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Re: Diverter Valve and Backfiring
high vacuum causes the valve to put the air from the pump into the air cleaner when you back off the gas so it is not directed into the exhaust system and causing backfiring through the exhaust.if you allow the hot exhaust gas to enter the tubing it will burn thru in a short period of time so the air must keep going thru the plumbing and if you plug at the check valve no air will cool the thin wall tubing. -
Re: Diverter Valve and Backfiring
high vacuum causes the valve to put the air from the pump into the air cleaner when you back off the gas so it is not directed into the exhaust system and causing backfiring through the exhaust.if you allow the hot exhaust gas to enter the tubing it will burn thru in a short period of time so the air must keep going thru the plumbing and if you plug at the check valve no air will cool the thin wall tubing.Comment
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PS
i forgot that open air cleaner engined cars just had the air go into the engine compartment. the diverter valve did the same thing on both styles.Comment
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PS
i forgot that open air cleaner engined cars just had the air go into the engine compartment. the diverter valve did the same thing on both styles.Comment
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Re: Diverter Valve and Backfiring
Geoffrey-----
The problem that I see with your approach is that it leaves the AIR pump operational and pumping against a closed discharge line. That would mean that the AIR pump discharge would have to be constantly "dumped" through the diverter valve or, in the case of the 68-only pump, through the relief valve on the body of the pump. Neither of these scenarios are good ones.
If I were you, I'd do the following:
1) disable the AIR pump by removing the internal vanes. If you don't want to destroy an existing/original type pump WITH "DATES", then you can purchase a rebuilt pump at an auto parts store, gut it, and install it. Gutting the pump is easy and you can purchase one of these at an auto parts store for about $50 with exchange or about $75 without exchange. It may or may not be correctly "dated", though. It might even be configured a bit differently. Hardly anyone will know the difference;
2) install the "penny" as you described between the smog tube and the check valve. It's not absolutely necessary since the check valve will prevent any backflow of exhaust, but it will serve as a "back-up" should the check valve fail. Plus, it's cheap; it only costs 2 cents per car;
3) Remove the diverter valve vacuum hose from the carburetor. Insatll a "bb" in the hose and press it down about an inch. Then, reconnect the hose to the carburetor. You can also do this at the valve end if you wish. Presto; the valve is rendered inoperable and just a "shell" of its former self. By the way, "bb's" are cheap, but you have to purchase a whole package of them; you can't just buy one. If you go to a store and ask them to purchase just one "bb", someone will probably get grouchy and, perhaps, snarl at you. So, my recommendation is to just buy the whole package. You can give the surplus to some needy kid with a bb gun that can't afford to buy "bb's";
If you wish,you can send your bad diverter valve off to Bill Hodel. He may be able to rebuild it.In Appreciation of John HinckleyComment
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Re: Diverter Valve and Backfiring
Geoffrey-----
The problem that I see with your approach is that it leaves the AIR pump operational and pumping against a closed discharge line. That would mean that the AIR pump discharge would have to be constantly "dumped" through the diverter valve or, in the case of the 68-only pump, through the relief valve on the body of the pump. Neither of these scenarios are good ones.
If I were you, I'd do the following:
1) disable the AIR pump by removing the internal vanes. If you don't want to destroy an existing/original type pump WITH "DATES", then you can purchase a rebuilt pump at an auto parts store, gut it, and install it. Gutting the pump is easy and you can purchase one of these at an auto parts store for about $50 with exchange or about $75 without exchange. It may or may not be correctly "dated", though. It might even be configured a bit differently. Hardly anyone will know the difference;
2) install the "penny" as you described between the smog tube and the check valve. It's not absolutely necessary since the check valve will prevent any backflow of exhaust, but it will serve as a "back-up" should the check valve fail. Plus, it's cheap; it only costs 2 cents per car;
3) Remove the diverter valve vacuum hose from the carburetor. Insatll a "bb" in the hose and press it down about an inch. Then, reconnect the hose to the carburetor. You can also do this at the valve end if you wish. Presto; the valve is rendered inoperable and just a "shell" of its former self. By the way, "bb's" are cheap, but you have to purchase a whole package of them; you can't just buy one. If you go to a store and ask them to purchase just one "bb", someone will probably get grouchy and, perhaps, snarl at you. So, my recommendation is to just buy the whole package. You can give the surplus to some needy kid with a bb gun that can't afford to buy "bb's";
If you wish,you can send your bad diverter valve off to Bill Hodel. He may be able to rebuild it.In Appreciation of John HinckleyComment
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Re: Diverter Valve and Backfiring
joe, you must plug of at the exhaust manifold because of the exhaust heat backfeeding thru the plumbing will burn out the small thinwall tubing spider that connects to the exhaust manifold. i guess if you do not drive the car much this is not a problem but i replaced a lot of the parts that burned thru.Comment
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Re: Diverter Valve and Backfiring
joe, you must plug of at the exhaust manifold because of the exhaust heat backfeeding thru the plumbing will burn out the small thinwall tubing spider that connects to the exhaust manifold. i guess if you do not drive the car much this is not a problem but i replaced a lot of the parts that burned thru.Comment
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Re: Diverter Valve and Backfiring
Geoffrey -
Assuming you plan to "gut" the pump by removing the vanes (as I have done with my '69 Z/28) and plug the vacuum line (to avoid a vacuum leak, as about every old diverter valve around has a shot diaphragm), instead of using the penny approach (which is marvelously cost-efficient), I'd recommend going to the hardware store where you get your BB's and get (8) #10 x 1/2" flat head screws. Unscrew the air manifold tube nuts at the manifold, pull the little stainless tube inserts, drop a screw in each hole, and re-install the air manifolds. This gets the tube inserts out of the exhaust stream, and plugs the holes very neatly; the tube nuts will screw right back into place at the same depth they were originally, blocking exhaust backflow into the air manifold tubes - if the air manifolds are new, they will stay looking that way without "cooking" their coating. Nobody will ever know (except the happy kid who gets your leftover BB's)Comment
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Re: Diverter Valve and Backfiring
Geoffrey -
Assuming you plan to "gut" the pump by removing the vanes (as I have done with my '69 Z/28) and plug the vacuum line (to avoid a vacuum leak, as about every old diverter valve around has a shot diaphragm), instead of using the penny approach (which is marvelously cost-efficient), I'd recommend going to the hardware store where you get your BB's and get (8) #10 x 1/2" flat head screws. Unscrew the air manifold tube nuts at the manifold, pull the little stainless tube inserts, drop a screw in each hole, and re-install the air manifolds. This gets the tube inserts out of the exhaust stream, and plugs the holes very neatly; the tube nuts will screw right back into place at the same depth they were originally, blocking exhaust backflow into the air manifold tubes - if the air manifolds are new, they will stay looking that way without "cooking" their coating. Nobody will ever know (except the happy kid who gets your leftover BB's)Comment
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THANK YOU all & Clem I'll call if stuck *NM*
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THANK YOU all & Clem I'll call if stuck *NM*
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