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post #1 of 12 (permalink) Old 12-09-2018, 03:32 PM Thread Starter
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Question Alfa 6C 2500 Series 2

Hi, I am currently assisting a friend to re-assemble the engine of his Alfa 6C 2500 Series 2, which has been in "mothballs" for over twenty years. I have the original owners handbook (in Italian) & I have been able to get a fair bit of information from it, by translating selected text that appears to be relevant, however I need more detailed information than that included in the handbook.
Would anyone out there have a workshop manual (or even learned information) about the following topics?
1. Valve timing process - I presume that the crankshaft must be placed in the "TDC" position before being engaged with the camshaft gears. The camshaft gears each have one line & a "0" marked on them but I am unsure which to use & exactly what they align with.
2. Setup tolerance adjustment for the intermediate camshaft drive gear.
3. Exploded view of the valve & top/bottom tappets setup
4. Ignition timing settings & process used for modern fuels
5. Cylinder head & camshaft torque settings, cylinder head tightening sequence & valve clearances.
The information I have so far is: Cylinder head tension:36.2 ft/lb, Valve clearance 0.45mm (inlet & exhaust the same?)
If anyone has any information on this, I would be very grateful for some text or even a scanned copy of relevant pages from a workshop service manual.
Best regards, Trev L
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post #2 of 12 (permalink) Old 12-10-2018, 06:57 PM
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Quote:
Originally Posted by Trev L View Post
Hi, I am currently assisting a friend to re-assemble the engine of his Alfa 6C 2500 Series 2, which has been in "mothballs" for over twenty years. I have the original owners handbook (in Italian) & I have been able to get a fair bit of information from it, by translating selected text that appears to be relevant, however I need more detailed information than that included in the handbook.
Would anyone out there have a workshop manual (or even learned information) about the following topics?
1. Valve timing process - I presume that the crankshaft must be placed in the "TDC" position before being engaged with the camshaft gears. The camshaft gears each have one line & a "0" marked on them but I am unsure which to use & exactly what they align with.
2. Setup tolerance adjustment for the intermediate camshaft drive gear.
3. Exploded view of the valve & top/bottom tappets setup
4. Ignition timing settings & process used for modern fuels
5. Cylinder head & camshaft torque settings, cylinder head tightening sequence & valve clearances.
The information I have so far is: Cylinder head tension:36.2 ft/lb, Valve clearance 0.45mm (inlet & exhaust the same?)
If anyone has any information on this, I would be very grateful for some text or even a scanned copy of relevant pages from a workshop service manual.
Best regards, Trev L
Your questions would be better answered in this forum: https://www.alfabb.com/bb/forums/lim...ion-1910-1949/
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post #3 of 12 (permalink) Old 12-10-2018, 07:34 PM
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Originally Posted by 6alfas View Post
Your questions would be better answered in this forum: https://www.alfabb.com/bb/forums/lim...ion-1910-1949/
I agree that the topic will get better exposure there and asked the moderators to move the thread.

-Ruedi
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]
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post #4 of 12 (permalink) Old 12-10-2018, 07:37 PM
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Quote:
Originally Posted by Trev L View Post
Hi, I am currently assisting a friend to re-assemble the engine of his Alfa 6C 2500 Series 2, which has been in "mothballs" for over twenty years. I have the original owners handbook (in Italian) & I have been able to get a fair bit of information from it, by translating selected text that appears to be relevant, however I need more detailed information than that included in the handbook.
Would anyone out there have a workshop manual (or even learned information) about the following topics?
1. Valve timing process - I presume that the crankshaft must be placed in the "TDC" position before being engaged with the camshaft gears. The camshaft gears each have one line & a "0" marked on them but I am unsure which to use & exactly what they align with.
2. Setup tolerance adjustment for the intermediate camshaft drive gear.
3. Exploded view of the valve & top/bottom tappets setup
4. Ignition timing settings & process used for modern fuels
5. Cylinder head & camshaft torque settings, cylinder head tightening sequence & valve clearances.
The information I have so far is: Cylinder head tension:36.2 ft/lb, Valve clearance 0.45mm (inlet & exhaust the same?)
If anyone has any information on this, I would be very grateful for some text or even a scanned copy of relevant pages from a workshop service manual.
Best regards, Trev L

Welcome to AlfaBB, Trev L!

The AROC Tech Library seems to have a copy of the repair/service manual (Pub. 492) which may have been published in Italian only. Still, you may want to ask for electronic copies of this manual and the parts catalog (listed as Pub. 4912, I'm not sure if this is a typo), as they may give you answers to several of the questions you asked.

-Ruedi
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]
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post #5 of 12 (permalink) Old 12-10-2018, 09:52 PM Thread Starter
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Thanks for the good advice, I'm just trying to learn how this forum works!
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post #6 of 12 (permalink) Old 12-11-2018, 01:10 PM
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Hey, Trev, no worries about being new here!

I found a copy of Pub. 4912, dated 10 - 1949 (so, the name is indeed correct and, I'm guessing, potentially may be the 12th Alfa publication in 1949?) to answer you question #3. The first image shows a cropped detail of the valve mechanism from the drawing in the parts catalog (from the AROC Tech Library PDF).

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Originally Posted by Trev L View Post
3. Exploded view of the valve & top/bottom tappets setup
Name:  Pub. 4912 (10-1949) - p.025 (cropped).jpg
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Name:  Pub. 4912 (10-1949) - p.025 (700 wide).jpg
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Name:  Pub. 4912 (10-1949) - p.024 (700 wide).jpg
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Name:  Pub. 4912 (10-1949) - p.026 (700 wide).jpg
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Size:  142.8 KB

-Ruedi
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]
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post #7 of 12 (permalink) Old 12-11-2018, 01:19 PM
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This crop may help, too:

Name:  Pub. 4912 (10-1949) - p.025 (cropped 2).jpg
Views: 161
Size:  114.1 KB

-Ruedi
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]
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post #8 of 12 (permalink) Old 12-11-2018, 02:48 PM Thread Starter
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Thanks very much tubut, I have also sent off a request for an electronic copy of Publication 492 to the AROC Tech Library.
Our main need is for something that tells us exactly the setup of the two camshafts with relation to the crankshaft. I presume it would be with crank in TDC position, the mark on the inlet side camshaft aligns with ??? and the mark on the exhaust side camshaft aligns with ???
The engine was fully restored about 20 years ago, stored with the head off but otherwise ready for re-assembly so we don't want to damage any components by having any components colliding!
I really appreciate what you have given me! Regards, Trev L
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post #9 of 12 (permalink) Old 12-12-2018, 05:01 AM
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The diagram of the valve arrangement look similar to that on my 1931 1750 DOHC unblown engine. Over the years I’ve experimented with various valve clearances but at present have settled on 0.25mm inlet 0.30mm exhaust, not sure why I ended up here but just done a tour to Portugal from UK, 1600 miles, and it ran OK. For ignition timing my car has a manual advance/retard lever, for hand crank starting, and there is a centrifugal advance retard in the distributor. I have set ignition to TDC at full manual retard, when running I set it at full manual advance and allow the centrifugal mechanism to advance further. I don’t know what this represents in degrees but arrived at it by slowly advancing at the distributor until the engine pinked under load and then retarded it a bit. This may be the best method for you too as fuels and operating conditions vary so much these days. I buy unleaded 98 in the UK and try and get equivalent when abroad but sometimes have to make do with 95.

The cam shaft drive arrangement is different, my engine has a vertical drive shaft and bevel gears but the actual camshafts and cam wheels may be similar. For valve timing the cam wheels have three marks each. Using clock face analogy, albeit hung at a bit of an angle, when number 1 piston is at compression TDC the cam wheels have a 0 at the 12 o’clock position that corresponds to the oil supply pipe running along the top of the camshaft bearing caps. There is a faintly scored line at 3 and 9 o’clock which aligns with the top surface of the camshaft housing.

Chris
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post #10 of 12 (permalink) Old 12-12-2018, 02:43 PM Thread Starter
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Thanks Chris. That makes sense to me, ours has a "0" and two almost faint lines on the inside (or rear facing) side of the cam gears, so your clock analogy seems to fit. Ours doesn't have an oil supply pipe running along the bearing caps but otherwise it sounds similar. I now have an electronic copy of the service manual (in Italian) but with an "Italian to English" technical phrase reference sheet, so that may help although I will still need to do some translations of the actual procedures. The ignition timing process you suggest I have used on other cars from pre-unleaded fuel days so that also sounds like the way to go.
Thanks again, Trev L
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post #11 of 12 (permalink) Old 12-12-2018, 02:50 PM Thread Starter
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Just an update tubut, thanks to you (and the AROC Technical Library) I now have an electronic copy of: 6C 2500 Repair #492, Italian, 6C 2500 Parts #4912, Italian, Technical Dictionary #1100 from the AROC Technical Library people. It is great to see how people pull together like this to help get these "elder statesmen of cars" back on the road! I hope to be able to post that "she's running" soon but I am still waiting on gasket sets & a few other parts.
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post #12 of 12 (permalink) Old 12-12-2018, 04:08 PM
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I'm glad you got the manuals.

A a rule of thumb, it seems the more info you can share about the car (chassis and engine number, pictures, etc.), the more info you will get when questions arise.

-Ruedi
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]
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