Fiat Coupé 20V Turbo cylinder head - question about porting?

Road-race engines and ancillaries - general discussion
kaci
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Fiat Coupé 20V Turbo cylinder head - question about porting?

Post by kaci » August 13th, 2011, 1:33 pm

Hello everyone.
This is my first post in this forum and my first request for help.
Currently I preparing to repair engine for my Fiat Coupe 20V Turbo.
I have a question for the cylinder head. On the pictures you can see the condition of exhaust and intake ports. For me they are terrible!
I did not find any advice for Fiat 20V cylinder head in this forum.
Anyone know how much material is safely removed from the ports?
Thanks, Krastyo
Attachments
S4020895.JPG
In. port
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Ex. port
S4020890.JPG (533.95 KiB) Viewed 10337 times

FERRARIST
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by FERRARIST » August 15th, 2011, 5:59 pm

Porting Fiat Coupe 20VT head is a real pain. I'm on my way to do mine, and i wont remove more than 1,5mm.
Will post my pictures latter when ready.

TomLouwrier
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by TomLouwrier » August 15th, 2011, 7:17 pm

hi Krastyo,

Our host Guy did one of those about a year ago -maybe two- and there was quite a detailed write-up about it on the site. Interested me plenty since I have the related 1.8 engine. It's mentioned in his second book as well.
Seems not to be here any more though. I found traces of it through Google, but even their cache says 'the discussion does not exist any more'.

Might be Guy has good reasons for taking it down, or it got lost when there were some problems with the forum last March and so far it has escaped repair?

regards
Tom
GC_29

Guy Croft
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by Guy Croft » August 16th, 2011, 3:32 pm

In the 20v you can comfortably remove 2mm thick anywhere you want!

I took that topic down along with a load of stuff we don't do here anymore.

G

kaci
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Location: Sofia, Bulgaria

Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by kaci » September 30th, 2011, 8:27 am

Thanks for the answers.
The theme for the five-cylinder Fiat engine would be very useful.
Pity that no longer exists!
Greetings from Bulgaria.

FERRARIST
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by FERRARIST » October 4th, 2011, 12:35 pm

Few days ago i finished my head prep, it took me almost 6-7 summary days to complete.....it's real pain doing 20VT head.....
Image Image Image Image Image Image Image Image Image Image Image
Open to any critics.....:)

4v6
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by 4v6 » October 4th, 2011, 5:42 pm

If the material on these Fiat 20 valve heads is anywhere near as hard as that on the Audi 20 valve heads I've done (several) then you most definitely have my sympathies indeed!
Looks quite similar apart from the inclined exhaust valves and the slightly different chamber shape.
Tony Warren. GC #96.

FERRARIST
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by FERRARIST » October 5th, 2011, 8:56 am

My porting experience is with few Alfa 156 TS heads, 2 156's 2.5 V6, and one Fiat20VT, and really have no idea how hard other heads is......
But the problem with 20VT is that port length is way too much for normal carbide burr and its difficult to remove even parts of the port.....
Image

Guy Croft
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by Guy Croft » October 5th, 2011, 9:09 am

The compact flexi shaft for the Metabo die grinder I use permits me to work in even the most restrictive and long ports, but you can buy 'long series' burrs which have a much longer shank.

Those diamond cut burrs are hopeless for aluminium - the rake is wrong on the tooth form and they're always getting material stuck to the teeth - though if you wet the metal with spray oil frequently they work ok.

G
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FERRARIST
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by FERRARIST » October 5th, 2011, 9:56 am

Guy Croft wrote: they're always getting material stuck to the teeth - though if you wet the metal with spray oil frequently they work ok.
G
True - but few drops WD40 every 5-8 min's works fine for now......and getting 'long series' burrs is next on my list.....

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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by WhizzMan » October 5th, 2011, 5:25 pm

I have seen people rave about a bee wax candle they dip their burr in to lubricate it. I have yet to try it, haven't done any aluminium since I got the suggestion on some forum.
Book #348

Guy Croft
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by Guy Croft » October 10th, 2011, 11:02 am

Doing an article for the respected Fiat Coupe Forum on this, see: '20v head prep' by GCRE at:


http://www.fccuk.org/forum/ubbthreads.p ... =17&page=1

G

kaci
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by kaci » October 10th, 2011, 11:36 am

Thanks for the topic, Mr. Croft.
Many people will be happy!

WhizzMan
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by WhizzMan » October 15th, 2011, 11:22 am

Very interesting reading indeed. I take it a lot of this will apply to the Alfa 16V TS heads as well? The engines are generally designed the same and share a lot of parts.
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Guy Croft
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Re: Fiat Coupé 20V Turbo cylinder head - question about port

Post by Guy Croft » October 15th, 2011, 11:51 am

in practice - not a million miles removed probably though I have not worked on one of those Ricardo designed heads

G

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