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Removal of the Smog Equipment

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[ QUOTE ]
Thanks Bret, I tried to email you but it was kicked back for some reason. I'm in RB. Thanks for the info - have gotten several things concerning the holes in the block - do you know if I have to have BSPP plugs - thats British Standard Pipe Parallel - or can I use the ones you suggested?

Lonnie - I don't think you'd have to have the smog equipment on unless they're going to do a visual inspection - but I have not had a visual done, I usually go to AAA to do my registration.

Drew

[/ QUOTE ]

Drew,

Sorry about the email being kicked back. I currently have the spam settings on High. I’ll email you using your email address in the BFC and put you in my address book.

Regarding the air rail plugs I don’t know for sure but I believe that any 7/16-20 will work. But I’d go with a fine thread rather than a course thread. Likewise I would use a set screw. Length ½ to ¾ will work fine and use some anti seize. If you ain’t sure take the air rail off and bring it with you to the store. Anyway I found a link that mentions the size required.
https://www.custompistols.com/cars/articles/18vbolt.htm

Also a former employer gave me a used company car back in the mid-90s. I took it to the DMV and all they looked at was the vin # number. No under the hood or safety inspection. I did have to have the car smog tested – but other than that the DMV doesn’t seem to do anything but confirm the vin.

/ubbthreads/images/graemlins/cheers.gif
Cheers!
 
Bret,

took most of the smog equipment off tonight - it runs much better - any thoughts on the vacumn advance distributor - when I capped it the engine would bog down pretty hard but when I reconnected it to the carb it does just fine - it's been awhile but it makes sense if the timing isn't being advanced that it will bog down (had a VW that did that) but I can't remember what I did to fix it. Any thoughts?

Drew
 
To be honest - I’ve never actually worked on a late model MGB with all the smog equipment pulled off. Maybe that’s the issue, but I’ve disconnected the smog pump many times as spelled out in the Bentley service manual and didn’t have any problems.

That said – I suspect you shouldn’t have any problems running a B with all the smog equipment removed, keeping the basic timing settings stock even with the emissions equipment removed. Oh sure you might need to do some minor adjustments to the idle & air fuel mixture. But the problem you describe makes me think you have other issues. Best bet in my view - is that your timing it off and/or you might have a leak in & around the carburetor and intake manifold.

I have for various reasons disconnected my vacuum advance before and it really didn’t make a difference with my 78B except in fourth gear when the stock vacuum switch kicks in to advance the distributor.

Perhaps someone who has removed their smog equipment in the BFC can better help you.

Good luck?
Bret

PS I sent you an email did you get it?
 
Bret,

sorry it's been a few days to reply - got busy - was going to attend the meeting but....Orange Bowl - wow did USC do a number on Ok! So when is the next meeting?

Drew
 
That's ok Drew,

The next meeting will be on the Tuesday the 1st of February. There are a few things going on this month but they are mostly administrative stuff dealing with the installation of our new officers and the like.

However dues are only $20 per/year among the things we offer are monthly tech sessions where members get together to do various projects like brakes & tune-ups etc.. I highly recommend that you try to make it to next months meeting

Also we do have our own private Yahoo group that keeps you up on the events and last minute things that might not have made it into the newsletter in time for publication. There are also periodic “junk yard reports” where members report on wreaking yard finds and items others might have for sale or trade.

As for SC whopping up on Okalahoma: I was pulling for the Trojans but my mom is a huge Sooner fan. So needless to say she ain’t talking to me right now. /ubbthreads/images/graemlins/wink.gif
 
I wrote something similar on another thread..Fellas don't remove your emission control systems. These engines were designed around the system.You will get less power (not more) your gas mileage will go south. And then you'll sit back and say "gee" I wonder what went wrong. I'm an old guy who has been working on cars for longer than you have been driving. And I've never seen any good come of disconnecting these controls. Keep them in good shape ie change hoses when they need it, Your engine will love you for it and so will the atmosphere..Trust me on this one LEAVE THE EMISSION CONTROLS WHERE THEY ARE..
 
First don’t take this personally as it is not my intention to start a fight or belittle you in any way. That said I am sorry but I disagree your assertion.

Anyway I find it hard to believe that my 78B engine would have “less power” if I removed the emissions equipment. Everything I’ve ever read or heard on the subject, tells a totally different story. Time & time again, that one of the first things to get rid of on late model MGBs (75 onward) is that stupid single ZS crab setup, with its woefully inadequate and overly restrictive intake/exhaust manifold. It is my view after dealing with CARB for several years now that the B’s engine wasn’t designed around the emission equipment, but rather the other way around and IMHO it seems like more of an after thought than any real engineering on the part of the manufacture.

Regardless while it is a moot point for most folks in the rest of the US – the “real” problem here in the Socialist Republic of Kalifornia is the loony far left militant tree hugging environmentalist movement. They don’t just want to make sure your old B meets emissions standards, in fact just the opposite – they want you to fail. These groups and the pandering legislative representatives are increasingly trying to introduce legislation that is intended to take vehicles such as ours “off of the road” by imposing harsher laws regarding emissions.
 
Gotta agree with Bret here. The B series engine has been around since long before emissions controls were ever dreamed up. In the later years, both HP and economy went down the toilet as one band-aid after another was tacked on as engineers were going through the learning process of trying to make a decades old design cope with modern regulations. Same thing was true of US cars during the early-mid 70s as well. By 1980 the EPA mileage rating of the MGB was something like 17 MPG! I get about 25 MPH in town with my desmogged, DCOE equipped '78....and with excellent driveability.

Sure, more recently introduced engines were designed from the beginning to produce low emissions as well as good fuel economy and power - and the results are impressive. They are made to closer tolerances, designed to run at higher temps, etc. The art of engine design has come a long way in the past 30 years....
 
It looks like I'm coming in on the end of this discussion, but over here on the opposite coast of the country, North Carolina to be more specific, we have a rule similar to the one mentioned in an earlier post.

Regardless of the smog test, part of the standard inspection is to confirm the presence of all original equipment emissions controls.

I read that you've already removed parts, so it's a moot point, but I would have suggested merely removing the belt from the pump and bypassing any other device without actually removing it.

That makes it less likely that you'll lose the parts (should you want to find them later) and much easier to reinstall if it becomes required.

While I have your attention and you're removing pieces, did you discover a reducer in the hose that connects the air pump to the manifold? Mine used to be at the outlet of the pump, but it pulled a disappearing act when I moved the pump from the parts car to the keeper.

Would like to have the dimensions if yours still exists.


Mike
 
Since I reside in Alabama (land of the free emissions) I know nothing about the nuances of Kalifornia. My MGB is completely purged from any emission devices and runs just great. For a daily driver I prefer it over my E type which is too valuable for parking lots. I have a theory that an engine devoid of emission control devices but in excellent tune/internal condition runs cleaner than an engine that is equipped with average to poor condition emission control devices. Bear in mind that the gammut of emission devices rely on manifold vacuum and older devices probably have some leakage and other malfunctions that degrade the quality of the emission clean up. I would be interested if before and after checks of emissions might shed some light on this theory. Since I have no access to a testing station in the great state of Alabama, would anyone be willing to verify or at least comment on the above. I realize that a voluntary visit to the smog check station is not what we MG drivers like to do on Saturdays.
 
I have to agree with donandmax; I don't see the point of removing 'smog' equipment.

The AIR pump (smog pump) takes no measurable power to drive. The injection of fresh air into the exhaust will help with exhaust gas velocity which could help scavenging (which helps power).

The PCV produced negative pressure in the crankcase which helps ring seal, which helps power. It also ventilate the crankcase, which keeps the oil cleaner. It also helps prevent oil leaks.

EGR is turned off when the throttle is opened, so it doesn't diminish full throttle power. It helps increase compression pressure at part throttle, which helps power at part throttle. It also helps with fuel economy. It also causes the engine to run cooler. And the distributor is recurved to compensate for the altered burn rate; if you remove the EGR, your part-throttle timing will be off.

The only 'smog' parts of the engine that I would suggest changing are the cam timing, and the combustion chamber arrangement.

But that's not so easy as removing random bit of engine.

Best regards,

Paul
 
[ QUOTE ]
I have to agree with donandmax; I don't see the point of removing 'smog' equipment.

<<SNIP>>

Best regards,

Paul

[/ QUOTE ]

Sorry Paul,

I have to disagree with your statments. But please remember I ain’t trying to pick a fight – only wishing to point out the simple facts.

While retaining the original emissions equipment might be the legal & right (or <font color="green"> "GREEN" </font> /ubbthreads/images/graemlins/rolleyes.gif if you will) thing to do, just about any book on the subject says that the 1800cc engine’s performance is indeed hampered by the introduction of the emissions equipment on N. American MGBs.

In Jonathan Edwards’ book titled “MGB and MGC” the differences are spelled out quite clearly.

Example:
1800cc Engine.
UK Peak HP = 95bhp @ 5400rpms.
UK Peak Torque = 110lb.ft @ 3000rpms.

N. American Peak HP = 65hp @ 4600rpms.
N. American Peak Torque = 92lb.ft @ 2500rpms.

FYI both the UK & N.A, engines had the same bore, stroke and compression ratio.

BTW if emissions equipment had the kind of positive affect on the performance you are sighting – why aren’t distributors selling emissions equipment as performance improvements to the owners of older B’s? /ubbthreads/images/graemlins/wink.gif

/ubbthreads/images/graemlins/cheers.gif
 
[ QUOTE ]

Example:
1800cc Engine.
UK Peak HP = 95bhp @ 5400rpms.
UK Peak Torque = 110lb.ft @ 3000rpms.

N. American Peak HP = 65hp @ 4600rpms.
N. American Peak Torque = 92lb.ft @ 2500rpms.

FYI both the UK & N.A, engines had the same bore, stroke and compression ratio.


[/ QUOTE ]
Hi Brett,
You missed a vital fact. Note that the "smog" engine has it's torque & horsepower peaks at considerably lower rpm. This is in large part due to the smog engine having a milder cam. Particularly, less intake duration. Just removing the external stuff won't help all that much without also replacing the cam.
D
 
[ QUOTE ]

Hi Brett,
You missed a vital fact. Note that the "smog" engine has it's torque & horsepower peaks at considerably lower rpm. This is in large part due to the smog engine having a milder cam. Particularly, less intake duration. Just removing the external stuff won't help all that much without also replacing the cam.
D

[/ QUOTE ]

Thanks Dave,

Great point, I knew that – but didn't think about adding that fact.

Point is if emissions equipment was a true "performance" enhancer as Paul suggested you'd think more folks with older (none-smog) vehicles would want to add those to their

While you are correct simply removing the emissions equipment “alone” from a North American vehicle wouldn’t see the output of the engines in the UK market. But it would certainly be an improvement.

Without even touching the engines innards (Cam & headwork). I would think that just replacing the restrictive single ZS carb setup (Manifold, Cat etc) and installing any number of carburetion setups (twin SUs or Weber) would see drastic improvements.

That’d be the way I’d go if I didn’t have to adhere to the strict emissions laws.

Cheers,
/ubbthreads/images/graemlins/cheers.gif
 
[ QUOTE ]

Without even touching the engines innards (Cam & headwork). I would think that just replacing the restrictive single ZS carb setup (Manifold, Cat etc) and installing any number of carburetion setups (twin SUs or Weber) would see drastic improvements.

[/ QUOTE ]
Brett,
I feel that Paul is largely correct. The ZS carb has about all of the flow capacity that the cam will let in. The smog engines, sad as they are, were designed as a system. You can't change just one or two parts on ANY engine & realize the full benefit. Cam, compression, carb, exhaust, ports, & valve size all need to be coordinated. Dozens of published dyno tests show that it doesn't all come together until all parts are working together.

Adding carbs or increasing carb size, without any other changes, especially with Webers, often gives the "illusion" of more power simply because there is more throttle area opened for the same amount of pedal movement. True that the engine may rev quicker under light load, but maximum power may be the same or less. Also true for increased exhaust flow. The extra noise may give the illusion of more power but actual maximum power may be the same or less. Cats are not particularly restrictive unless they are clogged.

The advantage of the SU type of carb is that it will not open any further than the engine can actually use, no matter how big it is, how many there are, or how far you push the pedal. /ubbthreads/images/graemlins/yesnod.gif
D
 
David,

Hmmm? /ubbthreads/images/graemlins/rolleyes.gif So if you I understand you correctly – you are telling me that if you take two identical engines (cam, valve train, compression ration etc) and allow one to simply breathe better by utilizing a less restrictive intake & exhaust setup – you are asserting that both engines will have the same HP & Torque output? /ubbthreads/images/graemlins/confused.gif

If that is what you are saying – then again that would go against everything I have ever read or heard. I mean after all what is an engine? It’s nothing more than an air pump. So the better it can breathe the more efficient it will become. Granted to gain the “full” effect of removing all of the emissions equipment, I would opt for a more aggressive camshaft to compliment any carburetion, intake & exhaust modifications I performed.

But while the gains might be small without any other internal or external changes discounting the basic settings (idle, timing, air/fuel mixture etc), I find it hard to believe that removing the emissions equipment (Cat & Smog Pump etc.) would actually “decrease” the performance of the 1800cc engine.

If that is your position then I guess we’re just going to have to agree to disagree on this one.

Cheers,
/ubbthreads/images/graemlins/cheers.gif
 
"Hmmm? So if you I understand you correctly – you are telling me that if you take two identical engines (cam, valve train, compression ration etc) and allow one to simply breathe better by utilizing a less restrictive intake & exhaust setup – you are asserting that both engines will have the same HP & Torque output?"
--------------
The modified engine may have more power. Port, valve size, & camshaft would still be restricting output. More free flowing carbs & exhaust won't do much if the other parts are restricting entry & exit.

Actually, there is a chance that an exhaust that is too free flowing will tend to decrease the amount of combustible mixture in the cylinder. The intake valve is opened before the exhaust valve closes. Some of the intake charge can be sucked out the exhaust during valve overlap. (over scavenging) This can be used to advantage on a race engine to help get the intake charge started flowing, but it only happens at high rpm. This is what the much touted "fith cycle" Iskenderian cam of long ago was refering to.

Carbs require a certain velocity to get the fuel "atomized". Liquid fuel just will not burn in the combustion chamber. The larger the carb for a given rpm, the lower the velocity & at low to mid rpm, there isn't enough velocity to make the carb do it's mixing job. A case in point. People sometimes put 40 or 45 MM Weber carbs on a small engine. In reality, they have to put small 30 to 34 MM venturi tubes in the carbs to get the intake mixture velocity back up to where the engine will run correctly at low to mid rpm. The big carbs may look impressive but when it's done, a 30 to 34 MM carb is in effect, what they have. Again, the beauty of the SU, it will not open its throat so far that mixture velocity drops, even if the carb IS too large. A 1.75" SU will only open about half way if it is put on an engine that can only utilize a 1.25" carb.
---------------
"If that is what you are saying – then again that would go against everything I have ever read or heard. I mean after all what is an engine? It’s nothing more than an air pump. So the better it can breathe the more efficient it will become. Granted to gain the “full” effect of removing all of the emissions equipment, I would opt for a more aggressive camshaft to compliment any carburetion, intake & exhaust modifications I performed."
--------------
The air pump can't pump any more air than the most restrictive part of the system will allow. Just like a series electrical circuit. A resistor in the middle reduces current flow in all parts.
--------------
"But while the gains might be small without any other internal or external changes discounting the basic settings (idle, timing, air/fuel mixture etc), I find it hard to believe that removing the emissions equipment (Cat & Smog Pump etc.) would actually “decrease” the performance of the 1800cc engine."
---------------
I guess I wasn't clear. Too large carbs or exhaust, by themselves, may reduce power. The smog air pump is likely neutral. The cat is likely neutral unless it plugged up. The best reason for removing the air pump & it's controls or the cat is if they are defective & they are definitely expensive to replace. Removing this stuff will save having to replace it & removal will un clutter the engine compartment. Just don't attribute much power gain to the removal.

It's a series circuit. The engine can flow no more fuel/air than it's most restrictive part allows.
D
 
David,

Lets take a breath, we’re just having a friendly conversation here.

Ok now, I like the your electrical circuit analogy. Let's look at this from that angle a little deeper.

Keeping it simple – if we have a series circuit with three resistors (R1, R2 & R3) arranged in series. All three resistors in the circuit equal 2 ohms each. That means that the total circuit resistance (Rt) would equal 6 ohms.

Example: R1 (2ohms) + R2 (2ohms) + R3 (2ohms) = Rt (6ohms).

Now let’s say for the sake of argument that the R1 represents the intake. R2 is the engine and R3 is our engines exhaust. Now if you decrease the resistance of R1 and R3 to say 1 ohm each and leave R2 alone at 2 ohms, then the total resistance (Rt) of your “series” circuit would be less. Equaling 4 ohms.

Now using Ohms law I = E/R, lets say that you put 10volts across the two different series circuits to see which one has the least amount of current.

Where E = volts, R = Resistance (in this case R total of the series circuit) and I is the current of the circuit represented in by amperage.
10/6 = 1.66 Amps
10/4 = 2.5 Amps

Less resistance represents more current or in the case of our little engine when you remove the added restrictions equals = more flow. In other words if it breaths better it seems logical that it would more efficient.

That aside, I understand that there are situations where too large of a carburetor won’t work with a milder cam profile. Likewise too large of an exhaust will affect backpressure and affect your torque & BHP ratings. But nobody mentioned anything about putting a 3 inch exhaust and a Holly 850 double pumper on our poor little engine in this case. Besides speaking as an engineer myself I find it hard to believe that the 1800 engine designers would have carried the design to the upper edge of the component tolerances envelope. Most engineers tend to pad their designs & component selection to stay safe.

Anyway all I am saying is that (IMHO) emissions equipment doesn’t do anything for performance. If it did – you wouldn’t see folks pulling it off the minute they think they can “legally” get away with discarding it. Rather if it was a way of improving the performance, you’d see exactly the opposite.

Dave, I don't want to argue with you about this but if you wish to continue this conversation & don't think we can do so without getting each other upset - let's take it off line.

Thanks,
Bret
 
[ QUOTE ]

Anyway all I am saying is that (IMHO) emissions equipment doesn’t do anything for performance. If it did – you wouldn’t see folks pulling it off the minute they think they can “legally” get away with discarding it. Rather if it was a way of improving the performance, you’d see exactly the opposite.
Thanks,
Bret

[/ QUOTE ]
Hi Bret,
I don't think that we are really that far apart. There ARE two different topics involved. That of removing emission controls & the other of changing carbs & exhaust.

No doubt that removing the "stuff" could produce some gain if corrections are made for all of the changes.

I do think that the example of doubling intake & exhaust flow (R1 & R3) is a bit optomistic. I'm certain that going back to the earlier cam along with header & good carbs would make a much larger improvement. There is really no way to increase HP on a normally aspirated engine except by increasing compression ratio, displacement, or rpm. You "need" the cam to accomplish the rpm.
Cheers,
D
 
Dave,

Yes, admittedly R1 & R3 where simply round numbers. But optimism had nothing to do with their selection. Rather those values where chosen to represent the subject at hand in a “simple” mathematical equation. It was merely meant as an aid to state my case.

Sticking with the electronic circuit analogy for our engine, a better example might look something like this:
R1 Intake = 10ohms.
R2 Engine internals (as sum of both series & parallel circuits /ubbthreads/images/graemlins/wink.gif) = 50ohms.
R3 Exhaust = 10ohms.

I personally feel that the emissions equipment having the added affect of say 5 ohms to the entire series circuit representing our little engine. While the numbers wouldn’t have that much of an affect it if it was removed it certainly wouldn’t decrease current flow.

But it appears where we have our major difference of opinion is concerning any gains to a stock engine. But if you look there are a lot of aftermarket goodies out there, that are focused on improving useable performance gains without playing around with the engines internals. While certainly some of these are mild gains in the overall picture – never the less they do exist.

Cheers,
Bret
 
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