S2 1750 rebuild - Alfa Romeo Bulletin Board & Forums
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post #1 of 235 (permalink) Old 11-01-2016, 08:27 AM Thread Starter
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S2 1750 rebuild

I'm about to tear down my 1750 engine and looking over some upgrades.

Gantry is almost complete and the engine is drained and isolated with only the trans bolts, tach cable and engine mounts remaining.

Looking at new parts a Spruel kit includes most of what I need and also increases the cc to 1840 and a compression of 10.5:1. I'd like to add some performance and reliability while doing this word. The kit also has oversize valves:
Intake: 45 degree seats 9x42.5mm
Exhaust: 45 degree seats 9x38mm

My stock cams are: 10548 03200 01 European 1750 10mm.
Can these still serve OK? I have a tip from alphaparticle to adjust the intake and exhaust 3 degrees from the factory settings (further down the road)

I'm figuring new cams and tappets will add quite a bit more to the bill but if the valves demand it I'd like to know.

Also are oversize valves even worth it? The stock ones I have were lapped when the engine was resurrected so I could just replace the guides provided the stems were still within spec.

This would save on valves and seats. I could concentrate more on duration and lift and porting.
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68' Parisian Alfa GTV 1750

Last edited by BostonBertone; 11-01-2016 at 09:05 AM.
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post #2 of 235 (permalink) Old 11-01-2016, 09:17 AM
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Subscribed. Good luck! Jim
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post #3 of 235 (permalink) Old 11-01-2016, 10:12 AM
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I think alfar7 has addressed oversized valves and whether or not there is any real benefit on a street motor. I think a good head rework may yield more of a gain the bigger valves. The info is somewhere in the BB. Fran
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post #4 of 235 (permalink) Old 11-01-2016, 05:45 PM
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Having pulled more Alfa motors than I can count it is easier to pull the motor and trans as a unit. It's the method the factory shop manuals use.


The passenger seat is 15 miles an hour faster than the drivers seat.

currently
74 GTV restored daily driver
another 74 GTV restored driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1977 Spider
1974 Spider
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post #5 of 235 (permalink) Old 11-01-2016, 06:52 PM
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Interesting chassis, it appears to have come with dual carbs from the factory, is it a euro 1750? The mounting(s) for the snorkel air cleaner were early as I understand.

current:
84 Spider Veloce
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post #6 of 235 (permalink) Old 11-01-2016, 07:28 PM
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I don't think oversize exhaust valves have any benefit. I have big intake valves in my Berlina and GTV and they run pretty good. While refaced valves are fine (heat transfer?) given the stems spec out it will reduce the shim thickness needed to adjust the lash even more so than what cutting the seats subtract from shim thickness. That's not a problem unless things are cut so much the thinnest shims won't give the correct setting.
You might want to remove the fan. Your going to need all the room you can get.

The passenger seat is 15 miles an hour faster than the drivers seat.

currently
74 GTV restored daily driver
another 74 GTV restored driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1977 Spider
1974 Spider

Last edited by gigem75; 11-01-2016 at 07:30 PM.
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post #7 of 235 (permalink) Old 11-02-2016, 11:08 AM
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If originality does not matter, you might find a core 2.0L engine....you can drop a 2.0L engine since parts are readily available and more HP.

Giorgio
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post #8 of 235 (permalink) Old 11-02-2016, 12:48 PM
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To each his own; I pull just the engine or trans as needed. Seems like more work to me to do both if not needed. But I know folks have different methods and facilities.
US cars got 10502 cams, these 10548 cams are a small but noticeable step up. Depends on what you want in your car/engine. A good 1750 is a great thing. Looks like a Euro car, carbs not Spica?
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post #9 of 235 (permalink) Old 11-02-2016, 04:52 PM Thread Starter
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I'm not committing to any of the upgrades yet and am definitely interested in advice/opinion. I plan to make a thorough examination of the piston liners and valves as well before spending $.

I'm not really into a swap at this time and only want to make upgrades if it makes sense and I have to replace parts anyway. I think the guides are in the cards for sure but I'll check the valve diam to see if they are still spec. They fit the current seats perfect and the clearances were recently redone but I'll re-verify after all the work. If oversize won't gain much I'd rather not have to incur the expense of having the seats done.

The engine even in its oil burning state is a blast to use and really comes alive in the higher revs. Anything that improves the lower end might be better so it might be wiser to get an upgraded exhaust. Anyways I agree a perfect 1750 is a special thing.

It is a Euro 1750. It is however an S2 engine so the original engine is somewhere else or gone. In my prior restoration I had to find a lot of the missing air box parts. It came with Dellorto carbs but I am currently using weber DCOE151s.

Fan is off. I may keep it off and try out a electric Spal puller but that is another topic for later.

I can now see the wisdom of pulling both trans and engine. The trans bolts were a pain to get at but I was eventually successful tonight. All that remains right now are two engine mount bolts. I'll jack up the rear and see if I can get things to move. The pull will be this weekend after I add a few more bolts to the gantry.

I can't wait to start getting into it

68' Parisian Alfa GTV 1750

Last edited by BostonBertone; 11-25-2016 at 05:51 PM.
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post #10 of 235 (permalink) Old 11-02-2016, 05:03 PM
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I agree, to each his own. I don't see any advantage to jacking up the rear if you are just pulling the motor but since I'm not well versed in that method someone else might want to chime in. I do have a confession to make though, I recently dropped just the gearbox when I had a Sachs clutch cover come apart and I was pleasantly surprised at the ease of it especially since it was a one man job.

The passenger seat is 15 miles an hour faster than the drivers seat.

currently
74 GTV restored daily driver
another 74 GTV restored driver
71 Berlina in 2L restored driver
the ones that got away:
1959 750 series Giulietta Spider Veloce
1962 Giulietta Spider normale
1965 Giulia Sprint normale
1972 GTV
1974 GTV
1977 Spider
1974 Spider
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post #11 of 235 (permalink) Old 11-03-2016, 03:55 AM
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Make sure you remove the bell housing dust cover, otherwise it will not come out. It happened to me first time when I removed the engine only.

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{Oo==V==oO}

Currently:
'75 Giulia Nuova Super 1300 Blu Olandese
'71 Euro Berlina 2000 (on a restoration process)
'85 GTV6 Nero
'87 Milano Verde
'87 Milano Platinum

{OO==V==OO}
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post #12 of 235 (permalink) Old 11-03-2016, 05:19 AM
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My old track GTV was a mild 2000, basically a street engine with Euro cams and big intake valves. Original Borgo rings, burned a quart every 200 miles, but had 190 lbs compression, I drove it like that for 10 years. Cars can run great while burning a ton of oil. Once I rebuilt it it no longer burned oil, but wasn't really any faster.
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post #13 of 235 (permalink) Old 11-03-2016, 05:32 AM Thread Starter
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Quote:
Originally Posted by Giorgio68 View Post
Make sure you remove the bell housing dust cover, otherwise it will not come out. It happened to me first time when I removed the engine only.
This might be easy as I don't think I have one. The whole time I've had this car there there is an open part of the bell housing just behind the center steering rod. I can see the bottom of flywheel. It has always struck me as odd but I haven't yet seen what should be there. Does anyone have a picture? I can start looking for a replacement.

68' Parisian Alfa GTV 1750

Last edited by BostonBertone; 11-25-2016 at 05:53 PM.
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post #14 of 235 (permalink) Old 11-03-2016, 05:36 AM
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On mechanical clutch cars, the whole bottom of the bellhousing is closed by a tin cover. You can get at the clutch bolts, unbolt/bolt before/after mating the engine/trans. On hydraulic clutch cars, the tin cover is just that little vertical thing behind the steering rod, shows you the front of the flywheel. You have to remove it to separate the engine/trans, but it doesn't give you any access to the back.
It's not necessary, but keeps junk from getting into the flywheel area.

Andrew
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post #15 of 235 (permalink) Old 11-03-2016, 05:42 AM Thread Starter
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Yeah. I don't have this. It always looked wrong to me but it is hard to know what you are missing when it was never there.. I'll look for one or just make one if someone can share a picture. I have the earlier hydraulic clutch.

**** Found one. I just need to clean it up but it will go back on when I put everything back together. I saw the two types and the thinner one was stated to be for a 1750.

68' Parisian Alfa GTV 1750

Last edited by BostonBertone; 11-03-2016 at 06:39 AM.
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