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Discussion Starter #1
All -

My 72 GT is all show and no go at this point. It has a stock rebuild on a 2L Nord.





However, I plan to change that in the near future -- I have a spare 2L Nord block (casting 512 - 1972 or so), crank, and I have a twin spark head on the way here from Europe. I don't plan to do anything exotic here; just want a strong N/A motor for track days and a bit of street driving.

My basic plan -- balanced bottom end, aftermarket rods (MaxSpeeding?), quality forged pistons (recommendations?) with about 10.5:1 or 11:1 compression (something that will live with 93 pump premium if I back off timing, but will usually have some race fuel mixed in), aftermarket camshafts (recommendations?), aftermarket ignition (MSD 6AL box + 8 plug distributor?), and I'm guessing Weber 45's.

I plan to have the head ported. Will tackle it myself if I can't find anyone to do it.

Questions -

1. Recommended block and crank mods - drilling the oil passage in the block, staking the plugs in the crank, right?

2. Recommended pistons and compression ratio? How far can I go on an overbore?

3. Recommendation on camshafts and valvetrain?

4. Recommendation on ignition?

5. Recommendation on carbs and intake?

6. I know the TS head is thicker, so I'll need to either mill the bosses where the studs go through or remove the shorter Nord studs and install TS studs. Will probably leave this to the machine shop. Any other needed mods that I'm forgetting?

7. If you have any recommendations on someone to port the head, please post here or send me a message. I'll do the engine assembly myself.

Almost forgot -- I don't necessarily have a hp goal; just want to make as much as reasonably possible without exotic components and/or twisting it to 9,000 rpm. Having said that, I think 200+ at the crank sounds reasonable.

Thanks in advance for any info!

Scott
 

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6. I know the TS head is thicker, so I'll need to either mill the bosses where the studs go through or remove the shorter Nord studs and install TS studs. Will probably leave this to the machine shop. Any other needed mods that I'm forgetting?
Yes. Fitting a TS head on a Nord block requires in total 17 different mods to make it work.

Oil passages in block vs. oil passages in head, chain gear mods (sprocket position of crank relatively to cam sprockets) and head studs/nuts (including sealing against water!) are the most important.

It's not a plug and play job!
 

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Are you using a 75 or a 155 head? There is a good thread covering the differences with you should review.

If a 155 you'll need a manifold block and associated plumbing to bring the radiator upper hose up front. PM me if you need help with that.
 

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My 8V Nord makes 190 HP on pump gas with good driveability and I am confident that it would make 200 HP at about 6800 rpm with 38 mm Venturis. PM me if you want to talk about it.
 

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Discussion Starter #6
Yes. Fitting a TS head on a Nord block requires in total 17 different mods to make it work.

Oil passages in block vs. oil passages in head, chain gear mods (sprocket position of crank relatively to cam sprockets) and head studs/nuts (including sealing against water!) are the most important.

It's not a plug and play job!
Yes, I know there are a few threads on the subject that I need to review. thanks

Are you using a 75 or a 155 head? There is a good thread covering the differences with you should review.

If a 155 you'll need a manifold block and associated plumbing to bring the radiator upper hose up front. PM me if you need help with that.
Thanks, I'm going with a 75 head.

Its from a 75 TS,I´m selling him the head, Scott, look asap in your mail, I need something from you to ship the head.
Ok, I'll check. thanks

My 8V Nord makes 190 HP on pump gas with good driveability and I am confident that it would make 200 HP at about 6800 rpm with 38 mm Venturis. PM me if you want to talk about it.
I'm familiar with your Nord; impressive research and results. I'm going with a TS, but I'll send a message anyway; I'm sure most of the lessons learned are applicable to both. Thanks
 

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Discussion Starter #7
Ok, so here's a simple question - is there any reason to use a Nord block over a TS other than the fact that I have a Nord block and crank sitting in the garage? Put another way -- am I a dumbass for wanting to use a Nord?
 

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Ok, so here's a simple question - is there any reason to use a Nord block over a TS other than the fact that I have a Nord block and crank sitting in the garage? Put another way -- am I a dumbass for wanting to use a Nord?
No, there is absolutely no reason. And a TS is stronger than a 0512 block as well. TS blocks have several differences in casting leading to a much stronger block.

The only reason is you want to spend several hours on extra work for realizing the mentioned and required mods . No advantage, only extra work. Less structural and torsional rigidity included as well.

Drop me a PM if you like.

I've built 3 engines w/TS heads on Nord blocks. 2x 75, 1x 155. Only because the customers wanted that for homologation/historical basic reasons.

I never would do that if I could come across a 75 block easily. Never.
 

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Discussion Starter #10
No, there is absolutely no reason. And a TS is stronger than a 0512 block as well. TS blocks have several differences in casting leading to a much stronger block.

The only reason is you want to spend several hours on extra work for realizing the mentioned and required mods . No advantage, only extra work. Less structural and torsional rigidity included as well.

Drop me a PM if you like.

I've built 3 engines w/TS heads on Nord blocks. 2x 75, 1x 155. Only because the customers wanted that for homologation/historical basic reasons.

I never would do that if I could come across a 75 block easily. Never.
Thanks for the detailed response. I appreciate it.
 

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Starting to look at camshaft options -

I see Alfaholics has 4 different profiles to choose from with their TS cams. Spendy at $850 or so.

C&B cams can be had for $700 or so for a pair.

Cat Cams in the UK is a new one for me; they have about half a dozen different profiles - Alfa Romeo 75 & 164 2.0L Twin Spark

Tij Power in Germany lists 4 different grinds as well - https://www.tij-power.com/product_info.php?language=en&products_id=168339
I'm using a set of cams from Richard Jemison for my Twin Spark build.
 

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This Nord information relates to your prospective TS build.
Jim Steck recently dyno'd a race motor with cams from Paul Spruell. He then swapped out the exhaust cam for an RJ785 from Richard Jemison and made no other changes. The RJ785 made a little more peak HP but it made almost 25 HP more at 5000 rpm. The Spruell cam has longer duration. So beware of long duration cams!
 

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Discussion Starter #17
This Nord information relates to your prospective TS build.
Jim Steck recently dyno'd a race motor with cams from Paul Spruell. He then swapped out the exhaust cam for an RJ785 from Richard Jemison and made no other changes. The RJ785 made a little more peak HP but it made almost 25 HP more at 5000 rpm. The Spruell cam has longer duration. So beware of long duration cams!
Thanks, Ed. Excellent data.
 

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Hello!

Quick (dummy?) question:

I've got an Alfa 164 2L Twin Spark (8v) (1995), that I recently messed up the timing chain and bent a couple of valves. I'd like to know if the intake & exhaust valves and valve guides are the same on the Alfa nord 2L TS (Alfa 75) and the newer Twin Spark engines?? I know that the head gaskets are not the same. But the intake and exhaust valves seem to be the exact same thing? I came to that conclusion after comparing part numbers online. I'd appreciate if someone could kindly confirm that for me :D

Thank you!!
 

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Hello!

I'd like to know if the intake & exhaust valves and valve guides are the same on the Alfa 2L TS (Alfa 75) and the newer Twin Spark engines?? I know that the head gaskets are not the same.
Yes, they are. Valves are interchangeable.

Head gasket's different by rear length and 1 different bolt hole pattern at the chain cover side.
 
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