1600 Rebuild - Stock or Modified? - Alfa Romeo Bulletin Board & Forums

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post #1 of 29 (permalink) Old 08-06-2016, 03:31 PM Thread Starter
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1600 Rebuild - Stock or Modified?

Hi all,

My father and I (mathcg) are rebuilding his 67' Giulia GTV. The car is currently at the bodyshop, however within a few weeks we should be receiving the engine (which we were unable to pull since we do not own an engine lift). For those unaware, it is our intention to rebuild the car ourselves (with the exception of the body / chassis work). Our next step will be to rebuild the engine. My main question here stems from a conversation I had with my father. I thought it would be better to do a "stock" rebuild, whereas he leaned towards adding some performance while we were rebuilding it anyways.

- For those that have driven both stock and modified 1600 engines, which would you prefer for a weekend street driven car?

Some backstory for why I'm asking. I feel that the engine really determines the "feel" of the car to a large part. I used to own a modified 91' 300ZX Twin-Turbo. The car was seriously fast, probably ranging from 400-500 bhp on high-boost. However, for me it was too much. The power was rarely usable on the street and mostly went to waste. I could use a very small percentage of it's available power. The un-reliability that ensued from owning a modified turbo car was also too much for me to afford. My current car is a stock 83' RX-7. The car has a meager 100 bhp, but I find it much more enjoyable to drive. For the most part I can use 100% of it's power in a legal, safe way while driving on the street. For me this is much more fulfilling. I don't want my father's car to have a peaky race engine that can hardly be enjoyed or used to it's full potential on the street.

So for those that have driven both, which would you prefer? There's probably no "right" answer here, but since neither my father nor I have ever driven the car, we don't have much to go by. I'm of the opinion that the car is probably a real joy to drive in stock form, but again I have nothing to really go by. If we did decide to modify it, my idea would be to do a free-flowing exhaust (we probably plan on doing this anyways), upping the compression a bit and putting a mild cam in the engine. Nothing crazy. My father is not wanting to do anything crazy either.

Few disclaimers:

- We're set on keeping the stock 1600 engine, and aren't interested in swapping to a 1750 or 2000 engine. Originality is important to both my father and myself. We also own two 1600 engines anyways.

- Neither my father nor I have ever taken apart an engine and rebuilt it. We're intentionally trying to do this ourselves (that's part of the point of this car), so please don't suggest we pay someone to do it for us. I can't imagine we won't be able to figure it out, at least with a bit of help.

As an addendum: if we do decide to go the stock route, what can be reused, or would people recommend reusing? Should we be able to reuse the rods and pistons? Either way should we have a machine shop balance everything?

Thanks in advance!
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post #2 of 29 (permalink) Old 08-06-2016, 03:55 PM
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You have asked more questions and broader questions than I could answer in a single post. Let me just address a couple of your points:

- There's "modified" and then there's "MODIFIED!!!". I would vote for "modified" - perhaps higher lift cams, slightly higher compression, electronic ignition. I don't think you risk getting close to the 400-500 hp that your 91' 300ZX Twin-Turbo puts out.

- Yes, an amateur can rebuild an Alfa engine in his garage. I would recommend getting the Kartalamakis and Braden books as well as a manual such as Autobooks.

- Your job will be a lot easier if your machinist has some Alfa experience. There is nothing magic about the bottom end, but many machinists won't get the head right; they fail to understand that Alfa valve shims come in a finite range. I know you are in Colorado, but you didn't specify where. Find a local Alfa enthusiast and ask what machinist they recommend. It is worth travelling to an experienced Alfa machinist - guys who mostly do small block Chevys will disappoint you.

Jay Mackro
San Juan Capistrano, CA

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'65 Guilia Sprint GT
'67 Duetto
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Last edited by Alfajay; 08-06-2016 at 04:01 PM.
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post #3 of 29 (permalink) Old 08-06-2016, 03:55 PM
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Good choice on staying with the original 1600! Too many of these have had major changes that affect the 'feel'of the car. Alfa really did design and build a wonderfull ballance into the cars that I love. I've had my blue '67 GTV for 42 years and restored it 3 times so I'm familiar with them ! ;^)
You can do some practical motor mods that make a little more hp and torque while keeping the external parts intact...
Get a copy of the FACTORY engine/trans rebuild manual. It will give you all of the specs and how much wear on parts is permissable. Follow the assembly steps and you will have a great runner.
The best running 105 that I have owned was the '66 Duetto that I built a few years ago. Stock rebuild by the book except for some mild smoothing of the intake tract and the intake cam replaced with a 10548 cam from a 1750 model.
Tighten up the valve lash measurements to .012" intake and .016" exhaust.
This improves torque and makes the car a delight to drive.
Leave the "race" parts for the race cars!
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post #4 of 29 (permalink) Old 08-06-2016, 04:13 PM
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Stock! Always


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post #5 of 29 (permalink) Old 08-06-2016, 04:31 PM
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Any stock Alfa from the 60's and 70's will benefit from modern cams provided that they have carburetors that can be adjusted. There is no downside just more torque, better driveability, better gas mileage.

Ed Prytherch
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post #6 of 29 (permalink) Old 08-06-2016, 04:53 PM
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Originally Posted by alfaparticle View Post
Any stock Alfa from the 60's and 70's will benefit from modern cams provided that they have carburetors that can be adjusted. There is no downside just more torque, better driveability, better gas mileage.
+1

Your talking about 109 hp stock. Adding a little more will simply increase the fun factor. As Ed says "there is no downside".

Rich Hanning
'65 Sprint GT, '78 Spider, '88 Quad
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post #7 of 29 (permalink) Old 08-08-2016, 06:47 PM Thread Starter
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Thanks for the replies so far everyone. Looks like most are leaning towards a mild modification of the engine. The example I used was over-exaggerated, but I suppose the point I was trying to make is that I feel it's more fun to drive a slow car fast, than a fast car slow - a position I assume most people here will sympathize with. In addition, I was trying to emphasize that I find a nice NA engine more enjoyable to drive than a turbo engine.

I can definitely do the research on my own to determine what are good parts for the build, but in terms of what items people would upgrade, does the following seem logical: pistons, camshafts, valve-springs, ignition and exhaust? We have the (stock?) Weber carburetors that came with the car, which we plan on reusing. Does the head usually require any porting / polishing, or for a mild street build is it usually sufficient in stock form?

What about items that change the acceleration, but aren't directly related to the engine. For instance a lighter-weight flywheel or different ratio differential?

For those that said keep the engine stock, why did you choose this? Simply because it's stock, or because you feel it drives better this way?

I apologize if my questions are redundant. I've just started my research on these engines and I'm definitely learning. My father is very busy, so I'm trying to help him out with some of the parts selection, etc. I usually don't like to keep my cars "bone-stock", but rather I like to make a few changes that emphasize the original qualities from the factory, without taking away from the original spirit of the car.
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post #8 of 29 (permalink) Old 08-08-2016, 07:16 PM
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Spruell Motorsport has a piston and liner upgrade kit if you want a few more cc. If you are doing the head a port and polish can only be good along with some different cams (lots of opinions here). Stock exhaust manifolds are actually pretty good but if you like shiny the the Alfaholics one is the goods. If you have a cable clutch car you will have the heaviest version of the flywheel so lightened options will be an improvement.

I would consider my car stockish with its original engine. I purposely went this way because I wanted the car to feel like it was designed. Of course a few small reversible tweaks were done since they weren't expensive mods! I have different cams, head was ported and polished and matched to intake manifold. I have an electric pusher fan (which adds 3HP!!! haha). There are different 1600 heads too as I recall the later heads allowed a bit more power as well. My car still has a 1300 diff from a previous owner which does make it zippy in the city traffic. A 123 programmable distributor is next on my list as my stock dizzy which I was hoping to keep for originality has too much play. The elec dizzy certainly helps across the board and doesn't look terrible in the engine bay.
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post #9 of 29 (permalink) Old 08-08-2016, 08:26 PM
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I'm planning on polishing my valve cover. Good for 3-5 hp!!
I just say that in jest.
Since my car was restored about 5 yrs ago with only about 1200 km since, I'm keeping my engine as is because of two reasons. One, the rebuild work is too recent to want to mess with. Two, 'I' feel that the engine would be hardest to return to stock if you're keeping the remainder of the car close to stock, for future sale reasons. My suspension and wheel changes can be changed back to stock in a day. Even headers can be a day away from stock.
It just depends on what your restoration goals are.

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post #10 of 29 (permalink) Old 08-08-2016, 08:42 PM
Your best bang for the buck in the engine would be cams. The cheapest bring a 10548 cam.

But the overall best improvement you can make on these cars is the suspension. That's where these cars shine and is generally overlooked in favor of an extra few HP.
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post #11 of 29 (permalink) Old 08-08-2016, 09:14 PM
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Quote:
Originally Posted by hcaulfield57 View Post
Thanks for the replies so far everyone. Looks like most are leaning towards a mild modification of the engine. The example I used was over-exaggerated, but I suppose the point I was trying to make is that I feel it's more fun to drive a slow car fast, than a fast car slow - a position I assume most people here will sympathize with. In addition, I was trying to emphasize that I find a nice NA engine more enjoyable to drive than a turbo engine.

I can definitely do the research on my own to determine what are good parts for the build, but in terms of what items people would upgrade, does the following seem logical: pistons, camshafts, valve-springs, ignition and exhaust? We have the (stock?) Weber carburetors that came with the car, which we plan on reusing. Does the head usually require any porting / polishing, or for a mild street build is it usually sufficient in stock form?

What about items that change the acceleration, but aren't directly related to the engine. For instance a lighter-weight flywheel or different ratio differential?

For those that said keep the engine stock, why did you choose this? Simply because it's stock, or because you feel it drives better this way?

I apologize if my questions are redundant. I've just started my research on these engines and I'm definitely learning. My father is very busy, so I'm trying to help him out with some of the parts selection, etc. I usually don't like to keep my cars "bone-stock", but rather I like to make a few changes that emphasize the original qualities from the factory, without taking away from the original spirit of the car.
My second Alfa was a 1965 Sprint GT. Very close to same as yours.

Everything about the car was delightful. I rebuilt the engine twice, both times stock. Never felt there was a shortage of power.

My opinion is that any hot rodding would add far more to the cost than to the fun. The car is nice and light as compared to later models, so it is a thrill to drive with the stock engine.

Note that I'm not hawkish on staying stock. I've done some significant things to the engine is n my 59 Touring 2000. That is a much heavier car, and needed more engine.

The 1600 is a magic engine. Revvy thing in stock form.

Don P
Carson City, NV

Past Alfas...
59 102 Touring (first Alfa $500 running)
65 Sprint GT (2nd Alfa, $500 daily driver)
102 Sprint (never did anything with it, but wish I had)
74 Berlina (first new car - now certainly rusted into oblivion)
61 Giulietta Spider G-Prod Race Car (where is it now?)
84 Spider Veloce (rarely drove it, so sold it)
86 Quadrifoglio (Dull car - no more 115s for me)
1971 Montreal "The Full Monty". Fair winds and following seas

Current Alfas
59 102 Touring Roadster - restoration complete, enough Alfa for any rational man. Or irrational, for that matter
And past...
Two 1946 Stampe SV4C (c/n 294 "Rocinante" - wife's favorite airplane. RIP), and c/n 235 "La Bon Temps Femme" (gone to a new home, but never forgotten)
Zlin 50LA (+9 -6 gees, titanium spar, 1200 lbs, 260HP rumored to now be in Brazil)
1946 Luscombe 8A
Starduster Too (recently spotted at the Nevada City, CA airport - over 20 years and an entire continent separating it from our stewardship in Binghamton, NY)
1955 Cessna 170B (wife taught me to fly tailwheel in this)

And present...
64 Mooney M20E ("Rambo". My faithful steed for over 30 years) Nearly 50 years old, and just returned from a trip to Argentina in him
Newest in the fleet
1967 Piper Super Cub on Wipline amphibious floats (a true "all terrain vehicle")
2010 Triumph Thunderbird


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post #12 of 29 (permalink) Old 08-09-2016, 06:29 AM
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FWIW, stock is less expensive, simpler overall, and more in keeping with the car that rolled off the assembly line. (You found this out with your 300ZX Twin Turbo science project). The GTVs are a delight to drive in stock form. How much wheel spin is enough? How much chassis stiffening is enough? How much complication is enough. I fully get and commend those who mod their cars and race them. However, in my case I have been fortunate enough to have a couple of other older cars that are faster and handle better than a GTV so I don't expect mine to carry the load of being the fleet rocketship. I just enjoy the hell out of driving it for what it is.
Again, this is FWIW.
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post #13 of 29 (permalink) Old 08-09-2016, 07:42 AM
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Originally Posted by hcaulfield57 View Post
What about items that change the acceleration, but aren't directly related to the engine. For instance a lighter-weight flywheel or different ratio differential?
You can lighten an Alfa flywheel for better acceleration. Just don't go overboard if you are building a street car.

Your '67 probably has a 4.56 differential - already pretty good for acceleration. The next readily-available higher ratio is 5.12 which is not well-suited for modern street use (e.g. freeway driving). The Alfa gearbox has a wide range of ratios - first gear is particularly low - so acceleration isn't a problem.

Jay Mackro
San Juan Capistrano, CA

'63 Guilia spider
'65 Guilia Sprint GT
'67 Duetto
'91 164L

Last edited by Alfajay; 08-09-2016 at 07:45 AM.
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post #14 of 29 (permalink) Old 08-21-2016, 07:34 PM Thread Starter
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My second Alfa was a 1965 Sprint GT. Very close to same as yours.

Everything about the car was delightful. I rebuilt the engine twice, both times stock. Never felt there was a shortage of power.

My opinion is that any hot rodding would add far more to the cost than to the fun. The car is nice and light as compared to later models, so it is a thrill to drive with the stock engine.

Note that I'm not hawkish on staying stock. I've done some significant things to the engine is n my 59 Touring 2000. That is a much heavier car, and needed more engine.

The 1600 is a magic engine. Revvy thing in stock form.
Quote:
Originally Posted by tuttebenne View Post
FWIW, stock is less expensive, simpler overall, and more in keeping with the car that rolled off the assembly line. (You found this out with your 300ZX Twin Turbo science project). The GTVs are a delight to drive in stock form. How much wheel spin is enough? How much chassis stiffening is enough? How much complication is enough. I fully get and commend those who mod their cars and race them. However, in my case I have been fortunate enough to have a couple of other older cars that are faster and handle better than a GTV so I don't expect mine to carry the load of being the fleet rocketship. I just enjoy the hell out of driving it for what it is.
Again, this is FWIW.
What you two highlighted reflects what I'm thinking somewhat. The GTV is a very light car (especially by modern standards), and I'd imagine it feels very "go-kart" like. I still somewhat question how much horsepower it needs to be fun. Again having never driven one, I'd imagine it feels like you're going fast, even though you're not. I've found that the lighter the car gets the less horsepower you need to have fun with. This is my experience with small cars that I've driven. I think we'd like to focus on handling over all out power. Having looked at the suspension layout when taking the car apart, it sure seems like it should handle really well with a little tweaking.
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Originally Posted by Alfajay View Post
You can lighten an Alfa flywheel for better acceleration. Just don't go overboard if you are building a street car.

Your '67 probably has a 4.56 differential - already pretty good for acceleration. The next readily-available higher ratio is 5.12 which is not well-suited for modern street use (e.g. freeway driving). The Alfa gearbox has a wide range of ratios - first gear is particularly low - so acceleration isn't a problem.
Okay, I didn't realize that the differential was geared so high, - doubt we would want to change that. Do people find that a lighter-weight flywheel improves the driving experience, or does it just make it just make it more difficult to drive. Granted, this won't be a car that is driven in traffic, but it shouldn't be miserable to drive.

We still haven't decided what we'll be doing yet. We plan on picking up the engine soon, and taking it apart and then deciding and ordering what parts we need. We're still trying to get a space set up to take the engine apart. Having never taken apart an engine before this is very exciting for us! I've found from working on my own cars (and helping take apart my father's GTV) that I get a much greater appreciation of the car and how it works and functions then simply from driving it.
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post #15 of 29 (permalink) Old 08-22-2016, 08:33 AM
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One other item we haven't talked about is tires......

Diameter will have an affect on gearing. Smaller diameter for more accelleration, larger for less revs on the freeway. Stock 155-15 is the best overall, as the Alfa Gods intended !

Wider tires will make the steering heavier and you will lose the lightness that Alfa designed in. Better to use stock size tires and enjoy the car !

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