dlr944

I've been researching 3.0 liter options and I am still unclear about a couple of points:

1. Since the S2 and 968 are both 3.0 liters, are there any difference in the block or engine that would be better for building a 3.0 liter turbo?

2. Is there a good source for 968 turbo pistions to be used? I assume these are the correct pistions to be used for 8:1CR?

3. If you modify the 2.5 liter turbo head to accomendate the 3.0 liter block are there any disadvantages or advantages to using this head over the 2.7 liter head?

4. What connecting rods does one use - what spec?

5. Are there any other major compenonts need for this build?

Appreciate any advice in scoping out this project

macnewma

Step number 1...set aside about $20k.

Step number 2...beats me.

Jfrahm

The 968 block has oil squirters that cool the underside of the piston crowns. That would be nice to have. They can be added to an S2 block for several hundred dollars, the squirters need to be tapped into the oil galley.

The 8.0:1 pistons are hard to find and pricey.

A modded 951 head already has the turbo valves (sodium filled to conduct heat) and the ceramic lined exhaust ports. The 2.7l head has a slightly different shaped intake port, the 951 intake will need a little port matching to fit well.

Any old rods will do for a conservative build, Pauter or Carillo for higher HP applications.

You will also need a 104mm widefire or MLS head gasket, piles and piles of money, appropriate turbo, wastegate, exhaust, engine management, etc. Are you trying for a 500HP motor or just a 325HP motor with more low end?

-Joel

87_944s

1. piston squirter feature on 968 engines.

2. Lindsey Racing sells the pistons

3. 2.7 liter head hard to come by, 2.5 valves can be modded to larger size.

4. Stock 951 forged rods will work, same dimensions as 968 rods.

5. Once you got above ingredients, nothing left is "major"....

Everyone goes on about how expensive this build is....

Find a good used or new S2 or 968 block......$1000-$1500
1 set Mahle 104 turbo pistons w/pins, clips, rings (8.0 CR)....$1299
1- S2 or 968 crankshaft....$1000 (one just went for $700 on Ebay)
1- used 951 cylinder head.....$200 (seen 'em go for $150 on ebay)
Figure around $300 for seals and gaskets.

You've got yourself an assembled 3.0l turbo long block for $4500

I had all the stuff (sans pistons) ready to build up a 3.0 liter turbo engine crated up secure in a wooden crate, my dream engine project for a later date.
Turned out though that my daughter needs $5000 worth of braces and a local orthodonist that races a 968 engined 944 at my local track blew a rod cap out of the bottom pan.....

So.....you've heard of "oil for food" right....?
I've got a "968 engine for braces" deal going....
Assembly Friday night....

***Whoops, just realized I'm logged in under my son's ID***

TS (951and944S)

dlr944

At this point, I am just interested in understanding the necessary items for a 3.0 liter build. I currently have Vitesse SIII kit but was interested in learning what's required for a 3.0 liter project.

Seems like you could buy a used S2 engine for a reasonable amount and add the pistons and rods to complete the short block.

Current setup 1989 turbo:
SMT6
Vitesse Stage III turbo w/ MAF
MBC
3" full exhaust
Tial WG 38mm
930 clutch and lighten flywheel
SFR intercooler pipes

Pauerman

Emphasis on Step 1!!

dlr,

Give Andial a call - I believe they've run another batch of 104mm (8:1CR) turbo pistons. Last I checked, they had a couple of 1st over sets left.

The 2.7 head offers a larger intake valve, does not have ceramic liners and is a direct bolt on for the 3.0L short block. The intake ports are also oval, so some work has to be done to the intake to accomdate this head.

I went with a 2.7 head which has been converted to a solid lifter configuration with 7mm custom length valves, stiffer springs and titanium retainers - none of this accomplished by Lindsey Racing.

Considering everything else I've currently invested - Carrillo rods, turbo, clutch, Standalone EMS, injectors, WB 02, wastegate + so much small stuff, I'd say that 20K is a realistic figure.

Shoot me a PM if you'd like some further details or insight.

Good luck
Vic

dlr944

87_944 - I appreciate the insight - my thoughts exactly. However, does Lindsey sell 968 turbo pistons - are these just 104mm Mahle pistons?

Pauerman

So, you've got around 7k in stuff already.

Here's how I'll add to your list:

968 or S2 short block: $2500-$3000
Stock 2.7 head: $1000 - not considering any machine work.
Stock 951 head: $250-$350 + all mods necessary - new exh. valves, water passage, custom head work = conservative $1400 total
Rods: Stock will work - going this far are you going to risk using them?!? Add $1200 Carrillo rods for peace of mind.
Pistons: $1300 Mahle LC 104mm
Smaller Details: Head studs, gaskets, head gasket - ranging from $400-$600 depending on your what brands you choose.

With a 2.7 head option (not machined) you're up to an approximate total of 14K. If you stick with the 2.7 head, add $1000 for head work plus $500 if you want a cam. You're now up to 15.5K not factoring many of the incidentals ANDconsidering that you do all the work yourself.

It can be done for under 20K provided that much of the work is accomplished yourself.

fortysixandtwo

If you are planning on using the 16 valve head, I would stick with an S2 engine. This way, you will not have to deal with the vario-cam setup. Custom intake and headers will need to be made to use a 16 valve head with the tubo system. The rest of the parts needed can be taked from your existing 951.

dlr944

I was only interested in using an 8v head given the simplicity and cost of this solution over the 16v. Any problems mating a 951 head to a 968 block over than the water passage?

chilibluepepper

I'm going through this "slippery slope" myself, as are others on this list. The most important components are going to be 1) plenty o'money, and 2) a strong stomach for all the money you are going to spend beyond that! If you have 1 and 2 covered, everthing else is a piece of cake! Not to discourage you, but you need to be realistic. No matter how frugal you think you can be, you should count on spending at least $15K on this endeavor, and that is being very budget-conscious, and very hands on. Unless you are dead-set on building a 3.0, consider that building a VERY strong 2.5 is a much more straight-forward and cost effective project. That being said:

I bought my Mahle 3.0 turbo (8V) pistons from Andial couple years ago for about $1,400. At the time they only had 1st O.S. pistons available. Scott Gomes also had some of these pistons available at the time. If going 16V, Heritage Motorcar Research has custom Mahle pistons for this application.

Regarding the cylinder head, using the 2.7L is nice because it is designed to mate with the 3.0L block and has larger intake ports and valves. You can use your 951 exhaust valves in this head, as well as 951 intake and exhaust valve springs. As Jfrahm said, you will need to match-port your your intake manifold to the oval intake ports of the 2.7, that is if you are using the stock 951 manifold - not that big a deal. The biggest drawback is people want stupid money for these heads.

Upgraded connecting rods are nice, but may not be necessary depending on your application, and will set you back another $1,000. It doesn't seem the stock connecting rods are the weak link in most applications.

You need to seriously consider your goals and the intended use for this engine, and plan accordingly. Changes really mess with the time-line and budget!

evil 944t

dlr944,

If your looking for an all bore 2.8ltr short block I have one. Pm me for details

dlr944

Currently I am enjoying the SIII Vitesse kit. However, at some point a rebuild will be required and I'd like to move up to a 3.0 liter. The car is a PCA concours winner and I have already spent more than I every care to calculate. The plan is to start acquring the 3.0 liter pieces and enjoy the current condition of the car. As time and money dictate, the next major items will be purchase.

So regarding the build, if a 3.0 liter 968 block is used, can you use a 951 oil pan? Also, is there really any benefit to using a 2.7 liter head now that LR has addressed the exhaust side with their "New High Velocity Exhaust" head service?

Thanks!

Pauerman

The 3.0L pan can be used - it must be modified accomodate the turbo's drain line. The 2.5L pan can be used as well, but the crank scrapers incorpoated into the pan needs a little work to accomodate the 3.0L crank.

Mike Lindsey explained their "high velocity" option is accomplished by using a different cut on the exhaust valve seat. On their higher dollar heads, I think they're also using a larger Chevy valve (11/32?)for the intake.

87_944s

Yes Dlr, Lindsey sells the low compression 104mm turbo pistons for S2 or 968 block with pins, clips and rings for $1299.

And just to add.....if you did buy an S2 engine, used, to rebuild and wanted to add the pistons as your recipe describes above, the larger cc dish of the piston face should be enough clearance for 16V head's valves.

A user here even used the stock 968 pistons with relief machining to the piston face coupled with slight milling to a 2.7 liter head to lower the CR to 9:1 iirc....
More than a year ago I contacted Arias (had used them for customs before) and they said they could replicate the 3.0 high compression piston's dimensions and coating in any ratio I wanted but since then I think an individual may have solidified an agreement with them for sole distribution...

The factory header for the S2 and 968 (would come with the used engine) can be used and bolt right up to your factory 951 exhaust by turning the clock position of the two exit flanges and rewelding......

Hardly "extensive" exhaust mods....

There's no need to spring for the rods either unless you plan on making a 600hp super high boost engine.
You won't have to search too far to see that there are several users here making 400, even 500 hp on stock 951 bottom ends....

$1200 rods are overkill imo...

I guess it's reasonable to say that if you can't turn a wrench or fabricate something as simple as the exhaust mod above yourself that you may be forced to fork out 20K for a turnkey engine.
These people will dissuade you from spending anything less than what they did when in fact the same sorts who *must* pay someone else to do the work for them from lack of mechanical abilities are the first ones lining up to tell you how it must be done.

TS