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EGR question

arcticvette

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50
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white 1980 Corvette
ok had a leaking valve cover gasket on passenger side of my '80 L48, so in the process of replacing it i removed the egr from the intake manifold and found that the two holes were almost completely plugged with black sooty looking stuff. so the question is what causes this( assuming that this isn't how things should be) and what is the next step(s) to correct the situation?

also, there is a 6"-8" ground strap connected to the top left valve cover bolt that was not connected to anything, where should this go?


by the way the valve cover gasket replacement was a major project for me as a complete beginner. :eek:hnoes did some research and everyone said how easy it is to do and overall it is. found an old thread in which JohnZ offered his wisdom, and as usual he was bang on with his advice so thank you sir. i don't post much but am on this site everyday trying to learn as much as i can. feels good to accomplish even a small project on your own

:beer Mike
 

SIXFOOTER

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Jul 15, 2007
Messages
117
Location
Boca Raton Fl
Corvette
1981 L81 Tan Coupe
Your correct, the holes should not be plugged up, clean it out best as you can and run it. The RGR recycles some exhaust back into the engine to be reburned, it only does this at speed, not around town. Keep an eye on performance, see what it does. The ground strap should be on a bolt on the back end of the head and connect to the graound stuf on the firewall by the corner of the evaporator box.


ok had a leaking valve cover gasket on passenger side of my '80 L48, so in the process of replacing it i removed the egr from the intake manifold and found that the two holes were almost completely plugged with black sooty looking stuff. so the question is what causes this( assuming that this isn't how things should be) and what is the next step(s) to correct the situation?

also, there is a 6"-8" ground strap connected to the top left valve cover bolt that was not connected to anything, where should this go?


by the way the valve cover gasket replacement was a major project for me as a complete beginner. :eek:hnoes did some research and everyone said how easy it is to do and overall it is. found an old thread in which JohnZ offered his wisdom, and as usual he was bang on with his advice so thank you sir. i don't post much but am on this site everyday trying to learn as much as i can. feels good to accomplish even a small project on your own

:beer Mike
 

Vette79

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Jan 23, 2007
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Millersville, MD
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1979 L-48 Black Coupe
"The Ground Strap actually goes to a Distibutor Shield Cover that appears you no longer have". They are a little hard to find since they are no longer being reproduced. It was used to prevent interference with your Delco Stereo. I removed all of my emissions and all is good.
 

Evolution1980

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Mike, I may be incorrect here, but I don't recall the 80's ever having a ground to the valve cover bolt. I thought most of the grounds were on the block or frame. :confused

As for the "black sooty stuff". Is it dry or greasy? I'd think it was just oil and dirt...:confused But it's been so long since I've had emission stuff on my car, I'm probably not remembering all the things associated with it.;shrug :)
 

Yoda

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Amarillo, TX
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1981 UL5
Vette79 is 100% correct ;)

The ground strap goes to the last bolt on the valve cover, passengers side, then to the sheild on the plastic shield over the distr. The plastic shield in these years has an aluminum looking shielding on the inside of the cover to help reduce radio noise ;) esp. on AM ...

Bud
 

Evolution1980

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arcticvette

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Messages
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Friendly Manitoba
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white 1980 Corvette
hey thanks guys, the distributor sheild cover is still on my car so will put ground strap back on the proper stud. as for the grime under the egr, it is like dirt and oil mixed together. I have been thinking about removing all the emissions crap from engine. from what I understand I need to plug the tappings on exhaust manifold with 1/4" brass plugs as well as some vacuum lines, and remove air pump. can I plug off the egr or do I go with a different intake manifold? is there anything I'm missing other than an ZZ4 crate engine and headers? :)

thanks again, Mike
 

Evolution1980

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I have been thinking about removing all the emissions crap from engine. from what I understand I need to plug the tappings on exhaust manifold with 1/4" brass plugs as well as some vacuum lines, and remove air pump. can I plug off the egr or do I go with a different intake manifold?
As long as you don't have any emissions checks/testing, you can get rid of all that stuff. Getting the existing fitting out of the OEM cast iron exhaust manifolds may be an issue, as they obviously get exceptionally hot and after 20+ years of heating/cooling cycles, they can seem like they're fused together.
But to answer your question, essentially "yes" you can just cap everything and I believe it should be fine. You can just cap the EGR port on your existing manifold. On the ZZ4, when I got mine, the intake manifold port was still there, but capped at the factory. Don't know if it's still there or not. Bill75 could likely tell you since he has a newer one.

Dumping all the emissions stuff, you should notice a nice bump in power on the butt-dyno. :) The biggest difference on the stock engine comes when you get better flowing headers and whatnot.
 

Vette79

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1979 L-48 Black Coupe
EVO's correct. You can just cap everything. Remember to make sure that the valve on the passenger exhaust right below the exhaust manifold is open. Not sure what the piece is called off hand. I installed headers and dual exhaust then removed the emissions. And if you want to completely remove the EGR you can go to Sumitt and purchase a EGR Block Off Plate. Don't forget to get a new gasket. I removed the EGR so I could remove the valve cover much easier. I did notice a bump in performance with the removal of the emissions.
 

Evolution1980

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The 'factory installed' caps...

958343573_1af9b46c9f_o.jpg
 

corvette66

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Mattawan MI
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1969 427
You can also cut off the skinny metal tubes that are hanging off the exhaust manifolds. Then pull the plugs out of the manifolds with a socket, take them down to ACE HARDWARE and buy some solid brass plugs to fill the holes. Not only does it clean up the look, but makes it much easier to remove valve covers etc.
 
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'67 Marina Blue Convertible
95% of the performance reduction related to the emission system is due to the carburetor calibration, base ignition timing, and the centrifugal advance curve in the distributor, not the A.I.R. pump (the pump only consumes about 1/8th hp). Removing the A.I.R. pump and plumbing may be visually pleasing, but it won't gain you any performance - the REAL gains are to be had in carb and distributor tuning.

By the way, if you remove the A.I.R. system, save it in a box - good used complete systems for restorations go these days for $500-$1,000.

:beer
 

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