Technical Engine Performance Due to Heat

[the hobbler]

Yes, I would reccomend that you still fit the housing with the thermostat and re-install the heater flap. Fiat designed it so that, with the thermostat closed, the engine will warm up quicker, and then with the thermostat open stay (hopefully!) cooler. They don't come up for sale very often, so I would suggest that you grab the one from 'Van de Laan' and get it cleaned, painted and fitted. A new thermostat might be needed, but you can test the old one in a bowl of water on the cooker---as it heats up, it should extend.

 

[IanEmery]

Another, very simple, answer to the coil getting too hot is to do what Fiat did with the 500N&D and that is mount the coil on the other side of the engine where it is so much cooler. Of course you will need a longer ‘King’ lead but they are available where prototipi parts are sold!

Simples

 

[the hobbler]

Or, any good engine shop should be able to make up a lead to the length you require. Just make sure that it is located well away from the exhaust on its way back to the distributor.

 

[ilgrilleto]

Thanks guys, suffice to say i've got quite a few solid options here. I'll keep you all posted on the progress. The most tempting option at the moment is to relocate the coil, but first i'll have to install those spark plug grommets and new coil, and see if that doesn't just solve my issue. Thanks again everyone!

 

[Labman]

Another, very simple, answer to the coil getting too hot is to do what Fiat did with the 500N&D and that is mount the coil on the other side of the engine where it is so much cooler. Of course you will need a longer ‘King’ lead but they are available where prototipi parts are sold!

Simples

Limited access on that side of engine due to air filter and tinwork getting in the way of a drill. I thought about that but seems hard to mount on that side.

 

[ronstox]

Hi, sorry for the non-sequitur here, but I have a question for IlGrilleto about importing a Fiat 500 into Canada. Maybe you can help. I'll send you a private message with the details.
That is all. Carry on.

 

[the hobbler]

I realise that it may not very elegant, but why not make up a bracket that will utilise a couple of the bolts that hold the top and bottom of the fan shroud together. If you use the 2 bolts to the extreme left of the shrouding, it will be out of the way of the dynamo, but very accessable

 

[ilgrilleto]

Hi Everyone,

I promised updates so here they are.

First off, my new Bosch Blue coil arrived today from Pelican Parts, and I was able to find a few minutes this morning to install it in place of my OEM Magneti Marelli coil that I mistakenly ordered when ordering my 123 Ignition System . Anyways, this evening I went out for a 30 minute spirited drive, and all I can say is WOW! What a difference, the engine cold starts much easier and feels like it's ready to go in about 30 seconds vs +/- 5 min. When driving it feels like an entirely different car. Throttle response and power delivery feel much smoother, and honestly it just feels like the car has more power. I was able to drive much further than I typically would before the engine starts to act up, however upon reaching my house, instead of down shifting I put it in neutral to coast, and the engine sputtered a bit and died. That said, a hot start was also a breeze compared to the previous coil. After parking the car, I reached down to feel the coil and it was too hot to hold for any length of time. So at this point, the new coil is definitely an improvement but there's still a heat issue.

Taking inspiration from Labman's heat shield, I decided to try making up a temporary one and was measuring and marking and measuring again when I stumbled across a small pile of license plates that I've been meaning to return to our Ministry of Transportation for a few years now. They are ideal in size and flexibility to create a mockup heatshield, who would have known. Attached is an image showing what I've managed to put together (the curve of the plate is much more pronounced in person and essentially wraps the coil), and tomorrow i'm going to repeat that same drive and see what happens.

The final heat shield will be made from much better steel than our license plates, and cut a bit more nicely to look somewhat OEM (that's the plan anyways).

Hopefully tomorrow the heat issue will be that much closer to being resolved. Spark plug wire grommets should be here sometime this week hopefully as well, so that'll be nice. If all else fails, it is tempting to consider just relocating the coil but we'll wait and see.

 

[lazylobster]

So, I had similar issues and tried 3 different coils. All get too hot to touch so I think this is normal. My problem was a bad plug that once it got hot post 20 mins, it started to break down and short. I also observed resistance in the spark leads.


So, for cheap insurance, I replaced.
Plugs
Rota
Dist cap
leads to Silicone ones.
coil


Also installed electronic ignition. Not 123, hall effect.


The coil is still too hot to touch, so as someone said to me, don't touch it! But my car does not have any issues when hot.

I adjusted the tickover to 800rpm (when engine hot) , as I'd rather have some oil pressure and cooling going on.

Finally, I noticed that you appear to have an original fuel pump. for a few pounds, euro's, dollars, you could consider to change it. Do you know how old it is, it could be very old!

Anyway, just my opinion.


Rob

 

[ilgrilleto]

Hi Rob,

Last summer I replaced the plugs, wires (new silicon wires), coil (which has just been swapped), and distributor (123ignition). I'm going to have a look at the plugs today as well as wire resistance and depending on their state, maybe throw in a new set of plugs for good measure as the oil coil was clearly producing a weak spark. I'm using NGK BPR7HS which I understand from these forums is a good and recommended plug.

As for the fuel pump, no idea of its age as I just got the car last year and haven't had a chance to really dig into it much until recently. I assume you would either rebuild it or swap it with a new mechanical unit?

As for the idle speed, i think that this would help quite a bit, I don't have access to a temporary tach or timing light at the moment so going to try and rectify that today!

 

[the hobbler]

Looking at the picture you initially put on the Forum of your engine. it looks like you have an alternator on your engine. If so, be aware that you will need a 126 fuel-pump and NOT a 500 version. The pump for the engines with alternators is a different shape to that for engines fitted with a dynamo, to allow you to fit it without having to take the alternator off!
It would also be wise to purchase a selection of gaskets for the pump-spacer. The pump operating pin has a specific distance that it must stick out past the spacer AND THE GASKETS---it is between 1 and 1-1/2mm at the START of its movement--i.e. at its furthest IN position. This measurement is achieved with gaskets on iether side of the spacer.

 

[ilgrilleto]

Thanks very much! I was just browsing on mrfiat.com and noticed the different version of the fuel pump for Fiat 500/126's with an alternator and suspected that's what i'm looking for, and your comment confirms! For $46 US, might just add that to the cart!

 

[lazylobster]

Thanks very much! I was just browsing on mrfiat.com and noticed the different version of the fuel pump for Fiat 500/126's with an alternator and suspected that's what i'm looking for, and your comment confirms! For $46 US, might just add that to the cart!

For not a lot of money, makes sense. At least you know where you stand etc

At the end of 500 ownership, after many years, you'll end up having a new car

R

 

[ilgrilleto]

Hahah, already well en-route to that a new car at this point!

 

[ilgrilleto]

Hi Everyone,

Yesterday I took a test drive using my mockup heatshield, and while the problem is not yet solved, I felt like I was making progress. I had no issues with idle on my drive until I pulled up to my driveway and car sputtered and died, but I no longer think the issue is with my coil as the mockup heatshield performed admirably and the coil was barely warm to the touch. Luckily my neighbour owns a machine shop, so he's going to make me a permanent heatshield that looks a bit better than a bent up license plate and some Ikea "L" Brackets.

However, onto today. I installed a pair of brand new NGK BPR7HS plugs (installing those with the carb in place is a nightmare btw), gapped to 0.024" just like the pair I removed and took it for a drive. It started great, but even after about 5 minute of driving (drove great as well), it would slowly die at idle, I had to feather the throttle to keep the engine alive. When I got home, restarting the engine when hot became a chore. I tried to cheat a bit and tried to adjust the idle speed on the carb, however it didn't help any at all. I could rev to any range i wanted with no issue, and if i held the throttle open even the smallest amount, there was no issue, but the second I let off the throttle entirely, regardless of hot/cold, idle adjustment/no idle adjustment, the engine would slow down and die.

At this point, I'm not sure heat is the issue anymore, though my intake manifold still heats up quite a bit (but the fuel line running to the carb isn't even warm). I'm thinking I should probably just adjust the valves as I have no idea when they were last done, and from all my reading on these forums, it seems like a good amount of the issue i'm experiencing might be able to be tied back to them. Toshi, I remember in a previous reply you mentioned that you would allow for an extra thou or two of clearance due to the head I'm using, it that based on an inlet of 0.20mm and 0.25mm exhaust?

What do you guys think?

Thanks again!
Vince

 

[ilgrilleto]

Update...Success...All Issues Appear to be Resolved!!!

After a bit of research on the forums, I decided to give the valve adjustment a try. I used 0.20mm intake/0.25mm exhaust as a reference point and did my best to guesstimate a small amount of extra clearance so that the feelers passed through with a little less resistance than would be typical. Initially the exhaust valves had no play and took alot of adjustment to bring them into spec, the intake valves weren't as bad, but still far out of spec.

The first start after the adjustment was impressive. The engine immediately fired to life and began to idle, while cold, which I had never seen happen with this engine. It also sounded awesome! I took it for about a one hour drive, pulling over twice to test hot starts which, i'm extremely happy to say, were almost instantaneous. The engine is more responsive, runs much more smoothly, and sounds better. It really feels like driving an entirely different car. Suffice to say, the idling issue is completely gone. Regardless of what speed I decelerated from, or how hot/cool the engine way, the idle was rock solid.

Another thing to note was that the engine bay, while still fairly warm, was nowhere near hot. I'm still going to have the coil heatshield fabricated, because at this point why not, however I didn't realize how drastic of a difference that valve adjustment would make.

Thanks to everyone on this thread for their time and knowledge, it was much appreciated!

 

[DimitriL]

So happy for you! I learned a lot from your posts. My engine bay is also getting hot, but I have no issues with my car, other than a hot start being somewhat difficult. I plan to wrap the exhaust headers, and shield the coil somehow. Will also take a look at valve clearance. Thanks again!

 

[ilgrilleto]

Hi DimitriL,

Happy to hear that these adventures have been helpful Good luck with the wrap, coil shield, and valve adjustment. All of these things take a bit of time, but are by no means difficult. My newly made coil shield is having it's paint dry right now, but when it's done, i'll post a photo of it installed. It's just a small piece of stainless steel bent to fit, but it works perfectly!

 

[lazylobster]

Hi DimitriL,

Happy to hear that these adventures have been helpful Good luck with the wrap, coil shield, and valve adjustment. All of these things take a bit of time, but are by no means difficult. My newly made coil shield is having it's paint dry right now, but when it's done, i'll post a photo of it installed. It's just a small piece of stainless steel bent to fit, but it works perfectly!

Do you have an infra red heat temp gun? A reading of the coil before and after fitment of the shield would be interesting. Same duration drive etc.

R

 

[ilgrilleto]

Hi lazylobster,

Unfortunately not, the best thermometer I have available right now is just my hand. I will say that after the valve adjustment, and without the heatshield, the coil gets hot to that point where it's uncomfortable to hold but it is possible. With the heatshield, the coil barely gets warm. If I get access to a thermometer or pick one up on sale, i'll post an update with those numbers!