[ScottSmith]

It looks like I'll be building my spare engine. When should notching the block be done during the build process? Before or after:
1. Converting to closed deck
2. Installing dry sleeves (or maybe nickel silicone-carbide coating...)

The downside to doing it before sending the block out is that I don't really want to throw in the new pistons to test-rotate the assembly just to see if it fits...

[sqwinny]

Unless you want to push more than 500hp closing the block isn't necessary. You'd notch the block after installing sleeves. I'm in the same process, looking for a crankshaft and getting all supporting mods in first (fuel pump + upgraded ekp, upgraded radiator, clutch and flywheel since I'm 6MT)

[ScottSmith]

Shouldn't it be related to torque, not horsepower? I would like to safely be able to run 400 ft lbs in race conditions. I do agree it's probably not needed for what I'm doing, but closing the deck is pretty cheap to do, and I think it's notable that the industry trend is toward closed deck engines:
1. The S55, nominally based on the N55, went with a closed deck.
2. The next generation is all closed deck: B38/B48/B58/S58
3. Mercedes M133/M139 (their 400hp 4-cyl) is closed deck; btw the cylinder spacing minus bore size is the same on the M133/M139 as the N20.

Audi RS3 LMS uses a closed deck engine, though it's an iron block so I'm not sure how comparable that is.

[sqwinny]

Torque, not hp kills these motors due to the small factory rods. the n55 can hold more as the stress is across 6 cylinders instead of 4. Just sleeving the block with pistons and rods will work for what your goals are. I'm going this route with a pure stage 2 turbo. sure i should do a custom manifold and turbo, but im lazy, as well as the dyno showing 380whp/440wtq is only 23psi not 27-28. my goal is around 500whp with little to no lag compared to stock while driving around town/occasional HPDE day + oil pan/accusump.

[navardi]

Originally Posted by sqwinny

Torque, not hp kills these motors due to the small factory rods. the n55 can hold more as the stress is across 6 cylinders instead of 4. Just sleeving the block with pistons and rods will work for what your goals are. I'm going this route with a pure stage 2 turbo. sure i should do a custom manifold and turbo, but im lazy, as well as the dyno showing 380whp/440wtq is only 23psi not 27-28. my goal is around 500whp with little to no lag compared to stock while driving around town/occasional HPDE day + oil pan/accusump.

Notching required for H beam rods regardless of sleeves or reapplying plasma arc wire spary.

Pure stage 2 or any N20 stage 2 turbo regardless of boost won't flow enough air to get over 40lbs/min of airflow or for that matter 400whp.

So you no real benefit of a built motor with a turbo that barely maxes out a stock motor.

[navardi]

Originally Posted by ScottSmith

Shouldn't it be related to torque, not horsepower? I would like to safely be able to run 400 ft lbs in race conditions. I do agree it's probably not needed for what I'm doing, but closing the deck is pretty cheap to do, and I think it's notable that the industry trend is toward closed deck engines:
1. The S55, nominally based on the N55, went with a closed deck.
2. The next generation is all closed deck: B38/B48/B58/S58
3. Mercedes M133/M139 (their 400hp 4-cyl) is closed deck; btw the cylinder spacing minus bore size is the same on the M133/M139 as the N20.

Audi RS3 LMS uses a closed deck engine, though it's an iron block so I'm not sure how comparable that is.

Closing the deck really only necessary for those that don't sleeve the block and reapply the plasma arc wire spray. Or for those with sleeves and use the motor in an extreme way i.e racing. If its cheap enough and given your use case, would definitely recommend getting it done. For a street motor, unless you're pushing 40psi relative then closing the deck is abit overkill but all depends on the cost, if you can justify it then do it.

[ScottSmith]

Originally Posted by navardi

Closing the deck really only necessary for those that don't sleeve the block and reapply the plasma arc wire spray. Or for those with sleeves and use the motor in an extreme way i.e racing. If its cheap enough and given your use case, would definitely recommend getting it done. For a street motor, unless you're pushing 40psi relative then closing the deck is abit overkill but all depends on the cost, if you can justify it then do it.

I haven't found anyone who can redo a plasma arc wire spray. I have found a couple places that can do nickel silicon carbide plating, basically Nikasil. It should retain most of the same characteristics as the stock lining (better heat transfer than iron sleeves, even if just dry sleeves).

CSS can do the closed deck install.

[navardi]

Originally Posted by ScottSmith

I haven't found anyone who can redo a plasma arc wire spray. I have found a couple places that can do nickel silicon carbide plating, basically Nikasil. It should retain most of the same characteristics as the stock lining (better heat transfer than iron sleeves, even if just dry sleeves).

CSS can do the closed deck install.

Up to you, sleeves can take abit more of a beating, but depends on your budget and use case/goals

[soldiermedic711]

These N20 sleeves seem impossible to find.

[sqwinny]

Navardi tunes sells blocks with Darton mid wet sleeves installed with pistons and the sleeves bored and honed.

https://navardituned.com/en-us/produ...ine-block-only

Css (there has been a report or two of work quality). They close repair sleeves and close the deck making the closed deck conversion a “sandwich”. Have to mail them your block.

https://cylindersupportsystem.com/

Lastly you can call LA Sleeve for standard flanged performance dry sleeves for the n20/n26 or they sell their “open deck strong sleeves” that’s semi wet sleeve similar to evolves offering. - note you can order these and la sleeve will mail them to you as the development of these items have happened already, they just have to be made.


La Sleeve also makes a direct competitor to Darton mid wet sleeves, but you’ll have to send them your block and they will make it for you.

https://www.lasleeve.com/