What do I need to build a 3.4 from a 3.0?

[JP911]

I'm ready to start collecting parts for a 3.0 to 3.4 engine build using CIS (similar to rdane's setup). It will be primarily for street use, with the occasional track day. I currently have the original 2.7 in my car, but have a good lead on a 3.0 longblock. So what parts do I need to build the 3.4?
New Crank?
Which P/Cs?
Distributor?
Will my SSIs and single out Dansk be sufficient?
Which cams?
Will the CIS on my 2.7 work on the 3.0?
Etc...

[Shuie]

New Crank? ->74mm crank from a 3.2 Carrera

Which P/Cs? ->98mm Max Moritz with 23mm wrist pins

Distributor? ->Flip the drive gear on the crank? I had not thought about this part of the conversion

Will my SSIs and single out Dansk be sufficient? -> you are good to go here

Which cams? ->20/21

I dont know about the CIS.

Dont forget about the rods either. You wont be able to use the 3.0 rods.

[vash]

didnt "rdane" just do this? you can start by kidnapping him

this will be a killer project! i cant wait. you are smogtest free next year! get personal plates fast, i like "snore" for the sleeper aspect.

[JP911]

Thanks for the help! I've read several of rdane's posts, but wasn't able to track down a complete list of what he used. I was thinking about a 3.2 swap, but I think this will be more fun! The other plus will be that it will look stock.

Cliff - How's the SC treating you? Is the 3.0 a big improvement or just different?

[emcon5]

You will probably save money by starting with a 3.2.

You won't have to do the ports, you will get the crank and rods you need, and (as much as I like CIS) the Motronic is probably more versatile. Twin plug would be easier as well if you decide to go thar way, all you would need it the splitter from andial and a 964 distributor.

You lose the whole "looks stock" thing though.

Tom

[Grady Clay]

JP911,

I agree with Tom, twin ignition is very worthwhile.

You can make a 3.0 (original 70.4 crank and rods) into a 3.3 with 100 mm P&Cs and into a 3.5 with the additional addition of 74.4 mm crank, rods, and appropriate wrist pins. It takes lots of careful work to do any of these conversions.

Yes, follow some of the experienced Pelicans. There are lots of subtle issues.

Best,
Grady

[89911]

Shown: 3.4 twin plugged motronic, 20/21 cams, etc.

I've got 275 miles on my engine, so I'm getting a better feel for it. Haven't pushed the redline yet. It's hard to tell comparison wise from the old 3.2. It definetly isn't going to challenge a Corvette off the line though. Still pulls very hard up till I let off the throttle, spools up faster and harder. I have to wait for a few hundred miles before I really push it hard.

[JP911]

89911 - If you don't mind, what exactly was required to do the 3.4 twin plug build and what was the bill?

[911nut]

89911, I got wood when I saw that picture of your motor.
I want one.

[89911]

Originally posted by JP911
89911 - If you don't mind, what exactly was required to do the 3.4 twin plug build and what was the bill?

Discretion prevents me from revealing I can give you the list after I check my receipts. Basically Mahle 3.4 P/C's, ARP rod bolts, Andial Valve springs, and a list of about a dozen or so other items that go into race hardening a 3.2 from stock. Twin plugging machining the lower head, Andial splitter, dual distributer, custom spark harness. Extrudehoned the intakes, port and polished the intake and exhaust ports. A good preface is reading the "Gold Plated Porsche" to understanding how this gets into a lot of money.

[rdane]

Here is what I used. Costs can go past 15K$ or be less than 10K depending on what you are starting with for a 3.0.

I would not do it again on a CIS. Great engine as is...amazing really, unless I was starting with a 3.0 with SSIs and hopefully a good performance cam.

But you will spend less money doing it on a 3.2 if you don't have a block to start with and end up with a better engine IMO. I am currently in the process of building a 3.8 Motronic.

What most forget is all the street flat 6s will cost the same to build basically, if new cranks, P&Cs and rods are part of your needs. At that point look around for options. IMO having done it and beat the 3.6 transplant costs by a good deal with similar performance I would look for a 3.2 Motronic and start there for a 3.4 or bigger engine.

Also the Max Moritz P&C is specifically designed for single plug and 93 octane gas.

The cost of case work, P&Cs, rods and cranks become trivial in the long run for a street engine that will last well over 100K miles, so plan well.

My 3.0 to 3.4 has the following at 258hp and 251# of torque.

3.2 crank
Puater rods and bolts
Mahle 98 P&Cs @ 9.8 for a 3.364
SFL Piston skirts, Ceramic coat on the Pistons
EBS valve spring
TI retainers
APR case studs
New injectors
new exhaust valves
boat tail the crank cases and half moon the cylinders
Bored throttle body
match and polish the intakes
20/21 webcams
SSI
sport muffler
light flywheel
sachs power clutch

Twin plugs? I didn't do them but I did the machining so they could be added at a later date. I also live at sea level and in a mild climate with 93 octane gas available.

Skip the older dual plug stuff and do Electromotive twin plugs. It is good insurance on bad gas and cheaper to install. Twin plugs add virtually nothing to 3.4 street performance IMO. But it is insurance to keep your engine in one piece. Problem you'll have is deciding where to stop with case work, twin plugs, induction, cams, compression ect. My budget was $15K and I beat that by $1500 even with extras like the coatings, case work, injectors and throttle body and got a great engine. I could do it again and get 99% of what I have for well under 10K.

My matra was big as it gets, street gas, single plug and no case work. That defined the 98 P&Cs, 74.4 crank for 3.4, and 9.8:1 compression.

But I also had a great engine going into it with a new clutch, flywheel, cams and SSIs which is not part of that budget number.
If I had not already done all those I would not have started my 3.4 CIS project. I could do a better (read bigger, 3.6/3,8, with more HP/T) Motronic for less. New budget is 10K plus the engine which I expect to come in under as well.

[JP911]

Well, this is giving me a healthy dose of reality. Being that I'm in CA and can only get 91 octane (unless I track down a station that sells race gas every time I fill up) is this type of project even feasible without twin plugs? Assuming that I do move forward with this, it sounds like starting with a 3.2 is a better way to go.

rdane - did you do most of the work yourself or do your costs reflect mechanic's time?

[rdane]

My engine was done commercially which reflects my prices but I had to be involved more than I liked a couple of times.
You have several shops in SC that have done the conversions so that is a good step. Talk to Andial on the 3.2/3.4 and single plug...they are comfortable with the idea I think and have done many of them.

The next one (3.2 motronic) I am doing myself with those numbers.

Opinions not withstanding, with 92 gas I would twin plug which adds between 2500 and 3K$ best case scenario on my prices. If it isn't a daily driver a 25:75 race gas mix can keep you going till you can finish the twin plugs. 50 gallons of trick 114 is $250 which equals 10 tanks of gas for a 3.4 and 92 octane.

Just remember you are risking your rebuild without twin plugs or better than 93 octane.

[JP911]

I can see the look on my wife's face:
Wife: Honey, what's that?

Me: Oh, it's a 50 gallon drum of 114 octane race gas

Wife: Really. Would you like me to get you a straw or will you be just shoving your head down in there.

Me: So...you don't like the highly flammable/explosive race gas here in the garage???

[rdane]

Race gas sounded silly to me at first. I got used to the idea with 9.8:1 compression You can always cut the compression loosing HP and keep the torque I think? Is that right? If so you can run 92 or less on the octane. Which is what I suspect Andial does for the California single plug cars.

Isn't your 2.7 case the same as a 3.0 case? Can someone clarify if the cases are the same. If so you can indeed use all your CIS parts. Just add the cams, a 74.4 crank and a set of 98 P&Cs for a 3.4 or drop the crank (which I wouldn't do) and just do a 3.2 short stroke. It would be a less than 8K$ engine @ 3.2 I suspect and you could run 92 octane single plug.

You'd love it!

[JP911]

The 2.7 is the magnesium case and is stressed by the 2.7 liter displacement to begin with, so I'd be a bit concerned about increasing the displacement. I was thinking about doing an engine swap to begin with, so in a sense the cost of the new motor is a given. The reason I was thinking about starting with a 3.0 was because I can use my CIS, keep my exhaust (SSIs and Dansk 2 into 1), and not change much of the wiring that would be required for motronic. Out of curiosity, can you put numbers to the parts?
3.2 Crank = $
98mm P/Cs = $
Pauter Rods = $
20/21 cams = $

[rdane]

Too bad on the mag case. The rest would work I think and better than the US 3.0 stuff is my thought.

This is what I paid late last winter:
3.2 Crank = 1600
98mm P/Cs = 3400
Pauter Rods = 1100
20/21 cams = 1000 with new OEM rockers

[JP911]

I am defintely seeing how quickly this can add up. With the crank, P/Cs, Rods, and 20/21 cams I'm looking at $7,100. Add on $3,500 for the 3.0 (estimated), approx. $3,000 for machine work and labor, and the thought of adding another $3K for twin plugging pushes this whole project right over the edge. I suppose I could just take the cash and my targa and trade the whole lot for a 930...nahhh, that wouldn't be any fun!

[rdane]

It is a shocker price wise to rebuild. I needed a valve job on my 3.0 which is typically $5K here. At that point the engine is apart and it makes some sense to look farther since I already had several thousand invested in my 3.0 with cams and exhaust.

Plus a preset limit of $500 for the stock engine to come out and go back in. No fuss or muss since it was staying "stock".

I decent 3.2 would have been an easy enough swap. But a decent 3.2 usually means a new topend too. Which brings you back to 10K.

When you go over 10K lots of options open up including the older 3.6s. At 15K$ you can get some awesome engines or a good transplant. The better variocam 3.6s will set you back even more.

If I were in your situation I would look for a good 3.0 or 3.2 and just do a simple transplant. Couple days in the shop and drive away....still using 92 octane or less and make emissions.

[emcon5]

Originally posted by JP911
I am defintely seeing how quickly this can add up. With the crank, P/Cs, Rods, and 20/21 cams I'm looking at $7,100. Add on $3,500 for the 3.0 (estimated), approx. $3,000 for machine work and labor, and the thought of adding another $3K for twin plugging pushes this whole project right over the edge. I suppose I could just take the cash and my targa and trade the whole lot for a 930...nahhh, that wouldn't be any fun!

That is why we said you should start with a 3.2. You don't have to buy the crank and rods, the ports are already large enough for a 3.4 to breath. The machine work will cost ~$1500 for a standard top end with the holes drilled for twin plug (twin plug machine work is only ~$350). With a motronic car, the DME can drive a 964 distributor ($250-500) with Andial's splitter ($???),

Another advantige is factory 95mm 3.2 cylinders can be bored out to 98mm and replated with Nikasil, and you can go with JE pistons for less than a Mahle set.

Or you could just buy this and do all the fun stuff when it needs to be rebuilt.

Tom