103 P/C's

[Eddie Brown]

Hello, I'd like to know if anyone is or has run 103 P & C's in their 914? How well did it run? How long did it last? What kind of oil, and cylinder head temps did you have?
I'm building a 2599cc motor(103x78). I'm trying to get an idea of what to expect with this combination. I'll be running a stock cylinder cooling system, as well as oil cooling. I'll probably end up adding an external oil cooler.
Also, what kind of HP/TORQUE can I expect ? I know that there are many variables to this (C/R, heads, fuel system). I'm still a bit away from finishing my recently purchased 72 914. But I'm very curious of other teeners experiences with this type of engine.

Thanks,

Eddie.

[maf 914]

Eddie, You might want to go to the ShopTalkForums, Type4rum, and do a search for 103. Lots of good info and strong opinions about them.

http://shoptalkforums.com/

Mike

[campbellcj]

My car has a 2.4 with Eurorace 103mm barrels and JE 103mm forged pistons. (71mm stroke, 60cc chamber volume).

The PO had this engine built as a street/autox motor so it is a fairly mild build (in terms of cams, and little/no head work) but seems to have been done well.

The PO reported no heat issues in his minimal street use, based on the stock cruddy center console gauge. I am just about to wire up a new set of gauges and hit the track in November so I will know a lot more at that time.

As to longevity, I can't really say, because this motor is still pretty fresh with only a few thousand miles on it. For my planned purposes with this car, even if it only lasted 20-30K miles that would be quite a few years and it will hopefully be replaced by a sixer well before that. (Of course this is assuming I don't explode the motor at the track before it has a chance to die a slow natural death).

[Eddie Brown]

Thanks Chris for the reply, I remember seeing your car before on the net. It really is a beautiful machine. Do you like the power that it provides?? And how drivable is it?? I got my bottom end kit from European, and it fit without any clearance issues. I can't wait to finish putting it together.
Anyone else out there with any input regarding these P & C's? BTW Chris, I'll make sure to bookmark your page for future reference.

Thanks,

Eddie.

[Jake Raby]

There are several big issues with 103 P/C sets. Mainlty they are not machined correctly, no matter where they came from.

when the 102 nickies came available we ditched all cast iron 103/105 cylinders. the lifespan is low for the expense, about 20K miles is all you will ever see from these cylinders, during that time extreme oil temps, head leakage, and etc can be expected due to the huge bore, uneven expansion, and cast iron content of the cylinders.

I stick with a 96mm bore size for most of my combos, and equal or make more power that the same combo with a 103/105 bore. All that beore demands more from the heads, if the heads cannot flow to fill the rest of the engine all you will do is move the powerband down.


Concentrate on making a combination that can be fed with the TIV cylinder head, it barely can keep up with a 96mm bore size even with excess work, a 103/105 is even tougher.

It does not take huge to make big power, we turn 150-185BHP out of TIV engines of less than 2.3 liters all the time (weekly) and these engines have long lives, are cooled with a stock cooling system, fed with 44mm Weber carbs, and pump gas.....

[campbellcj]

Originally posted by Eddie Brown
Thanks Chris for the reply, I remember seeing your car before on the net. It really is a beautiful machine. Do you like the power that it provides?? And how drivable is it??

Thanks Eddie. BTW the car doesn't look like those pics on my web site anymore. It is undergoing extensive race prep.

Because the PO had the engine work done, I can't take any credit/blame for the way it was built. But compared to my previous cars (2.0/four D-Jet and 2.2/six MFI) it feels very strong from midrange up to 6k or so. It pulls significantly harder from 80-90mph than I recall those cars doing. It hasn't been on a dyno yet but I may do that if I decide to swap the cams and distributor for something a bit hotter, for top-end power. The engine is currently quite streetable with a modest 280/429 cam, although it is carbed so not as "get-in-and-go" friendly as a good FI car.

When I get it out on the track (November) I anticipate that it will 'hang' pretty well with just about any non-turbo four or six under 2.5L. The 2.4 911S cars will crush it on the top-end, but they are heavier and have their engine in the wrong place and won't be in my class (POC V5, PCA AI/AM) anyway.

From what I've read, I would probably have to agree with Jake that the >2.3L configurations are a compromise that is probably not worth it for many folks, esp. in regular street drivers. As I mentioned before, it is not an issue for me with my planned use for the car/engine and also because it was a great buy (the entire car with this engine was in the same ballpark as a Raby 2270 or a strong used six cyl engine alone).