Dino engine characteristic

I don't own a 246 or Fiat Dino, but I will say carb tuning is a lost art for most mechanics. Some mechanics can do it, most can't. It took me two years to realize my Europa with two Stromberg carbs wasn't quite right, and they are simple compared to Webers. It seemed fine the way my mechanic set it up, but as I learned and experimented, I found another level of power I didn't think my car had just due to correcting the carb set up. It was a long trial and error procedure for me as I am not an experienced mechanic.

I would not be at all surprised if the same applied to the three carburetor Dinos, or any carb Ferrari/Fiat. It's expensive to get a pro to do it, and complex for a DIY guy. I know there's a few of you who CAN proporly tune and balance a Weber system but I bet most of you cannot.

Add to that an aftermarket exhaust system to "maximize" performence (or rob you of it!), the correct timing with that exhaust and maybe an after market ignition, correct spark plug gap and heat rating for the above systems...lots to think about that no factory spec sheet will cover.

Ken

 

Stratos

Get your hand off it mate. Don't you dare to tell me that what I have been doing all day every day since 1987 is a figment of my imagination!!

If you have had toubles and found that sinking $ after $ into new parts has helped you out, then bully for you.

My customers benefit from servicing with attention to detail without waste.

246 WILL run properly with minimal changes to carbs/ignition.

The Dinoplex is fine beyond 7500 rpm too.

Try to express opinions or experiences, not blatant disregard for other people FACTS.

 

I did not take the discussion to personal levels and I'm always careful when professionals are involved.
However saying the problem can be "fixed" is simply not true whether this comes from a professional or not.
I'm am the lucky owner of a Stratos as the name says and my Dino engine outputs a reliable and very useable 275 bhp in Group 4 competition guise. My car never had this problem as Stratoses are fitted with the proper IDF carbs as OEM equipment.
I have at least 5 close friends who have 246GT or GTS and they all know and experience the problem. Additionally I am a close friend of my Ferrari mechanic who has more than 40 years experience in these cars and our discussions on such issues are never on a customer-provider mode, i.e. they are frank.
What we're discussing here is not on a personal level and if professionals are involved then the least they could do is provide correct information and advice.
How can a professional deny the presence of a 40 year old notoriously known problem?

 

Then he's been doing it wrong for 40 years and been giving you wrong advice.

Fuel quality has changed a little, and when Dino's were new they has 100RON fuel. Now with 98 or even lower the best available you need to move with the times.

An ostrich of a mechanic with his head well and truly sunk in the sand will probably have 6 months experience repeated 80 times.

Dino's can be made to run properly, It really is that simple.

So, for the benefit of the forum, express your opinions as just that. My experience of approx 30 different Dino's is that they can be made to run properly.

I've also serviced and maintained a 24V Stratos, it had flat spots initially and had been suffering for years, but a proper tune fixed it.

Oh, and yes you did take it to personal levels..by assuming this forum is read by imbiciles. The Fiat Dino owners are probably quite aware of how their OWN cars are running.

 

I read your arrogant comments above and wonder what interest you might have submitting them to public view. Then the answer emerged, a commercial interest as opposed to me.
What added value have your comments brought to the discussion eludes me.
You bring down other Ferrari engine-tuning experts, assume that I take FIAT Dino owners for fools, etc.

What would be nice however from such a great mechanic as yourself would be to provide valid arguments for your statements. Not a single one was provided, no facts just arrogant, misplaced comments. In contrast I argued and mentioned facts (2x6 carbs being the same as for longitudinal applications, eccentric floats, previous uses of the Dino engine in competition, latter applications of the Dino engine and the way they addressed the problem,...).

You pretend to be able to fix a problem the Dino community has known for decades by "tuning". Sure you can raise the level in the float chambers to decrease the risk of starvation but this is not tuning, it's using the carbs inappropriately.

Am I impressed by the 24V Stratos? No. I have several friends who have a few of those (7 cars in total and 10 24V engines) and I wonder who would ever trust a mechanic other than the 2 known specialists to touch their engines.

Incidentally my mechanic's Dino outputs 290bhp in 2 valve guise from 2.4 litres, I wonder what your engines are able to deliver. He needs no lessons from arrogant individuals with no substance such as yourself.


I will leave to others to judge the added value of your contribution.

 

I'm not saying the problem doesn't exist, merely that it's fixable.

I suggest you re-read the thread and others to judge contribution.

I guess my serviced engines deliver about 195BHP smoothly, as designed, with no flat spots after modifying the distributor slightly. The carbs are NOT the problem.

It's a simple mod, but i'll not waste/divulge the exact methods to you, suffice to say it retains std advance curve after an altered static setting.

I've a Dino in my shop right now, that I haven't even done the mod to, Maybe I should go and re check the carbs again, I'm sure they are std DCN though. Perhaps in your wisdom you know different.

As for arrogance and contribution to the forum...., well, you're the one stating the problem can't be fixed, and that the only cure is to replace the carbs and ignition unit.......when there are just one or two (thousand) Dino's out there that prove you wholly wrong.

Judge away forum, no problem there Mr Stratos. You've stated your case very well my friend. Good luck.

 

Phil.

Unless you're willing to come to Villanova and tweak my car up, I'd appreciate a little more information.

I'm considering replacing the floats with the composite material ones that are available. My car does not have a Dinoplex, it has an aftermarket ignition system.

We're switching to a Euro Spec distributor to get the extra 10 degrees of advance on the timing without the microswitch, and changing the idle jets.

Other than that, what exactly should we do to eliminate the stumble. My mechanic, who services at least a half a dozen Dinos regularly, and I are anxious to hear about your solution.

Ignore Stratos, he's been bugging at us Dino guys to tweak our cars to his spec for as long as I've been on here.

Thanks,

DM.

 

Finally your reasoning is clear. You acknowledge the problem (at last) and now you say you have a cure for it which you will not divulge. Lowly commercial practices. Why don't you say things simply so that everyone understands?
Question: Are the 40 DCNF carbs fitted in the 246 Dino supposed to be operated in transversally mounted engines?

Answer:


I'm waiting.

P.S. I never said anything that could lead to believe that the Dinoplex has something to do with the left-hand turn fuel starvation problem.

 

If the DCNF was simply 100% unsuited to transverse mountings, then every single Dino 206/246 out there would have the problem. But many do not. Admitedly it is not the best carb for the mounting style, but it can, and often does, work quite properly.

Many people chase carb problems around and around, before they get their ignition system 100%. I always tell people to start there.

And for the record, the dinoplex, if functioning correctly, is fine well past 10,000rpm. The dinoplex was used in several race cars of the late 60s early 70s, including the Ferrari 312P, Alfa Tipo 33, etc.). I reved my own car to 8000rpm fairly regularly without problem - no stumbling, no fuel loss, nothing. What is more critical to smooth running, and what made the biggest difference in my own car, is to put the distributor on a machine and perfectly set the two sets of distributor points so they are exactly 180 degrees from each other.

Furthermore, to whomever claimed Fiat Dinos have the same problem: I've been reading the Fiat Dino yahoo group for years and haven't heard a single person complain about the dcnf carbs as mounted in the front engined cars. I would take a DCNF over an IDF anyday. (Although I do have some IDFs sitting on my workbench to put on a fiat spider at some point).

 

Agreed. But consider that it depends on how you use your car. Like I said previously the problem only makes its presence felt when the car is hard cornering situations. Track use reveals it immediately and on track even the cars that appear not to have it will suffer fuel starvation.

That's always a good idea.

I will have to disagree with you here. The Dinoplex used in race applications had very little in common with the commercially available Dinoplex. Much like today's Motronic applications. If perfectly set, like in your case, it will function adequately but for how long until new adjustments are required.
The problem here also includes the fact that the spark is not powerful enough above 6000rpm.

That's exactly what I said, Fiat Dinos will not display the fuel starvation problem.

 

Phil.

Any advice forthcoming?

Seems to me you'd do your credibility some good by helping out here.

DM

 

think i'm now confused as to IDF vs DCNF for longitudinal/transverse applications.

i have always heard that the DCNF's were best for transverse, whereas IDF's are for longitudinally mounted donks.

i have IDF's (40) on my 1608, mounted transversly in my X1/9. the engine belongs in a Fiat 124BC sport which has the engine setup longitudinally.

i've always had issues with the setup on cornering, however the engine was never werking correctly, always a problem with the intake or ignition at some stage. engine has now been rebuilt, balanced and lightened and all that gear, and i'm upgrading to full MSD ignition setup. so in a few weeks it'll be interesting to see how my carb tuning goes.

 

Yes, it gets confusing. A DCNF has the float bowl in the correct place when mounted on a transverse X1/9 or 128 engine, because the engine is an inline 4 and the carb gets mounted with its two barrels side by side, left to right, or however you want to describe it. The carb will face the same direction when mounted in a Fiat Dino, even though the engine isn't transverse because the carbs sit in the V of the engine (and the right side of the carb feeds a cylinder on the right side while the left side of the same carb feeds a cylinder on the left side of the engine V).

Similarly, twin IDFs mounted on an inline-4 like the 124 spider DOHC will have their barrels one in front of the other and mounted in the V of a transverse dino motor they'd be facing the same way.

In short, for IDFs you want the two barrels of the carb to be front-back and on DCNFs, you want them to be left-right. Then the float bowls are such that fuel won't slosh away during hard cornering.

BTW, on the topic of the dinoplex: if any doubt on it's functioning, the MSD 6A of 6AL is a good replacement and can even be made to hide inside the original Dinoplex case.

 

I've tried that but the problem is that the MSD's spark is too strong and will "jump" from one connector to the other inside the distributor. I haven't tried without the MSD ignition coil (which is not recommented anyway) but all in all I went back to the Bosch ignition module which works perfectly well.

 

Ok, go back to the start. raywongs very first complaint is that his car "Bucks if he hits the gas too fast".

That is what I'm saying can be fixed with an ignition mod. Which dmnstuff now knows about and will no doubt try and let us know his results.

The cornering flat spot is also fixable if using road tyres. By having accuratley set up and tuned carbs. However, if you increase power and cornering forces you'll struggle to feed the carbs fast enough. But that's the same on 308 or Dino, which use different axis for mounting their carbs. Setting Dino's DCN's to 308 DCNF's float levels is worth a try. Also, check fuel flow rate by measuring delivery per minute into an accurately calibrated jug.

Also, control fuel evaporation by using clean shiny silver fuel tanks and baulkhead, properly fitted heat shield to every exhaust position, and a well ventilated engine bay. Even propping the bonnet open 30mm when on track will help.

It's clear to me that Stratos will not be told. So he must be shown. Perhaps there is someone near him with a Dino that runs properly, or he could just go to the Uk, where I know of about 20 that are good.........

 

Still generic comments and bla-bla. What about the origin of the issue, what about an answer to my question?
Let's play the count the Dinos game:
Image Unavailable, Please Login

 

not sure if this is relevant to the topic on-hand, the dino wars are distracting me.

anyhoo, the following is a little thesis on DCOE vs IDF from a fiat enthusiast. fairly long but if you find it interesting grab a coffee/beer/sandwich and read on.

original post

bear in mind the engines spoken of are old 4banger fiats, 1.5-1.8 L or so.

 

Stratos

If by generic you mean "Vague", then just read a workshop manual. It's where I get my info to start from. Then I've found VERY few things that need to be done differently from it. One of them being the Distributor mod, which is very easy.

So if you need to be spoon fed, I'm sorry, I have other priorities.

And you don't need to be Einstien to know that any Dino's found under one roof like in your photo are likely to be maintained the same way, so of course they'll all be no good if they're getting set up badly......

Try finding some that are at people homes where they live because they work properly.

I took the Series 1 car I just serviced back to it's owners house today.... it was a delight to drive.

I'll not waste any more time on you now. You're obviously smarter than most of us so we'll just sit back and let you enjoy yourself.

 

Just your usual self, helpful, constructive, modest. Just keep these customers coming in on the bilief of some secret lore that will override the nature of things.

 

Stratos and Phil.

Isn't this section of the forum supposed to be a technical and interest section that helps other owners???

You guys bickering isn't getting the rest of us anywhere.

How about you agree to disagree, fight it out with PM's, and try to give us some actual advice on how to make our Dinos work better.

I don't want 275 gazillion horsepower. I don't want a car that's been hacked and slashed to get me there. I want a stock Dino, that works properly, and gets performance that the factory would have been happy with in 1972, or now.

IF you have hints or clues about how to get the cornering stumble out of the car without external mods, then let us all know. I'd love to drive my Dino hard into a corner and not have to worry about fuel starvation.

Do either of you guys know if the plastic float Dennis McCann offers helps with this problem?

Thanks,

Dave

 

Well, back to the original discussion back on the first page.

The answer, and a bit of the solution in my opinion, to the conundrum is simply answered by looking at the carbs. Like most things, especially cars, these are designed to a set of compromises. The DCNF were designed to have the fuel resevoir face forward, and it is deep and narrow side-to-side to minimize front- rear slosh. The shape of the fuel resevoir is meant to accomodate the most common accellative force, i.e. straight ahead. This tends to press the fuel back up against the resevoir wall next to the barrels where the fuel pick up points are. In decelleration, you don't really need the gas so it can slosh anywhere it wants.

Even in 'normally' mounted DCNFs (float chambers forward) PARTIAL throttle, you can have some stumbling in g-loaded corners. This has to do I think with what I believe is a combination of what circuit you are on, idle vs main, and their relative fuel pick-up points. Remember at partial throttle settings you are probably still on the idle circuit until perhaps over 60 mph level cruise. You'll find if you drive it more like a Porsche 911, i.e. judiciously power through a corner (more fun anyway), this brings the accelerator pump and main circuit into play and the stumble goes away as the fuel is injected by the accell pump and higher throttle openings are covered by the main circuit.

If you think about a sideways mounted DCNF, a la Dino 246, think about where the fuel pick-ups are located and where gas sloshes.

Next time you are in a g-loaded corner and it stumbles, I'll bet it is under partial power, and you'll find it will smooth out by giving it some throttle. I think unless you are hard core racing, if your ignition and carbs are set up well, the Dino DCNFs work fine for day-to-day. Is there cost effective value added for IDFs? - Well, depends on you.

Anyway. Appreciate the excellent tuning wave post by the Ash and the Fiat guys - well written!

best
rt

 

cliff's notes: let the IDF's pump-jet do it's job, like this. no stumble there then.

cheers, oneday i'll start letting the guy know when i flog his material.

 

As Ash so aptly demonstates the use of the accelerator pump in highly g-loaded turn! And his IDF are mounted 'the wrong way', i.e. side to side on a transverse engine as DCNFs on a 246! DCNFs behave the same. It's all about the throttle!
Brilliant demo.

best
rt

 

dm n stuff

I replied to your pm but it bounced back saying ID not known. I explained exactly the mod required, which is very easy, it's just some educated guess work to change the very low rpm advance and a spacer as previously said.

Anyway, I've never tried the plastic floats. I haven't found the need to vary from stock yet.

Although I did find some in a 308...that suffered flat spots, and rectified with float levels setting to stock levels.

 

sorry are we talking DCNF or IDF now? my IDF's have plastic floats...

http://www2.freepichosting.com/Images/95715/49.jpg
http://www2.freepichosting.com/Images/95715/42.jpg
http://www2.freepichosting.com/Images/95715/41.jpg

as you can see from pic #2 there the problem i had with the IDF's was that the float pivot arm broke.