EGR: To block or not to block? That is the question.

[satchmo]

1978 Westy. EGR valve/filter required to pass smog in CA, but functional replacement EGR valves are hard to come by if this one fails.

So the question is, should I remove/save the EGR stuff and block the port on the plenum and the exhaust? I can always put it back when smog time rolls around.

For those that have removed the EGR, what changes, if any, did you make to your fuel mixture (AFM adjustments) to keep the CHT under control?

Thanks, Tim

[hiwaycallin]

Tim, if you decide to do it GS makes a nice block-off kit:
http://germansupply.com/home/customer/s ... ng=egr+kit

[SlowLane]

My van had no EGR for most of the 13 years I've owned it. I only installed an EGR system (and was fortunate enough to find an EGR filter) last summer when I brought it to California. I had great expectations of seeing lower head temperatures. But I didn't really.

I'd be hard-pressed to say that I see any significant difference at all in CHT or in how the van runs with or without the EGR functioning. Maybe if mine were a CA-spec model and running closer to lean I would see more of a difference. I don't know.

If the '78 uses a mechanical system like the Vanagon it would be a simple matter to temporarily disengage the control rod from the valve and run with basically no EGR, just to see how it goes. If you have a CHT gauge then you'll quickly arrive at the truth of the matter for your bus.

[Amskeptic]

1978 Westy. EGR valve/filter required to pass smog in CA, but functional replacement EGR valves are hard to come by if this one fails.

So the question is, should I remove/save the EGR stuff and block the port on the plenum and the exhaust? I can always put it back when smog time rolls around.

For those that have removed the EGR, what changes, if any, did you make to your fuel mixture (AFM adjustments) to keep the CHT under control?

Thanks, Tim

It is a simple mechanically operated pintle valve. Clean it and use it. MidAmerica had a filter for $79.00 last time I looked. I will be doing an egr vs head temp test on the BobD on July 9th if Vdubtech has sent me a filter.
Colin

[satchmo]

1978 Westy. EGR valve/filter required to pass smog in CA, but functional replacement EGR valves are hard to come by if this one fails.

So the question is, should I remove/save the EGR stuff and block the port on the plenum and the exhaust? I can always put it back when smog time rolls around.

For those that have removed the EGR, what changes, if any, did you make to your fuel mixture (AFM adjustments) to keep the CHT under control?

Thanks, Tim

It is a simple mechanically operated pintle valve. Clean it and use it. MidAmerica had a filter for $79.00 last time I looked. I will be doing an egr vs head temp test on the BobD on July 9th if Vdubtech has sent me a filter.
Colin

Yes and no. There is a little rubber gasket/collar inside the valve that prevents exhaust gas from escaping while the valve is closed while at the same time allowing the shaft to move in and out. That rubber collar is subject to high heat and cracks, and really isn't repairable. The EGR filter also seems to rust from the inside out quite easily. Those two concerns, along with the fact that the gaskets for the EGR are NLA, make me want to save the EGR components for when they are most needed; like at smog inspection time. It the EGR is really useful for engine health, I will keep it there full time (no matter how difficult it makes for access to the valve cover on the left).

Tim

[RSorak 71Westy]

Its not there for engine health I guarantee that ! It's strictly a device to reduce oxides of nitrogen which only form at high combustion temps.

[Amskeptic]

1978 Westy. EGR valve/filter required to pass smog in CA, but functional replacement EGR valves are hard to come by if this one fails.

So the question is, should I remove/save the EGR stuff and block the port on the plenum and the exhaust? I can always put it back when smog time rolls around.

For those that have removed the EGR, what changes, if any, did you make to your fuel mixture (AFM adjustments) to keep the CHT under control?

Thanks, Tim

It is a simple mechanically operated pintle valve. Clean it and use it. MidAmerica had a filter for $79.00 last time I looked. I will be doing an egr vs head temp test on the BobD on July 9th if Vdubtech has sent me a filter.
Colin

Yes and no. There is a little rubber gasket/collar inside the valve that prevents exhaust gas from escaping while the valve is closed while at the same time allowing the shaft to move in and out. That rubber collar is subject to high heat and cracks, and really isn't repairable. The EGR filter also seems to rust from the inside out quite easily. Those two concerns, along with the fact that the gaskets for the EGR are NLA, make me want to save the EGR components for when they are most needed; like at smog inspection time. It the EGR is really useful for engine health, I will keep it there full time (no matter how difficult it makes for access to the valve cover on the left).

Tim

Let me be more specific, now that I am not hurrying off to an appointment.
"Clean it and use it" - meaning whatever state your current egr valve is in, you don't have to be concerned about its functionality on smog day. They cannot do the stall test with the link hooked up. Only the vacuum controlled valves allow a functionality test. If there is leakage past the shaft that has sooted up the outside of the valve where the lever is, carb cleaner will spiff it up.

There is no adjustment to be made for CHT control, because the EGR does not make the engine run hotter or leaner, and the lack of an egr does not make the engine run cooler or richer. It only knocks the top off the combustion temps at partial throttle where we don't worry so much about CHTs anyway.

The BobD had a nice new egr filter as of 2008 that cracked at a weld for no good reason. It is still there, repaired with ultra-orange rtv. The gaskets for the EGR are tough little buggers. If you do not lose them, there are reuseable almost indefinitely.
Colin

[Amskeptic]

Twelve years later (!) and the BobD's EGR is still motoring along. I wish I could offer a coherent argument as to the effects of EGR on fuel economy and CHTs, but this year's 1,000 mile test has only shown me that it has very little effect on anything but a slight driveability issue. Stay tuned. I will make a final report in 2036 /s.

[satchmo]

So the jury’s still out. I await your 2036 report.

[Amskeptic]

Well, here it is, 2036. I am 77 years old now, thanks to Best Mind Dear Leader Donald Trump III.

EGR does not have a material effect on CHT readings at full throttle, may offer a punky 3-5* reduction at moderate throttle, increases CHTs modestly at low throttle/idle, I believe by virtue of the fact that exhaust gas is hot and being pumped into the intake air.

Fuel economy was not affected by EGR.

A caveat to all of this, is that I do not know if the rubber seal survived this last go-around intact. It could cause an unexpected leaning of the mixture at partial throttle where we don't care. Once the pintle is closed, it is irrelevant. Will check.
Colin