Technical Uno Racer Not Idling

[CLXCraig]

If a new carb is needed, see this
https://www.fiatforum.com/classifieds/showproduct.php?product=14273
could get it fairly cheap.

 

[Chas Uno]

If a new carb is needed, see this
https://www.fiatforum.com/classifieds/showproduct.php?product=14273
could get it fairly cheap.

Thanks for the link but that's not a 1.4 SPi throttle body (as described in the ad) nor is it suitable for the RSF car (which uses a real carb, not a Single Point Injection (SPi) unit). The carb pictured in classifieds looks more like a single choke Weber 32 TLF used on the FIRE engines. The RSF car uses a Weber twin choke that has totally different fittings and flange mountings.

The 'spitting back' through the carburettor in Matt's car is the giveaway to me. I can almost guarantee that is a classic symptom of an ignition timing problem. Before anything else can be deduced it is essential that Matt gets the ignition timed dynamically with a strobe. The strobe will also show if the advance/ retard mechanisms are working correctly too. Once this is established and ruled out then it would make sense to start looking for other problems.

A shame Matt is not nearer as I could time his car using my strobe light!

 

[Louie Bee]

Same here as I got one off a car boot sale last year for £3 .

People just don't need them any longer as there sin't much you can do on new cars .

Worked well on the SPI Uno but I couldn't find out what the advance should be .

 

[randomspeedfreak]

Thanks for the link but that's not a 1.4 SPi throttle body (as described in the ad) nor is it suitable for the RSF car (which uses a real carb, not a Single Point Injection (SPi) unit). The carb pictured in classifieds looks more like a single choke Weber 32 TLF used on the FIRE engines. The RSF car uses a Weber twin choke that has totally different fittings and flange mountings.

The 'spitting back' through the carburettor in Matt's car is the giveaway to me. I can almost guarantee that is a classic symptom of an ignition timing problem. Before anything else can be deduced it is essential that Matt gets the ignition timed dynamically with a strobe. The strobe will also show if the advance/ retard mechanisms are working correctly too. Once this is established and ruled out then it would make sense to start looking for other problems.

A shame Matt is not nearer as I could time his car using my strobe light!

Same here as I got one off a car boot sale last year for £3 .

People just don't need them any longer as there sin't much you can do on new cars .

Worked well on the SPI Uno but I couldn't find out what the advance should be .

it looks like i need a strobe then asap!

what i dont understand is how you can accurately set up the timing with a strobe? if the engine is spinning, and all the light does is shine a light when there is a spark, then how do you know accurately where the spark is, or where its supposed to be?

or am i missing something?

 

[Louie Bee]

You need a timing strobe, not one you borrowed after raving with Mampi Swift, Dj Markey or Andy C LOL.

It only triggers when there is a spark on Plug 1 (every other spin of the crank as Sorum reminded me ).

You point the strobe at the flywheel (after removing the rubber bung from the bell housing).

Then the timing mark on the flywheel appears stationary and aligns with the timing scale stamped on the gearbox (usually 5 10 15 IIR) meaning however many degrees btdc it's acutely firing at.

You may find it helpful to put a small blob of tipex on the timing mark, but stop the engine first as it's only an illusion the mark is still .

Set timing in the usual way till you get what you should need . that's twist the distributor to you and I, and wonder what the difference is between a couple of degrees. :slayer:

This is where you wish you'd marked up the exact position of the dizzy before starting and decide it's a good time to scribe a line in for reference next time

Have a good read of how to wire it in with the instructions (if you get any :devil.

I think it can be fired at the crank or cam pulley but I remember someone saying you get a different reading .

 

[randomspeedfreak]

You need a timing strobe, not one you borrowed after raving with Mampi Swift, Dj Markey or Andy C LOL.

It only triggers when there is a spark on Plug 1 (every other spin of the crank as Sorum reminded me ).

You point the strobe at the flywheel (after removing the rubber bung from the bell housing).

Then the timing mark on the flywheel appears stationary and aligns with the timing scale stamped on the gearbox (usually 5 10 15 IIR) meaning however many degrees btdc it's acutely firing at.

You may find it helpful to put a small blob of tipex on the timing mark, but stop the engine first as it's only an illusion the mark is still .

Set timing in the usual way till you get what you should need . that's twist the distributor to you and I, and wonder what the difference is between a couple of degrees. :slayer:

This is where you wish you'd marked up the exact position of the dizzy before starting and decide it's a good time to scribe a line in for reference next time

Have a good read of how to wire it in with the instructions (if you get any :devil.

I think it can be fired at the crank or cam pulley but I remember someone saying you get a different reading .

lol one of my mates did actually buy me a rave strobe as a present lolol

thanks for explaining that louie - i didnt understand that it is just an illusion.
I expect it will be obvious when i use one.


i was under teh impression (alex GS) that it was the 4th cylinder that is marked on the crank?

 

[Sorum91]

lol one of my mates did actually buy me a rave strobe as a present lolol

thanks for explaining that louie - i didnt understand that it is just an illusion.
I expect it will be obvious when i use one.


i was under teh impression (alex GS) that it was the 4th cylinder that is marked on the crank?

It was a good explanation Louie
and your right Matt, it will be obvious when you use it
but if you got a block of post-its and you draw a figure thats (for example) about to kick a ball. then on the next post-it in the block draw the same figure but the ball a little closer (and so on) and you scroll really fast through it, it will look like the figure is really kicking the ball, like in a movie (a really bad one, but still) if thats what you draw though
but if you think of the mark on the flywheel as the drawing and the timing strobe as the post-its, so each flash is a post-it, and when you turn the distributor you will see the mark "moving" kinda like the figure on the post-its

don't know if that made any sence at all to you, but I had nothing better to do right now

Sorum91

 

[Louie Bee]

i was under teh impression (alex GS) that it was the 4th cylinder that is marked on the crank?

Guess it can be either as pistons 1 and 4 are both at TDC at the same time, just spark at alternate strokes, so you'd see no difference as it will be at the same crank position.

The cam turns at half crank speed to allow for 4 stroke cycle.

Could be plug 2 or 3 but there will probably be no mark on the flywheel on the opposite side (180 degrees later).

you conect the trigger wire between the HT lead and the sparkplug of choice.

 

[Sorum91]

Guess it can be either as pistons 1 and 4 are both at TDC at the same time, just spark at alternate strokes, so you'd see no difference as it will be at the same crank position.

The cam turns at half crank speed to allow for 4 stroke cycle.

Could be plug 2 or 3 but there will probably be no mark on the flywheel on the opposite side (180 degrees later).

you conect the trigger wire between the HT lead and the sparkplug of choice.

yep, you are right louie, it could be both sylinder 1 and 4, but it's a unwritten rule that you always use number one abd there's almost never a mark on the opposite side of the flywheel

Sorum91

 

[alexGS]

OK, Louie is correct - the strobe light will illuminate the mark for either cylinder 1 or cylinder 4, because the crankshaft is in the same position either when cylinder 1 is about to fire, or when cylinder 4 is about to fire.

The difference is in the camshaft position. The camshaft timing mark will only be lined up when cylinder 4 (of the non-FIRE 1116/1299/1301 engine) is about to fire.

Therefore, when checking ignition timing, you can use either #1 or #4. But when installing the distributor and fitting the cambelt, the distributor must be set to fire #4. Hope that makes sense

-Alex

 

[randomspeedfreak]

OK, Louie is correct - the strobe light will illuminate the mark for either cylinder 1 or cylinder 4, because the crankshaft is in the same position either when cylinder 1 is about to fire, or when cylinder 4 is about to fire.

The difference is in the camshaft position. The camshaft timing mark will only be lined up when cylinder 4 (of the non-FIRE 1116/1299/1301 engine) is about to fire.

Therefore, when checking ignition timing, you can use either #1 or #4. But when installing the distributor and fitting the cambelt, the distributor must be set to fire #4. Hope that makes sense

-Alex

ok sorted,
just so people know - i p.m.ed alex to post on the thread, as i thought he had told me something different, turns out he didnt
thanks again mate for your help :worship: