Fiat TC - Alquati 87 cams timing data

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F138
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Fiat TC - Alquati 87 cams timing data

Post by F138 » June 27th, 2006, 12:12 pm

I got steel cams for my TC some years ago. But I got no diagram and times for adjusting.
Creating the diagram for opening times should not be the problem. Standard adjusting with GCs manual also - but as I don‚´t have the times I won‚´t be able to do the right timing, right? So I can only adjust them at the dyno?

Thanks in advace for help!

Guy Croft
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Post by Guy Croft » June 27th, 2006, 12:24 pm

Ok

we need to be a bit careful here because whilst most TC cams will run at anything from 100 -110 deg FL (full lift), the lift at TDC is affected by the full lift position and has a huge bearing on peformance. Moreover too much will lead to valve to piston clash.
Are there any markings on cam end of cam nose? Steel would tend to be mine or Alquati or Colombo & Bariani; Abarth marked their cams on the shaft but mainly they are cast iron.

See also my post on cam timing in my section.

Come back to me on this asap


GC

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Post by F138 » June 27th, 2006, 12:40 pm

thanks for quick response.

Yes, forgot to tell: Theres a "87" at both cams. The seller (I bought a complete car for wrecking) told me he bought them from "Winz Motorsport" here at Germany. I sent a mail but had no response until now.

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Post by Guy Croft » June 27th, 2006, 12:55 pm

Well done!

Alquati StII 42/82 82/42 10.6mm nominal lift, setting clearance 0.4mm in/ex

Full lift setting inlet and ex is from [(42 + 82 + 180)/2] - 42 = 110 deg
That's 110 crank degrees:
inlet full lift 110 deg after TDC on intake stroke
ex full lift 110 deg before TDC on exhaust stroke

Refer to my 'how to cam timing' in GC V/W (Virtual workshop). TC cams must be set up with head off. The can be checked with the belt on, but not really setup on the engine without grave risk of bending a valve.

GC

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Post by F138 » June 27th, 2006, 1:18 pm

BIG thanks!

I got your workshop manual also some years ago so I am aware of those critical issues.

Thanks for sharing your knowledge!

Acki

Post by Acki » June 27th, 2006, 1:24 pm

Guy Croft wrote:Well done!

Alquati StII 42/82 82/42 10.6mm nominal lift, setting clearance 0.4mm in/ex

Full lift setting inlet and ex is from [(42 + 82 + 180)/2] - 42 = 110 deg
That's 110 crank degrees:
But camshaft normally in camshaft degress or?

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Post by Guy Croft » June 27th, 2006, 3:25 pm

OK - A lot of people don't understand this at first.

Cam timing figures are always quoted in crank degrees:

IN 42/82 (inlet is always quoted first) means it opens 42 crank deg before tdc and closes 82 deg after bdc

EX 82/42 means it opens 82 crank deg before bdc and closes 42 deg after tdc

The overlap where both cams are open at the same time on the scavenge phase at is 42 + 42 = 84 crank deg

Look at the OE Fiat Argenta 15/55 57/13 cam timing diagram below, the inlet and exhaust cycles are overlaid. The Argenta (based on the industry standard - and Fiat's - method of using wide running clearance to specify cam timing figures) has 28 crank deg of overlap.

This is the standard overlay everyone uses to assess cam timing inlet-exhaust.
Attachments
Argenta cam timing diagram 001.jpg
Argenta cam timing diagram 001.jpg (28.72 KiB) Viewed 13472 times

Acki

Post by Acki » June 27th, 2006, 5:10 pm

Guy Croft wrote: Look at the OE Fiat Argenta 15/55 57/13 cam timing diagram below, the inlet and exhaust cycles are overlaid. The Argenta (based on the industry standard - and Fiat's - method of using wide running clearance to specify cam timing figures) has 28 crank deg of overlap.
Means inlet: 15 + 180 + 55 = 250‚°
Means outlet: 57 + 180 +13 = 250‚°

So you can say it's a 250‚° camshaft.

First you name the inlet deg then the outlet (when outlet is other like on asymmetric camshafts) then you say for example 250/220, lift the same :)

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Post by Guy Croft » June 28th, 2006, 8:56 am

that's right, based on the timing figures as they are presented, and the full lift point is simply the angular measurement from TDC - of the halfway point of the duration.

GC

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unknown cam? does this number mean something?

Post by antonio » June 29th, 2006, 6:16 pm

hi there! hi GC!
i was thinking about congratulating you first, but i think you must be feed up with it!your website is wonderful and should be translate in others language, because in this side of country it's very difficult to get info on engine tuning...someone interested in translation??

well,let's start...
i have a set of 8V camshafts, on wich i can read A 25/87 (on both)
they look like standard , but someone tell me they must be race because they don't have rought surface like standard.

guy, i've noticed on previous topic that you are giffted in reading in numbers...i hope you can still do that for me!!
antonio

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Post by Guy Croft » June 29th, 2006, 7:30 pm

Un peux de sport maintenant.

Au premier, mon Copain!

Tres bien merci pour votre letter, et bienvenue ici! Je suis tres content que vous aimez nouvel GCRE.com! A vos services! Aidez -mois: Vous pouvais peut etre informer- comme vous voulez - a vos amis qu'il y a quelq'un ici qui connait tres bien toute sortes de moteurs pour circuit et rally - et qui parle aussi tres mauvais (?) Francais!

Touts les '87' sont Alquati et sont tous la meme. Vous pouvrais oublier le numero '25' - ca na rien-a-faire avec la type ou l'operation. Il ya naturellement beacoup d'autres abres a cammes Alquati, j'ai tous les numeros chez GCRE.
Les characteristiques de vos abres a cammes sont exactement la meme que celiu de Martin, au dessous (above?)

(Camilo Alquati, etait tres bien connu, habite Cremona, Italie, mort par - je crois deux ans, je regrette)

Mon Dieu - ca - c'etait difficile...!! Phew - any bi-linguals types out there??!!

GC

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Post by antonio » June 30th, 2006, 6:18 am

merci, merci!
your french is not so bad as you can imagine, i would even say pretty good! thanks for answering in molieres' language!!
happy to hear they are alquati.i also have a set of other fast road cams, but they look very different from alquati, even if specs are quite similar:
timing 50 80 /80 50
duration 310 deg
10.6 lift
they come with a machined cam housing as there lobs are much more rounded than stock, or alquati.
how to now wich cam use, as they look indentical on specs??
see attached picture of "rounded" cam.
why use a breather hole on inlet cam housing?

ps: above=au dessus
below=au dessous
teach me how to tune engine, i'll teach you Molieres' language...ok?
merci beaucoup
antonio
[/img][/url]
Attachments
d1_1_b.jpg
"rounded" cams
d1_1_b.jpg (21.28 KiB) Viewed 13966 times

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Post by Guy Croft » June 30th, 2006, 7:41 am

Hello Antonio

thanks, that was fun! Aux dessus, I never got it right!

I cannot id cams unless I recognise the maker's style or there are markings. These are usually on either end (Kent, Piper, Alquati, GC) or on the shaft (Abarth - cast iron and usually rough cast between ground sections, Colombo & Bariani - easil stand out because of their rahter big shafts + nitrided steel).

Try the photo again, it did not upload, as for teaching about tuning engines that is precisely what this site is for.

GC

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Post by antonio » June 30th, 2006, 9:01 am

Attachments
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Post by antonio » June 30th, 2006, 9:22 am

i think it works now...

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