F54 or N42 block for building a 3.1 stroker

[Tak510]

It has been a long year mystery for me...

For building a 3.1 or 3.2 stroker, is it better using the F54 block or N42? Almost every article I read in English says, the F54 is the best choice when building the stroker." But, what I hear in Japan (yes, my native language.) is totally the opposite. They say, "If you're going to bore 89mm or more, then the N42 is your best bet, especially if you were building it for drag racing. The largest bore you can go safely with the F54 is 88mm." That seems to be the common understanding among the L engine tuners in Japan.

More interesting to note, they say that some early production of the N42 up to the certain lot number came with thicker cylinder walls and had more rigidity than the later produced N42s, hence it's even more desirable for building the strokers, but they are a very rare find now...

The F54 came out later than N42 and it has improvements like the added water passages between the cylinders for a better cooling. But my question is, is the F54 really not safe if boring 89mm?

What do you guys think?

[Diseazd]

http://www.geocities.com/inlinestroker/index.htm

This might help.

[jbuenviaje]

As for blocks to use with an overbore: the N42 block has better thickness in the cylinder walls and is a FULL siamesed block. Also, I have never heard any reports of the lack of coolant passages between cylinders being a problem in terms of cooling.

The best years of N42 being the ones made for the USA market in 75-76. From what I understand they had higher nickel content in the block. However, any of the N42's are good as they are all very strong blocks.

As for the F54, the cylinder walls are thinner for better cooling and coolant passages between the cylinders (hence the non-siamessed). You you can overbore the F54, but the F54 is really not the first choice as it is a non-siamesed block. I have even seen a rebuild book that states it is siamesed, but it has large passages between the cylinders, and hence is not really siamesed, and not all of the cylinders in the F54 even have any joining material between them. I would use an F54 on a turbo engine with stock bore or for high compression on a stock bore.

So, do not believe anyone who tells you the F54 is the choice block for a overbore or that the F54 is superior to the N42! They are just repeating what others have been told. People who have been to Japan will tell you that the engine builders in Japan have been using the N42 since the start, as they knew the properties of the N42 are way superior. Leave it to the Japanese to be way ahead!

Also, get the block sonic tested and balance all components!!! Do not skip this for a power build. For a stock build with stock bore, you can just rebuild like normal.

Also just to comment on my understanding of the L28ET limits (stock internals, but sitll I would get ungraded rod bolts! The rod bolts being the weakest link in the L-series engines).

From my understanding, the stock L28ET can do 350 BHP at the upper limit with no internal modifications (external only like stand-alone, injectors, ignition, etc.)

[Tak510]

http://www.geocities.com/inlinestroker/index.htm

This might help.

Thank you! Yes, I read this one before, too. He says, "The block of choice for the 3.1 stroker is the F54. Although some people have used the N42, the F54 block has webbing built in between the cylinders for extra rigidity."

The F54 has a better cooling design without sacrificing rigidity by adding the webbing between the cylinders, and I am totally for that, too. But, the N42 has less water passage, means has more metals left between the cylinders than the F54?? My wild guess is, the F54 gained water passages but also had to shave some metals out of the block. Nissan engineers managed to maintain the needed rigidity by using the webbing design. When the F54's cylinders are bored out beyond the certain point and the walls get thinner, the advantage of the webbing design for extra rigidity may be lessened?? I don't know. I'm just curious.

[Tak510]

Thank you, jbuenviaje! Wow, you solved my mystery. This forum is great!!

[Tak510]

http://www.geocities.com/inlinestroker/index.htm

This might help.

Thank you! Yes, I read this one before, too. He says, "The block of choice for the 3.1 stroker is the F54. Although some people have used the N42, the F54 block has webbing built in between the cylinders for extra rigidity."

The F54 has a better cooling design without sacrificing rigidity by adding the webbing between the cylinders, and I am totally for that, too. But, the N42 has less water passage, means has more metals left between the cylinders than the F54?? My wild guess is, the F54 gained water passages but also had to shave some metals out of the block. Nissan engineers managed to maintain the needed rigidity by using the webbing design. When the F54's cylinders are bored out beyond the certain point and the walls get thinner, the advantage of the webbing design for extra rigidity may be lessened?? I don't know. I'm just curious.