I have reed that later 650 engines have differencies and are better than early model's. Some say that late type don't even need a panda 30 head mod for those that want to go faster except if you going for heavy modified unit, not my case.
Since I am looking for a 650 engine do you know how I can tell which are those late engines? Any serial numbers or date of manufacture? If I do the mod I think it will be better to put the best 650 available.

Thomas

If I had the choice of any 650 engine then I would go for a 1986 onwards one but not the very later Polish models that do not have a distributor. That engine has the later camshaft and larger valves with unleaded seats. In standard form it will pull quite well in a 500. Not sure about engine numbers but the earlier engines just had 650 on the cylinder head casting and the later ones have an additional code above the 650 marks.

The 650E came in 1984 model year for the 126 (E means economy). The head on that engine is different from the older type head. The compression ratio is 8.0:1 vs 7.5:1. Those engines also have different carburetor jetting, and the wasted spark ignition. All the FL (face-lift) models 1985-1994 have this engine. The wasted spark ignition has a distributor with points but no rotor or cap. Both plugs fire at the same time. You can remove the points and install an electronic system like Pertronix.
The EL model 1994-2000 is the same, except it has the Nanoplex ignition with no distributor, different jetting and exhaust. I personally would stay away from the Nanoplex as it is more expensive to replace parts and there is more wiring and complexity to contend with.

I would look for a Polish FSM 650 engine from 1985-94. The engine I have that I am rebuilding is a 1994 FSM 650 with the wasted spark ignition system. This gets you 8.0:1 compression ratio. Using a 0.5mm copper head gasket you can get the compression up even a little higher and not have to do any heavy machining of the head which removes the safety gas ring cast into the head.
If your FSM engine has a serial number of 6621475 or higher then you have hardened valve seats.

These later 126 cylinder heads have some letters and numbers along with "650" on the casting where it is visible. Just 650 in that cross hatched area will be an earlier head I believe. Pictures are of my cylinder head showing 650 cast into head (with additional numbers and letters) and the date code stamped into the head (94 = 1994). The picture clearly shows the filled in area of the combustion chamber which increased the compression ratio to 8.0:1
My engine case is also stamped 1994.

John

Ooh not much love for the distributorless Nanoplex setup on this thread? If anything it is a lot less complex and less to go wrong than having a distributor. The only thing that can really go wrong with it is the control unit and they cost about £50, a lot less than a replacement distributor. Once installed forget about it, no timing to adjust.

I would have probably thought the same a few years ago until I saw the distributorless setup but I definitely see it as an upgrade now.

Vitesse said:

I would have probably thought the same a few years ago until I saw the distributorless setup but I definitely see it as an upgrade now.

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I think the key thing about the Nanoplex system is that there is very little that is ever likely to need replacing or adjustment. I suppose that on the spectrum of divergences from our Fiat 500 comfort-zones, it just falls too far out for some people.

I like the ability to modify the timing quickly by adjusting the distributor, just ask Peter he's an expert by now!
The wasted spark ignition is really very reliable. If you are rebuilding the engine, then making sure the distributor is in good shape is easy. Replacing the points with Pertronix or another electronic trigger system makes it foolproof.
John

I remember wasted spark ignition being used on some older Japanese motorcycles.

I'm also familiar with the Citroen 2CV (2 cyl. air-cooled), one set of points, no distributor cap/rotor arm which had a double-ended coil (2 outputs) which connected directly to the spark plugs.

But I've wondered if a wasted-spark ignition system doesn't, at least potentially, result in a weaker spark being produced at both spark plugs ?

Al.

I guess that I am anti nanoplex as I have no experience of running it. However I did buy a bundle of 500/126 parts a few weeks back which included a nanoplex control unit. Interesting to see that it is made in Italy but they were only fitted on the Polish cars. The guy charged me £10 for it and I am happy to sell it on if anyone wants to carry a back up spare.

I have just been out to garage to check my engine number and it starts with 625. So mine is not the latest but not bad.It came with the car which was a complete lot of bits.

phoenix1 said:

I have just been out to garage to check my engine number and it starts with 625. So mine is not the latest but not bad.It came with the car which was a complete lot of bits.

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You have earlyer s/n but does it has the 650 stamp with the numbers and letters? Is it a high compression engine?

Thomas

Yes It is a Polish engine I think .Can you tell me if its got hardened valve seats.

If I understand well since you have the stamp 650 with numbers and letters then you have high compression head but early s/n means non hardened valve seats, I am not an expert, so better wait for a second opinion

An interesting thing that has come to light with the Nanoplex setup, is it comes with a vacuum sensor that connects to the Nanoplex on one of the pins. On the end of the sensor is a rubber pipe.

I have been having PM conversations with Stevehg and Pod500 (Chris). Chris was asking whether the sensor needed the rubber pipe connecting anywhere as his engine wouldn't rev? Steve didn't have this sensor on his Nanoplex engine and it ran fine without it, so we came to the conclusion that the Nanoplex would sense whether the sensor was there or not and compensate accordingly. When I bench tested my engine I just left the sensor swinging in the wind and it ran fine.

A little more research and I think it is a possibly a MAP sensor that adjusts the timing by sensing the vacuum pressure in the inlet manifold? If it is then it would suggest there should be somewhere on the carb for it to plug into? Oddly on the spacer between the carb and the head there are two little pipes that look like they should take a pipe, but why two? I just assumed they were overflow pipes for the carb. I need to do a bit more investigation to see where the other end of these little pipes go? Looking at the picture it does look like only one of the pipes might have something on it judging by the colour?

Vitesse said:

A little more research and I think it is a possibly a MAP sensor ?

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You're not doing much to enhance the love for that ignition setup among the masses, although personally I can see the benefits of it for optimal fuel economy and emissions control. I guess those factors don't figure too large for many 500 owners.
I had already come across a site (Hungarian I think) where this was touched upon. It seems that although not used on the 126, some of these Nanoplex systems could also turn off the fuel at the carb solenoid when the engine was on over-run. That might explain those two possible vacuum pipes.
See post 267 here:
http://fiat126.hu/?p=116&t=18&d=1&v=5&q=

Starting to get interesting.

The late Polish built 126's were designated EL and the last lot were ELX. The ELX had a lambda sensor as it was knocking around when emissions started to become highlighted. The engine I have is an EL which as that post suggests does have a MAP sensor.

The other fuel cut off solenoid they refer to is that thing that Sean had problems with. My understanding is that it was an anti run on valve but from what they are saying it appears that it does do that job but also would cut the fuel supply during engine braking, so it must have taken a signal from the Nanoplex to tell it when the revs were low? I don't have that solenoid anymore as I managed to trash that carb and bought a new one, also I sent Sean the solenoid.

A lot of these additions were to do with emissions by the look of it and I know for a fact the engine runs fine without the MAP sensor but it will be interesting to see where those two little pipes go on the carb spacer, I would have thought if they were just holes into the inlet manifold then they would create problems?

ELX
http://www.ebay.co.uk/itm/Distanzpl...307201?hash=item360bfc2241:g:o8oAAOSwt6ZWVZvP

fiat500 said:

ELX
http://www.ebay.co.uk/itm/Distanzpl...307201?hash=item360bfc2241:g:o8oAAOSwt6ZWVZvP

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Ok thanks I looked for some pictures of the ELX engine bay and you can clearly see the two rubber pipes connecting to the carb spacer. One seems to run away to a black box mounted in the engine bay. The other looks like it is connected to the vacuum sensor, which makes sense. I wonder what the black box does?

I can easily get rid of all the sensors and just put a normal carb spacer in but I am intrigued now as to what all the other bits do?

I will post on the 126 part of the forum and see if anyone knows?

So i might have found one of those EL or ELX engines like at your picture, (i am still negotiating), do you think is the best choice for me?
I can see some extra wiring attached to the fan case, is this the pic-up wire for the electronic ignition?
Besides the engine are there any other parts (electronic modules etc) that i should buy together?

gordinir8 said:

So i might have found one of those EL or ELX engines like at your picture, (i am still negotiating), do you think is the best choice for me?
I can see some extra wiring attached to the fan case, is this the pic-up wire for the electronic ignition?
Besides the engine are there any other parts (electronic modules etc) that i should buy together?

Click to expand...

It really depends if it is complete or not? You need to make sure you get all the components that are needed for it to work and how competent you are at electrics, as it requires a bit of tinkering.

The extra wiring on the engine casing is the sensor for the flywheel, it uses little tabs on the back of the flywheel to send a signal to the Nanoplex control unit, which in turn send a signal to the twin coil to tell it when to spark. It's certainly a lot simpler using a standard distributor setup but this offers a step up in technology.

Having spent all day virtually on Google translate reading German and Italian websites. The vacuum switch is connected to the carb spacer which is obviously the inlet manifold as well. The vacuum senses the pressure inside the inlet and this allows the control unit to switch between two different maps, so in theory the engine should run more efficiently.