Anyone have a picture of a smog pump installed on a 1.8? Options

[DaveB]

Need help again. I found out my car was originally from California. Any indication of smog equipment is gone. So how is the smog pump mounted to front of the engine? I've seen the parts and would like to see an engine with this installed.

Thanks,

DaveB

[Van B]

Is it a 75 model then?

[JeffBowlsby]

1.8s even for the CA-market never had air injection (smog pump)

https://bowlsby.net/914/Classic/Emissions.htm

[Steve]

Check out the originality forum.
http://www.914world.com/bbs2/index.php?sho...=smog&st=20
I think its a 2.0 though..

[Dave_Darling]

Yes, the pics in that thread are from a 2.0 liter.

@JeffBowlsby -- Your chart says "modified exhaust with thermal reactors", and the last part of that is not accurate. Perhaps "with provision for catalyst" would be a better way to phrase it?

--DD

[DaveB]

1.8s even for the CA-market never had air injection (smog pump)

https://bowlsby.net/914/Classic/Emissions.htm

That's what I needed to know. I checked the 1975 emissions control system maintenance book and I found it notes the air pump is 914 - 2.0.

Thanks

DaveB

[JeffBowlsby]

@Dave_Darling

Thanks Dave, great to hear from you, hope all is well.

My chart is based on some factory literature which organized it that way. The cat req. for 1975 1.8s is the last line of the chart.

PS, I may have misundertood your full comment. The factory called the heavy steel exhaust stubs (F-pipes) mounted to the heads on the 75-76 exhaust 'reactors' beacsue the heat they store helps burn off unburnt fuel as an emiision thing. Perhaps you wwere aware of that.

[Van B]

Geez this question brought out some serious expertise lol!

[DaveB]

I have a different question on the smog system. Why is the catalytic converter placed at the exhaust end between two mufflers? I am use to feeding the cats directly from the engine to get the necessary temperature for the reduction then heading into a resonator. I just don't understand why they didn't keep the earlier heat exchange design and feed into a cat then a resonator. Was it a space issue or is there a reason for this split muffler set-up?

DaveB

[wonkipop]

I have a different question on the smog system. Why is the catalytic converter placed at the exhaust end between two mufflers? I am use to feeding the cats directly from the engine to get the necessary temperature for the reduction then heading into a resonator. I just don't understand why they didn't keep the earlier heat exchange design and feed into a cat then a resonator. Was it a space issue or is there a reason for this split muffler set-up?

DaveB

space limitations? you really only have the space across the back behind the end of the gearbox and you don't want expense of two cats.

secondly i think it has to do with the mufflers on a 75 even though being separate still more or less imitating vw mufflers before cats.

in earlier mufflers even though the pipes come either end, usually one side has a feed pipe to a first chamber on either one end of the muffler or both feed to a central chamber and from there back into a chamber at one and and then through a pipe again through the central chamber to finally exit on the other side in the last chamber there. its a kind of side to side and back and forth labyrinth.

they just externalised that with the 75s into three components with the cat in the centre?

it fits nicely and cats run hot, was a position where it could be in airstream and radiat heat more harmlessly? it gets hot enough in the rear trunk with an ordinary muffler.

lastly - this is only a thought.
the originals were 2 way cats. they pulled the EGR off after the cat and from the final muffler. 2 way cats don't convert NOx. the NOx i guess got sent back through the engine and maybe that helped deal with it. someone with a bit more knowledge might know more. but they seemed to want to pull that EGR off the second muffler.

[wonkipop]

there was an intact cal 1.8 that sold through sotherby's a few years back.
you can see the EGR etc installed in the engine shots.

probably one of the few that survived.

https://rmsothebys.com/en/auctions/mo17/mon...e-914-18/430426

don't know how you would go trying to get all the bits, particularly the exhaust system.

the 75 49 state cars were a lot simpler.
basically ran the 74 cal 1.8 set up.

[wonkipop]

@DaveB

out of interest dave, is there still a painted stencil number on the engine tin of your car.
be on either the left hand side near where the blower fan hose goes down into the top of the engine tin or on the rhs opposite the battery.

if there is, what is the number. should be a 9 xomething something.

[914Mels]

Need help again. I found out my car was originally from California. Any indication of smog equipment is gone. So how is the smog pump mounted to front of the engine? I've seen the parts and would like to see an engine with this installed.

Thanks,

DaveB

Here are pictures from my old smog book that I used to certify cars back in the 70's. Cat "test pipes" were very popular and usually stayed on long after the "test" was done.

[wonkipop]

neat set of docs @914Mels


@DaveB

attached docs @JeffBowlsby pointed us 74-1.8 owners at last year when he alerted us there was a 49 states and a cal version of the 1.8 in 74, despite other accounts saying it was a 50 state engine.

bit more difference in 75. these docs outline it.



jeff has the whole document (75 training manual) on his website if you want to look it right through.

interesting idea putting the emissions equipment back on.

as far as i can tell the equipment on a 1.8 had no negative impact on horsepower.
the 1.8s suffered from reduced horsepower due to low compression for unleaded fuel, but the emissions equipment itself produced no losses. at least at that point in time.
the L jet electronic fuel injection helped these little motors cope.
possibly some impacts on driveability and throttle response.
and like all 1.8s 74 and 75 running hot at idle due to ignition retard from vac chamber on distributor to lower NOx (remembering the 2 way cat does nothing for NOx so they were doing it by running lean and retarded at idle/or cruise).


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it looks from the info that jeff had that it was only the 75 49 state 2.0 that had a smog pump.
and CAL 75 2.0 had EGR and CAT but no smog pump.



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thinking a bit more about your cat location question.
the 914 has a short exhaust system.
don't think the cat was bothered by trouble heating up or having a correctly hot exhaust system like conventional cars with much longer exhausts where it makes sense to get them up nearer to the engine.

[DaveB]

@wonkipop

I did find what looks like a stencil mark on the tin. Unfortunately is not legible. This is a snapshot of what I found:





The car is a '75. The engine is a 1.8 but built in late '73, so it's not original to this chassis. Getting the links and info from you and @914Mels helped. I want to understand how it should have been configured to find out what's been done to this car over the years. After I do that, I can figure out how I want to build the drivetrain.

Thanks,

DaveB

[Van B]

Looks like a 604 same as mine. Which is also why there is no indication of an EGR. That engine never came with any of those things.
What’s the engine stamp number?

[wonkipop]

@DaveB

thanks for the photo. appreciated.


link to a thread in the originality section of this website.

http://www.914world.com/bbs2/index.php?showtopic=357407

the discussion is 1.8s in 1974.
at the bottom of the first page is the hose diagram for the 75 1.8 cal spec.
that helps you.

if you read the thread as well you will get the basics of the 1.8s from 74 which helps you then with how it went in 75.

the truth is in some ways more has been forgotten about the 1.8s than any other variant of the cars. jeff bowlsby has prompted a few of us who own them to do some work to get a bit more forensic about them.

a few of us who own 74s got to the bottom of those in much finer detail last year.

i was thinking of putting out a call to 75 owners when i had a little spare time this year to do the same thing.

the simplest way to put it is they are all variations on a theme.

once you get the basics of the theme it gets a lot easier to see how each version worked. they all have a double vacuum distributor. but they do not necessarily make use of both functions of the distributor.

they all have a similar but slightly different variation on the throttle body.

does your car run an L jet system or has it been converted to carbs.

if its still got an L jet set up on it post up some photos of whats there.
distributor, throttle body and a general view or two of the top.
take some shots underneath of the heat exchangers.
we can tell you exactly what you have on your hands then.

the main things that differ from 74 to 75 will be the following.

the throttle body and how it is connected to other things.

the distributor and how its vacuum connections are made.

the decel valve.

whether its got an EGR or not.

the charcoal cannister, how it is connected up and mounting location.

the exhaust system.


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the way all of these cars worked in emissions terms, being early "smog" cars was by using retarded ignition and lean mixtures.
the retarded ignition and lean mixture cut down NOx emissions from the engines.
as a side effect though CO emissions increased.
when these cars finally got cats these early strategies got the last component that did the job. the increased CO was dealt with by the cat which converted the CO to CO2.
the cat also converted hydrocarbons that were unburnt to CO2 and H2O. the early cats did not react with NOx. NOx strategy was retarded timing settings.

there was no need to use a smog pump with the 1.8s. they ran clean enough to pass with the above strategies.

the 49 state EC-B of 74 ran clean at idle with retarded timing and lean mixture.
"clean" meaning it produced lower amounts of NOx. (main ingredient of smog).
it was clean sitting in an urban traffic jam.
it ran hotter at idle.

the cal state EC-A of 74 ran clean at idle and clean at cruise and part load.
(retarded timing and lean mixture in both those conditions).
ie it was "clean" sitting in a traffic jam or cruising on the freeway.
but it ran hotter in both those conditions.

the 49 state EC-a of 75 duplicated the 74 EC-A (cal). the set up was the same.
however it had an updated decel valve and it used the 75 exhaust system, heat exchangers and mufflers minus the cat and EGR.
the ECU and the AFM were also slightly updated and changed.

the cal EC-b of 75 had the full set up that all 50 states were intended to achieve in 76.
(the 1.8s never made it to 1976).
it ran "clean at idle via retarded timing like all the others.
it ran clean at cruise using the EGR. a lot cleaner than all the other versions.
the EGR may have marginally increased fuel economy and also may have allowed the engine to run slightly cooler at cruise. the EGR did not work at all time. it was activated by vacuum from the throttle body.

when you get your head fully around what they were doing with the throttle body it gets a lot easier to see how the various additional systems work.

most folks just tore this stuff as soon as it wore out.
the exhaust system was more expensive. so it got replaced with the 74 system as soon as the mufflers or the heat exchangers rusted out.
without the original exhaust system the EGR could not work so it would get torn off.

and if you want to put it back on you have to go find those items.
which will be rare and getting rarer. particularly the exhaust system.

setting up to 74 spec is easier to do. the parts are still relatively obtainable.

EDIT

i forgot to mention that 75 Cal 1.8 also ran a different distributor.
without speed limited rotor.
it had a fuel cut off switch (a kind of relay like component) positioned under the battery off the side of battery support where other EFI L jet relays were. this switch replaced the speed limited rotors on the distributor that was fitted to all other 1.8 variants.

i found out way too much late last year doing our "research".
still processing a lot of it. so apologies for info download.

there is more detail, but its best to just step your way into it and ask questions as you go. i don't know everything and i don't own a 75.

but guys on this website between them will have all the detail down to the nitty gritty.

[Dave_Darling]

The factory called the heavy steel exhaust stubs (F-pipes) mounted to the heads on the 75-76 exhaust 'reactors' beacsue the heat they store helps burn off unburnt fuel as an emiision thing. Perhaps you wwere aware of that.

I was not aware of that! I thought that thermal reactors were the extra complicated exhaust headers that came on the ~75-77 911s, and assumed that any on the 914 would have been similarly complicated!!

Thanks for the education, Jeff!

--DD

[wonkipop]

The factory called the heavy steel exhaust stubs (F-pipes) mounted to the heads on the 75-76 exhaust 'reactors' beacsue the heat they store helps burn off unburnt fuel as an emiision thing. Perhaps you wwere aware of that.

I was not aware of that! I thought that thermal reactors were the extra complicated exhaust headers that came on the ~75-77 911s, and assumed that any on the 914 would have been similarly complicated!!

Thanks for the education, Jeff!

--DD

jeff is right. those exhaust stubs were intended to better exploit the retarded timing that all 1.8s (74 and 75 all states) were set to at idle. they all did lower combustion temp - less NOx but the exhaust and to some extent head temps increased. late combustion.
the unburnt hydrocarbons were intended to burn in the first section of the exhaust.
those stub pipes assisted with that in 75. Van B helped me get my head around that.

pretty dumb primordial thermal reactors but "reactors" none the less.

[wonkipop]

@914Mels

those docs you posted are great.
test procedure for EGR makes it clear how it operates at higher revs off intake vacuum (pre throttle plate in throttle body) rather than idle manifold vacuum.

EGR line should be cool after EGR valve to intake boot at idle.
supposed to get warm when you hold it at 4200 rpm.

the EGR let them reconnect to that throttle body port upstream of throttle plate with the distributor vacuum advance port again just like the 49 state cars in 74.
meant you could regain the vacuum advance function of distributor for highway cruise and part throttle just like earlier VWs without causing increase in NOx emissions.
i believe the EGR by feeding in exhaust gases lowered combustion temps and that lowered NOx. you got a bit of benefit reburning some exhaust gas but i believe the main objective of feeding in that exhaust gas was to lower combustion temp slightly at cruise - just enough to get the NOx down.

it wasn't all bad that emissions gear by the time you got to the 75 cal car.
EFI helped compared to carb equiped domestic USA product.
main problem was it was expensive kit that raised the price of the manufacture.
but i don't think it really hindered performance too much.
the big hit on that front was lowered compression for unleaded fuel since the first unleaded fuel was much lower octane.

countries like australia and japan got lucky because we sat back a few years and let it get ironed out in the USA before we adopted the standards. by then all this stuff was well and truly resolved.