General chugging on idle

[fingers99]

0.35 to 0.45 (inlet) 0.45 to 0.55 (exhaust) with a cold engine.

I'm not doing the maths for you, but all the clearances are too tight. Plus, I don't know whether a particular valve is inlet or exhaust.

Take the first one:

1 - 0.13 - 4.75

If it's inlet it should be 0.40 plus or minus 0.05, if exhaust, 0.50 plus or minus 0.05.

So (inlet) 0.40 - 0.13 = 0.27. Too tight, so shim should be 0.27 thinner = 4.48. So the acceptable range for that shim is 4.43 to 4.53

Or (exhaust) 0.50 - 0.13 = 0.37. Too tight, so shim should be 0.37 thinner = 3.48. So the acceptable range is 3.43 to 4.53.

And so on. They're all too tight, so the maths is easy enough. Always fit the shim you've chosen and re-check (everyone makes mistakes with their maths).

 

[levemircento]

OK, so we know we have a problem. I would be tempted to whip the head off and check the valves first, but if you want to go ahead, see what you can make of this.

Another wee pointer, I presume the shims are marked, you haven't checked them, just incase they've been ground.

I have only just put the head on!! however, i did look at the valves beforehand [as fitted] and there was nothing unusual about them or areas that were burnt or broken

All shim sizes quoted by me are as marked on their bottom faces, there is no wear evident on the top of any of them.

As mentioned earlier, this head thats now fitted has had some porting done, will that affect my idle? - as I am using an unmodified inlet manifold

As you mention a 4.5 shim, is that the same as a 4.50 ?

 

[rusty1989]

my mpi seicento is doing the same thing, reving low about 500revs and shakes wen ideling, had the car on a diagnostic and brings nothing up

 

[fingers99]

As mentioned earlier, this head thats now fitted has had some porting done, will that affect my idle? - as I am using an unmodified inlet manifold

It shouldn't --

As you mention a 4.5 shim, is that the same as a 4.50 ?

Yep. Or a 4.500! A zero behind signifies nothing.

 

[levemircento]

Yep. Or a 4.500! A zero behind signifies nothing.

see, told you I was no good at the maths!!

fluffy has quoted me a price for shims, just hope he has the ones I want now

edit: just re-read his mail to me, he only does them up to 4.25, is there anywhere else I can get them from? approx price?

 

[fingers99]

Fiat dealer.

Fluffy should be able to get anything within the available range pretty quick, failing the above, try Guy Croft (I think all FIAT engines use the same valve shims).

 

[levemircento]

I have sent him a message saying what I need, so hopefully might get it sorted one way or another.

How do I find out who is trading as my local fiat dealer? the last place I went to was in macclesfield but that closed down, next place is stockport but what WAS a fiat dealer is now a citroen one

 

[fingers99]

Fiat have thought of you! Try this. I didn't wait for it to load but suspect it might be Mangoletsi.

 

[levemircento]

Fiat have thought of you! Try this. I didn't wait for it to load but suspect it might be Mangoletsi.

cool. Looks like the dealership in Macclesfield I went to last year [cos it was for a Rover part I wanted.. but found out that they did Fiat too] is still there, it was in the process of either being knocked, or closed down, it was like walking into a dealership in the '70s, decor wise!!

 

[levemircento]

Having a bit of a mare with all of this, however today I unexpectedly was given some money I was owed, so I have found a few local engine refurb places and am going to take my original cylinder head to them to look at to see if it can be repaired [welding/skim]

Now, if I remove the head thats on the car now in the event my original can be repaired, can I reuse the head gasket? or is that scrimping a bit too much?

 

[fingers99]

I'd not risk it. Indeed, I'd forget about the first head and proceed with the second.

 

[randomizered]

yee gods no! Don't reuse the gasket You can probably get the head gasket on its own, from a specialist head place for a few ££ cash!

Kristian

 

[levemircento]

Righto, heres where I am with all of this.

I took my original head, that was corroded near to where the fire ring sits, to a few engine places near here, I had 5 places to go to for them to see it, first place was closed, had been for a year, second place was a back street engine machining place, very grubby, they didnt do welding on site so could only guess at that [no use to me], third place was a lot more upmarket with people who know whats what, spotlessly clean, and the machinists at work seen though a window from reception, the owner had a look, "an easy repair" was his opinion, they were Quasar Engineering, also known as Tecno Racing engines, quote was £60, to cut away the corrosion, weld in new aluminium, then skim off to make a good surface, I didnt even have to remove the valves, and neither did they.

So, I left it with them, on Tuesday lunchtime, "call us thursday morning, should be ready", they said.

I have never used a engine machining place before, I half expected a call on wednesday saying there was a problem, or it cant be done, or for me to phone thursday [today] and for them to say, "not done, call back", etc.

However, done it was, by 9.30am. So I called by, the head had been cleaned somewhat and shown to me by the owner, pointing out in detail exactly what they had done to it, tips on refitting, he printed the invoice off, it was £60 PLUS VAT - they didnt initially say that, good job I had a few extra quid - "dont matter if you aint got the full £70.50 [extra £10.50], drop it in when you next go past" he said; that was nice of him, considering he didnt know me.

We then chatted about these things, they do stuff mainly for the trade, but specialise in racing engines, he took me through to the back, and there was a 1242 FIRE that was just needing its head gasket fitted, for a track day car [he didnt say what it was], turns out that my repair was quite a common thing on these engines, the spot just at the back of the combustion chamber between the plug and the fire ring, tends to run slightly lean, meaning more heat[?]. He showed me the head of this engine, one of the other water jackets had been repaired like just mine.

So, refitting commenced today, with a new H/G

Some pics:

Head, as skimmed:


Black lines show approx where the new metal was put in/where it was corroded:


Close up of one of the welds, small black line shows where the corrision went to, and thick red line the "approx" place where the fire ring would need to be:


Yeah, my drawing is awful!! hehe

Its not great, but they have a website, if any use to anyone: www.quasarengineering.co.uk


Therefore, I shall soon be putting a ported cylinder head on ebay, it be a bare head with valves still in, look out for it.

 

[randomizered]

He should let you off the vat, purely for all that pimping

Looks good though Would never tell! They do a leak test etc on it?


Just hope its all ok for you when you refit it. Perfect time to do the steam seals and cam seal while your there...save any future problems

Possibly heats more there as that will be at the end of the flame front and no fuel dumping there either, plus spark plug end will obstruct flow coming in at that angle?

Kristian

 

[fingers99]

Interesting, but I really don't understand why you did this. The ported head, surely, needed shimming, this head needed welding and skimming and will need shimming anyway.

Did they re-temper the head before skimming?

 

[levemircento]

I am refitting as it is, it was ok beforehand, dont know about a leak test, I would guess it was - remember I said it had a plug crossthreaded, well all the threads were cleaned out, and the plugg fitted perfectly like it should, he was quite open to the fact that he rarely gets people bringing stuff back due to their work. And I believed him.

However, I have my sight set on a neighbours punto 60, he can no longer drive it due to his age and disability, his wife said she would let it go cheap or scrap it low miles too!!

 

[fingers99]

Nice engine, easy swap.

But I'm still :bang: and screaming AAAAAARRRRGGGHHHH!

 

[markstorey]

ok, done the head gasket and head

the cam is worn/or need the shims doing

when driving the car feels ok, but its chugging like mad at idle, this, and the fact than in just 15 miles of driving, its used a shed load of fuel, a tad less than a 1/4 of a tank

I took the airbox off to check the connections to the injector unit, I did this with it running to see if anything made a difference, the throttle position sensor didnt make any difference when unplugged and plugged back in, neither did the connector [intake temp?] when undone and put back in, the plug at the top/back of the spi unit made it die when undone.

I also pulled the vac pipe off the map sensor, not much difference, and not much with its connector undone either

I didnt disturb any other connectors anywhere.

any ideas?

Have you fixed it yet ??

I've had the same problem ! - And just fixed it TODAY !!!! ;-)

Did the head gasket two months ago and been trying to suss idle chugging ever since.
Fitted new throttle idle control air valve & a new Lambda without any changes.

Finally sussed that the idle improved when I disconnected the MAP sensor.
( tried a spare MAP sensor without change )

It was an air leek / bad seal between the throttle body & inlet manifold.

I just removed the orange spacer, scrapped off the old gasket, slapped on some instant gasket from a tube & it's now perfect !

I couldn't see replacement spacer gaskets on the Fiat ePER when I originally did the head, but I've just looked at it again and the spacer is only £5 so I assume that a new spacer comes with new gaskets already on it.

 

[levemircento]

I had my original head welded and machined from a reputable engine machine shop, got a new h/g, refitted and from the first flick of the key she ran as smooth as silk and has done ever since.

I have the ported head for sale, doesnt really suit my car as I only have standard induction and exhaust systems.