How do turn my 3l into a 3.2lt Engine

[slow car]

Hi what do you end up with if you put the Euro 3.2 10.3:1 Mahle pistons and barrels on a 3lt Sc engine?
Will this make it 3.2 or just a low compression 3lt?
Thanks

[Flat6pac]

Yes, low compression, but I dont know how low..thinking low 9.?
Best thing to do is get a set of 3.2 cylinders and send them out to EBS for opening to 98mm and renikisil. Order a set of JE pistons to fit at 9.5CR and install with the C2 cams and you should be good for 200+ horses with out problem and still running the CIS.
Thats the 3.2 short stroke
Bruce

[slow car]

Hi Thanks for that information. I will try and find some cores to have machined.
Can EBS machine 3lt 75mm to 98mm ?is there enough thickness in the barrel .
What is the quality of these for racing?

[Flat6pac]

They dont like to do it on 95mm SC because you run too close to the sealing ring.
The least expensive way to go is find a set of KS, alucil cylinders from a Carrera because they will be opened to re nikisil as part of the machine work. The KS have less value because people tend not to reuse the KS on rebuild.
The quality is excellent and the JE pistons give lots of cam variables.
I know a few guys who run real hard and the units hold up.
Bruce

[3literpwr]

Don @ EBS is plating my 95mm cylinders right now. I asked the same question about boring to 98mm, but he suggested against it...

[slow car]

Bruce ,
What is KS? where would i find these?

[Flat6pac]

Kohlbien/Schmidt, the other manufacture other than Mahle.
Bruce

[KTL]

Yep there's no displacement gain from the Euro 3.2 pistons. But you can take advantage of the Euro 3.2 pistons by having your SC rods offset overbored by someone like Ollies or Supertec.

The benefit you get from the rod modification is a better rod length : stroke ratio. Engine likes to spin more easily due to the reduced rod angularity.

Upgrading 80 SC w/ 88 3.2 P&C's

Con Rod Bushings

So my point is that if you're going to buy 98mm pistons, you can buy the shorter compression height 98mm pistons for the Carrera 3.2-3.4 conversion. Offset bore your rods and you get a better 3.2 than the typical choice of just adding 98mm pistons.

[slow car]

Hi
Well that was interesting reading,
I have a set of 10.3:1 95mm Mahle barrel and pistons.and was going to sell them but now i have the option of off setting the rod ends and enlarging them to 23mm I dont understand all the talk about deck height ? What will i need to do other than off set rod ends for a 83 SC ROW motor?

[IXjamesXI]

I heartily recommend that you get a copy of Bruce Anderson's book if you don't already have one.. he does a a good job of explaining the geometry involved in displacement and compression ratio.

If you modified your rods to use the pistons you have in hand, it is my guess you would end up exactly where you started.

For example.. if these pistons are supposed to be a nominal 10.3:1 compression ratio on a Carerra (3.2) motor, the figures might look like this:



I assumed a deck height of 1mm, we know all the other figures except for the piston dome volume. I worked backwards from 10.3, and the piston dome volume you get is about 40.5 cc.

So keeping everything constant and changing the stroke from the 3.2 Carerra spec (74.4mm) to what you have in your SC engine (70.4mm) you end up at about 9.8:1 compression..



Which is what your ROW engine already is anyway, right? I am hazy on this but I seem to recall they are 9.8-ish.

Therefore, in my opinion, if you are looking for "more" then you might want to think of another strategy.. maybe new 95mm pistons, and carbs or ITB and a funky cam, or keep your CIS and bump up to 98mm pistons and cylinders and maybe regrind your cam to a 964 or similar... there are a lot of different recipes depending on what you are looking for. What KTL suggests is a cool idea and people like Henry have explained it in more depth, but I think it's more like Porsche engine class 301, not 101. You would have to make sure that you spec the piston dome volume really carefully in that instance. I am building a 3.2 short stroke at the moment, and I considered buying 10.5 JE's meant for Carrera rods and offset boring my SC rods to land at about 10.0:1, but eventually decided in the interest of simplicity against going to those lengths (no pun intended). The next time around with a project like this I might consider it, and certainly if I were building a race motor and looking for every possible "edge."

[slow car]

I have decided to purchase a set of Motorsport Mahle 98 mm barrels and je 10.5: 1 pistons with Sc size pins , a set of GE 60 cams .i have a set of 40 mm webers and after reading Bruce Andersons book page 174 says they are ok to use on a 3.2 lt ? I will run 104 octane fuel 1.1/5 " headers with straight through hot dog mufflers.
Well that's the plan so far.
Would love to hear from others who have don similar.
Maybe I will need to go to 46 mm webers to feed the compression and cams?