shield plate, then another gasket between the heat shield and the carb.
If you buy a carb rebuild kit, these parts are generally in there.... - Composite gasket with the cutouts for the exh. passage goes on first - Metal Plate goes on next - Solid composite gasket goes on last, then carb.
I thought I had my problem solved, but it turns out the metal heat spacer isn't wide enough to cover the ex. gas passages. So I'm back to the dealership tomorrow looking for a wider one. What is the downside of just plugging the passageway. o No: I have an Olds manifold and it doesn't have the ex. gas passageway. Harvey
Harvey, I have to admit I'm not sure about my earlier advice, I checked my '67 chassis manual as well as the Buick Assembly book...no detail on the correct stack on the gasket/heat shield. It's been ages (1985) since I messed with one and I ended up doing the same thing you're contemplating...blocking the exhaust passage completely. If I remember correctly, I tapped the holes on each side of the crossover passage and installed set screws. The stock engine might've taken a few more minutes to warm up to easy drivability, that's it. Devon
Hi Adam Yes that is the one. It is too narrow at the front to cover the passageway completely. As to my question, do we need these passageways? What happens if I plug them? Harvey
Sorry Harvey, I commented about my mistake in your other thread. I agree the plate needs to go on the intake first. I don't remember ever using a sealer... Devon
I just came in from working on it all day and two problems got solved. First it now idles properly and secondly I now have vacuum for my brakes!!! Thanks again to everyone for assistance. Harvey
Harvey, How did you stack the gaskets or did you plug the holes? I will need to do this on my engine soon. Thanks Ed
Hi Ed I spent the first half of the day looking for the correct gasket and heat shield. I had no luck finding the correct pieces so I purchased a Mr. Gasket universal Q jet gasket. To make this gasket work, the holes have to be plugged. I cut a 3/8 bolt to fill the holes. You can drop a bolt/rod down the holes and they stop on their own. I cut them so the top of the bolt was about 1/4" below the passageway. Then I followed the above advice and spent $4.00 on JB weld. I filled the holes and the passageway about 1/2 full. Let that dry for an hour and then filled the passageway to the top. Let it sit another hour then used the universal gasket with a bit of sealer. Problem solved! Harvey
I have this GM plate part number 1383634 that I hope is correct. I dont know if the other gaskets come with the carb kit or not.
Hi Ed, Lay it on your intake and make sure it covers the passageways. You have to make sure the gaskets do the same! Harvey
