Technical Heater tube arrangements for a 650 engine i a Fiat 500

[fiat500]

I've put the 500 version of the thermostat housing on the 650 engine. The direction that the hot-air outlet points is no problem despite the starter-motor appearing to be in the line of it.
I've adapted the metal transfer tube from the 500 tofit by drilling and filing a slot for the starter-cable stop and bashing it out of shape. But the problem I'm having is that despite that, there is not quite enough clearance between the tube and the starter to allow me to fully slip on the rubber outlet pipe, so the clip doesn't really grip.
MAL_3875[1] by Peter Thompson, on Flickr
It looks like the alternative steel transfer-tube available for the 126 and "R" doesn't have any different geometry to the 500 version, just the dent to clear the starter and the hole for the nylon stop.
Some of you must already have achieved this and I would appreciate knowing how.

 

[Vitesse]

I've put the 500 version of the thermostat housing on the 650 engine. The direction that the hot-air outlet points is no problem despite the starter-motor appearing to be in the line of it.
I've adapted the metal transfer tube from the 500 tofit by drilling and filing a slot for the starter-cable stop and bashing it out of shape. But the problem I'm having is that despite that, there is not quite enough clearance between the tube and the starter to allow me to fully slip on the rubber outlet pipe, so the clip doesn't really grip.
MAL_3875[1] by Peter Thompson, on Flickr
It looks like the alternative steel transfer-tube available for the 126 and "R" doesn't have any different geometry to the 500 version, just the dent to clear the starter and the hole for the nylon stop.
Some of you must already have achieved this and I would appreciate knowing how.

Which end are you having problems with? The left hand by the dent? I've got a 126 one in the garage. I can measure it for you if you need any comparisons? Let me go and get it and I'll post a picture.

 

[Vitesse]

Here you go fresh off the press! Just noticed as well there are two little metal tabs to the right of the hole where the starter cable stop goes which I assume you tuck the cable behind?

 

[fiat500]

Thank you for that. I think I've worked out that the position of this item under the floor may be slightly different on a 126. Temporarily I have removed the screw nearest the engine and will re-drill in a new position that takes it away from the starter just enough. I was going to use chassis wiring clips to emulate those tabs but the cable l
simply found its own route and the surplus from one of the hose clips on the final flexi-pipe wrapped round and secures it. At least it's sorted sufficient to let me pull the starter. All sorts of factors may have contributed but the starter action is more positive now.

 

[Vitesse]

The dent is for the solenoid isn't it?

You could have gone all sophisticated like what I am!!!!! Well the plan is I should say and ditch the starter cable and start it all modern with a key!!!!!

I thought it would have been right up your street seeing you have turned into a modster

 

[fiat500]

I actually traded in my solenoid operated one for a pull-starter. I don't mind adding things but I won't take the away.

 

[stevehg]

I actually traded in my solenoid operated one for a pull-starter. I don't mind adding things but I won't take the away.

Agreed, like you, in a bizarre way I personally prefer the hand starter. Part of the cars character. Glad you got the cable sorted in the end.

Cheers, Steve

 

[fiat500]

Re: Heater tube arrangements for a 650 engine in a Fiat 500

The flexible rubber tube from the thermostat cowling was barely long enough with the new engine, which was odd as I have used a 500-type cowling and it was OK before. After a couple of hundred miles it has already been forced off at one end. In the course of digging through my many boxes of old spares I found what I presume is an original flexi-tube; it's quite a bit longer.
MAL_4807 by Peter Thompson, on Flickr
So with that problem sorted I have encountered another one; despite having bashed the metal heater tube to clear the starter, when the metal clip is fitted it all but touches the starter terminal. Obviously this is a lethal situation to have and the tight clearances are almost certainly why the starter was originally fitted at the top on the 500. Another less serious problem is that the heater tube is very close to the suspension spring as I attempt to move it away from the starter. I have also had to shorten the exhaust shield plate by a significant amount.
I wll get hold of a 126-type heater tube but I suspect that I will have to do some more modification to that by way of removing and re-welding the mounting brackets.
I wonder how straightforward this proces of modification has been for other people.

 

[fiat500]

I notice that VdL have started selling the correct exhaust deflector for a 500R.
viewarticle.php by Peter Thompson, on Flickr
This would be much better modification to my F than the current deformed shield which I think vibrates at some speeds.
So I'm going to do the job properly and fit the proper 126/R thermostat cowling and buy the proper heater tube:
1 by Peter Thompson, on Flickr
So my question is; which flexible tube will I need? There are two types of this listed as 19mm and 21mm.
t by Peter Thompson, on Flickr

 

[Bigvtwin996]

Thin end of the wedge is all I will say...

 

[fiat500]

Thin end of the wedge is all I will say...

Better???

shield by Peter Thompson, on Flickr

 

[Vitesse]

I think you mean 19 or 21 cm? I was trying to get my head around what measurement you asking about, so looked on their page. I would go 21cm as they have another one on there which says "similar to original 21cm". If you bought the shorter one and it is too short you are knackered. With the 21cm one at least you can loose the extra length in the concertinas or trim it.

 

[fiat500]

Re: Heater tube arrangements for a 650 engine in a Fiat 500

When I fitted the 126-type engine I had to deal with the heater transfer-tube dilemma. So I followed the advice of others and bashed a dent in it so that it cleared the starter motor and filed a key-slot to fit the nylon cable-stop for the starter-cable. But with all this I still struggled to re-fit the thing securely and safely. One of the spring clamps for the flexible pipe had to be removed as I was worried it might cause a short at the starter. I was unable to fit one of the two self-tapping screws that fix the solid tube under the floor because when the brackets were aligned with the holes it meant that the tube was too close to the starter.
I blamed myself for being a cheapskate and supposed that my modification to the tube had been done badly; that wouldn’t be surprising as I only had photos to work from and I’m not good at tin-bashing.
There were incidental problems caused by my bodging; the heated air was being slightly diluted with cold air sucked in where the clip was missing and there was a rattle which may have been caused by setup being insecure.
Eventually I bought the correct solid tube as was standard equipment on the 126 and I suspect also on the 500R. From experience I know that the coating that this sort of item is supplied with has a tendency to flake off and rust very quickly, so it was stripped, epoxy-primed and painted with black matt spray enamel. https://www.screwfix.com/p/no-nonsense-anti-corrosive-spray-paint-matt-black-400ml/4702r
It can be seen from the images that I did do a useless job with the indentation but was remarkably accurate with the slot.

MAL_5391 by Peter Thompson, on Flickr


But the real problem with the original becomes apparent when you see where the brackets are on the new one. One of them is offset at a different angle than on the original Fiat 500 and this changes the whole orientation of the tube, which helps in avoiding a collision with the starter-motor.

MAL_5390 by Peter Thompson, on Flickr
In conclusion, you can change the engine for a 126 and either keep its thermostat housing or, as in my case, keep the 500 one, but if you want to re-use the transfer tube, in addition to making the slot and bashing a heck of a dent in it, you also need to remove and re-orientate the fixing bracket at the starter-motor end; much easier I think to simply buy a new tube.
Incidentally, as the heat deflector plate that fits above the exhaust is now available brand-new as fitted to the 500R, I also bought one of those. I had to cut down the original one and it looked a bit messy and maybe caused some vibration.

MAL_5392 by Peter Thompson, on Flickr

Although the anti-modsters will think I’ve sold out even more, all I’ve done with this one is found the proper engineering solution to bring this area up to 500R specification.

 

[Vitesse]

Re: Heater tube arrangements for a 650 engine in a Fiat 500

I blamed myself for being a cheapskate and supposed that my modification to the tube had been done badly; that wouldn’t be surprising as I only had photos to work from and I’m not good at tin-bashing

Are you getting ready for winter and keeping nice and crispy?

So you can rebuild cars and weld like a pro but you haven’t mastered the art of bashing a bit of tin with a hammer!!!!

 

[fiat500]

Re: Heater tube arrangements for a 650 engine in a Fiat 500

Are you getting ready for winter and keeping nice and crispy?

So you can rebuild cars and weld like a pro but you haven’t mastered the art of bashing a bit of tin with a hammer!!!!

I'm already wearing a fleecy jacket and a woolly hat most days. Just waiting for the salt to hit the roads on which I will not be driving this year.:yuck:
It's kind of you to compliment me like that, but if you see my recent pictures of the neat and uniform layer of bodyfiller on the front of my van then its obvious what I mean. As long as the metal is there, some people can get back the shape in any dented panel; :worship: my "achievements" are noticeably more limited. :bang:

 

[Vitesse]

What’s the difference Peter between the exhaust deflector shield on the 500 engine and 650? Is it the exhaust getting in the way? I wonder if I really need one, as I haven’t got a distributor? I am guessing the main purpose of it is to attempt to lessen the heat on the distributor?

 

[fiat500]

What’s the difference Peter between the exhaust deflector shield on the 500 engine and 650? Is it the exhaust getting in the way? I wonder if I really need one, as I haven’t got a distributor? I am guessing the main purpose of it is to attempt to lessen the heat on the distributor?

It pulls in a bit sharper at the back so as to avoid the downpipe. It might not be a problem if you have that later,-type exhaust.

 

[Vitesse]

It pulls in a bit sharper at the back so as to avoid the downpipe. It might not be a problem if you have that later,-type exhaust.

Yeah you’re probably right as it has that odd up and over two into one exhaust.

 

[gordinir8]

This is a mod I am thinking to do when winter come. I always disconnect the heater flex tube at summer for better cooling and to avoid any heat air get into the cabin since this heater flap is not the tightest you can have. Anyway I am thinking to put a flexi tube all the way to the tunnel input and discard the metal tube. Not sure yet about the 500 housing or I will keep the 650. Do you believe a silicon spiral tube that can stand 150 celcious is appropiate?

Thomas

 

[Vitesse]

Re: Heater tube arrangements for a 650 engine in a Fiat 500

But the real problem with the original becomes apparent when you see where the brackets are on the new one. One of them is offset at a different angle than on the original Fiat 500 and this changes the whole orientation of the tube, which helps in avoiding a collision with the starter-motor.

Peter did you use the existing holes under the car on the floor pan, well seat pan and just change the orientation to fix it using the self tappers?