Guide to how our engines work
 

Admission of ignorance :

I have owned a '79 911SC since '86, yet apart from changing the oil and checking the coolant (yes, j/k), I know very little about maintaining these engines. More so, I know zilch about how they work.

Is there a publication which goes into detail for dummies like me? kind of of like the leg bone's connected to the knee bone, the knee bone's connected to the thigh bone ...

I have a Bentley, but it seems more geared toward repairing rather than explaining.

Any suggestions?

This forum is a great place to start and to ask how to questions

They make a model that you can build, it's made of clear plastic and shows all the parts moving, Look it up on here there is a tread about it, very cool

Introduction to K-Jetronic or CIS.......
 

The first thing you need to know how your engine works is to learn these common acronyms, and how they work and where they are located in the engine. Search for acronyms in this forum and other related terms to help you started. For example:

Fuel pressures (system, control, residual, etc.)
Air box
intake runners
Air box
WUR
FD
AAR
TTS
TV
CSV
AFM
FV
FF
FA
FP
Fuel line
Fuel injector
Return line
Etc.

It would take some time and practice learn and identify these important parts for your induction system. And for the engine, there as many more components to know. Where do you want to start?

Tony

Suck
Squeeze
Bang
Blow

That’s the essence of it

I read Wayne's engine rebuild book cover to cover at least twice before I even had the idea I'd rebuild one. Then when I went to rebuild it, I felt like Neo uploading Jiu Jitsu. I was ready to go and had a pretty solid "book learning" understanding of what does what. I don't know if there's a basic engine explanation out there for 911's, although Wayne's 101 book does give a decent overview of the rebuild process.

My earliest exposure to a chain driven overhead cam engine was Honda motorcycles.
Nearly identical architecture - as said - ohc, rocker arms on shafts, elephant foot adjustors, separate heads, slide-on cylinders and 2 piece crankcase with studs for the top end.
My suggestion is to find a blown up twin or 4 cylinder (air cooled) Honda engine and take it apart.

Short of that, maybe a local shop will give you a tour through a 911 engine while it's apart. Offer to bring donuts and sweep the floor. They're pretty simple in theory, but definitely quirky when compared to traditional water-cooled power plants. Some of the control systems are odd too, until you get used to the principles behind the design. CIS comes to mind...

Hi here is some basic info regarding oil travel..;-)

Ivan

http://img.pccreation.net/photos/20171204213239382.JPG

and here is one more

https://i.pinimg.com/originals/80/aa...77cabfb96e.gif

similar in concept to this subie engine

<iframe width="560" height="315" src="https://www.youtube.com/embed/y5oRsvRH_Ig" frameborder="0" allowfullscreen></iframe>

i thought he was asking about Porsche 911 engines;-)? not ruabus types...

ivan

LIRS6,

I think you are saying you don't know squat. Full stop.

Buy Charles Probst's book on Bosch continuous injection systems.

You have K-Jetronic without Lambda.

Spend several hours with this book and buy pressure gauges. Couple of wrenches too.

Thanks to all - and Bob, I appreciate the book suggestion .. I've thrown some issues q's out here on the forum before, and many kind souls - Tony for one, as he did again above - have responded, but often times in terms that are too technical for me to understand at this stage. E.g. right now, if I bought pressure gauges, I wouldn't know what to get, what to do with them, where they are useful ...

I'll ask for Probst's book for x-mas and start with that - my car is in hibernation already for the winter, so plenty of time to read Wayne's as well.

When I started looking for my Porsche earlier this year it had been a while since I had worked on a car in any serious way. So, I wanted to get up to speed. I found this website, which is not specific to Porsche but will also help with the basics of a combustion engine. And the wonder of internet software allows it to be animated, which really helps.

https://animagraffs.com/how-a-car-engine-works/

https://www.goodreads.com/book/show/203743.Bosch_Fuel_Injection_and_Engine_Management

Porsche had to deal with environmental sensitivities probably starting in the late 60's. CIS came along just short of 1974. CIS is the core of your engine not counting the crank, pistons and cams.

It morphed into a system that has band aids (in Bruce Anderson's words) to help it comply with advancing EPA type requirements.

Each part can be tested individually. Tony can help you with that. He is an engineer. I am a talker.

Just gain an overall appreciation. Then when Tony and others provides guidance you won't be a babe in the woods.

It's a interesting system.

All the best.

Getting to know your engine........
 

LIRS6,

Come and visit me this winter. I have two (2) SC engines one on the engine stand and one on the test stand for start up. I would be more than happy to spend time with you to show and explain how these engines work. And how to do CIS troubleshooting using conventional tools.

Do not be intimidated. There is really nothing difficult to understand how this engineering wonder works. The best way to really know and understand how this engine works is more hands on experience. Reading books and manuals are helpful but there is no substitute to actually tearing down the motor to pieces and assemble them back and run the motor. This experience alone is beyond description and very addictive.

PM me if you are interested. Warning: I don’t have a heated garage. So bring your heavy winter coat. Or let’s do it in the springtime. My ‘78SC and ‘89 cabriolet are back home too.

Tony

Probst's and Wayne's ordered.

Any suggestions for a gauge kit for CIS system? Other diagnostic tools? My wife needs x-mas gift ideas :)

Bosch K-Jetronic manual.......
 

LIRS6,

This is the Bosch K-Jetronic Manual I would strongly recommend to anyone wanting to know and learn CIS troubleshooting. And supplement this manual with other books is also very desirable.

http://forums.pelicanparts.com/uploa...1512431509.jpg

Tony

I think the answer depends on what you mean by "how it works".

One sense of the question is really "how does an engine make power?" That answer leads you down a path of understanding displacement, volumetric efficiency, cams, ignition timing, etc. A good read is Engine Management: Advanced Tuning by Greg Banish. It's really a book about EFI but the first half or so is an easy to read explanation of fundamental engine theory.

Another sense of the question is how the intake, ignition and fuel delivery works on various 911. To that end you have carbs, MFI, CIS, Motronic, etc. Each is a different system with their own nuances but all fundamentally are trying to accomplish the same thing.

To me, once you understand the theory it's easier to understand how the various different intake, fuel delivery & ignition systems work and their relative pros and cons.

I’m not sure why you’re focusing on the CIS unless it is clearly suspect. As for gauges, the Harbor Freight one’s are adequate for the occasional use. As for your broader question, what is your knowledge level of internal combustion engines in general? You need to know the basic principals first, then you can broaden that to the way Porsche does/did things.
Another free resource is the PET parts diagram that shows literally every part in your car. Armed with that and some basic knowledge you’ll have a good start on a thorough understanding.


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I keep asking for that model for Christmas! Still haven't gotten it. Just another lump of coal in my stocking.

What I want to see is version 2 of the model that replicates all the common oil leaks just in the spirit of real accuracy! I think it would be awesome if you could pour in a bottle of ink and have a little puddle under your assembled model. Then you could have your friends over for a spirited game of Guess the Oil Leaks.

Lower valve cover gaskets?

Rocker arms seals?

The classic Triangle of Death?

Or maybe they could put the little casting imperfection in the case by the engine oil cooler? It should come with a tiny bottle of JB Weld too!

It would be fun like the game Operation. Everybody gets connected to a 12V battery and if you guess the wrong oil leak source... ZZZZZZTTTTTTT!!!!!