Might be a weird request, but if someone has some pics of the seicento mpi valves up close, i'd love to see them. Also, i'd love to see pics of the punto sporting 1.2 16v valves.

It would be great if someone would know how many angles those valves are cut to from factory.

Thanks in advance!

nmrmak said:

Might be a weird request, but if someone has some pics of the seicento mpi valves up close, i'd love to see them. Also, i'd love to see pics of the punto sporting 1.2 16v valves.

It would be great if someone would know how many angles those valves are cut to from factory.

Thanks in advance!

Click to expand...

the valves will be the same as any 1.1 or 1.2 8valve fire engine!
there seemed to be some confusion with people saying the punto 75 had larger valves. i can tell you this is not true. the valves from my original cento 1.1 engine are identical to the punto 75s 1.2 valves

Yeah, that's why i asked for info both for the 8v and the 16v engines. What i'd really love to know is the number of angles they're cut in Pics would be a great bonus

Cheers

well i put that mainly so if anyone has pics/info of a 1.1 valve they might post it

Yeah, you're right, thanks, any 1.1 8v valve should do, and i suppose any 1.2 16v valve will do either. The reason i'm asking this is to see whether a 3 or 4 angle cut would improve the flow (if it's a 3 angle cut from factory, i won't get much by doing a 4 angle cut, but if it's a 1 angle cut, then a 3 angle cut will make a big difference)

its only 1 cheap engine after all.

as bad as it is, it's still great news for me
Means that doing a 3 angle cut won't be useless. Is that info valid for both 8v and 16v engines?

well i dunno i guess so. I cant see many car engines having this kind of work done as it cost so much but has so little gain.

well, i dunno, but it's not that costly around here, i'd be surprised if it went above 50 eur or so (living in serbia though, guess prices are different on the island)

its not expensive i had it done on my bike. but when we are talking about selling thousands of cars even if it cost 10p to do they wouldnt!
car manufactures more then likley wouldnt do that as it shortens the service life of the engine

I can't agree a three angle cut valve would have a shorter service life, it could even have a longer life since the valve would conduct heat to the engine head better (having a larger contact area to do so), and there would be less hot spots (i guess).

You have a good point, however. They'd do anything to make the car cheaper. That's why we're here to do all the stuff they forgot to

wait ive never heard of angles cut onto the valve but have onto valve seats (this is what ive got done on the bike) its where the seat have 3 or more angles cut to make it more of a smooth flow. are you talking about the same thing?

http://www.popularhotrodding.com/tech/0610phr_cylinder_head_porting/photo_03.html

That pic is a good description of what i'm talking about. Hope the link works. Was that what you had done to your bike head? It makes sense that the same thing should be done on both the valve and the valve seat though.

Edited to add: In serbian language, the distinction between a valve cut and a valve seat cut is a bit confusing, so i can't be sure how it would translate to english, but it makes sense that both parts are cut to increase the contact area.

EDIT2: Okay, i read up a little to refresh my memory on english terms
The valve seats are said to be "cut" and the actual valves are said to be "back cut". You can actually do a 3 angle valve seat cut without back-cutting the valve. What i'd like to do is back-cut the valves as well as the valve seats.

So a better form of my question in the first place would be "how many angles are fiat 8v and 16v engines cut to, and are the valves back cut to 2 angles (99.99% that they're not).

This is what a back cut looks like: http://www.carcraft.com/techarticles/116_0612_valve_angle/photo_02.html
Double back cut: http://www.carcraft.com/techarticles/116_0612_valve_angle/photo_11.html
Double back cuts are rare though, as far as i know. But single back cuts are said to increase the flow a lot, and since i'm thinking about swapping a 16v engine into my mpi sei, and then turboing it, i want the most flow i can get out of it.

Sorry for the misunderstanding, i'm still learning the english terms for all these tech things

hummm ok i do get you but i have to say that (if we are talking about the same thing) the valve seat area is smaller I was warned about this when i had mine done (but im not worried 350single cylinder engines need rebuilding very often)
the way i see its done is they cut a few angles into the seat to make it more rounded this causes a smoother flow in and out the combustion chamber.
also the smooth rounded surface acts as a kind of airfoil.
On the intake side the flow closest to the valve seat will be moving slower then the flow further out. as the faster moving gases go past the end of the seat they fold over the slower moving gasses causing a vortex (< kind of on my display photo of a air plane wing tip) this causes a more even mixture and cylinder fill which means a much more even and compeate burn.

Yeah, those are all good reasons to have this relatively cheap mod done. Much better flow (up to 25% on ford heads, resource: http://www.carcraft.com/techarticles/116_0612_valve_angle/testing.html) and better fuel dispersion = more efficient fuel burning process = more power.

You're right when you say that if you do a valve seat cut, you'll reduce the contact area. But if you do a valve seat cut, and a valve back cut, then you'll increase the contact area (by my logic at least ). Correct me if i'm wrong. Either way, it shouldn't be dangerous to the engine in anyway, i guess.

If anyone has pics of their valves, please post them up

I can imagin good results on a turbo car! what have you already done on yours? there is lots of work to be done in the ports. my head has LOADS of nasty edges and gaps in the ports where there seat goes into the head. I spent a day ginding and filling with liquid metal.

Haven't done anything yet, probably buying a 1.2 16v engine next week, and when i take it apart, my first task will be to see how i can reduce the compression on it. Since it's a 16v, there's little material to be removed from the pistons, so i'll either have to grind some off the head or see if a decomp plate would be good (have to check all the pulleys and see what i have to mod if i go 1mm+) After that's done, I'll take the head in for the valve seat cutting and valve back cutting and after that do some porting by hand. After all of that is done, i'll put the engine in the car and start turboing it (pipe work, getting the parts, going megasquirt and so on). I can't say it'll be a 2 week project, it's probably going to take months, but i'm doing my research in advance

And it wouldn't be possible without great input i get from some users here, i'd like to thank them very much!

cool Guess you will be hanging around in the megasquirt thread with the rest of us soon then
I dont think ill ever turbo mine (not reliable enough for me and expensive)
Im REALLY tempted by a 16v 1.4. It has a bit more go then a turbo (so im told) while been reliable and a bit cheaper (lot cheaper in the long run) BUT the 1.2 punto 75 engine is running reallly well with megasquirt and really gets the car shifting along nicely maybe one day or a summer holiday project (my cinq is my only car and need to do 40mile a day)

craigb244 said:

there seemed to be some confusion with people saying the punto 75 had larger valves.

Click to expand...

no no, you've got confused. the cento 1108 engine, the p75 and the 176.b4 punto60 engines have inlet valves that are 1mm bigger than the punto55's 1108 and the punto60's 1242 engine

this is the best i can do on the 1242 16v exhaust, i didn't take any bigger ones im afraid.

Sure they only have a single angle though.



Kristian