Technical Major Components - Pictures

[col7104]

Not really a guide, but I'm sure a mod will do something with it if its in the wrong place

Afew pics for anyone to use as reference/self learning. I know that I would have loved this thread to be here when I first arrived on this forum! Add/correct as you please.

1. Cylinder Head (stem guides, core plug, thermostat, spraybar, ports, valves)
2. Cam Pulley and camshaft
3. MPI Inlet Manifold
4. Mk1 Seicento Fuel Filter
5. HT Leads
6. Coil Packs
7. Catalytic Converter
8. Valve Stem Oil Seal

1. Cylinder Head

We'll start with a bare head, here's a bottom view:

If we flip the head over, we can see two oil stem seals in place, the rest do not have any installed:

These are valve stem guides, where the valve stems are guided....simple isn't it! These can be ground down flush when porting to enable a better flow of gases.

Right, here's an assembled head labelled up for you:

The oil spray bar's purpose is to spray oil onto the camshaft, minimising wear.

If we flip the head around we can see the inlet side:

Let's turn it 90 degrees:

If insufficient antifreeze is present in the water, during cold conditions the water will freeze. What happens when water freezes? It expands! The core plug is there to 'pop' out, thus escaping serious engine damage, however it does of course mean you'll have to replace it after. You can also see how the cambelt tensioner bearing works.

Need to change your cambelt? https://www.fiatforum.com/cinquecento-seicento-guides/100553-cam-belt-change.html

If we flip the assembled head over, we get a good look at the valves:

Cylinder heads can be modified to create more power in a number of ways. To coin it briefly, the ports can be enlarged and smoothed to allow more volume to be passed through the engine and the head surface can be skimmed to raise the compression ratio. As with everything in life, there are limits to how much you can port/skim, depending on the end result you want, and the design of the head. Fiat didn't put material there just for you to grind away!

2. Cam pulley and camshaft

Note the marking on the cam, this is a standard camshaft for the 1108cc engines.

Camshafts can be reprofiled to generate more torque, horsepower, or a balance of the two. This is attained by varying the lift and duration characteristics the lobes have on the camshaft. I would explain more but I don't know much about camshafts!

The cam pulley has a key in it which corresponds with the camshaft, so don't worry about putting it on wrong!

3. MPI Inlet Manifold

The MPI manifold has egg shaped ports, to accomodate the injectors which are in the top sections. Compare this port shape with the ones on an SPI head.

The top of an MPI manifold:

Manifolds can also be ported (although maybe not this plastic one ). Again, depending on the result you want, the amount of porting, if any, is variable.

4. Mk1 Seicento Fuel Filter

This is located on a bracket at the side of the fuel tank. On the driver's side of the car, look underneath the car just infront of the rear wheel. This filter comes off with 2 bolts, and the fuel lines simply unclip from each end.

5. HT Leads

These can be upgraded to items made by companies such as Magnecor. These do not add power, however they are a key component in maintaining a strong ignition system.

6. Coil Packs

Located on the side of the engine, these can be replaced by simply removing 4 allen bolts per pack. Note the corresponding cylinders for each lead stamped into the coil pack mount.

Having trouble with your coil packs? https://www.fiatforum.com/punto-guides/52068-punto-coil-ecu-checks.html

Here is a mock up of the ignition system on a fire engine:

7. Catalytic Converter

These are found underneath the car in the exhaust system. They convert bad gases into not so bad gases For a more detailed explanation, go here: [ame]http://en.wikipedia.org/wiki/Catalytic_converter[/ame]

8. Valve Stem Oil Seal

A valve stem oil seal:

The valve stem needs to go from an oily top end where the camshaft is to the oil-free combustion chamber. The seals purpose is to stop oil leaking through from the top end to the combustion chamber. That is why when these expire, you get blue smoke, as oil leaks past these seals and burns.

 

[custard]

Re: Components *56k unfriendly*

nice post,i'll leave this as is for feedback and when i get a chance do something with it

 

[fingers99]

Re: Components *56k unfriendly*

Lots to like about this, but

If insufficient antifreeze is present in the water, during cold conditions the water will freeze. What happens when water freezes? It expands! The core plug is there to 'pop' out, thus escaping serious engine damage, however it does of course mean you'll have to replace it after.

Is wrong. Core plugs do pop out if the coolant freezes, but this is not their function. Take a look at a block without core plugs in and you'll see how incredibly complex it is inside. Once, molten iron was poored into a mold made of sand to form that block. The sand needs to get out somewhere. Hence the hole that is later machined out to form the core plug.

Although the Americans (bless them) call core plugs "freeze plugs", I have my doubts as to how much protection a core plug actually affords.

 

[K4RL]

Re: Components *56k unfriendly*

Lots to like about this, but



Is wrong. Core plugs do pop out if the coolant freezes, but this is not their function. Take a look at a block without core plugs in and you'll see how incredibly complex it is inside. Once, molten iron was poored into a mold made of sand to form that block. The sand needs to get out somewhere. Hence the hole that is later machined out to form the core plug.

Although the Americans (bless them) call core plugs "freeze plugs", I have my doubts as to how much protection a core plug actually affords.

aaahh, very clever, never knew that. used to forge the block and coincidently also acts as a fail safe if it need to go pop! lol



and, very usefull thread if you planning on work on the head.

 

[bean]

Re: Components *56k unfriendly*

great work,

much needed post for novices,

nath

 

[randomizered]

Re: Components *56k unfriendly*

I have to ask what engine you have

MPI manifold but spi head (temp sender), spi cat, spi fuel filter.

Most parts are interchangable however, but you seem to have two different cars there, or have you done some mods?

If it any use i can tak e a pic of the mpi cat and head if you like. They are on the garage floor at the mo

KRistian

 

[col7104]

Re: Components *56k unfriendly*

What I envisage in my head....I HAVE A DREAM..... that we can build a sort of database with pics and maybe brief explanations. I remember when I was new here reading the various posts with people referring to things such as cam spray bars, but I kept wondering wtf a cam spray bar looks like. So the answers above

And er, yeh its an SPI Sei I have......check my blog

So the answer to your question, by all means add whatever you want.

Oh and Fingers, I never knew that, good to know a little more

 

[Jamie]

Re: Components *56k unfriendly*

What I envisage in my head....I HAVE A DREAM..... that we can build a sort of database with pics and maybe brief explanations. I remember when I was new here reading the various posts with people referring to things such as cam spray bars, but I kept wondering wtf a cam spray bar looks like. So the answers above

And er, yeh its an SPI Sei I have......check my blog

So the answer to your question, by all means add whatever you want.

Oh and Fingers, I never knew that, good to know a little more

Off topic sorry

but col i see you live in romford, i often venture down there every month as i have relatives who live there, have you not seen my GP around? auntie borrowed it for a week last month. oh and they live near the eastbrookend pub, near dagenhem east station and dagenham and redbrige football club

 

[arseofbox]

Re: Components *56k unfriendly*

aaahh, very clever, never knew that. used to forge the block and coincidently also acts as a fail safe if it need to go pop

Karl, FYI thats not a forging process. Casting and forging are two massively different processes.

Casting involves using a liquid or very near liquid phase solid of the material and allowing it to flow to the shape of the mould.

Forging on the other hand is basically ramming a lump of metal into a mould at very high speed with a lot of force - causing it to flow to the shape, but unlike casting this doesnt interrupt the material's grain structure - resulting in a material that is much more predictable in terms of behaviour under load, as it can be designed to be loaded to exploit the grain direction.

Hence why its used for high performance pistons. It does have the disadvantage that the custom tooling that's needed tends to be more expensive than the tooling required for casting.

 

[col7104]

Re: Components *56k unfriendly*

Off topic sorry

but col i see you live in romford, i often venture down there every month as i have relatives who live there, have you not seen my GP around? auntie borrowed it for a week last month. oh and they live near the eastbrookend pub, near dagenhem east station and dagenham and redbrige football club

Hi no don't think I have seen it I'm afraid. I'm only five minutes from there lol, I'll keep a look out in the future lol. There's two red Sei sportings local around here so chances are if you see one its me

 

[Jamie]

Re: Components *56k unfriendly*

Hi no don't think I have seen it I'm afraid. I'm only five minutes from there lol, I'll keep a look out in the future lol. There's two red Sei sportings local around here so chances are if you see one its me

im down there on the 4th on my way to autoitalia

ill keep a look out :wave:

 

[ralphtown]

Re: Components *56k unfriendly*

Heres a question....

On the pic of the MPi Manifold,you can clearly see the mounting for the air filter and a brass/copper thing,not sure what that is,all in the bottom right of the pic.

Can you tell me,what is the tiny tube between the 2??

I think its for the Rocker cover breather.In the pic,there seems to be a hole in the top of it but on my MS edition,I don,t have a hole.....Did Fiat render this redundant or could the fact that I don,t have a hole be one of the reasons my car is rough and jerky thru the intermediate gears but great in 5th??

Anyone??

RALPH.

 

[cc1]

Re: Components *56k unfriendly*

Should be a hole.
Some one may have filled it in when an aftermarket air filter was used?

 

[ralphtown]

Re: Components *56k unfriendly*

Cheers Mate!!

I,m wondering,if there was some kind of sleeve as part of a K&N kit.

I,ll take a look during the weekend and if its not a sleeve,then I,ll drill it out with a pin vice.

Thanks again.

RALPH.

 

[ralphtown]

Re: Components *56k unfriendly*

I drilled it out.It was covered or blocked by a sleeve but its not made any difference to the running.
Still coughs about around 2k thru all the gears but is fine in 5th.
Fuel consumption is fine,so I,m not convinced its Lambdas.

I,ll just continue to throw sensors at it and if that don,t work,I,ll throw the car at the scrappy and buy a Volvo!!


RALPH.

 

[fingers99]

Re: Components *56k unfriendly*

Given it's MPI, cheaper to throw a code reader at it?

 

[Eklipze3k]

Re: Components *56k unfriendly*

Very handy old thread - stickied and title edited.

 

[ralphtown]

Heres an update.

I handed the car over to "the experts" before Christmas for work,inc new clutch and cable.
They balls it right up and I decided to be less lazy and sort it myself.

So...sorted.
But anyone that has been reading anything I,ve been posting has seen that I,ve had rough running/hesitation thru the gears but fine in 5th.

Well....

SORTED!!

Turns out it was the so called,performance exhaust.
After "the experts" had finished with it,I had a smell inside the car at lights and rattles and knocking on the rear valance.
I took it to my local tyre and exhaust emporium,that I have used before...good blokes...And they showed me,before they started work on the car,what was wrong.

The exhaust was split at the flexi joint and slight leak.The middle silencer/baffle had been removed and a section welded in.it was leaking from the joint going into the big silencer,so called "Powerflow" muffler.

Talking with one of the guys there (thanks Pete) he told me about a Lexus he put a "performance" exhaust on.He had similar issues and the car was down on power and lacked torque.

One brand new standard exhaust,Cat back,later and normal service is resumed.
The car is smoother,quieter and has a nice little torque "hump" right where there was a nasty flat spot before.

I,m still replacing the MAP sensor,just coz I have one but its everything I always knew it could be now.A right little nippy motor and I,m sure it,ll run me down to Hastings from Nottingham,in a months time.Heck...I,m even going to service the engine and get it valetted,as a reward

RALPH.

 

[OldGuy69]

This is amazing to see, i always wanted to learn more about mechanics. This way of posting helps me understand better what makes my seicento work. Thank you very much! Keep it comming

 

[Bubble Trouble]

Re: Components *56k unfriendly*

Lots to like about this, but



Is wrong. Core plugs do pop out if the coolant freezes, but this is not their function. Take a look at a block without core plugs in and you'll see how incredibly complex it is inside. Once, molten iron was poored into a mold made of sand to form that block. The sand needs to get out somewhere. Hence the hole that is later machined out to form the core plug.

Although the Americans (bless them) call core plugs "freeze plugs", I have my doubts as to how much protection a core plug actually affords.

Correct purely an engineering necessity during the casting/production process. Commonly know as ‘Welch Plugs’ in Great Britain.