Help me build a high performance 3.4L street engine
 

Hey Guys,

Happy New Years to everyone!

It's rebuild time. The compression on my 1987 3.2 Carrera is shot due to a bad top-end rebuild 5K miles ago, and I'd like to covert it to a high performance 3.4L street car. There are 75,000 miles on everything but the top end. Reliability is priority #1 as I depend on my p-car for getting around town. Although, I plan on bringing it to the track for DE events from time to time - maybe 2 or 3 per year. Smog is not a concern, so I'm flexible on cams and exhaust. Above all, I want to enjoy this engine for a long time to come

Budget

My budget is $10-12k. I'll be able to sell some of the spare parts I have on hand or those that come off the car with the build. I'd like to ask for your guidance on how to spend wisely.

Ignition/Fuel

I'm running twin plugs on my Motronic with a 964/993 dizzy and an Andial Splitter. I'm also sitting on a good, used Electromotive Tec3-r system. I could go either way on this. I'm inclined to stick with Motronic because it seems like less hassle and cost (install/tuning). But on the other hand, I'll probably be able to extract more power by tuning the Tec3-r and eliminate that bulky AFM! Thoughts? Will I be able to appreciate the difference in a car primarily driven on the street?

Heads/Cylinders/Pistons/Cams

My heads were rebuilt by Supertec within the past 5,000 miles and drilled for twin plugs (otherwise stock). Supertec head studs installed. After looking at the piston/cylinder combinations that are available and chatting with Henry at Supertec, EBS' bored & replated 3.4L cylinders with JE Pistons are a good fit for me. Nickies/Mahles are great but will cost me twice as much, and I'd rather put the difference toward a nice exhaust system. Henry suggested going with 10.0:1 static compression ratio (or less) and then running more aggressive cams. The JE Pistons are cut with valve reliefs and can be ceramic coated. Is this a suitable combination?

Webcams 20/21, DC19 and DC20 seem like proven solutions for similar builds. Any ideas here? Are these cams compatible with stock heads? I read that stiffer springs may be required depending on the lift characteristics of some cams. Is it worth it to further modify my heads? Drive-ability is important, but I do enjoy getting shoved at 5K RPM.

Rods/Crank/Oil Pump

I've got stock rods with ARP rod bolts. The crank and oil pump are stock as well. The crankcase has 75,000 miles on it. Should I bother splitting the case? Or would it be a sin not to? If I do split the case, what work should be done?

-Balance Rods?
-Cross Drill Crank?
-Modify Oil Pump

I'm concerned that splitting the case will be a slippery slope, but I want to do this RIGHT. What's important and what's overkill?

Exhaust

I want heat and to be able to hold a conversation with my wife. I'm not concerned about emissions. It seems there are not that many aftermarket headers with heat that fellow Pelicans can agree on. I need some direction here.

Transmission/Clutch

Stock G50 with update kit and new clutch assembly within past 5K miles.

Oil Cooling

Stock Carrera fender cooler.

Tuning

If I go Motronic, I'll work with Steve Wong to have a custom chip created and modified based on dyno results. If I go Tec3-r, it'll be dyno tuned all the way.

What else should I be thinking about? Thanks so much for your time. I'm looking forward to the next steps.

Looks like you have a great Winter project thereSmileWavy
If you are sticking to that budget then forget EFI for now cuz if done right a total rebuild and EFI conversion wont be that cheap even with you doing the work. If it were me I'd split the case and measure everything and cross drill the crank. Then go back with all new brgs to insure the longjevity of your rebuild.

Good luck,
RC

I also want a 3.4 street engine

my attitude is to have the torque curve down low
ie: max torque, not max hp

Cap - I see that you've ventured down the aftermarket EFI route as well. I have to imagine it can be a tedious endeavor to install these reliably. And to your point, my budget doesn't allow for much wiggle room. I'll stick with Motronic and sell the Tec3-r to recoup some cash

Could you give me a rough break down of the cost on this? (Parts, labor, machining cost) This is my first time considering a bottom end rebuild, so I'd like some more information.

Thanks!

Bump. Interested in hearing more thoughts on this build!

Let me know if you can source any of the following:

1. Good set of 3.2L Carrera cylinders that can be bored and nikasil plated
2. Webcams 20/21
3. 993 Heat Exchangers with flanges angled for 3.2 Heads

I would think that with a 3.4 you could safely go with a hotter cam than the 20/21.

What about boring out the throttle body (steve wong) and smoothing out the inside of the intake manifold (extrude hone)?

With that budget and a plethora of new parts you might be able to Henry to build that for you.
might be worth a call.

If you're going to do this, I would do it with a bit more cam than the 20/21. Say a DC60. Twin plug it. And for the love of all things good the intake manifold should be changed to PMOs or Webers, or even PMO ITB if you want. The engine would breath and the difference between the two intake manifolds with those cams would be brilliant. As above and it would easily yield over 300bhp. I just built a 3.4L Ferrari V8 with Webers and it made 332bhp using a cam very similar to a DC60, and it's definitely a street motor.

John makes a DC44 which is has intake duration of DC40 and exhaust duration of DC60 and a wide LSA so you could use it with single intake plenum.