Rebuilding My 930
 

Well after 5 years of ownership and about 130,000 miles (70K of which are mine) I have recently dropped and broken down my 930 motor for a complete rebuild. I was hoping to put it off a bit longer but the starter ring gear lost a few teeth so the motor had to come out anyways. Its been needing a rering and reseal for a while.

Thanks to recent economic trends I will have to pull off my rebuild and mods on a tight budget. Fortunatley have access to a high end machince shop and porsche dealer service area due to my employment and engineering backgroud (BS in Aerospace Engineering, U of F, Class of 95) so I do not need to pay for anything but parts and dyno time.

Here is what I am planning on doing to extend my existing mods. I would appreciate any input people would like to give me on my project.

All the hardware looks beautiful except for a mild scratch in one cylinder. Everything mics to about 0.0005 of factory specs.

For this reason I am just going to rering the cylinders. I am seriously contemplating going with gapless rings.

Here is a list of most of the other stuff I have on my todo/toget list. (Updated 2/4/05)

ARP rod bolts and cylinder studs
All harware flycut and/or lapped and rods resized
New bearings and gaskets
New chains and tensioners
New valve guides and valve job
New performance cams, and rocker shaft seals
Slight compression bump
8:39 Ring & Pinion
Carrera Intake Manifold
Megasquirt II EFI
Distributorless Igntion
HKS EVC IV (Electronic Boost Controller)
Boring and Porting the Heads and Intake
Headers

My current spreadsheet for my project shows that the total cost for all this will about $8.5K.

I figure I have a few months before I will have all the time and money I need to pull this off. (As the thread shows I suffered from quite a bit of project creep from the 'while you are in there' phenomena)

I look forward to the wisdom this board is sure to bring me. (And it has brought me much since I started this thread)

Tony

http://www.tamparacing.com/photopost.../11516Pic4.jpg

Pics for your amusement . . .

Motor Drop
http://AnthonyRawson.com/Cars/930EngineRemoval/

http://AnthonyRawson.com/Cars/930Eng...rAndEngine.jpg

Some parts and pieces laying around . . .

http://AnthonyRawson.com/Cars/Engine...crossFloor.jpg

Sounds like your budget may need some revision? Do you have a copy of the Engine Rebuild book? Did you measure the ovality of the cylinders?

-Wayne

Yup, I measured the cylinders.

After 20 years of rebuilding automotive, motorcycle and aircraft engines I'm not sure if the ERB will reveal anything to me, but I have concidered getting it.

And while there might be something that I need to add to my list as time goes on, its pretty much on the mark.

For example, while you guys want $165 for cam chain tensioners, I can get them for $130 from porsche (love that employee discount).

Don't worry though, I have spent a lot of money with you guys over the years. I'm sure their might be something I get from you guys this time around. ;)

I don't know if I'm being overly anal but I always change the sprockets when I change the chain and I replace the keepers and retainers when I replace the valves.
-Chris

Re: Rebuilding My 930
 

This is the only thing on the list I wonder about. Why not ARP or raceware? I can't see building a turbo motor and not crossing the t's and dotting the i's.

Boattailing the cylinder case webs, eye-browing the cylinder bores, knife-edging the crank are nice horsepower additions(20HP is the talk). I was on a budget too(then again, aren't we all) and didin't go with the ARP head studs. Chose the 993 turbo studs. If they're good for 500+HP 993 turbo's, they're good enough for me. I hope your head job includes new springs, retainers and locks.
Are you going to retain the stock intercooler, exhaust? Highly recommend going to Kokeln IC, GHL exhaust system and upgrading to K27 turbo(7006). Remarkable differance in turbo response.

Actually I do not want to do any additional machining to the case than what is necessary to true up the appropriate surfaces and bores.

Supposedly windage losses only get really bad at very high RPMs (like 6K RPM and up) and my motor is going to be set up for between 3K RPM and 6,500 RPM.

High revs are some of the most stressful forces any motor has to deal with anyways and I want to keep those stresses minimised.

If by eyebrowing you mean notching the cylinders near the valves I don't really see how there is much obstruction in the stock valve geometry. Perhaps you could explain what could be done there.

I see you have already answered the question about why I am using the 993 studs. I trust the recently engineered solution from the air cooled experts at porsche more than I do a company that is mostly focussed on making studs for a lot of water cooled equipment. I do trust their rod assembly hardware though.

The fact that a set only costs $168 is also very nice too compared to the cost of the aftermarket head studs.

If they spec out OK I may reuse a few valvetrain components I am replacing the springs and the retainer clips.

I have remanufactured enough motors to know what is suitable for additional service and what is likely to not survive past the 2,000 hour mark.

As a result of the low budget I will be reusing all my old factory plumbing, with the exception of my K&N intake, K27 and a pass through muffler which have served me well for several years. I would love to upgrade the exhaust and intercooler, but my current mod list will bring me more performance than those will.

Between the piggy back fuel injection system I will use to push the power past the 350 HP CIS limit and some other 'optimizations' this is a project that will attempt to get at least 400 HP at the back wheels from nothing more than a warmed over CIS 930 with cams and an additional fuel injector.

Chains yes, sprokets no.

Chains will stretch and sprokets will wear, but the wear on a sproket running a minimally stretched chain is negligible.

A chain that has stretched too far can decimate a sprocket.

After years of working on motorcycles you learn a few tricks about inspecting chains and sprockets and get an eye for judging what is good and bad. Let me just say that I was amazed at the condition of the cam chains and sprockets in my motor.

As far as recycling valvetrain components go, retainers yes, keepers no.

Its like how when you rebuild a tranny you may change syncros, but if they are still in spec you don't change your gears.

I got that quote from an article in my local PCA mag

with CIS you can see some serious hp.. with the mods you listed you will probably see over 350hp easily

Try SC sport cams, coupled with opened up ports.

you may want to open the dia of the cis manifold ( perhaps extrude hone it) and the phenolic blocks cant be opened that much, so get a set of aluminum blocks... with the intake pathe free of restrictions and a good cam the power will be there.

I have heard that a cleaned up 930 CIS system can flow about 500 HP worth of air but that the best the distributor, lines and injectors can do is about 400 HP worth of fuel.

I figure that the 300 HP of CIS fuel plus plus another 200 HP of EFI fuel should allow me to maximise what my modified plumbing will allow.

Plus the HKS AIC III will allow me to tune my A/F mix over the different boost and rpm ranges for the best possible output.

'79 fuel dist will make about 450 hp.. at some point after that they had different fuel systems for US vs Euro cars..

One thing missing in your list of things to do , is....
install a good EGT gauge..its a must have!

you don't say whether you are versed in 911 rebuilding, or just have done a lot of engines. 911s are different enough, that wayne's book is a necessity if you want to succeed on the first attempt, or do it again. no substitute for all the hard learned info in that book. one good trick learned is worth the price.

OK, you got me sold. I have done quite a few similar engines but never a porsche flat six.

And good point about the EGT. I am doing one better

The only additional guages I am running in addition to the giant boost guage where the clock used to be will be these two guages in pods on the pillar.

http://jandssafeguard.com/images/dualmonitor.jpg

http://www.chiefaircraft.com/Aircraf...s/WES_K31X.jpg

Nice project! I can't help but notice that jack you have holding up your engine and tranny. I want one! I am really starting to do many 911 at the shop, and was recently wondering what the dealer uses to remove an engine... Is that it?

JW said it all - I specifically wrote the Engine Rebuild Book with all of those tips and tricks in mind. I'll offer you a money-back guarantee if you're not satisfied and don't think it's worth the $35 for the book and CD...

-Wayne

We have a couple different jacks for different porsche models, but thats the one we have for the older 911s and 930s.

The jack is an OMC tranny jack with a special adaptor plate for the older air cooled motors.

The angle is adjustable on the lift plate and there are casters at all four ends which makes getting the shifter shaft in and out of the chassis and the motor in and out a lot easier than the rolling shop table method I used to use.

For the newer porsches the shop also has a table lift which is a rolling table on a scissor jack mechanism that can go up to about 6' in height.

Lets just say this makes the daily routing of changing motors out as easy as it gets.

If you haven't acquired an A/F gauge, you might want to take a look at this product from Nordskog Performance Products;
http://www.nordskogperformance.net/d70140.html
It has some nice features such as memory for lean and rich recall. It also doesn't use led's which look a little "ricey". Gauge appearance fits in nicely with existing VDO look. Not affiliated with Nordskog, just my $0.02. I found the unit at Summit Racing, pricing competitive.

Damn, that is a beautiful A/F guage.

If not for the fact that I want to upgrade (I currently have a cheap intellitronics unit on a pillar pod) to the J&S unit so I can see when the engine is beginning to detonate for tuning purposes I would jump on that in a heartbeat.

Thanks for the info anyways though.

http://www.tamparacing.com/photopost...020706Dash.JPG

Wondering how you settled on the 993 studs instead of going with the highly recommended ARP or Racewere while you have it apart. Also with 130K on the P&C's they will probably need replacing which will change your budget by 2-3.5K depending on if you go with stock 3.3 or upgrade to 3.4? Or are you just going to hone and re-ring and hope for the best?

As stated on the previous page I have very good reasons for using the 993 turbo studs and if the cylinders are round, in spec and immaculate I see no good reason to change them.

I have a hard time spending thousands of dollars on parts that spec out ok and have a lot of good miles left on them.

Just in case a hone and rering do not work out it won't be the end of the world if I have to drop the motor and rebuild the top end.

After working in a shop that has assembled many race motors over the years I have an appreciation for sturdy parts that have been properly 'seasoned' versus those that have yet to creep, warp and weather.

Hone??
 

Hello,
What process were you going to use to prep the cylinder walls for new rings?

Les

I have been told that nikasil cylinders should get a mild honing with a specific type of ball hone while I have some people telling me to just clean the cylinders.

I am leaning towards the honing route since I have seen enough motors with ring seating problems to not want to risk that problem.

This is a matter of critical importance so I need to do some additional research before I do anything with the cylinders.

Great Thread !!!

350hp, I was interested to know what sort of driving you intend to do with the new motor, How you plan to run it in and how many miles you expect to get out of the engine. Can you actually get the same amount of miles as when the engine rolled out of Porsche ?

This has been my daily driver and weekend auto crosser (which it does very well at) and that will be its continued usage except that I may cut down on the daily driving now that I have bought a $250 POS escort wagon to get around and haul parts with.

The break in will be like that for a new motor since I will have both a set of cams and rings to break in.

Since I am reusing the cylinders they will probably be the weakest link in this whole project.

Then again I have heard that they can work well with a rering all the up to and past 250K miles, so we will see.

Since most of the resused hardware will have been fully stress and heat cycled (or seasoned as some people like to call it) and remachined I am hoping that they will be good for another 150K or more.

If all the stories about 930 cranks, cases, rods, pistons and cylinders being extremely hardy are true (and my teardown appears to support this fact) then I look forward for the next 100K+ miles being all mine.

Knowing how fun 300+ RWHP was before I pulled the motor, I look forward to how fun 400+ will be with the lower ratio ring gear in the tranny to boot.

How about an update?

Thanks,
Dave

Blah, money has been tight so the project has been rather stagnant lately.

Now that I am financially recovering from the hollidays I hope to have about $500 to spend at the end of January.

:(

I have been thinking about getting an A/F guage myself. Is
that a wideband O2 gauge?

BTW. I have heard that thermal wraps can ruin your
exhaust system.

No, the pictured guage was just running off the regular bosch sensor so I could make sure the car was never running too lean and that all was well with the CIS

Right now I am looking into several different wide band solutions so I can do most of the fine tuning of the new fuel controller myself.

Since I wrote this thread I have also decided against the thermal wraps. I will probably just fabricate a few heat sheilds to keep the worse of the radiant heat off of the motor instead.

I'm in the process of rebuilding my motor too, and am also
bumping up the compression, but going twin plug to mitigate
the chance of detonation. I read that if you have flat
top pistons, twin plugging is not really necessary.
But I just wanted to be on the safe side, because I want
this motor to last a long time. :-)

I am also getting my fuel head modified to gain 15-18% more
fuel for my CIS motor so that I can maintain proper A/F ratio
under boost.

Since I was planning on building a street car, I decided to
not port the heads and manifold to maintain torque on the
low end. However, I decided to extrude hone the intake
manifold to get an even flow. Similarly, I am flowing and
balancing the fuel injectors.

I'm hoping for 425+rwhp on this build. I hope I'm making
the right decisions. :-)

Your decisions and estimates sound rather good to me.

I had also concidered tweaking the fuel distributor but in the end decided to go with the AIC for tuneability.

What is the best deal you have found on extrude honing the manifold? I concidered doing the same to mine until I found out how much most places wanted to do so and my concerns that it may aggravate the stock manifold's tendency to favor certain cylinders.

I was also hesitant to Extrude Hone because of the costs. Then I found
a place in Canada that will extrude hone my manifold for $600 canadian
dollars. I think that translates to about 460 dollars vs. the $620
asking price in the states.
I also found something on the web stating that if you are a SCOA
member, then Extrude Hone will give you a 20% discount. Just
tell them you are a SCOA member before getting a quote.

I opted to ship my manifold to Canada. If you can wait a few
weeks, I can keep you posted on how well the work went.
Below is the url for the shop that is working on
my manifold.

http://apexmodified.ca/html/extrude.html

The AIC.. is that a reference to a 7th injector?

If so, I think I have read it does not work very well. Can't
remember which board I read it on though.

www.c2turbo.com
www.911turbo.com
www.turbo911.com
www.rennlist.com

hello there 350HP930,

I was thinking about resealing and getting a partial rebuild done to my 81 930. I read in 9 magazine a while back that a cheap compression bump can be made be flycutting the heads. What do you think. Does this compromise the chains and there slack or does it have any other negative affects? Is it worthy to even do the mod?

The change could also be be performed via case or cylinder flycutting in addition to the heads. For a small compression bump you would not need to remove much material but you should also have your chain housings machined to reflect the new component heights. The timing chains and tensioners should be able to handle the changes in cam location as long as they arn't extreme.

For example I am only going to bump the comression about a half a point so if my memory serves me correctly I think thats only about a 0.5 mm piston height change.

How many miles do you have on your 930? Mine didn't start hemoraging oil till it had about 110K miles on it.

Update?

Shortblock should be together in the next couple of weeks, heads in the next month or two.

It should all be downhill from there. I will make sure to post some pics and an update when things proceed. I need to stop wasting so much time on the OT board.

Well, it appears I too may begin my engine rebuild (a little earlier than I anticipated). I recently purchased an 89’ 930 and I am looking to make it more responsive at lower RPM. I imagine bumping up the CR and trying a different Cam will help do the trick. However, while I’m in there, I would also like to replace the Con Rods. I hate to ask general questions, but I would like to start generating some ideas from some of the options that you guys/gals are aware of.

I have read quite a bit of Wayne’s “How to Rebuild & Modify Porsche 911 Engines”, but I still feel a little left in the dark as to what all my options are in getting the most out of my 3.3L turbo. I did notice that his top picks for this particular motor was to basically increase piston size. Does anyone have experience with that? Wayne, if you’re around can you please expand on this? Results?

The stock 930 rods are very durable. While its your choice I think there are better motor mods you could put your money into.