Removing the EGR

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Nov 6, 2003 | 11:35 AM

JoeBlow

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From: Bayonne NJ

Removing the EGR

I posted this in the carb forum, but it doesn't appear that that forum gets alot of traffic so I'll try it here.
I have a 79 F100 302/2v carb. I have completely removed the thermactor system and now i want to remove or disable the EGR. is this possible? what would it hurt if i removed the plate under the carb and put a spacer in there?

Thanks

Nov 6, 2003 | 12:51 PM

1979f100

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Upon my rebuild of my 79 f100 302 I just yanked off the cast iron 2 bbl boat anchor and installed an edelbrock 289 performer 4 bbl intake pn 2121 with a 500 cfm 4 bbl edelbrock pn 1403. runs well and aparently you dont care about emissions so this should work well. hope this helps, 1979f100

Nov 6, 2003 | 01:26 PM

JoeBlow

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From: Bayonne NJ

unfortunately i can't afford a new carb right now. I plan on making that swap in the future though.

How would I know if my EGR is bad or not working?

Nov 6, 2003 | 02:12 PM

1979f100

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apply vacuum to the little nipple on the egr diaphragm and closely look to see if the valve ( if off ) or shaft (if installed ) moves then release vacuum and it should move back. if its off you might want to spray a carb and choke cleaner on the valve to clean any carbon out. hope this helps

Nov 6, 2003 | 04:28 PM

pdqford

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From: Central NYS

Correct me if I'm wrong, but I believe the '79 302 used a back-pressure transducer type EGR valve and applying vacuum to the nipple won't open the EGR valve unless there is some back-pressure against the underside of the diaphram.

The back-pressure closes the bleed hole and then the vacuum can lift the diaphram and pintle. Once that happens the bleed hole is uncovered and the diaphram and pintal fall back down, covering the bleed hole and it keeps on a-cycling itself.

Adding dual exhaust and/or headers (i.e, reducing the back-pressure) will effect the EGR flow in this type of EGR system.

If you remove/disable the EGR valve you'll need to change the advance curve (by changing the spring pressure of the mechanical advance springs deep inside the distributor and tweeking the vacuum advance can) to keep the engine from pinging. (Engines with EGR were designed with more spark advance in the cruise mode - the only time that EGR is activated.)

Nov 7, 2003 | 02:54 AM

macguyver

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From: Minneapolis, MN

Check out this link Bubbaf250 just posted in the 351m/400 forum... correcting an over-lean fuel mixture
There's a good side bar about EGR.
Also, follow the links on the bottom of the page about setting the advance.
Good information.

Nov 7, 2003 | 11:11 AM

beartracks

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From: Albuquerque

Keep in mind if you remove the EGR you should remove the spacer plate as it has hot exhaust passages that can burn through over time and cause vacuum leaks you cannot find.