S30 engine part juggle possibilities?

[Tony 260Z]

Hi All,

First off, Merry Christmas everyone, and I hope you all have a great New Year.

I'm wondering how to get some more grunt from my Z's.

Here's what I've got available to juggle...

My 260Z has an L28 with an F54 block and P90 head. She's running 2" SU's and a (GDS?) 6-branch header but as far as I know a stock cam. The head did have a little skim a few years ago.

My 240Z has an L28 with an N42 block and N42 head. She's running round-top carbs, a Nismo 6-branch header and as far I know a stock cam and head.

Dotted around I have a set of triple Mikuni's, a couple of Mangoletsi manifolds for triples, one of Sean's lovely stainless 6-branch headers, an adjustable cam pulley and a P90A head that I bought a couple of years ago from a very well-known member of the Z community who told me it was "Samuri Spec" (which I'm guessing means bigger valves or some porting or some magical blend of the two but no specific info was given at the time).

I also have a spare engine but this confused me because it seems to have a Y70 block with an E88 or E80 head (difficult to read). I've heard of the heads but what block is this? I've found a Y70 head on Google but not a Y70 block. Hmmm....

I've thought about engine swaps but the above keep the same gearboxes etc.

Any thoughts on which bits to juggle?

Please excuse my asking the question if it's on here elsewhere... got a few memory issues and don't remember stuff!

Tony

 

[Tony 260Z]

Checked the block again... it definitely says Y70 on the block.

Anyone know what it is?

 

[Albrecht]

Checked the block again... it definitely says Y70 on the block.

Anyone know what it is?

'Y70' = Late L20AE casting.

 

[SeanDezart]

Hi All,

First off, Merry Christmas everyone, and I hope you all have a great New Year.

I'm wondering how to get some more grunt from my Z's.

Here's what I've got available to juggle...

My 260Z has an L28 with an F54 block and P90 head. She's running 2" SU's and a (GDS?) 6-branch header but as far as I know a stock cam. The head did have a little skim a few years ago.

My 240Z has an L28 with an N42 block and N42 head. She's running round-top carbs, a Nismo 6-branch header and as far I know a stock cam and head.

Dotted around I have a set of triple Mikuni's, a couple of Mangoletsi manifolds for triples, one of Sean's lovely stainless 6-branch headers, an adjustable cam pulley and a P90A head that I bought a couple of years ago from a very well-known member of the Z community who told me it was "Samuri Spec" (which I'm guessing means bigger valves or some porting or some magical blend of the two but no specific info was given at the time).

Any thoughts on which bits to juggle?

What 'grunt' have you measured on your current set-up ? What therefore is your starting point and does 'grunt' mean torque (low down power) or bhp (top end power) ?

L28 with an F54 block and P90 head = good stroker base whether used with the same 2" SUs or not.

L28 with an N42 block and N42 head = good screamer base - up the CR, add a wild cam and triple Mikunis.

And thanks for the compliment.

 

[jonbills]

I don't think you'll get a worthwhile improvement by just juggling that collection of parts.
I think you have to start with slightly more of an idea of what you want to achieve and how much you want to spend.
The spare p90a might be the best place to start thinking about a project. Get some photos and measurements of valve sizes and chamber volume?

 

[Alphabettispaghetti]

I'd have a look at the head, measure the CC, valves, see if its a proper port job, go from there.

However Seans manifold/Mangoletsi manifold would be in use.

 

[Tony 260Z]

'Y70' = Late L20AE casting.

Thanks Alan... how intriguing... I think that lump was in my 260 when I first got her but that was over 16 years ago so I'm not sure.

I thought that the L20 was a two-litre? It's got me confused again because the block number on the other side starts "L28".

What on earth kind of frankensteins monster have I got sitting in my garage?!

Thanks everyone for your comments - all guidance and information much appreciated.

I seem to remember my 260 hit 199 bhp on a rolling road a few years ago but I don't know if that was flywheel or at the wheels. She's not bad performance-wise but to be honest half the little turbo'd shopping trolleys you can buy these days would give her a nasty shock. Although she did OK racing Clarkson many moons ago... maybe she was having a good day!

I think the 240 will prob get the Mikunis and a hotter cam etc. Should be fun!

 

[SeanDezart]

I thought that the L20 was a two-litre? It's got me confused again because the block number on the other side starts "L28".

I seem to remember my 260 hit 199 bhp on a rolling road a few years ago but I don't know if that was flywheel or at the wheels. She's not bad performance-wise but to be honest half the little turbo'd shopping trolleys you can buy these days would give her a nasty shock.

L20 vs. L28 ?

199'll be at the flywheel - not bad at all.

Those turbo-thingies are also probably FWD and ABS'ed which all helps....

 

[Tony 260Z]

Thanks Sean... 199 horse was a few years ago though - she desperately needs a tune-up now!

I'm puzzled by the block markings on that spare engine though. How can it have a stamp for a two-litre injected engine on one side but L28 on the other? I'll see if I can grab photos in case anyone thinks I've had too much vino over Christmas and started seeing things!

I'll have a look at that head I bought too - see if it looks like it's been worked on and if I can measure the valves.

It raises an interesting thought though... if any of us buys a block or a head, all of which can be thirty to forty years old, how do we know we're buying what we think we are? lol!

 

[Albrecht]

I'm puzzled by the block markings on that spare engine though. How can it have a stamp for a two-litre injected engine on one side but L28 on the other? I'll see if I can grab photos in case anyone thinks I've had too much vino over Christmas and started seeing things!

'Y70' is the base casting code. Could be bored to any capacity that the cylinder walls would permit, depending on application. Both front sump and rear sump versions were made.

 

[SeanDezart]

'Y70' = Late L20AE casting.

Thanks Alan... how intriguing... I think that lump was in my 260 when I first got her........I thought that the L20 was a two-litre? It's got me confused again because the block number on the other side starts "L28".

'Y70' is the base casting code. Could be bored to any capacity that the cylinder walls would permit, depending on application. Both front sump and rear sump versions were made.

So, was it cast to L20A spec or L28 spec (when numbered 'L28') ?

 

[Albrecht]

So, was it cast to L20A spec or L28 spec (when numbered 'L28') ?

'L20A'? I quoted 'L20AE'. Devil is in the detail. We are talking 1969 vs 1979 here.

'E30', 'E31', 'P30', 'N42', 'F54', 'P90' etc etc are first three letter/number combination of the second half of the relevant part numbers. Part number 11010-Y7090 was first seen on L20AE cylinder block. Obviously cast first, then bored for 2 litre capacity and finally stamped up with individual engine serial number. If engine block in question is stamped up with 'L28' prefix it was - presumably - bored for L28 capacity, but 'Y70' block casting was L20AE base type as denoted by part number.

Above all 'by the book' obviously. If the engine (block) in question has been modified/altered/tampered with and/or true origin disguised then the only way to ascertain correct data for it is to inspect and measure. I would not assume anything as a given in this origin-unknown scenario, especially if intending to modify further.

 

[Tony 260Z]

Hi Alan,

Thanks... I'm a bit of a duffer here.... do you mean the block could have been originally cast as a two litre (L20AE) but then overbored to 2.8 litres in the factory and stamped L28? Even with potentially a decade between the two events? Is there any way I can find out more without taking the head off?

Could this engine be something unusual or rare? Or is this sort of thing comparatively common?

Cheers,

Tony

 

[Albrecht]

... do you mean the block could have been originally cast as a two litre (L20AE) but then overbored to 2.8 litres in the factory and stamped L28? Even with potentially a decade between the two events? Is there any way I can find out more without taking the head off?

I'd expect a 'Y70' block to date from approx. 1978 onwards. They were fitted to all sorts (including Japanese home market S130-series Z and 2-litre iterations of Cedric and Gloria, amongst others) but not particularly sought-after or desirable really.

A possibility is that it was supplied as a replacement block or a complete remanufactured short/long engine in period. Since I've seen nominally 'sedan' (Cedric/Gloria/Skyline etc, usually a cheap source of used engines in period) front-sump engines converted for use in Zs, nothing would surprise me. They usually had sump, oil pick-up and dipstick location modified to suit.

If it has fuel injection type E88 head it could be S130 Z or injected sedan, but if not I'd expect it to have come from a carburettor-type sedan with low compression.

I don't think there's any way of you really knowing what's what unless you strip and inspect, and all the more so considering you intend (?) to modify. Have you not got any memory of where/what it came from? What's the dipstick tube location?

 

[Tony 260Z]

Hi chaps,

Sorry it's taken a while to reply.

The dipstick tube is towards the rear of the engine, a couple of inches away from the oil filter. The sump is towards the back of the car too.

I think this is the engine that was in my 260 when I first got it, but I'm not sure. I wasn't intending to modify it, just wanted to identify it since I'd never heard of a Y70 block. Always nice to have a spare just in case!

I'll have a look at my spare "samuri spec" P90A head as well and see if I can do some measuring and establish if I think it has been worked on. Not that I'm sure what to look for!