Rebuilding the 3.2 motor

[mrtexas]

As a recent NSX purchaser I just got 3 books about NSX and have been finding out some details I didn't know before. I own a 1999.

From what I can gather the 3.2 engine did away with cylinder sleeves. That leaves the cylinder fiber re-enforced
aluminum? Not planning on scoring the cylinder walls but the engine block is not re-buildable if the cylinder walls get scored?

I test drove a 2001 Porche Boxter S red with hardtop 6 speed for a daily driver, probably not practical but I'm not that serious either. I'm practicing restraint and delay in buying cars as I already own 7 and don't have any covered space left for another one unless I park it under one of my 3 4-post lifts. 3 are daily drivers and 4 are collectibles. BTW custom designed my 3 car garage with 12 foot ceilings and 2 car carport with attached living quarters with car collecting in mind. One has to sleep while not driving/working on cars... Driving/sitting in the Boxter reminds me of driving my NSX. https://www.rtexpo.com/inventory/vi...ster-S-6-Spd-Manual-Very-Low-Miles-Houston-TX Old Boxters are a dime a dozen and sit on used car lots for long periods of time before selling. The one I test drove with only 26k miles that looked like new with a NADA retail dealer price of $12k vs $65k-$75k for the NSX. The dealer wants $16k. One reason for the give away price that I can gather from reading Porche forums is that a replacement block is $12k. Apparently the Boxter also has non-rebuildable all aluminum cylinder walls as well. Other would be Porche very famous for expensive repairs.

My question is this: The 3.2 NSX has a cylinder wall material similar to the Boxter?

 

[jwmelvin]

From what I can gather the 3.2 engine did away with cylinder sleeves. That leaves the cylinder fiber re-enforced
aluminum? Not planning on scoring the cylinder walls but the engine block is not re-buildable if the cylinder walls get scored?
. . .
Apparently the Boxter also has non-rebuildable all aluminum cylinder walls as well. Other would be Porche very famous for expensive repairs.

My question is this: The 3.2 NSX has a cylinder wall material similar to the Boxter?

The Honda liner is called Fiber-Reinforced-Metal, which seems to be a carbon-fiber and aluminum-oxide matrix impregnated with aluminum during casting. Here are a couple articles that describes Honda's FRM application: SuperStreet, Honda-Tech.

From what I gather (e.g., here or here), the Boxter engine you are talking about uses lokasil for the cylinder liner, another cast-in-place material that seems to be silicon-dioxide particles. In other engines (including later Boxters), Porsche used alusil, an aluminum-silicon alloy.

You are correct that you really can't just rebuild the C32B block: the FRM is difficult to bore/hone and difficult to find pistons & rings that can tolerate the FRM. My understanding is that there is a diamond-tool boring processing that can do it and some Japanese company supposedly makes pistons and rings that can work with FRM but it's not easy information to find. When I had my engine rebuilt, the cylinder walls were okay, but it makes it essentially impossible to use forged pistons without having the block sleeved (which would have added a bunch of expense).

Edit:
This is kind of an interesting article about various cylinder-liner materials.

 

[Old Guy]

From what I can gather the 3.2 engine did away with cylinder sleeves. That leaves the cylinder fiber re-enforced
aluminum? Not planning on scoring the cylinder walls but the engine block is not re-buildable if the cylinder walls get scored?

My question is this: The 3.2 NSX has a cylinder wall material similar to the Boxter?

Honda did not eliminate the 'sleeves' on the C32 since they never used a sleeve (as that term is commonly used) in the C30. Honda did use a traditional cast iron liner in the C30 which allowed for the engine block to be re bored to accept oversize pistons if there was excessive clearance or scoring / scratching / whatever on the cylinder walls. As [MENTION=28830]jwmelvin[/MENTION] describes, Honda did eliminate the iron liner on the C32B switching to their FRM cylinder lining. If you manage to score the lining on a C32B, there is no conventional boring the block up to the next oversize piston option. There are repair options involving the uses of sleeves (search Darton C32B). This is not an inexpensive repair option and probably best not attempted by fools.

The concept of the C32B cylinder liner is similar to the Porsche liner; but, the execution is different. I don't know anything about issues with Porsche liner wear on Boxsters. Liner wear and cylinder scoring from typical use operation does no appear to be an issue with the C32B. Honda did have some issues with high oil consumption on some FRM equipped engines; but, I believe the issue was that the piston rings did not play nicely with the FRM liner rather than a case of wear on the liner.

If you stick with the OEM air filter and change it and your oil at the correct intervals, having to deal with a scored cylinder lining will probably be at the absolute bottom of your list of things to think about.

 

[drew]

If your engine isn't sewing machine smooth, then figure out what is wrong always. A continued mis- or lack-of- fire can cause "cylinder wash" and destroy a cylinder reasonably quick.