My Twin-Plugged 3.4L Street Rod Build

[polizei]

Guys,

After more than 3 years since my top end rebuild and turbo conversion on my 1987 3.2 Carrera, I've spent too much money and not enough time behind the wheel! It turns out that the rebuild was not done properly - low compression after 5k miles and high oil consumption. After months of kicking around my options, I've decided to build an N/A car that I jump in and drive - and have for years to come! My hope is to build an engine that's reliable and fun to drive on the street as well as at the occasional DE event

I'm working with Mark Burkit at Specialty Cars in Allentown, PA. Mark has done a lot of work on my car and is a pleasure to deal with. Over the course of the last year, he's refreshed/upgraded my suspension, lowered the car, added 996 NA brakes and done a lot of maintenance. He's a patient, precise guy who involves me in the project every step of the way. I'm confident my engine's in the right hands.

We're planning a complete top end rebuild. The bottom end has 75,000 original miles on it and no leaks. We'll examine the rods and rod bearings, and then decide whether to rebuild the bottom end. I'm going to stick with stock Motronic induction/engine management for the time being, but we're going to build the long block so that I can move to ITBs down the road - and safely rev to 7k RPM

Here's what I already have that's going into the build:

98mm Mahle Cylinders with 10.4:1 static compression "RSR" pistons (Hemi-shaped domes - not Motronic/CIS)
Reconditioned Carrera rods with ARP Rod Bolts
Stock Carrera Case/Crank/Flywheel/Oil Pump
Supertec Head Studs
Twin Plugged Carrera Heads - Valve Job done by Supertec
Elgin Super C2 Cams
Stock Motronic Induction/Engine Management
Andial Signal Splitter with 964/993 Twin Plug Dizzy
993 Heat Exchangers with flipped flanges and Flowmaster Muffler

Here's what's coming:

Hi Performance Valve Springs with Titanium retainers
J&S Safeguard with Ignition Retard/AFR gauge
Reconditioned Rockers
Oil Cooler Air Scoop & Shroud for Front Oil Cooler
Steve Wong custom-tuned chip

Extras:

NHS rebuilt gauges with white LED lighting
New Vintage USA Quad Gauge - Oil Pressure (in PSI), Oil Temp (in degrees F), CHT and Voltmeter
D-Zug HID kit
Replace all A/C lines!

I'm intentionally 1) not replacing my AFM with MAF 2) not boring out my throttle body and 3) not extrude-honing my intake. I'd prefer to save my pennies to convert to ITBs down the road!

The engine is out of the car and up on a stand as of today. My hope is to keep this thread updated as the project progresses. I want to say thank you to all the Pelicans that have sold parts to me or taken the time to talk through the options available to me. You're a good group of guys making up this community. Thanks for your support!

[polizei]

Guys - I'm looking for some direction from the brain trust. A set of "affordable" reconditioned pauter rods is available to me, and I'd like to ask for your input regarding whether it would be beneficial for my build and usage of mostly street and some track. I'm building the engine to rev up to 7k rpm. Reconditioned stock rods with ARP rod bolts are already on the build sheets. Does this help me or distract me?

I'm trying to be cautious of the slippery slope...

[AlfonsoR]

I hope I don't come across as too critical, but you did ask for opinions and in my noob opinion, it seems you're spending a lot of money for not much more than what stock can do...unless you splurge for ITBs or Carbs now.

What if you select your cam for 6500 rpm max and instead of the rods, get a used set of PMO's or Webbers? I think that would be the ticket..

[polizei]

Originally Posted by AlfonsoR

I hope I don't come across as too critical, but you did ask for opinions and in my noob opinion, it seems you're spending a lot of money for not much more than what stock can do...unless you splurge for ITBs or Carbs now.

What if you select your cam for 6500 rpm max and instead of the rods, get a used set of PMO's or Webbers? I think that would be the ticket..

Hi Alfonso - I do not mind being critiqued - I appreciate it! I hope to benefit by the experience of others here.

I've given the topic of induction a great deal of thought, and I've decided that reliability and street-ability are my primary goals. Because of this combined with my budget for this year's project, I've decided to stick with Motronic. Carbs are a great option, but they cannot provide the level of reliability that Motronic can. When I have the time and money, I will convert to ITBs and aftermarket EFI. This requires a cam change but not a complete rebuild.

My focus right now is to build a long block that best suites my short and long term goals of 1) Street Rod and 2) Some DE. I will be revving up to 7k RPM, which has been consistently proven with stock rods and ARP rod bolts.

Bearing in mind that I'm trying to avoid "budget creep", will the Pauter rods really help me achieve my goals or distract me?

Thanks

[lvporschepilot]

You can always add the other intake stuff later. You're going the right way now. Stock motronic will make for a good engine, and with what you listed above I can see 280bhp+ as not being out of the realm of possible.

[lindy 911]

I don't think the rod change will provide any benefit over stock given your goals. Actually seeing 7,000 rpm on the street for very long is not going to happen if you paln on staying out of jail. If you're going to "race" the car, that's a different story where you'll see 7,000 rpm all the time.

I would agree with AlfonsoR about moving to carbs now instead of later. I had an opportunity to ride in one of William Knights cars with a 3.6 at Texas World last Friday. Really not much done to the motor except cams and 50mm PMOs. It is a rocket. Way too much fun.

[AlfonsoR]

On page 164 of Bruce Anderson's book, you can compare two 964 3.6 engines, one with 46mm carbs vs. one with Motec. The carb'ed engine is otherwise fairly stock except for Jerry Woods cams and headers, while the Motec one seems to have a lot more money into it.

The Motec definitely performs better and spins to higher revs but if you look closely the scales are different and the actual numbers are close.

I'm starting to form the opinion (and I can be convinced otherwise maybe) that unless you're building an all out race engine, that carbs is basically the "Easy" button vs ITB system. Lindy and others will attest to how reliable carbs can be too. They seem to get you to at least 95% or better (in terms of performance) of what a well tuned ITB system can get you and the carbs are "right now" bolt on. You don't have to spend countless hours tuning. Just some food for thought.

[KTL]

Stock rods are pretty darn good for rpms within the range of your intended use. I have a friend (cstreit) who's been using stock rods in his 250 WHP 3.3L N/A since 2005 and they've served him well. Actually had one failure but i'm not sure that's necessarily a rod issue. Spun a rod bearing which then did ruin the big end of the rod.

Pauter rods are nice (I have some) but for your type of use they don't really gain you anything. They're not massively lighter than stock rods and you don't necessarily need the added strength from them.

[jpnovak]

I am not sure why you say that carbs are not reliable. If you just have redundant filters and keep the gas supply clean they will be highly reliable. No sensors to go out, not flywheel VR signal to have issues. No AFM throttle response problems.

Are emissions an issue here? If yes, stay with Motronic. If not, keep reading.

Personally, I would use the money you spend on the Motronic splitter, dual CDI/coil, 964 distributor and J&S knock system and put the money towards a 12 plug distributor with a proper advance curve, dual MSD(or Crane) ignition and a used set of carbs.

Then you can run a truly fun cam with a broad torque curve and 7K redline. Something like a DC40 (Mod_S) cam would be perfect for this motor and the indicated CR.

Yes, you do need upgraded rod bolts for the 74mm stroke crank. No, you do not need aftermarket rods at 7K redline. I would suggest to cross drill the crank and grooved bearing to match. It helps with oiling and longevity.

Does it have to be a 3.4? Why not reuse your 95mm Carrera cylinders and just buy JE (for example) high compression pistons. Will save some coin and give you budget for the carbs. The difference in output between 95 and 98mm with a build described above will be relatively small compared to the gain in drive characteristics going to proper cams and carbs.

My $0.02.

[Flieger]

The carbed cars I have experienced (probably over carbed for the motor size) were real b!tches to start. Even in southern California weather. I think the Motronic is the easy way.

[polizei]

Guys - Thanks for all the input. On the topic of Pauter Rods vs Stock Rods with ARP rod bolts when used up to 7k RPM, it sounds like there's no meaningful benefit and that this issue can be put to rest.

As far as my build plans, again, my focus this winter/spring is to build the long block that will meet my goals for years to come and stay close to the budget I've established. Since stronger rods will not help me achieve my goals, then I shouldn't do it. Similarly, will carbs or ITBs help me achieve my goal? No - because they're not part of the long block. I've got to keep my project focused so I don't break the bank and can get to driving!!!

That being said, if I build the long block correctly, I'm staged well for replacing Motronic with Carbs or ITBs down the road - except for a cam change. The way I look at it is that I have years to sort out whether Carbs or ITBs are the right solution for me. I've had my Motronic induction system, Andial Splitter, 964/993 dizzy and coils for 4 years now. They're a sunk cost to me. I just need a custom chip and voilà! I'm going to give Motronic a try and see how I like it. If I don't, then I'll change cams and induction in a few years.

Originally Posted by jpnovak

Does it have to be a 3.4? Why not reuse your 95mm Carrera cylinders and just buy JE (for example) high compression pistons. Will save some coin and give you budget for the carbs. The difference in output between 95 and 98mm with a build described above will be relatively small compared to the gain in drive characteristics going to proper cams and carbs.

Hi JP - Yes, it does have to be a 3.4 because I've already purchased the pistons/cylinders There's no doubt that this is eating up a significant part of my budget since they're Mahles, but I decided that they are the best and most proven solution for my goals.

[KTL]

Two full pumps of the gas pedal and some light feathering of the throttle on cranking and they fire right up. Set the idle high enough (1500-2000 warm) and it'll run well without having to tend to the gas pedal while it's warming up.

[AlfonsoR]

on rods...on the other hand, by the time you inspect and recondition your stock rods for ARP bolts, you might be really close to a good set of used Pauters, maybe, depends on the deal you found.

Also don't forget about oiling mods, I think that's a must do, and possibly turbo piston squirters.

[polizei]

Originally Posted by AlfonsoR

on rods...on the other hand, by the time you inspect and recondition your stock rods for ARP bolts, you might be really close to a good set of used Pauters, maybe, depends on the deal you found.

Alfonso - That's a fair point. I'm going to chat with my engine builder to see how much of an effort/cost it'll be to recondition them.

[polizei]

I spoke with my engine builder, and he agrees that Pauter's won't do much for my intended use. I have 75,000 original miles on my rods, so I'm guessing it'll be more economical to freshen them up than purchase a set of new or reconditioned rods. I'll make the decision once the rods are pulled. Thanks!

[jager911]

Andy,
My advice is to stay with stock rods unless something is broken. Mark can get them Magnaflux'd.
I installed a stock 3.2L in 2003 and almost every shift except 1st is at 7k on the track and it hasn't broken yet. Now that I said that. I'm going to jinx myself. I like Motronic myself if this is going to remain a street car unless you're building a race motor.

Not the question you asked, but if you're just starting out with DE, spend the money on seat time, then some more seat time, then seats/harnesses, brake pads/fluid/cooling, tires, suspension. Anyway, that's my experience for bang for the buck with a limited play budget. I'm 20 mins from Mark's shop if you would like to see the upgrades on my car.

[polizei]

While the engine is being rebuilt by Specialty Cars, I'm storing the rest of my car at a nearby friend's garage. I'm taking the opportunity while she's out of commission to perform some much needed maintenance and upgrades.

Tonight I got her up on jack stands and removed the wheels. I found it more time consuming to get the car on jack stands when the engine and transmission are already out of the car. Without a good center point to jack the car up and without the weight in the rear, the car tends to want to lift on one side. It seemed precarious but it all worked out

I also received my new nifty HIDs in the mail today. These headlights are true plug 'n play for any 1964-1994 911. Notice the ballasts come with 3M adhesive strips already attached. Just remove the plastic barrier and attach to the back of the headlamp assembly. D-Zug pre-wires these to work with your stock wiring - mine have the H5 hookups. Also, the lens on these suckers are real glass and seem very high quality. I can't wait to install these guys Thanks D-Zug!!

[polizei]

Removed the front bumper tonight. Lots of cleaning to do now! With the bumper off, I'm planning to upgrade the A/C and shroud the front oil. Here are some before and after pics

[polizei]

Just heard from Mark over at New Vintage USA (NVU), and he provided this as a mock-up of how the quad gauge should come out:



This is the first work I've had done at NVU. They have a reputation for producing factory-like gauges, and I think this mock-up lives up to that!

[draab29]

Can't wait to see how those headlights look!