Tuning Fast road Camshaft 40/80

[Pod500]

Hi Guys,

Has anyone fitted a fast road camshaft??
I'm trying to get my engine running properly, and ruling things out.

The engine turns over fine, and starts & idles - but it will not allow any throttle at all. I've swapped carbs, checked fuel supply, changed HT leads, coil, and it is still the same!!!
(Luckily I had pretty much all of these as additional spares)
Timing isn't an issue as its a nanoplex 126 wasted spark engine, so Its all aligned properly and starts pretty easy.

New plugs arriving tomorrow, which could be it - but I doubt it.

After doing a bit of reading, I'm wondering of the camshaft is very slightly out of alignment??? It wasn't possible to adjust its advance in any way when fitting it, but this article I dug up shows that there is a reason to change the cam advance http://club126uk.co.uk/blitzracing/tuning.htm

Anyone else done this before???

Chris

 

[the hobbler]

You're saying the engine won't rev at all?--very curious, never run into this one before. Especially as you seem to have covered all the bases and the engine starts easily and idles. Are you operating the throttle at the pedal or at the carb? The camshaft is very easy to time (in standard form)---the cam-sprocket will only fit onto the cam in one position, the crankshaft sprocket, due to the Woodruf key, will only fit in one position (but there is an 'inside' and an 'outside'--the outside has the timing mark on it). Line up the mark on the cam-sprocket and the mark on the crank-sprocket (one is on a tooth, the other mark is between 2 teeth), and there it is. I know people have a 'thing' about them, but have you checked the tappet adjustment? Let us know how things pan out.

 

[AndrewHarvey]

I agree with Tom - tappets / compression test before spending any money

 

[Paolo66]

It's not something simple like a broken throttle cable is it? Unless of course you are trying it at the carb. When you say it won't allow any throttle do you mean the engine revs dont increase at all?

 

[1500500]

Has the side draft carby been set up for the twin cylinder engine? Maybe the venturis are too big ??

 

[Pod500]

Hi Guys,
Throttle is using the carb, so nothing to do with the throttle cable (as its not got one yet!)
Tappets are set to the standard gap and have been checked a couple of times. Wondering if the camshaft is different - should the gap be as original, or would it work to a different spec??
Engine compression seems good, Dunnah who I bought the car off tested it before I bought the car and he said all was good. Hard to turn over as it should be by hand.

Camshaft went in as you say hobbler, with the timing spots in alignment. The reason i query this is because on the lnk i attached above it says "Align the protractor at 0' at TDC and rotate clockwise until the specified maximum cam lift point is reached. This is likely to be around 103 -110 ' degrees after top dead center for the inlet valve depending on the cam type. Rotate the cam independently of its sprocket to the alignment point. The cam sprocket holes then need elongating so it can be bolted to this new point. A dab of JB weld can be used to infill the elongated holes afterwards to ensure the position does not change once set"

I'm wondering if this is something I need to look at.
Mrs P wont be happy if I have to put the engine back into the kitchen.....

 

[Pod500]

Has the side draft carby been set up for the twin cylinder engine? Maybe the venturis are too big ??

Carb not set up properly as yet, but I can rule this out as I tried the original weber 28 and symptoms were exactly the same.

I'll try and get a video of what its like this evening.
Its bloody loud I know that.

 

[the hobbler]

It would seem that you have the cam in and set as per standard. Don't confuse yourself with the very fine cam-timing information on the "Blitz" site---this is really only for getting the cam-timing absolutely 'spot-on'. The fact that you car starts well and idles OK would indicate that the cam-timing can be removed from the equation. Also, if the cam timing was so far out that it was effecting the engine running there is a good chance that valves and pistons would be 'kissing' (if not having a good snog!).

 

[the hobbler]

Whoops, the system put my notes through before I had finished--don't know what happened there!
Carb---the fact that the problem exists whichever carb you have on would SEEM to also take the carb out of the equation. Have you tried running it with a remote fuel supply (small bottle of fuel, with just a little head, feeding straight into the carb). Only have just enough 'head' to ensure plentiful supply of fuel to carb (and is the float level correct in the carb?).
The stupid this is this----on these engines, tappet setting, ignition timing etc. can all be out by a reasonable amount and the beast will still start and rev up to a greater or lesser degree. The fact that you say that the engine won't rev AT ALL is baffling, to put it mildly!
If the ignition leads were on the wrong way round, normally it wouldn't start (well not without a fairly big bang), but as you have a 'wasted spark' ignition system this shouldn't affect you, as the system produces a spark to BOTH spark plugs every 360 degrees.
Have you tried running the car without the exhaust on?, just in case there is a blockage in it---enough passage to let it idle, but not enough to allow the engine to rev.
Where about are in the UK---there may be a forum member near you who can help out--even if only to bounce ideas off.
All this waffling on would indicate that at the moment I am totally baffled!

 

[jjacob]

1. Valve clearance
2. Ignition timing
3. Vacuum leak

My guess is ignition timing. Have you checked with a timing light? Also check for vacuum leaks around base of carburetor. Make sure air filter is not blocked.

John

 

[fiat500]

My guess is ignition timing. Have you checked with a timing light?

....and further to that, it is possible that you have problems with seizure or partial seizure and/or damage to the centrifugal advance mechanism in the distributor. You could examine it to explore that possibility but using a strobe would also show something wrong there.

 

[jjacob]

Peter, if he is running Nanoplex then there is no distributor. Everything is controlled by the module.
Chris needs to check the timing with a timing light and see if the timing is advancing as the rpm increases.
John

 

[fiat500]

Ah, so what he needs is a distributor then Good old comprehensible points and he'll be sorted!

 

[Pod500]

Valve Clearance is ok, but I have managed to dig out the settings on these for the 126 elx engine which has the exhaust valves set a little looser -so I'm going to try that.

Spark plugs still haven't arrived.....Thinking this may be a big factor as they don't look great and spark isn't lovely and blue - more towards the yellow/orange colour indicating a poor spark.

Exhaust is definitely not blocked as it nearly blows a hole in the garage door every time it fires!

Timing - I'll see if I can borrow a timing light from somewhere over the next few days, but I'm pretty certain this isn't the problem as there is minimal adjustment on the hall sensor on the Crank (probably 2/3 degrees each way) and I've tried all positions and it runs pretty well when set bang on the timing marks.

Fuel, I've tried running from a petrol can direct into the carb (table higher than carb) and this didn't make any difference!

Float - could be this but I don't want to rip the carb apart just yet as the refurb kit is about £40. Plus, the same symptoms with the weber carb fitted, so chances of both floats being knackered???

Nanoplex module could be cream crackered? I've found replacement for this from poland for £25 plus postage so that is in the post too...


I've taken these things apart since I was a kid, and used to fix our old family 500 all the time - sometimes mid journey.... and this is really confusing me too :/

Chris

 

[Pod500]

I might add - I've not done a video tonight as I didnt get home until 9pm and I don't want an ASBO :nono:

 

[the hobbler]

No matter what ignition system is being used, opening the throttle should produce more revs, even if the timing isn't altering---true, the performance might be a bit 'flat', but it will still rev.

 

[Vitesse]

Hi Chris what Nanoplex has it got fitted? There is usually a number on the front of it and they are different colours? The standard Polish built 126 was a 213 and blue in colour.

Tony

 

[Pod500]

Hi Chris what Nanoplex has it got fitted? There is usually a number on the front of it and they are different colours? The standard Polish built 126 was a 213 and blue in colour.

Tony

Hi Tony, its the Nanoplex 213A
Blue with a black surround.

Chris

 

[Vitesse]

Hi Tony, its the Nanoplex 213A
Blue with a black surround.

Chris

Ok Chris, I have read on websites and have no personal experience but have become pretty web competent in Google translation for Polish, Italian and German!!! Because there is virtually zilch in English.

That the Nanoplex was designed specifically by Magneti Martelli and Fiat Poland for a standard 650 Polish lumps i.e. Not tuned, as in the case of your engine and that the standard blue 213A is setup with a map that has an rpm limiter.

The Blue 213A has by default a 10° BTDC, with as you say a potential 2-3 adjustment on the flywheel sensor. The grey one, I think it is a 211A, was a Cinquecento 700cc and had by default a 4° BTDC, so doesn't have enough movement on the flywheel sensor to get it to 500 or 650 timing specs.

But there is another after market one produced by APE that says it is designed with an 80% stronger spark, specifically for tuned engines and more timing advance that maybe needed in tuned engines.

I succeeded in reversing the polarity on my original Nanoplex engine whilst bench testing it and even though, hoping through gritted teeth, it would still work, it became clear I had cooked it. So the only replacement I could find was from Ricambi in Holland and it was the APE one, which works fine with my standard Polish 650cc EL engine, so could be something to consider. As I said I can't back that up with solid evidence but it is worth consideration.

https://www.fiat126ricambi.com/fiat126/Engine+parts/OS1084

 

[Pod500]

Tony,
I ordered one of those from Poland yesterday!
I too am becoming quite proficient in Polish.
Thanks for the info.

Should be home early today so will see if I can video....