Assuming that my fuel pressure is correct (no idea why you wouldnt), then can I adjust with the aforementioned gauge?

Not sure if there is a handheld O2 scanner on the market, but don't know? I have owned this meter called a gunson gastester. It worked great. It has a probe you stick in the tailpipe.
You calibrate it in the open out of the breeze, then up the pipe and it will give you AFR digital reading. They sold for @149$ but I see them for 199$ now.
You can use them on any engine, cycle etc.. Up stream of any cats. Wish I never sold it Sure there are some Youtubes showing it.

Gastester link

Innovate sells a clamp to mount the sensor on the tailpipe. So you need the clamp, the wideband kit. Clamp lists for 65$
clamp

That is what I am talking about! Thanks

You find it cheaper let me know I may buy another.

No need. Completely different from modern cars. I could be wrong but my mileage went from 10 mpg to 21 with correct fuel pressure.

What would you adjust? You have an idle screw, a sensor plate adjustment and the fuel pressure. Most guys try to adjust the sensor plate without checking the cold and warm fuel pressure. Bad idea.

I have a 3.0 system on a bastard 3.1 corvair engine. I "know" very little, exactly. I would like to be able to data track. I will check the fuel pressure, but A/F is still important and I may need to adjust the plate. I know the 914 needs the plate adjusted.

http://www.volvoclub.org.uk/tech/fuel_inje...elInjection.pdf

http://www.porsche928forums.com/download/m.../CISRebuild.pdf

http://forums.pelicanparts.com/porsche-911...p-got-pics.html

Totally old school. By the gauges. You will be surprised when you take your first reading.

That's the least of it's issues.....

Without proper fuel pressure any adjustment will only push the engine further out of whack. It doesn't matter what engine the CIS is on. You still need to start with fuel pressure. The fuel pressure acts on the sensor plate. Wrong pressure can't be compensated by messing with the senor plate and a tail pipe sniffer. I tried that and made it worse. The 911 system was designed to run on the same basic C.I. as your Vair engine and therefore needs to be tuned the same.

Mmmm, ya.

So, where do you recommend checking and adjusting fuel pressure? At the spring in the distributor?

There are several key "fuel pressures" in the CIS system. The delivery pressure (like you'd check on a 914) is the least of it. There is a "control pressure" and at least one other that you check. Those vary depending on load, O2 sensor feedback, warmup status, and so on. The system varies pressure in those circuits to deliver more fuel or less fuel.

Read up on CIS, it's a really weird hydraulic-based system. It's even a little weird when compared to screwy analog-electronic controlled systems like D-jet!!

--DD

I have read up on the CIS, and I have the basic so no 02 or lambda stuff. What I want to know is why I would go all over and check every pressure when all I did was put the system from one engine onto another. It is appearing like I will have to make several special fittings to check every fucking pressure. It ran, it just would not start warm sometimes (flooded), and is hard to cold start so the injector may be crap.

Nice links, Rick. Good refresher. I dont know if my AAR is working, my CSV is working, my WUR is working. I turned the key and drove it around lake Ontario....getting shitty mileage from the too tall gearing in the diff.

Set the pressure with the WUR. Add the special gauge set that is designed for this to your tool box if you want to add cool tools.

Seriously, I had the same issue. I never messed with the WUR or any of the settings. I bolted a complete 928 engine to my adaptor plate in my car. Never touched the WUR. My mileage at start up was 18. Shortly after I drove the car it started to drop. On one trip to the WCR I stopped at Carl's place in Vegas with John Peterson. We managed to stabilize the mileage at 10 mpg by messing with the sensor plate and a sniffer.

I tried all the hocus pocus with the 02 sniffer and the sensor plate tweek. I tried to pay shops to check things out. All they wanted to do was tweek the sensor plate. A couple old Volvo guys even told me they no longer had special tools. I located a gauge and a shop that knows the system. They refused to work on the engine but borrowed me the gauges. WHAM! fixed.

Get everything working and wired correctly. Adjust the WUR first, lean out the sensor plate after as you adjust the idle. You won't believe the difference.

This is funny. I didnt even know I had a problem and now I am on the way to, hopefully, fixing it. I figured; Bus = low mpg.

Any idea what the special tools are called? Pics? I will do some googling. I am typing between seeing patients so that is why I am not quick on the search function.

https://www.google.com/#q=cis%20fuel%20pres...ge&safe=off

Get the one that say's it's for K-Jet. Not all gauges are created equal.

Just ordered, thanks. Gonna be interesting.

Because the pressures are the control signals for the injection. So if the cam, compression, exhaust, intake flow, yadda yadda, are different on the second motor than the first, the signals will be wrong for the second motor. Kind of like when you take a VW 1600 MPS and bolt it up to your 2230cc hot-rod motor and it runs for crap--you have to adjust it. Or if you tear a set of Webers off an early 911S motor and put them on a 3.6--you have to re-jet, right?

--DD

Came home after working 12.5hr shift, put some work in on the bus and hope to have it running tomorrow so I dont have to ride to Scooters in the rain.

The plan last night was to sleep in the bus, in a parking lot....but it was supposed to be Scott Burnett's shop lot not Sheetz. I am fortunate to have been able to make it to Sheetz on what felt like 5 cylinders as I have food, bathroom, and internet. Waiting for my tow from Scotty to Scotty's. Time to source some cheap wheels while the bus is hard down. My 6hr trip was going to take 9 last night before the breakdown. I tried to go through the middle of WV, got lost, asked for directions, and came out about 80-100mi off target. No phone service for much of the drive, no directions on the phone. I ended up on 92 for most of the trip and popped out at 64......way away from where I intended. Ah well, adventures. Tonka is doing fine.

Doc,

See if the American Racing wheels & new tires fit your bus that I left at Scotty's...

Dave

Not sure I posted this link.

http://www.porsche928forums.com/download/m.../CISRebuild.pdf

Thanks! I got my K-jet tester. Now, I just have to wait for engine part and I can start tuning the beast.

Well, I am way overdue for an update.

The bus is down. On a trip to Scotty B's shop I lost some power and later found that I had snapped a rocker stud. I would guess that one of the circlips came off, the needle bearing let go, then the head cocked, then the stud broke.

I called the guy who makes and sells these. He lives in Canada during the summer and in AZ in the winter. He was surprised, very nice to deal with, and is sending out repair parts today. This is actually an easy fix and the failure mode protected the drive train Silver lining.

The carnage.

Well, I got home yesterday from being out of town. My new roller rocker arrived.....it was for the intake valve :facepalm: I called the guy, he apologized and will get me the exhaust one out in the next 32 hours.

Well, shit. I was all set to get the replacement rocker installed and get back on the road today. However, I decided to take a better look at the remaining rockers. Most of them look like they were about to have the same failure. WTF?

The bushing that the needle bearing is held into is coming out of many of them, the rockers are migrating to the side for reasons I do not know, and rubbing on the stud. This is obviously what happened to the one that failed.

So, I removed all of them and am not sure what the hell I am going to do. I need to call the guy that sells this kit and find out why most of them are not staying centered.

Weird. Did you leave it parked on a hill?

You have stubby fingers.

I am planing to switch back to the stock rockers. This is too much of a PITA.

Article in this months Hot Rod details a failure very similar to this. The geometry of the push rod/rocker arm is causing side loading, causing the wear and eventual snapping of the studs. It was blamed on the push rod guide plates being incorrect for the head, having the notch hogged out and inferior (read Chinese) manufactured studs. Don't know if this helps, but it might be good for a couple of clues.

Crap. This is lousy but you might have saved me from making the same purchase. Are these the ones from Corvair Specialties? If so, I wonder if the ones from Clark's would suffer the same problem.

-m.

The brains on the Corvair page feel that CorvairSpecialties parts are cheep Chinese crap. The guy copies designs and has them manufactured in China, with questionable quality - per their opinion.

The more expensive, quality, USA made parts have not seen failures like this.

Bozo - that is interesting. How bad would the geometry have to be off to cause this? I checked and unless my measurements were way off I would be surprised that this would occur. I honestly do not know, though.

Roller rockers are cool if you are looking to free up several HP or looking to increase the rev limit by reducing valvetrain weight (aluminum) but seems to me for your application the stamped steel OEM's will be more than fine.

I installed them to help with heat, as a precaution. Now that I have driven it, I dont feel I need them, either. I hope I still have the stock gear.....or I will be ordering it.

Hey did you ever finish reupholstering the seats in that zebra fun-fur yet?

I think once you finish that all these other problems will go away.

Double check your Geo just to be sure, but I agree that stock rockers are a smart idea here.

Zach

When did he buy a Geo ? Metro or Trakhur ? Or a metro-trakhur

How far would the geometry have to be off? I installed these with engine on stand and rotated and checked each rocker for contact and rang of motion. I did check the geometry and the rods were perfect as stock. This was surprising, but I bought the kit to check it and that is what I found.

I am going back to stock, it is just easier.

Well,

Again, not a rocket scientist, just one who has fixed their theoretical musings to make them work;-{

I have had to relearn what I knew previously about metallurgy, etc.

Nothing is wrong with Chinese methods, as long as you know that the aluminum they use differs greatly, and all depends on the mix/blend of aluminum oxide (more pure) as well as recycled content when they cast their Chinese boules or cast blanks.

It all looks high grade, only the metallurgist or end user at his wits end knows the truth.

So YES, they may be a perfect geometrical knockoff, and take anodizing perfectly.

Sadly, you get what you pay for or worse. If you take a brand new set of these rockers to a local CNC machinery, request them to make high-end aluminum blanks, maybe add pressed stainless or high grade bronze inserts, you will probably be extremely happy with the result.

And, it will bankrupt your hobby fund for 3 years going forward.

Hope that warms everyone's Xmas Spirits:-)

Dave

I'm not sure I follow you. Based on the type of failure there it doesn't seem to me that it would make a difference what the rockers are made of. It appears they drifted off to one side and started to grind themselves into the stand bolt. US or Chinese the drift would have been the same. Eventually even high end parts would have failed if they were running misaligned. The common failure of a low quality alloy rocker is breakage at the pivot shaft. I think you still have something running out of line.

these are cast aluminum parts?

If the roller assembly in the rocker is loose, or installed in the rocker at an incorrect geometry, or the stud hole is drilled off, it could cause wear.

Look at the picture Mike posted. The stud hole is either offset improperly, drilled at a wrong angle. or the circlips have failed allowing the roller to shift to one side in the rocker.

...

The 140 and 110 have slightly different geometry with respect to the angle that the valves sit in the heads. If you have the wrong rockers OR the manufacturer didn't know the difference, then that could explain why the rockers got side loaded.

Or Dr. ordered the wrong stuff.

No, the 110 and 140 use the same roller rockers. If my geometry was off, it was only by a fraction. I would check this, but I have decided to abandon the whole roller rocker thing. The gain just isnt there for me. As for why these all failed and the rocker was shifting on the roller cam, I do not know.

Hmmm, what tomeric said was not false, but what I found on certain sites was misleading. The one that I bought from had one option. American Pi has one options.....Clarks has 2, one for 140 and one for all others. Interesting.
http://www.corvair.com/user-cgi/catalog.cg...mp;page=OTTO-11

There's only a couple of degrees difference between the 140 and 110, but at 2000 rpm, the rocker is actuating 1000 times per minute. The rocker gets pulled off center and has nothing but time and cycles to get chipped away at.

The concept of roller rockers is precision and accuracy. That all goes out the window if the engineer who designed them lacks the precise details! The stamped steel rockers allow for lots of play. You're safer with them.