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I am about 2 busted knuckles into a water pump replacement on my 1974 GTV with Spica injection. It has been a great car for weekend cruising and one trackday over the past 10 years but the engine is tired, with a fair amount of pressure in the crankcase, which probably indicates worn rings. So my water pump replacement is turning into a possible engine rebuild. This presents another issue since I have a twinspark motor in the garage, which also needs a rebuild... maybe I should mothball the Spica/Nord setup and install the Alfa 75 twinspark along with its stock Bosch injection or else put some webbers on it. Aside from the cost to do either engine, what would the group feel might enhance or detract from the value of the car? I don’t plan on getting rid of it anytime soon, but that can always change as life priorities tend to evolve. Any pros/cons to consider?
 

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I finished a full rebuild of my 2L GTV motor (74 Spica) last year, same situation as you -- except I had a spare high-po SPICA motor - 2L - fast street motor -- that I dropped in and used while rebuilding the original. THe rebuild was really fun and I took my time -- about 6 -8 weeks I guess - then swapped back. I'd think the original 2L would be more valuable, but unless you plan to sell it, do whatever you want -- rebuild the twinspark, drop it in, and enjoy the car--- and over the next couple of years, rebuild the Spica motor. Nothing like a rebuilt motor in a GTV -- add a 4:10 diff and away you go....
 
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Twin spark all the way, and for my money I think the motronic is a fantastic system and don't know why more people don't keep it. I love originality but engine swaps are
A) un-doable
B) for you to enjoy
C) when done right, in today's market seem to add, not detract value. but I don't put too much stock in the whole value equation. see A and B.
 

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You would need to spend a lot of money to get the Nord to produce same power as the twinspark so if your after more power go twinspark. Is the Nord a matching number engine? If yes I'd still go with the TS but do a slow rebuild of the Nord and keep it for when you sell the car
 

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....., with a fair amount of pressure in the crankcase, which probably indicates worn rings.....
This is a common misdiagnosis for a failed OVS...and is a $120 fix... without going into ALL the issues with what COULD be happening.. I'll summarize it this way.. If your OVS is clogged and it probably is after 46 years .....your crank case ventilation becomes NO ventilation at all and it is like capping of the vent that goes to the OVS.. Think about it... as putting a cork in the cam cover vent. If that happens you will build pressure in your oil sum which results in basically pressurizing all the oil seals of your motor.. After the owner's hair fire is extinguished, there are simpler matters to address. If you search me on "OVS" in your advanced searches on this forum there is more about it in this thread attached and others on diagnostics for the OVS... There are many ring jobs that are attacked as a solution.. but is money spent for nothing. A Permanent Solution to FAILED CORRODING Oil Vapor...

In the end your rings perhaps are just fine and you will not have to rebuild your engine. I've been selling these since last July and unfortunately many of the GT crowd has not connected with the thread on the Spider forum where most of the action on OVS's has been posted. Don't throw the baby out with the bath water yet. I sincerely hope I have helped you wade through your issues .
 

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What is making you observe that there is excessive crankcase pressure? Are you measuring it? If you think piston/rings are on the way out, then do a compression test followed by a leakdown test. If indeed there is that much blow-by (which would overwhelm a properly functioning OVS system), then compression/leakdown will confirm it.

Agree with divotandtralee about OVS. Check basics first before condemning the motor, especially since the OVS system is notoriously brittle.
 

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I don't think there is a limit to a properly operational OVS.. I don't think you can coalesce oil from vapor to liquid faster than it drains back to the sump. There is room in the OVS to catch about a half pint of oil and there is an open drain to the sump at the bottom as it is accumulating...It's not that the are "brittle" .. The OEM OVS is bare carbon steel inside when new.. by now it is mostly FEO2 which mixed with oil and water become sludge .. Don't even give it 2 seconds thinking you can resurrect it. It's why I had no alternative than to make mine which spawned many happy customers.
 

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That makes sense. I agree with that. I guess what I meant by brittle was the original parts in the system and not the system itself. Also, by overwhelm, it's possible that too much oil vapor will be brought back into the intake. I was thinking it might not just be a coalescing issue. My thinking was spurned by how the original poster determined there was too much pressure. Was he just looking at the outlet on the valve cover with the hose removed? Was he inferring too much oil burning? Don't know.

fyi....happy with your OVS kit. Works flawlessly! Highly recommended and fun to assemble! Count me as a happy customer. 😁
 

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I knew what you meant but I ALWAYS have to have a word and many take as from an irksome nature.. I've sold over 100 of these and still there are probably many more muliples of hundreds out there that are patched painted and prettied up with the inclination all is well inside the OVS with little understanding the simple little inanimate object is not the equivalent of a "door knob". I wish folks would realize that a failed one can contribute to more mayhem and false diagnoses that is a mile long .. from smoking exhaust to hard starting.to oiled plugs to blamed piston rigs to blown and leaking oil gaskets to poor gas mileage and constant needs to add oil. ad nauseum.. all because of this "door knob" ( hung on there in the name of "tree hugging"). not working and there really is no way to resuscitate it once it goes south.. Thanks for the compliments BTW. .I'm tickled you are happy with the product and the assembly process.
 

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Couldn't agree more. The OVS is a measured orifice, which if malfunctioning, can affect idle, which owners then offset for by idle and SPICA adjustments, which then throws off the fuel map, transitions, drivability, etc. in addition to the things you mentioned above.
 

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I am about 2 busted knuckles into a water pump replacement on my 1974 GTV with Spica injection. It has been a great car for weekend cruising and one trackday over the past 10 years but the engine is tired, with a fair amount of pressure in the crankcase, which probably indicates worn rings. So my water pump replacement is turning into a possible engine rebuild. This presents another issue since I have a twinspark motor in the garage, which also needs a rebuild... maybe I should mothball the Spica/Nord setup and install the Alfa 75 twinspark along with its stock Bosch injection or else put some webbers on it. Aside from the cost to do either engine, what would the group feel might enhance or detract from the value of the car? I don’t plan on getting rid of it anytime soon, but that can always change as life priorities tend to evolve. Any pros/cons to consider?
fyi

muscle cars with late model F I engines "pro touring" are now worth alot more than nice cars with their original carbed slow,stinky, gas guzzling engines for obvious reasons, this thinking is even trickling down to ferrari as one dino owner put a a late model ferrari v8 in place of the original v6 and made the only dino that performs as good as they look
 

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I think it all depends on what you like. I'll start with my own experience. I've owned a string of GTVs and still enjoy driving my 2000 on a daily basis. What I like about driving an Alfa is finding an opportunity to string out the engine, shift gears, and listen to the music. I've played a bit with cams and cam timing to make it less of a lazy revver, and I'm contemplating lightening the flywheel anytime the gearbox is off. But if I give it any more power, it will just make it harder to wring out the revs decently on a public road. I would trade it anytime for a 1600 or 1750, maybe a 1300.

But there are many reasons you may want to modify the car deeply. Maybe, like the muscle car guys Frank refers to, you want to do some racing (they usually do it in a straight line though). Or you don't drive it much, and when you do you go for a quick run at obscene speeds. Or you enjoy to show off your mods at drive night. Or what you actually enjoy is the act of creating and building YOUR unique car.

The point about value is moot. Transforming a car to a different drivetrain is very tedious and certainly more expensive than a straight rebuild. Well done transformations will be well received on the market, while not necessarily profitable. But if you want to do it because that's what you want, do it. Just make sure you understand why you want to do it.

Final note: the OVS discussion is worth some attention. You wouldn't believe how this innocent looking device can play havoc with your engine. Been there...
 

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Regarding the swap, I'm all for the Twinspark swap. Not only are you getting more hp and torque, you are getting it where you want it for a street car - down low.

And if you are considering dropping the motronic I'd recommend looking into the Jenvey EFI "carbs" coupled with an Omex (or equivalent) ECM. Classic look and sound, modern software controls and Honda reliability...
 

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Discussion Starter #14
Thanks all for the information about the OVS. I realized mine was rotted out a while back and replaced it with an open draft tube going down by the block. I know, not ideal. I am deciding that I have crankcase pressure by removing the oil cap while idling and there is pressure blowing out. It actually runs okay in spite of this, but clearly im loosing some pressure somewhere. I suppose it could be worn exhaust valve guides but im suspecting rings and pistons. Perhaps I should do a leak down test.
 

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Probably worn or broken rings .. been there. Broken? the ring lands wear out and the rings loosen and flutter and eventually break like a cracker and just stay put in the pistons.. thus blowby and pressure in the sump faster than you can vent it when running
 
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