My gtv6's motor

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75evo
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Re: My gtv6's motor

Post by 75evo » Mon Oct 15, 2012 8:37 am

The compression increase will gain you good power. But a set of mild 10mm cams will really bring the 2.5 to life!! Just have a minor regrind of the cams if you know of someone who can do it locally.

Also have you thought about "de-shrouding" the combustion chamber where the valves are? Since the heads are out and you will probably take the valves out again when skimming the heads.

Nice effort and a beautiful car!
gatouille
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Re: My gtv6's motor

Post by gatouille » Mon Oct 15, 2012 9:53 am

Thank you, I choose my regrinded cam not "too much" because I was afraid to have a bad iddle especialy with AC on :wink:
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gatouille
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Re: My gtv6's motor

Post by gatouille » Mon Oct 15, 2012 10:57 am

It was a difficult choice between :

V6 2,0 - 2,5 - 3,0 12V

Applikation : Road


Duration: : 272
Peak timing: : 110
Valve lift: : 9,1
Lift at TDC: : 2,7
Valve timing: : 26/66 - 66/26
Valve clearence: : 50/25


and

V6 2,0 - 2,5 - 3,0 12V

Applikation : Sport


Duration: : 288
Peak timing: : 105
Valve lift: : 9,6
Lift at TDC: : 2,5
Valve timing: : 39/69 - 69/39
Valve clearence: : 50/25


I didn't anyone who had already use these camshafts, finaly I took the "little" one
Should I chose second one ? And what's about iddle ?
Thank you
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gatouille
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Re: My gtv6's motor

Post by gatouille » Mon Oct 15, 2012 11:06 am

We are ready !
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Heads :

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Manifolds have been repaired by my friend "Spish" who own a 75 turbo driftmachine

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gatouille
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Re: My gtv6's motor

Post by gatouille » Mon Oct 15, 2012 11:17 am

Motor is waiting....
url=http://www.servimg.com/image_preview.ph ... u=16548598]Image[/url]

Hydraulic system means too much leak, so we use as a mechanic one
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The deal is "not hurting my brand new paint" !
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I told you I found the exhaust line too much rigid, so :

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Very hard to mount these exhaust manifold hands and fingers are too big !

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It works !!!
img]http://img841.imageshack.us/img841/7607/dsc0698b2.jpg[/img]




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Brake leaks so I have to fix it...

Exhaust :

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Final silencer will be standard.
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gatouille
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Re: My gtv6's motor

Post by gatouille » Mon Oct 15, 2012 11:23 am

Now working on caliper :

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gatouille
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Re: My gtv6's motor

Post by gatouille » Mon Oct 15, 2012 11:26 am

The exhaust manifolds (2 pairs, mine and David's one)

Mine (oval)

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David's manifolds

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Jim K
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Re: My gtv6's motor

Post by Jim K » Mon Oct 15, 2012 6:36 pm

Pay very good attention to the following guidelines from Schrick:

The table below gives a guideline for valve lift at TDC.
2 Valve engines with solid lifters: 2.3 mm
4 Valve engines with solid lifters: 1.5 mm
2 Valve engines with hydraulic lifters: 1.9 mm
4 Valve engines with hydraulic lifters: 1.1 mm
When these values are exceeded, engine idle will become increasingly unstable and torque delivery in the lower rpm range will be noticeably weaker.
Camshafts with larger valve durations, and a resulting higher valve lift at TDC, should only be considered for racing applications, or when each cylinder has it`s own butterfly valve.


Jim K.
gatouille
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Re: My gtv6's motor

Post by gatouille » Mon Oct 15, 2012 11:23 pm

JimGreek wrote:Pay very good attention to the following guidelines from Schrick:

The table below gives a guideline for valve lift at TDC.
2 Valve engines with solid lifters: 2.3 mm
4 Valve engines with solid lifters: 1.5 mm
2 Valve engines with hydraulic lifters: 1.9 mm
4 Valve engines with hydraulic lifters: 1.1 mm
When these values are exceeded, engine idle will become increasingly unstable and torque delivery in the lower rpm range will be noticeably weaker.
Camshafts with larger valve durations, and a resulting higher valve lift at TDC, should only be considered for racing applications, or when each cylinder has it`s own butterfly valve.


Jim K.
Thank you for all answers, this place is a very good one for old Alfa owners !

If I understand
road profil've got a too big lift at TDC ?
:?:
V6 2,0 - 2,5 - 3,0 12V

Applikation : Road


Duration: : 272
Peak timing: : 110
Valve lift: : 9,1
Lift at TDC: : 2,7
Valve timing: : 26/66 - 66/26
Valve clearence: : 50/25


and

V6 2,0 - 2,5 - 3,0 12V

Applikation : Sport


Duration: : 288
Peak timing: : 105
Valve lift: : 9,6
Lift at TDC: : 2,5
Valve timing: : 39/69 - 69/39
Valve clearence: : 50/25
Introduce mysel :
viewtopic.php?f=17&t=4352
My garage is less poor than my english !!
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