Thread: blocking off egr

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Originally Posted by firebird77clone

Grandpa always said the PCV was the only decent thing the engineers ever did ( regarding emissions ) so don't disconnect the PCV. On the other hand, the EGR is shit. All it does is reduce performance ( yes, to reduce the carbon monoxide ) You don't even need to remove it. Just remove the vacuum line.

With all due respect to you and your grandfather, if I were building a max effort motor, it would not have EGR or PCV on it if I didn't have to pass any sort of emissions test in my area.

Woah woah woah. I have a pcv valve on the motor I built for my car and a breather on the other valve cover. Removing the PCV gives more horsepower? How come I was never told this?!

Quick: tell me what I need to make more horses. I have an edelbrock 600cfm with the pcv line running to it and the valve covers have the rubber grommets on the edelbrock valve covers. Would I have to plug the hole on the carburator as well? I don't want to have to get rid of my edelbrock valve covers unless I absolutely have to. I still have my old 283 '66 Valve covers that don't have holes punched in them from the factory.

But tell me. If I did remove the pcv.. would I get better or worse gas milage?

Installed the plate today and ended up with a rough idle. The plate is above the gasket and is sealed up good. Seems to be a rat-a-tat-tat at the plate.

Do I need to readjust the idle mixture? Up the idle RPM? Rough at 650 and smooths out at @800.

To correct myself in the initial post, I do have the PCV at the valve cover to the front of carb. I did'nt know that was an emissions piece.

14 degrees BTDC initial advance with timed vac.advance. The full time vac. and the rear vac. port of the carb are plugged off. Edelbrock 1406. Super unleaded 93.

Originally Posted by DennyW

There are different types. I didn't see where you mentioned on what motor this is, and what are you running for exhaust. Application is needed.

Here are the specs:

Engine Part Number: 12355345
Displacement: 350 Cubic Inches (5.7L)
Horsepower: 300 @ 5000 RPM
Torque: 369 Ft. Lbs. @ 3500 RPM
Maximum Recommended RPM: 5500 RPM
Compression Ratio: 9.1:1
Block: P/N 10105123 Cast Iron with straight four-bolt bearing caps, late model 1-piece rear main seal design.
Bore and Stroke: 4.00” x 3.48”
Crankshaft: P/N 14088527 Nodular cast iron, 1-piece rear main seal design.
Piston Material: P/N 12361371 Cast Aluminum
Connecting Rods: P/N 10108688, 1053 Forged Steel
Cylinder Heads: P/N 10159592 Bare Head, Cast Iron 64cc Chambers [Old P/N 12356026]
Valvetrain: Overhead Valve with Pushrod
Camshaft: Hydraulic Flat Tappet Design
Intake Valve Dia.: P/N 10093027 1.94”
Exhaust Valve Dia.: P/N 14088641 1.50”
Advertised Lift (Int/Ext): .435/460
Rocker Arm / Ratio: P/N 10089648 / 1.50 Ratio
Valve Lash: Zero
Engine Idle Speed: 650 RPM
Spark Plugs: R44TS
Spark Plug Gap: .035
Oil Pressure (Normal): 40 PSI @ 2000 RPM


GM aluminum 4bbl intake
Edelbrock 1406 (600CFM) electric choke
Headman swap/conversion headers
Flowmasters (40 series)
No cats.

THM 350.

Denny,
I used 1/8 plate steel and used the old housing. I dont know if the gaskets have the heat provisions. I do have a 1 inch spacer plate under the carb.

Originally Posted by DennyW

Ok. What I would do is try to reset my mixture and rpm's. Double check timing. If you have a vacuum gauge, that will really assist you in setting the mixtures on the carb. Keep total advance to 36-38 degrees.

ps: I would run the vacuum advance to full time vacuum. That will help all around on heat, and performance for what you have. Set base timing of course, with the vacuum line dis connected and pluged.

So, with the vac. gauge, adjust the mixtures until max vac.? I dont have anything other than the stock pointer on engine for timing. It goes to about 14 degrees. I usually run the highest timing just before detonation.

I have tried in the past to set timing with vac. gauge, but could not eliminate detonation at max vacuum.

Yep, I have had problems in the past with heat at idle. Had to get larger rad and more cfm fan. Maybe the full time advance will help that.
Thanks Denny

This is not a race vehicle by any means. Just trying to free up a little power, and clean up the engine bay. Pluged egr valves just aint pretty. I would like to keep the PCV to help keep the valve covers clean. I tried without once and just one trip down the road I was cleaning oil off the breathers and oil fill hole. Anyhow, Denny I got your point about setting idle mix with a gauge. The procedure is where I need help. Do I adjust the screws to achieve max vacuum? Do I check the vacuum at the manifold or the carb? Do this before or after setting the timing?

Techinspector,
I have no doubt in your experience and knowledge. Just a fun little s10 strickly for the street. Thanks for your suggestion.

o. kthx

Originally Posted by DennyW

Actually, the pcv valve functions the best on idle and part throttle. When you nail it for power, the pcv functions at such a decreased rate, it doesn't matter. I would keep the pcv simply because of the benefits of oil leaks.

Denny, with all due respect to you, when you're on the gas, off the gas, on the gas as in Gymkana, trials, road racing, etc, etc, everytime you're off the gas, you are sucking burned exhaust gases from the crankcase right into the intake manifold to dilute the fresh charge that comes available when you are on the gas again.

I repeat, for a max effort motor where it does not have to meet any emissions standards, I will vent the motor at the valve covers and run the hoses down to the back of the motor to atmosphere and run without EGR.