N42 Versus F54 The differences! The truth! turbo and overboring

Y

Yokohama

Active Forum User
OK, I was commenting on a different thread, but I feel compelled to put it in a easier to find location as there seems to be much disinformation out there on this subject.

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.).
 
Hi, what does 'siamesed' mean please ?

And what is this block from ? It is an N42 but the dipstick is in the 'wrong' place and it has an external oil pipe.:confused:
 
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Yokohama said:
OK, I was commenting on a different thread, but I feel compelled to put it in a easier to find location as there seems to be much disinformation out there on this subject.

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.).
Click to expand...

Well, that seems to have blown a hole in a few people's theories!;)
 
Saloon car engine which originally had front sump. The oil pipe is presumably a mod to redirect oil from incorrect pick-up pipe position (?).
How is the dipstick going to give useful information when it must be chopped down to work in the shallow part of the sump?
 
Hi, what does 'siamesed' mean please ?
Click to expand...

That there is material that joins the cylinder bores to each other (in the vertical), the N42 is like this. The F54 has cooling passages and is non-siamesed.


Its not as cut and dried as Yokohama makes out here (and generally on the overbore thread).
Click to expand...

Please explain. I can go into more details.
 
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Mr.F said:
Saloon car engine which originally had front sump. The oil pipe is presumably a mod to redirect oil from incorrect pick-up pipe position (?).
How is the dipstick going to give useful information when it must be chopped down to work in the shallow part of the sump?
Click to expand...

Sump holds 9 litres - when there is nothing registering on the dip-stick - time to put some in ! In reality, the level hasn't dropped in two years !
 
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Sorry guys, not enough time to expand more today....I am not saying Yokohama is wrong, it just has a bit more to it, maybe if Yokohama expands?....... as for over-bore..., I have said stuff on this on other posts to what is possible, but that just gets ignored/slatted, so I will see if I can put a bit more up next time.

Regards
Ian
 
Interesting thread, will follow it to listen and learn - rather than overbore, my bag is to fit a big displacement V8 (The coward's way out or the big boy's way out depending on your view point).

I know this thread is about comparing two blocks but it would be really useful and interesting to have a "Janet and John" thread about hoiw to build an overbored engine PROPERLY, not just bore it and throw in big pistons but how to build a serious 3.2L L series.
 
OK,
I thought this was the case, and from the data I got from Mr. F (thank you) it looks like I could be correct.

UK market cars, data taken from Nissan microfiche for the 280zx:

L28 P75 Oct-'78 to June '81
L28 F54 May-'80 to June'81
L28 P90 July -'81 to end and if you wanted to buy a new L28 from Nissan, then and any time after, it would be a P90. I doubt if they would be new from Nissan now....

Added to the mix, a source of L28 pertrol engines/blocks would be found in the 160 and 260 Nissan Patrol. This was available from 11/1979 and it was either F54 or the P90, with no correlation between block or date that was put into the Patrol. Also, Nissan UK gave a poor service of what the market wanted here, which did not help any. As you see from the above dates, it could be a bit of a lottery what specific block you got in your 280zx... I don't know if the L28 was in any other UK market car, which may have had a N42...if please chip in.

So, from this, the N42 block was never offically imported into the UK, unless someone privately imported a 280z or got an engine by some means. So, it it very difficult for us here in the UK to get hold of the N42 block. Charlie boy, good luck sourcing a N42 in the UK :unsure:

In the UK there has been cylinder head gasket problems when re-fitting a certain head to a block (water come out of the side of the block from a hidden waterway which is exposed when water is added),or gaskets blocking water passage ways from the block to the head. I would say this is due to the fact we in the UK we got three different blocks and not knowing which gasket (early or late) goes with what block. Don't worry, Mr F only sells the late gasket set which overcomes any problems.

Yokohama, you are on dangerous ground by using a general statement of what is best, as just because its the way its done in other countries, does not mean it can be done here (this being a UK website and mostly UK based users), as we did not get what other countries did. ... and does not just apply to engines/blocks.. In a way you are doing what you wrote in you post, don't listen to what others have told you.... I get the impression you are trying to give a definative answer to this area, good idea, but as I said its not as cut and dried.

And coupled to that, it is not as straight forward for you in the US (from Nissan microfiche:

L28 N42 Dec-'74 until the end of S30 period (not in 280zx)
L28 P75 1978 to 1981 (280zx)
L28 F54 May '80 to June '81
L28 P90 Dec. '80 standard fit (inc. turbo). Same if buying new from Nissan after the run of the 280zx, would be sold a P90 (and now if available)

Yes, maybe the N42 is the block of choice, but the F54 is only a short run, and what about the other two blocks? I can't see why you make a sweeping statement about two blocks when added together the other two blocks/engines take up about 6 years. Maybe people running a F54, are in fact running a P90 block (whether standard/turboed/or over bored)? From this data the P90 was around for approx. 3 years (and therefore probably much greater numbers than the F54), and as the same as the UK there is an over lap of what could be in a US 280zx. So from this data, can it be assumed it can't be said the F54 "is the turbo" block as most likely its the P90 (can't remember when the 280zx turbo was introduced in the US) though I think it was 1982....?

As I said, not quite as straight forward......

Enough for now...
Regards
Ian
 
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SeanDezart said:
Sump holds 9 litres - when there is nothing registering on the dip-stick - time to put some in ! In reality, the level hasn't dropped in two years !
Click to expand...

:conf2: looks like an Arizona Z pan like mine....mine only takes about 6 litres to max, must be small french litres :)
 
Ian Patmore said:
So, from this, the N42 block was never offically imported into the UK, unless someone privately imported a 280z or got an engine by some means. So, it it very difficult for us here in the UK to get hold of the N42 block. Charlie boy, good luck sourcing a N42 in the UK :unsure:
Click to expand...

Hi Ian, my engine is being assembled in Australia as that is were my two cars are for the moment, so I have had 3 N42 blocks sonic tested and the best one chosen:thumbs: As far as I am aware Australia only got the L28 blocks in N42 variants. Possibly the Patrols came with one of the blocks you have stated but I'm not sure. Having said that there seem to be quite a few F54 blocks and P90 heads around because quite a few engines have been imported from Japan, so plenty of choice around.

If people are intrested I could bring some N42's back with me?

C
 
Was'nt the discussion about siamesing and wall thickness? What is the 260z block which is what my "L28" uses (can't get at it at the moment)? The spare 82 L28 I have is a P54/P90 ( Janspeed turbo engine)
 
I think it was more to do with what was the best block to use for everboring.

Mike B
 
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