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Discussion Starter #1
After many years and many miles of enjoyable driving, (including 2 trips from New York to Florida: http://www.alfabb.com/bb/forums/gt-1965-1974/173482-new-york-florida-via-72-gtv.html) my GTV started to leak coolant from the exhaust side of the front cover. The best way to replace this gasket is to pull out the engine. Upon removal of the cylinder head it was clear that more then a gasket replacement was in order. The engine had been burning a bit of oil for quite some time and has caused a massive amount of carbon build up. A complet engine rebuild is now in order. And why bother to do a stock rebuild when a performance rebuild is only a few bucks more.

The plan so far is:
Motronic 10.1:1 pistons
1mm oversized intake valves
Jet coat standard exhaust
keep standard euro 2L cams
rebuild carbs possibly re-jet
polish crank journals
replace all bearings, chains, valve seals/guides, etc..

Also, since the motor was never pulled when the car was painted, now is a good time to have the engine bay painted.









 

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The plan so far is:
Motronic 10.1:1 pistons
1mm oversized intake valves
Jet coat standard exhaust
keep standard euro 2L cams
rebuild carbs possibly re-jet
polish crank journals
replace all bearings, chains, valve seals/guides, etc..
Fred,

This sounds like a very good recipe for a fast and dependable street rebuild.

However, with the higher compression and oversized valves I think something more aggressive than Euro cams will help significantly with power. Modern cam profiles mean you don't necessarily lose your midrange with high-lift cams.
 

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Discussion Starter #3
What do you recommend for cams? I've read that 11mm intake and 10.5 on exhaust is the way to go. Thoughts?
 

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I can't speak for all cams, but the 11.1mm cam that we sell works fine on both the intake and exhaust on a 2 liter. Like I said, these cams, despite their higher lift, offer a good mid-range especially with higher compression.
 

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Engine rebuild

Fred,

I built a motor for a customer that is similar to what you are looking at doing, the only difference is I installed a ported head from Joe at Centerline. I also used an 11mm cam on the intake side only with a Euro cam on the exhaust. If I remember correctly the cams were on 103 degree lobe centers. The customers only complaint when he got the car back was the car would not smoke the tires all the way to 3rd gear. My 100 miles before delivering the car where some of the most fun I have had in an Alfa.
 

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I agree that Euro cams and big valves makes little sense. I suggest that you consider the opposite - standard valves and big cams. There is a race engine making over 200HP with standard valves. Standard valves will not be a limiting factor unless you want to focus on high rpm power. I have 12.3 intake and 11.5 exhaust cams and standard valves and I have a car with great flexibility and impressive power to 7000, and it averages 23 mpg.
You may not need to re-jet your carbs, it depends upon the other changes. Just raising the compression ratio and fitting moderate cams is unlikely to require jet changes, but you will have to increase main jet size if you go to bigger venturis. Tinkering with valve timing and jetting can be a lot of fun.
 

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Ricard Jemison has some cams that provide a lot of torque over a broad rev band.

This and the correct head work makes for good performance.:D

The head on my Spider has RJ's cams and he built the whole engine for my Sprint.

:cool:
 

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Discussion Starter #8
Thanks to all for the comments.
I may possibly go with Alfaholics cams along with the larger intake.
P08 inlet – 12mm
P07 exhaust - 11.6mm
I like and trust Max.
And since I'm going with Motronic pistons (which are not as tall) I don't need to worry about valve contact with pistons.
One of the best things I ever did with this car was a lightened flywheel.
 

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P08 inlet – 12mm
P07 exhaust - 11.6mm
And since I'm going with Motronic pistons (which are not as tall) I don't need to worry about valve contact with pistons.
Uh, I wouldn't guarantee that. 12mm of lift is about 3mm over stock. My recommendation is to use modeling clay to check the P-V clearance. You may be OK, sure. But, it is worth checking.

What is the recommended P-V clearance? The value .020" sticks in my memory (you need to provide a little room for valve float, connecting rod stretch, peace of mind, etc.)
 

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I have a Richard Jemison head and cams too. I think that .020" is cutting it fine. Richard talked me through the whole procedure. You can make the valves hit the pistons with any high lift cams if you do not time them properly.
 

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throw in a good dizzy and a msd6al or equivlalnt and a good set of headers and you will have a blast! The 11m lift cams do give great mid range and you'll be passing cars on the interstate that were just even with you when you first entered the on ramp. Wouldn't hurt to port the head and manifold with JimK's book. All that stuff seems to come together in a really nice package where everything compliments everything else and you'll be in the mid 7's 0-60 with a 410 rear end. i believe stock was 9.6, 0-60 so you will :D:D:D:D
 

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Alfaparticle, could you give me a ballpark figure on how much extra power & torque your RJR cams are worth over euro cams in a 2litre engine, and if the low end driveability suffers much, if at all?

I'm thinking that at some point in the next 12 months I'll be wanting to put together a strong roadgoing engine, so I'm just figuring the best 'bang for buck' modifications. Eg. spending a few hundred dollars swapping 40mm webers for 45s would only net a few hp at high revs - not worthwhile, but a cold air intake and radiusing the carb inlets on the airbox would give similar gains, but could be done for very little, so are worthwhile.
 

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I started with SPICA cams, then Euro cams, then Colombo & Bariani CB47's then RJ136 intake and CB47 exhaust, then RJ136 intake RJ785 exhaust. Installing the RJ136 made the biggest difference. Installing the RJ785 made it even better.
My engine idles at 800 rpm. There is sufficient low down torque for the car to be driven normally. My wife often uses it to go shopping. It will pull from 2500 rpm up a steep hill in 5th gear, but there is not much below 2200 in 5th.
The torque builds steadily beyond 2500 and comes in strong at around 4000. It continues to make good power beyond 7000 rpm - that is where my mental rev limiter is set.
This cam combination gets better gas mileage than the CB47's but not as good as the Euro's.
I have not had my car on a dyno. It is faster than my 2.5 GTV6 but not as fast as my Milano Verde's.
 

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Thanks for that info Ed. It sounds like they are a bit more top endy than I'm after, as my plan would be to use standard internals to keep the budget under control, and 7000+ rpm might be stretching the friendship. High rpm starts getting really expensive when you add up all the bits needed to support it, good rods & pistons, extensive (expensive?) porting, bigger carbs, lower diff ratios, close ratio gearsets etc. My idea is to try and make the most of the standard bits, similar to what I think the the thread starter is intending. Though I do admit that thoughts of forced induction keep crossing my mind, small turbo or eaton supercharger, but that's a whole new story.

I'll contact Richard when I'm ready to go ahead, and let him suggest something suitable.
 

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Hamish

Initially, you might consider running the 40s--they could be more streetable.

Serious track time could entertain the 45s.

:)
 

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Oh, I have no intent of using 45s, if I was to change, it would be to EFI using motorcycle throttle bodies.

I've got a book by David Vizard with some flow bench figures comparing various choke sizes in 40 & 45 mm webers. I'll post a scan up later, but from memory it shows is a 40mm weber with 32mm chokes outflows a 45 with 32s, but when you get to 34mm chokes the 45 body starts to flow more. He also states that 34mm chokes are the largest functional size in a 40 body, as any bigger there isn't enough venturi shape to generate a decent signal at the auxiliary venturi to atomise the fuel well at lower revs. Which might explain why big chokes in the small carb body can be a real dog to drive.
 

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I have 40DCE's with 34mm venturis. You don't need special rods or pistons to let the motor run to 7000 provided you do not want to hold it up there. I have been doing it for years. But you will have to get the tappet bores relieved to accept high lift cams and racing valve springs are also a good idea.
You can choose where you want the power band to be by adjusting the cam timing. If you don't want power at 7000 then you can adjust the lobe centers and get even more low-mid range. It is amazing what 4 degrees difference makes.
 

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Here's that graph I mentioned earlier. It looks like there's little airflow to be gained with an unmodified 40dcoe weber over a 32mm choke.
 

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I have read Vizard for years and have found him to be pretty empirical about his findings so I will accept that there's some validity in his comments about 40 vrs. 45 dcoe flows.

I have several of his book but they're packed away - - - someplace. Can you tell us which of his books these comments are from?
 

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It's from his book on Carbs & Manifolds. It's mostly about tuning & modifying Holleys, but it does have a good little section on Webers & SUs, and some good basic theory of operation.

Anyway, my take from that and other comments on this site is that for a good 2.0l engine 45 webers are ideal, but if you've already got a set of 40s (Dellortos as well) you are giving very little away, especially for a road car.
 
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