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mikedjames
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Joined: July 02, 2012
Posts: 2752
Location: Hamble, Hampshire, UK
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 Posted: Fri Nov 21, 2014 10:46 am Post subject: K- Jetronic .. am I mad ? |
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I have just got hold of a Beetle K-Jetronic FI modified and then used with a 1776 T1 engine
I can see why the got rid of it as they plumbed it with the overrun air valve open all the time . Muat have made idling an unpleasant experience.
Is it worth trying it on my bus ?
Or is it better to use the FI manifolds and throttle body with an EFI set up?. If so are there any electrically triggered injectors that fit the Beetle T1 manifolds ?
It looks like a 10mm bore for the injector with an O ring to seal it.
My budget is restricted by having to continually replace parts on my bus so the budget is hundreds not thousands of pounds or dollars..
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Ancient vehicles and vessels
1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.
1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy |
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raygreenwood
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Joined: November 24, 2008
Posts: 21532
Location: Oklahoma City
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| Posted: Fri Nov 21, 2014 11:45 am Post subject: |
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K-jet (CIS for the under educated)...is simply awesome, dead reliable injection if its complete.
It makes killer throttle response....if you tune it properly (not too rich or lean)...and the throttle response is better when properly tuned than virtually ANY injection out there because its 100% sequential by default.
It is injecting from the moment the intake valve opens to the millisecond it closes
You can use it with type 4 or type 1 style injection runners and TB. Look in the type 4um on the STF at some of Piledrivers posts about slaving CIS to either a type 3 or 914....most specifically about injector bungs.
Its not nearly as tunable of course as a modern aftermarket EFI...but its certainly far more tunable and robust than L-jet injection.
If you keep the rust and water out it will last nearly forever.
I like the later CIS with the frequency/idle valve with Lambda box using the 02 sensor....which you can rig to a knob for your own fuel pressure tuning.
It guarantees that if something fails in the metering system you can always limp home without ever burning up the engine from running too lean because limp home mode is 50/50 pulsewidth on the frequency valve.
May be more than you want to get into...but once you get around installation mechanics its a simple, reliable and effective system. Ray |
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Dale M.
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Joined: April 12, 2006
Posts: 20394
Location: Just a tiny bit west of Yosemite Valley
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| Posted: Fri Nov 21, 2014 1:28 pm Post subject: |
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Going with newest EFI box (Magesquirt) could give many options to improve on what VW intended originally...
Dale
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“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
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All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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Boolean
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Joined: January 19, 2012
Posts: 1712
Location: Stockholm
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| Posted: Fri Nov 21, 2014 1:45 pm Post subject: |
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K-Jetronic works very well, and actually has quite unlimited adjustment possibilities. Those include, but are not limited to grinding, turning, hammering and other hands on methods.
I just love it, but I think it is definitely inferior to modern electronic injection systems in most if not all ways. The worst being that the sensor plate limits air flow.
If someone wants to give it a shot for a performance engine though, I'll be happy to add whatever info I can about modifications.
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raygreenwood
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Joined: November 24, 2008
Posts: 21532
Location: Oklahoma City
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| Posted: Fri Nov 21, 2014 3:41 pm Post subject: |
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| Boolean wrote: |
K-Jetronic works very well, and actually has quite unlimited adjustment possibilities. Those include, but are not limited to grinding, turning, hammering and other hands on methods.
I just love it, but I think it is definitely inferior to modern electronic injection systems in most if not all ways. The worst being that the sensor plate limits air flow.
If someone wants to give it a shot for a performance engine though, I'll be happy to add whatever info I can about modifications. |
Its been run on a GREAT many performance engines and more than a few race engines already.
Also the airclow meter is not a flow impediment by any means. Most flow about 5x the TB they are attached to....and depending on wram up regulator and settings....pressure required to lift the plate are measured in grams force.
Its the same physics as vacuum diaphrgms and pressure regulators etc......if you want to get large movement with very low air pressure or vacuum volume....you increase the plate diameter the air or vacuum is acting upon.
This confuses people when they are doing operational testing of the plate a plunger with the engine off...wherin they lift the plate with a magnet against the counter balance of fuel pressure and are surprised that it feels stiff. Thats because you are liftkng all of it by a single point.
However when have the flow of X100 cfm drivving against the square inches area of the plate.....the impediment to airflow is virtually nil.
Its a very interesting system and runs great. However when setting one up from scratch it will be one of the greatest teaching tools for the findamentals of fuel injection airflow you have ever worked with.
Ray |
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Boolean
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Joined: January 19, 2012
Posts: 1712
Location: Stockholm
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| Posted: Sat Nov 22, 2014 2:24 am Post subject: |
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It' been used on thousands of race engines from the seventies on. It has also been abandoned because it is inferior to modern systems.
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mikedjames
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Joined: July 02, 2012
Posts: 2752
Location: Hamble, Hampshire, UK
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| Posted: Sat Nov 22, 2014 4:54 am Post subject: |
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Thanks everybody for the information, I think I will continue with it as an experimental project, cleaning and checking all the parts and abandoning when I find something too disastrous to fix.
The parts seem not to be too rusty, apart from surface corrosion on the pump, and the pressure reservoir downstream from the pump, as these are mounted on the starter motor and exposed to spray.
Other places look like it has suffered from some condensation in storage over the last year.
At the moment I am thinking of putting the airbox/injector control unit over to the right of the engine where the oil bath is , so I can keep on using a hot air feed if I think it needs it.
Fortunately I have already got a wideband sensor plumbed in for daily driving and tuning, its one of the reasons I am looking to improve things, as I can see how a carburettor never quite gets it right except on cruise on a flat road.
I will keep my progressive carb setup with oil bath intact in case of total failure - as far as I can see the only major permanent change is providing the fuel return on the tank.
In the end, I want to build an engine out of mostly new parts with full EFI and crank timed ignition, as I can tell my 1641 is getting a bit tired after 40000 miles of pushing a bus with enthusiasm.
_________________
Ancient vehicles and vessels
1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.
1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy |
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Boolean
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Joined: January 19, 2012
Posts: 1712
Location: Stockholm
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| Posted: Sat Nov 22, 2014 7:38 am Post subject: |
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Many common faults with the CIS components can be fixed with a little ingenuity.
The warmup regulator is the most common problem, but those are almost always fixable unless they are totally smashed up.
The showstopper would probably be rust in the metering cylinder/piston. Check if the piston moves with very little effort. It may be gummed stuck with dried gas, but that should loosen up with WD40 or similar.
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helowrench
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Joined: August 27, 2003
Posts: 567
Location: dallas texas
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| Posted: Sat Nov 22, 2014 9:35 am Post subject: |
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Berryman's b12 is the go to cleaner for CIS/kjet.
Diluted with gas for general running problems, or full strength for detailed cleaning of components.
The one biggest piece of advice I can give is upon beginning of any symptoms, change and inspect the old fuel filter for water contamination, or debris.
(it causes funky irrational running problems, and has caused a few people to junk whole cars)
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70 bug vert for wifey
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raygreenwood
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Joined: November 24, 2008
Posts: 21532
Location: Oklahoma City
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| Posted: Sat Nov 22, 2014 9:45 am Post subject: |
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| Boolean wrote: |
| It' been used on thousands of race engines from the seventies on. It has also been abandoned because it is inferior to modern systems. |
Oh absolutely.....but inferior is not the right word. When you got to CIS-e and variants...it actually had quite a bit of programming. It had no issues with meeting modern emmissions or upgrading HP and Tq with virtually any application.....but making it do that was very costly and complex and takes a lot of training to work on....and the system is very sensitive to damage from fuel issues and lack of owner attention.
Ray |
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raygreenwood
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Joined: November 24, 2008
Posts: 21532
Location: Oklahoma City
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| Posted: Sat Nov 22, 2014 9:57 am Post subject: |
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| helowrench wrote: |
Berryman's b12 is the go to cleaner for CIS/kjet.
Diluted with gas for general running problems, or full strength for detailed cleaning of components.
The one biggest piece of advice I can give is upon beginning of any symptoms, change and inspect the old fuel filter for water contamination, or debris.
(it causes funky irrational running problems, and has caused a few people to junk whole cars) |
To add to that.....if you are going to set this up properly....you will need some gauges and fittings.
The problem most mechanics who worked on this injection had.....especially those mehlchanics who may have a lot of experience.....but no actual factory maintenance training on CIS....is that when diagnosing the system they did not work in the right order and check the pressure and flow between the different check valved segments of the system.
Typically with age the outflow check valve of the pump gets leaky, the check valve in the segment for the fuel accumulator gets leaky..... (you will need the accumulator) and the pressre differential across the metering rod chamber suffers.
The way to work this is hook up the system....t in the gauge in each segment...and before replacing or adjusting anything.....check pressure and leakdown on each line segment.
in 90% of the time....this will tell you what parts attached to that segment are weak or bad.
Also...you MUST have a feeder pump for the fuel pump that goes with this system (typically the main pump is a Bosch 044). This is because unlike EFI the pressure head on top of the fuel pumps check valve with be between 72 and 120 psi depending on running state.
The 044 makes pressure no problem but without a feeder it cannot maintain volume across the check valve and it cavitates.
The very best text I have hands down for describing function, tuning and testing of CIS......are the three metal back factory manuals from Saab that came with my 900. If you need something let me know.
That is the right spirit....as an experiment it will be a lot of fun. Ray |
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helowrench
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Joined: August 27, 2003
Posts: 567
Location: dallas texas
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| Posted: Sat Nov 22, 2014 11:25 am Post subject: |
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I keep looking at the 76x90.5 going together very slowly, and the box-o-mexinjection stuff, and the dark side of k jet whispers to me.
If I knew it would fit completely in the engine bay of a bug, it would be a slam dunk.
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Current VWs:
70 bug vert for wifey
73Thing bucket o rust
73 914 1.7
12 Passat 2.5 Highway cruiser |
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ArnoudH
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Joined: December 30, 2008
Posts: 162
Location: The Lowlands
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| Posted: Sat Nov 22, 2014 2:05 pm Post subject: |
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In the 80's the late German tuner Willibald had a 75Hp 1600cc type1 K-jet engine in his lineup.This was with a Porsche-fan setup.
He also did Type4 engines(up to 2.4Ltr)with K-jetronik.
I have K-jet setup that does fit in a Bug's enginebay but requires the use of a 'Ramflow'-shroud.
Some pictures:
This is the system I have that uses the 'Ramflow'-shroud:
Regards,Arnoud |
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mondshine
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Joined: October 27, 2006
Posts: 2771
Location: The World's Motor Capital
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| Posted: Sat Nov 22, 2014 4:00 pm Post subject: |
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My '74 Thing has run on CIS Basic since before "the turn of the century".
It has been very reliable; I clean the injectors in an ultrasonic cleaner about every other year. That, plus occasional filter replacement is all the maintenance it requires.
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FreeBug
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Joined: March 12, 2012
Posts: 4278
Location: deepest, darkest Switzerland
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| Posted: Sat Nov 22, 2014 5:10 pm Post subject: |
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| The only problem I see is only if you are interested in really precise metering as a function of load. It should run just fine with some tinkering, but if you want really precise A/F ratios through the various loads and rpm, you need to fine tune by making different shaped cones for the metering plate,along with the playing with sprigs, lots of trial and error to get it "perfect". |
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mondshine
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Location: The World's Motor Capital
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| Posted: Sat Nov 22, 2014 5:49 pm Post subject: |
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The only advantage I see to my CIS Basic is simplicity; it requires no electronics to operate.
When I did this conversion, Megasquirt had not yet been invented, and I certainly prefer K-Jet to D-jet.
If I were to start this conversion from scratch today, since my engine is pretty close to stock displacement (74x88=1800cc), I would probably use all VW Mexico FI hardware, controlled by a Megasquirt brain. I believe it would meter fuel much more accurately than my CIS Basic, but my current setup has been so trouble free that I'll stick with it for the foreseeable future.
Good luck, Mondshine |
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helowrench
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Joined: August 27, 2003
Posts: 567
Location: dallas texas
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| Posted: Sat Nov 22, 2014 8:00 pm Post subject: |
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Actually the CIS KE with the computer does a really good job of setting the A/F ratio.
And there is a bit of discussion on STF about using MS to give total user control, and replace the VW computer.
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70 bug vert for wifey
73Thing bucket o rust
73 914 1.7
12 Passat 2.5 Highway cruiser |
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FreeBug
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Joined: March 12, 2012
Posts: 4278
Location: deepest, darkest Switzerland
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| Posted: Sun Nov 23, 2014 2:26 am Post subject: |
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I think K-Jet has some advantages over electronic in performance applications because of the quality/shape of the fuel spray as a result of the design and pressures of K-jet; it was only phased out because of fine-metering emissions issues.
They patched it with K-E-Jetronic, with the oxygen sensor, but eventually, they all moved on to L-Jet...
I have to say, the K-Jet setups do look great to me somehow, still very evocative of power, like a nice set of carbs.... L-Jet setups, in my eyes, have all the sex-appeal of the inside of a washing machine. Too many wires, the magic was gone... |
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helowrench
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Joined: August 27, 2003
Posts: 567
Location: dallas texas
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| Posted: Sun Nov 23, 2014 3:35 am Post subject: |
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The appeal to me, lies in the lack of electronics.
K Basic requires a pump to be powered. That's it.
KE can be run "lobotomized" with a timing circuit, and give you all the fine tuning you need via $5 of Radio Shack parts and a wideband for monitoring.
The drawback to KJet is at idle. they are inherently dirty at idle, which is an emissions test point.
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Current VWs:
70 bug vert for wifey
73Thing bucket o rust
73 914 1.7
12 Passat 2.5 Highway cruiser |
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raygreenwood
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Joined: November 24, 2008
Posts: 21532
Location: Oklahoma City
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| Posted: Sun Nov 23, 2014 7:54 am Post subject: |
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| FreeBug wrote: |
I think K-Jet has some advantages over electronic in performance applications because of the quality/shape of the fuel spray as a result of the design and pressures of K-jet; it was only phased out because of fine-metering emissions issues.
They patched it with K-E-Jetronic, with the oxygen sensor, but eventually, they all moved on to L-Jet...
I have to say, the K-Jet setups do look great to me somehow, still very evocative of power, like a nice set of carbs.... L-Jet setups, in my eyes, have all the sex-appeal of the inside of a washing machine. Too many wires, the magic was gone... |
X2 and well said. Ray |
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