Engine Mods

I'm planning on having the motor in my 246 GT #05548 rebuilt this
winter and am considering whether and what sort of modifications might be fun. I wouldn't want to change the character of the engine but also wouldn't mind another 20 horsepower or so. Valves, cams, high compression
pistons? Superformance, J&E custom pistons, Dinoparts, etc. etc...? Would love to hear other's experience and opinions in this regard.

thanks,
Robert Willis

 

Big valves (45mm,39mm), big cams, 11.4:1 compression, ported heads, 48mm carbs, titanium conrods, interconnected headers, lightened flywheel, dual plate clutch, ..., racing gearbox, 278bhp, 29kg/m.

A different beast for the Stratos.

Not really compliant with your requests, not for the faint hearted.
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More...
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More please....what modifications to the inlet ports? What about 4 valve heads?

 

Ports have been enlarged and aligned to match 48mm cards on the inlet and the exhaust manifolds.

The 24V 246 Dino engines are a big story:
There was a total of 25 24 valve kits produced. As you can understand those left (less than 18 engines) are ultra rare and ultra expensive. Prices for complete 24V engines are now reaching 180K $.
The advantage of 24V heads is mainly 10-15% more power but less torque and their torque curve is higher up and less linear.
24V heads were made for competition only and where used until banned by the FIA in 1977. Some engines were also featuring Kuegelfischer mechanical injection. The fact that these heads were competition parts means that they are less durable (some say made out of cheese). Some castings were porous and consequently not used. They did however find their way into the modern market (picture of a porous long head attached). In my view they are unusable and beyond repair.
24V are GREAT engines but are, nowadays, better musuem ornaments than power units.
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Improving the seals and gaskets with modern ones that are made to hold synthetics. A vintage racing expert has done it on several older cars and claims it should be able to be done for the Dino, so we're about to launch into this.

 

Keep in mind however that the Dino, as most other Ferrari engines, is using 2x the clearances of a "normal" engine. Using modern seals and gaskets is not guaranteed to produce tangilbe results.

 

You can get some significant performance gains without going crazy.

I changed to the high compression superformance pistons, had the rest of the engine cleaned up, new valves, seats and guides, and changed the exhaust to a stebro sport exhaust.

My car makes 178 RW HP and has a very nice flat torque range. Considering it's a US spec car, and only made about 175 at the crank when it left the factory, that's more than the 20HP you're looking for without spending ungodly sums of money.

All in, these changes probably cost $7K.

DM

 

I justgot my Dino engine back from Italy and it dyno'd at 251 HP. Looks totally stock.

 

stratos, amazing information on the four valve heads, I had no idea that they existed. Do you have these heads on your Stratos?

 

We're getting 300hp out of the (2 valve) engine in our Stratos. It has modifications similar to those described by stratos here. The engine itself is quite tractable but the lightened flywheel/competition clutch is too hard to live with in a street car.

These engines respond very well to bigger valves and head porting, high comp pistons and bigger carbs. This is as far as I would go for a road car.

Superformance in the UK are good people to talk to.
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I don't have 24v heads, I use a big valve 12V. Many parts are different as compared to 12v Dino engines including distributor, inlet maniford and fixings, camshaft mounting gear (some camshafts were mounted on bearings too), ...
The list is endless and these parts are EXTREMELY hard to source today.

2 of the 24v kits made were "special" in the sense that their cam covers had the word "Lancia" etched on them instead of the "classic" Dino 246.
These were used for press pictures and PR at the time.
Here's a picture of one of these kits.
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Look at the exhaust units with the secondary piping.

 

24v exhaust manifolds are slightly different from 12v ones in the way the pipes are bent.

What you call "secondary piping" is in fact one of Maglioli's inventions that allows the engine to develop much more power and torque in intermediate RPMs.
The small tubes interconnect the main ones. Their position is precise to the millimeter, failing that the setup will not work.
Each main exhaust tube has 3 small holes at the location where the small tubes are connected. The size of the small holes is essential too for the setup to work.

This setup is exploiting engine harmonics to atteign very significant improvements of available torque and power (+10 to +25bhp) between 3000 and 7000 RPM while losing less than 1-3bhp at max RPM as compared to a simple manifold.

 

So who are the good, reliable Dino engine builders now?

By the way, Ian B, I have a Stratos too and your exhaust manifold looks VERY different from mine. Did you fabricate it yourself?

Stratos, your parts are incredible. Is there a good source for these, even if newly manufactured?

 

I have been rebuilding my Stratos for the last 3 years. Sourcing parts is most of the work. They are rare, expensive and you have to know where to look. Every now and then you get lucky. I have sourced parts mainly in Italy but also in Germany, US, Japan, Switzerland and wherever Stratos passionates are located.
The billet titanium conrods are a short story themselves:
They were made by the same small Italian workshop that was providing the Ferrari F1 team up to 2003. The old owner of the factory was going to retire and none of his familly member was willing to pursue the activity. He had 4 sets made for me and 3 of my friends and this was his last ever production...Note the craftmanship, they're so well made that you can't make out the cut of the big end part even when you look closely at it!!!

I limited myself to engine components here as those may be of interest to the Dino community. There is however so much more that is Stratos specific and that I have not mentionned.

The Stratos is my passion and for me is a unique case in automotive history just as the GT40 was for the track. The 1st and only purpose built pure racer designed from a blank sheet of paper and able to be used on the street for the last 35 years.

Did you know that the gearbox shortshaft is hollow?
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Amazing info, thanks you, I always wondered about the 4 valve heads...no i know. I'm sure there exists a video or dvd of the history of the Stratos any one know about it?

 

http://www.alapage.com/-/Fiche/DVDVideo/575585/DVD/?donnee_appel=EOMDO&sv=5-31027_B
English and French, almost accurate info, excellent.

 

Stratos, thanks for all the great dino info and pictures. I don't think anybody else has taken this motor to such heighths.

Gary

 

Nice items, very impressive, thank you for the photos.

I see your intake manifold has O-rings that are black in color. I've had great success cross referencing the intake manifold O-Rings on my Maserati Bora to modern O-Rings made of Viton (typically brown in color). This is a superior material that withstands heat and a variety of fluids far better than stock yet doesn't dry out or get as flatspotted as stand O-Rings. They are four times the cost of the $0.50 stock ones, but well worth it and fit nicely.

You may want to consider modern O-Rings, if these are not already.

 

Thanks, I shall order it today!

 

The engine was developed by a well known Lancia specialist over several years in the late 80's for GT circuit racing in the UK. The headers are a big part of the remarkable diveability of this engine and I haven't seen anything like them before either. It also has very trick cams, big valves, lumpy pistons, hand-made head gaskets, etc. Pic of the front headers attached.
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Sooo nice! What size ehaust ports on this unit?
The full fledged rally unit at the end was using 4 v heads and a twin turbos with intercoolers was it not? I heard a bout 1200BHP?

 

Only 2V engines were fitted with turbo (single). Outputs were in the region of 580bhp @ 1.7bar.

 

Thanks,
even 580 is pretty staggering.