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VWLover77 Samba Member
Joined: June 20, 2003 Posts: 999 Location: North Canton, Ohio
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Posted: Sun Jan 16, 2022 1:03 pm Post subject: To EGR or not to EGR? Stock 2.0L Type IV |
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'78 Westy with stock Type IV 2.0L, hydraulic lifters, Hoffman Blueprint Special heads, L-Jet, Dakota Digital CHT gauge, Innovate Motorsports AFR gauge.
All cooling tin, flaps, and foam seal in place, with a working thermostat.
100% stock exhaust including cat.
Some may remember from previous posts that I struggled last summer and Fall trying to get 65mph head temperatures under 400 degrees on this freshly rebuilt engine (now with about 3K miles on it). Reduced distributor advance (now around 26 deg max mechanical advance) and richer mixture (around 13 at flat 65mph cruise and 11.8 at full throttle) have yielded little to no improvement.
The EGR system was completely missing from this Bus when I bought it - the EGR valve holes are all plugged at the plenum.
Would reinstalling an EGR system provide any potential benefit? _________________ Don
1978 Westy
1971 Super Beetle Convertible
"If more of us valued food and cheer and song above hoarded gold, it would be a merrier world." - J.R.R. Tolkien |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sun Jan 16, 2022 1:20 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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a little but good luck finding good parts. The mechanical EGR valves have been NLA for 30 years, and no one builds quality replacement parts other than the gaskets. Mine works and is like new, but I am in California where it is required on 1976 and later buses. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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timvw7476 Samba Member
Joined: June 03, 2013 Posts: 2206 Location: seattle
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Posted: Sun Jan 16, 2022 4:14 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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don't know if you're in an emissions exemption zone but the cat, or at least running with a test-pipe instead, would be the first thing to try as far as getting it to run cooler. |
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VWLover77 Samba Member
Joined: June 20, 2003 Posts: 999 Location: North Canton, Ohio
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Posted: Sun Jan 16, 2022 4:22 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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I tried the test pipe in place of the cat last summer - no difference. _________________ Don
1978 Westy
1971 Super Beetle Convertible
"If more of us valued food and cheer and song above hoarded gold, it would be a merrier world." - J.R.R. Tolkien |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sun Jan 16, 2022 5:54 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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Getting under 400 F on a 2L engine is pretty hard if that is the ultimate goal. Keeping it below 450 F is certainly doable. The spark plug senders are in the hottest part of the head, and the plug itself conducts heat. I don't use a sealing ring on the plug with the sender, and let the sender act as the sealing washer. Sealing washers are beveled and they oval out the sender, allowing a little combustion gas to leak out, raising the sender temp. I'd consider putting the timing back to about 28 - 29 BTDC. Your mixture range is fine. If you go leaner the temp will go up then about 16:1 it will start going back down but you will be pushing more heat into the exhaust ports because the burn will be slower than at 14.7. Around 17:1 the head temps will fall a lot because there is less gas to burn, but exhaust temps go up because the burn is so late more of it goes into the exhaust. I have EGR and my head temps are similar to yours. My bus passes smog cleanly. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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Alan Brase Samba Member
Joined: March 28, 2004 Posts: 4532 Location: Cedar Falls, Iowa
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Posted: Sun Jan 16, 2022 9:31 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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I've become convinced it may be a help. Just a pattern I've noticed since buying my first bus in 1982:
These USUALLY served the first owner pretty good, perhaps lastin 100-120k miles. The somebody takes it apart, does a nice rebuild, and then the thing has hot heads problems from then on. Terminal problems, often. And in nearly every case, the EGR was removed, because, well: smog stuff, who needs it!
I will soon be resurrecting my 1980 Vanagon, built June, 1979, 49 state.
By god, I'm gonna put the EGR back on. Just bought a new repop filter. Found a good original 4 into one exhaust pipe with EGR connections.
We'll see. _________________ Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Mon Jan 17, 2022 1:49 am Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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even the unmolested low mile 2L buses garage finds run those +400F temps. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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Balidas Samba Member
Joined: August 25, 2020 Posts: 29 Location: Ft Lauderdale
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Posted: Mon Jan 17, 2022 7:05 am Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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You could look into ceramic coating your exhaust system. That could help lowering radiant heat and affecting your temperatures. |
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metahacker Samba Member
Joined: May 26, 2010 Posts: 692 Location: san.diego
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Posted: Mon Jan 17, 2022 10:06 am Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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11.8 - 13.0 is ideal
if you are running E10 your Lambda 1.0 is 14.13 AFR
so 11.8 is your ideal AFR
for light throttle as lean as 13.0 is ok
alternatively, tuning for 16-17 yes you can lower engine temps quite a bit (as SGKent said), but it's very difficult to set this tune up on Jetronic (and really should be done with a 123 distributor, since you will need lots of vacuum advance to make it work). in my experience i needed the EGR to "help" me get 17:1 cruise. the results were interesting (the engine definitely ran very very cool). but if i was shy on ignition advance for high vacuum, it would stutter. other than that, it was pretty awesome. although, it seemed a bit challenging to tune it perfectly and not compromise on idle quality with an automatic.
generally speaking, IMO, the EGR is not going to help you, it's just bad news IMO...except for lowering NOx. yes, in theory it could make it 'cooler' by dynamically reducing displacement..... but in practice i don't believe that has been observed for normal driving operation.
are you concerned about your highway temperatures?
you may benefit from an external oil cooler.....one that is ducted for high pressure cooling highway speed, not a stupid one with an electric fan (you already have one with a mechanical fan on your engine now). e.g. the opposite of what 99% of people are running for their external oil coolers
high rpm will give you high oil temp (although high rpm also means high fan speed, which is good), and highway cruising is sustained high rpm... it is also sustained high pressure air under your car, waiting to be directed through your oil cooler...... i run an oil cooler as described (sealed/ducted to force air in from the air stream underneath) and i like what it does for my bus under these conditions... and i do sustained 70-85 for hours and hours... the oil cooler may help a little bit...but ultimately, once your AFR and timing are correct, the CHT is mostly a product of your engine configuration (e.g. compression cam etc), and fan speed aka gearing vs the load of pushing a bus the engine is too weak for.
also you might think im a loon for saying this, but putting MMO in your gas every fill up can lower CHT. i know someone who rents a fleet of buses and tested this using the current production MMO "automatic oiler" for the intake system...and according to him his A/B testing demonstrated that it was saving engines in his rental buses .... since you are in testing/data collection mode, would be curious to hear your results if you try it either way, i've put 4oz in with every full tank...and daily drive flat-out |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Mon Jan 17, 2022 12:23 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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the other alternative that I did not mention because the bus engine is already built is to have the inside of the heads, and the piston tops ceramic coated with a special ceramic that slows heat transfer. It improves engine efficiency and is the only thing I know that truly lowers head temps. It will also lower oil temps and allow a thinner oil to be used in hot weather. Len Hoffman does this type work on AMC heads. He will not work on used German VW bus heads.
example from air cooled technology
_________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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VWLover77 Samba Member
Joined: June 20, 2003 Posts: 999 Location: North Canton, Ohio
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Posted: Wed Jan 19, 2022 1:17 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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SGKent wrote: |
Len Hoffman does this type work on AMC heads. |
Yes, Len offered this when I ordered the heads from him. I was at the end of my budget rope, so I passed. Hindsight is 20/20 they say!
I now have what I hope is a good EGR valve from Ken at BusCo. The connecting pipe from valve to filter is on the way from Ken. Now I just have to bite the bullet and order the EGR filter.
_________________ Don
1978 Westy
1971 Super Beetle Convertible
"If more of us valued food and cheer and song above hoarded gold, it would be a merrier world." - J.R.R. Tolkien |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Wed Jan 19, 2022 1:53 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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it cannot leak in either position, open or close. It will bypass inbetween. The diaphragm cannot leak.
closed at idle - cannot leak
closed at WOT - cannot leak
works between the two
Diaphragm cannot leak _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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Amskeptic Samba Member
Joined: October 18, 2002 Posts: 8568 Location: All Across The Country
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Posted: Wed Jan 19, 2022 4:13 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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VWLover77 wrote: |
Yes, Len offered this when I ordered the heads from him.
I was at the end of my budget rope, so I passed.
Hindsight is 20/20 they say!
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Hello Restless VWLover,
I have experience with the coated heads and without the coated heads on two almost identical 2.0 engines, Kit's '76 Westy (not-coated) and my '77 Westy (coated), both now with 30,000 and 47,000 miles, respectively. I see no real world difference between the two. I assume that they both have a nice layer of carbon all over the combustion chamber and piston head surfaces by now.
The value of coating is very specific to slightly increased efficiency due to *higher peak combustion temperature* > more expansion pressure against the piston, which racers like when they wringing everything they can out of combustion.
Read up on your favorite Chevy Mopar Ford performance forums about the downsides to coating. There are downsides, and you need to think about your bus on the highway vs a drag strip or a closed race course.
I also have experience with EGR and without EGR on two almost identical factory build engines, '77 NaranjaWesty and the '78 BobD. The difference between the two is almost negligible, and my test of the BobD with the actuator link on vs off, showed only a slight cooling effect at moderate throttle, and a little loss of responsiveness.
EGR is a solution to reduce peak combustion temperatures at mild-to-moderate throttle when the AFM may dial back lean, but at full throttle, you have no EGR.
WHEN are you getting your highest CHT readings, i.e. what accelerator position, what speed, what ambient?
Colin _________________ www.itinerant-air-cooled.com |
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VWLover77 Samba Member
Joined: June 20, 2003 Posts: 999 Location: North Canton, Ohio
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Posted: Wed Jan 19, 2022 5:00 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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Amskeptic wrote: |
Restless VWLover
WHEN are you getting your highest CHT readings, i.e. what accelerator position, what speed, what ambient? |
VWs grounded due to a foot of snow and the roads an absolute mess of salty slush and water. Restless indeed!
The highest CHT readings are of course at full throttle while climbing a grade and trying to maintain no more than 65mph, with summer ambient temps.
But even a medium throttle 65mph run on flat ground on a 50 degree day results in head temps in the 390-405 degree range, as I recall.
I know the EGR is shut off at full throttle, but I was hoping it might improve the temps at level cruise and provide a little "headroom" for the grades. _________________ Don
1978 Westy
1971 Super Beetle Convertible
"If more of us valued food and cheer and song above hoarded gold, it would be a merrier world." - J.R.R. Tolkien |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Wed Jan 19, 2022 6:07 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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Don it does a little. Part of what it does is lower the risk of detonation.
Think of fuel molecules like a little packet of energy, like a small balloon full of fuel waiting to burn as they sit there surrounded by the oxygen. When the spark occurs it lights off those near the spark. As they burn they set the fuel next to them on fire, which sets the next on fire etc.. As that happens the pressure in the cylinder goes up. If it goes up too high it is like a diesel, those fuel packets ignite simply from the heat and compression, so all the remaining fuel packets go off at the same time creating an explosion. This is bad for the engine and is like a hammer hitting it when it happens over and over. When the mixture is richer there are many more fuel packets than air, so they absorb some of the energy before they can burn, they have to wait for an oxygen molecule to snuggle up to them. One way of lowering that risk of explosion is to lower the compression in the engine. That puts the molecules farther apart, and lowers internal temperatures. But it also lowers efficiency and power, that is another lesson. What the EGR does is allow inert oxygenless gas to be sent into the mixture, thus keeping the compression up for efficiency and power, but keeping those fuel packets farther from an oxygen molecule. This is like lowering the compression so the temperature is lowered - but it really isn't. At idle those inert gases would make it hard for the engine to idle. And at full throttle you need all the power. So, it only operates at part throttle, which will help keep your engine a few degrees cooler but more importantly reduce the chance that the mixture will blow up all at once and detonate - being like a hammer on the inside of the engine.
To make it work, you will have to be sure that the carbon is cleaned out of the tube the EGR dumps into inside the plenum. It distributes the inert gases evenly into the cylinders. There is also a small hole in one of the gaskets, It is smaller on California buses with catalytic converters than Federal buses without cats.
Also - when you go down the highway, the bus is a load on the engine. Air, drag, weight etc., all combine to put a load on the bus. It takes X energy to move the bus. When you add the EGR you lose a little power so to maintain the same speed you are fractionally pushing the throttle more. You aren't burning more fuel, you are burning essentially the same as what you would have with out the EGR. That gives you the X energy to move the bus at the same speed. The heat output is the same because you are offering the engine more air and fuel to maintain the same speed. Since the FI monitors air and fuel, the efficiency remains about the same. The fuel molecules are now partially surrounded by inert gas so they burn slower, again lowering temperature for each molecule but there are more of them. That lowers NOX and helps prevent detonation. Think of it like hiring 15 weak people to do the job a crew of 10 strong people used to do. If you pay each person less your payroll can be the same, and the 15 can get the same work done as the strong crew, but each person now is doing less work. Each person is putting out less energy but the overall amount of energy being used is the same. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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Clatter Samba Member
Joined: September 24, 2003 Posts: 7549 Location: Santa Cruz
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Posted: Thu Jan 20, 2022 9:09 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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FWIW the ‘75-‘79 exhaust with the short f-pipes isn’t known to be efficient at moving the hot exhaust out of the motor.
A set of ‘72-‘74 heater boxes and a T-bird would likely make it run cooler.
After that, a cam with more duration, especially on the exhaust side, would help.
Supposedly VW was making these motors run hotter on purpose for emissions reasons at the time.. _________________ Bus Motor Build
What’s That Noise?!? |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Thu Jan 20, 2022 10:32 pm Post subject: Re: To EGR or not to EGR? Stock 2.0L Type IV |
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Clatter wrote: |
FWIW the ‘75-‘79 exhaust with the short f-pipes isn’t known to be efficient at moving the hot exhaust out of the motor.
A set of ‘72-‘74 heater boxes and a T-bird would likely make it run cooler.
After that, a cam with more duration, especially on the exhaust side, would help.
Supposedly VW was making these motors run hotter on purpose for emissions reasons at the time.. |
I can believe that. They gave an interview about 1978 to one of the car magazines that they were discontinuing the air cooled motors in the USA within 3 or 4 years because the only way to pass smog was to make the engines run in a temperature range they felt was destructive to air cooled engines. 1979 with the O2 sensors got so hot the had to redesign the exhausts again. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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