L Series capacity increases

[Rob Gaskin]

This Thread content has been split from another Thread because the content is more appropriate here.

 

[johnymd]

Didn't realise the L24 could be taken to 2.8.

 

[SeanDezart]

Isn't that what Nissan did ?

 

[richiep]

OK. Didn't realise the l24 could be take to 2.8.

86mm is considered the safe(ish) limit for the P30 block, like 89mm is for the L28 blocks. Although I read something recently that suggested Nissan offered pistons above 86mm for the P30 for race purposes.

Fiddling around with the Ozdat engine calculator recently I discovered how to make a P30 blocked L26 into a 2.8 using only a (safer) 85mm bore as opposed to 86mm. Involved a little offset crank grinding and some freely available Toyota forged rods (and custom pistons). Not the cheapest route, but totally do-able. It's a fun tool for playing about with engine specs.

 

[SeanDezart]

Can you copy it here to share please ?

 

[richiep]

What, the bit about the pistons above 86mm? I'll have a look. I think it was a post on hybridz.org by TonyD, who generally is one of the few who knows what he's talking about! I'm sure Alan would be able clarify too though.

 

[SeanDezart]

No, Ozdat engine calculator pleeZe.

 

[richiep]

http://www.ozdat.com/ozdatonline/enginedesign/

That's the link to the utility. The basic specs of the 85mm 2.8 required an 85mm bore obviously, combined with Toyota 3S-GTE rods, which are 138mm long. The key feature of those rods is the smaller big end diameter of 51mm vs 53mm of the standard L6 sizing. Thus, you offset grind the L26/L28 crank to fit those rods, gaining a couple of mm of stroke in the process. With custom pistons to achieve as good as zero deck height and fit the 22mm pin, you get a 2758cc engine. Standard L28 is 2753cc.

Useful if aiming for a built 2.8 in a country where the domestic supply of L28s is tight and unloved L24s and especially 26s can be found...

 

[richiep]

The other good thing I'd add about the utility for anyone who hasn't seen it is that you change the specs beyond the stock components listed in the drop downs. Hence you can experiment with all sorts of crazy combinations.

 

[SeanDezart]

Merci.

 

[Albrecht]

86mm is considered the safe(ish) limit for the P30 block, like 89mm is for the L28 blocks. Although I read something recently that suggested Nissan offered pistons above 86mm for the P30 for race purposes.

Nissan took the L24 up to 2868cc with their P30 'blocks on the Works race cars. They offered the E4620 piston set (87.8mm) and the E4621 narrow-journal high strength crank for privateer racers. They recommended Wills-ringing the 'block and using the Wills-ring type Sports Option head gasket.

 

[SeanDezart]

Are these the blocks used with the LY heads please ?

 

[Albrecht]

Are these the blocks used with the LY heads please ?

Yes. In the earliest LY24s. Year 1973.

LY was also used with other 'blocks later, though...

 

[SeanDezart]

Merci...so why did they move onto later 'blocks' - what were the improvement - block cooling ?

 

[Albrecht]

Merci...so why did they move onto later 'blocks' - what were the improvement - block cooling ?

Simply to use what they were currently selling...

 

[SeanDezart]

Always sounds too simple !

So the blocks were developped but the LY head remained 'the pinnacle' to have continued to be applied to later blocks ?

 

[Albrecht]

You say "developed" but it was just the - normal - incremental increase in displacement.

Don't forget that what they called the 'Oil Shock' in Japan (OAPEC oil embargo following the Yom Kippur Arab/Israeli War) had a huge effect on Japanese race-related activities in late 1973, on into 1974 and beyond. Japanese auto manufacturers were rocked to their very foundations, and anything motorsporty (read: being seen to waste fuel) was frowned upon to the extent that the government became involved.

If it hadn't been for that, we might have seen newer engines - with even more interesting/powerful motorsport-related developments and homologations - in Japan through the mid Seventies. So we can blame politics and the fact that Japan is a non oil-producing nation for the fact that Japanese auto manufacturers switched to four-bangers for a while, and the LY 'head was - arguably - the last knockings of hot stuff for the L-gata....

Mind you, a 2.9 litre LY on ECGI was not to be sniffed at. If the factory had added a turbo or two we might have seen something quite legendary.

 

[SeanDezart]

"If it hadn't been for that...." can be applied to every nation building cars in the early '70s - just as the post-war austerity gave way to 'anything goes' (in clothing as well as internal combustion) so everyone panicked....the 'oil shock' after the Iranian Revolution in '79 was worse in its' effects both short and long term.

But still, Nissan (if I read you correctly) was already playing with ECGI before the OPEC crisis and tubos weren't that far off but here I'm on unknown territory - first Nissan production turbo engine was the L6 for 1981/2 in the 280ZX ? Follwoed by the LZ in the S12 ? Not sure here....

 

[Albrecht]

I was talking more specifically about race-related engines, as the LY was what you were asking about. The LY wasn't a 'production' cylinder head.

But still, Nissan (if I read you correctly) was already playing with ECGI before the OPEC crisis and tubos weren't that far off but here I'm on unknown territory - first Nissan production turbo engine was the L6 for 1981/2 in the 280ZX ? Follwoed by the LZ in the S12 ? Not sure here....

ECGI was first tested and raced on Bluebirds (in 1971/72) so before the 'Oil Shock', and so were turbos.

First production turbocharged Nissan (ie, designed and built in order to be sold to the general public) was the L20ET (six), as used in the Japanese domestic market 211-series Skylines and the 430-series Glorias/Cedrics. Late 1979 early 1980.


My point was that Nissan - along with the other Japanese auto manufacturers - suddenly needed to be seen to be taking notice of the post 'Oil Shock' zeitgeist, ie avoiding being associated directly with gas-guzzling monsters in racing and being seen to be making efforts to 'test' fuel economising tech (eg ECGI, and more power from smaller capacities) even if it was a little false (eg turbochargers).

By my rough reckoning it set Nissan back about five or six years in its direct race operations, and had a knock-on effect that - arguably - lasted well into the mid to late 1980s. It could also be blamed for Nissan not winning the Le Mans 24hrs race in the Group C era, and may even have stopped them from entering Formula 1 as an engine supplier in the 1980s...

 

[SeanDezart]

You say "developed" but it was just the - normal - incremental increase in displacement.

Perhaps we’re clouding words « developped, evolved », this makes sense :

Simply to use what they were currently selling...

but as we know, a late L28 block isn’t merely a bored-out L20 and therefore not a

. The blocks’ internals must have been ‘changed’ (there’s a new word ) for some specific reasons – if I’ve learnt nothing else from you it’s that Nissan never did anything without reason, a goal (s).

I was talking more specifically about race-related engines, as the LY was what you were asking about. The LY wasn't a 'production' cylinder head.

ECGI was first tested and raced on Bluebirds (in 1971/72) so before the 'Oil Shock', and so were turbos.

First production turbocharged Nissan (ie, designed and built in order to be sold to the general public) was the L20ET (six), as used in the Japanese domestic market 211-series Skylines and the 430-series Glorias/Cedrics. Late 1979 early 1980.

My point was that Nissan - along with the other Japanese auto manufacturers - suddenly needed to be seen to be taking notice of the post 'Oil Shock' zeitgeist, ie avoiding being associated directly with gas-guzzling monsters in racing and being seen to be making efforts to 'test' fuel economising tech (eg ECGI, and more power from smaller capacities) even if it was a little false (eg turbochargers).

By my rough reckoning it set Nissan back about five or six years in its direct race operations, and had a knock-on effect that - arguably - lasted well into the mid to late 1980s. It could also be blamed for Nissan not winning the Le Mans 24hrs race in the Group C era, and may even have stopped them from entering Formula 1 as an engine supplier in the 1980s...

May I ask please what was the first production export market turbo-engined car ?

and anything motorsporty (read: being seen to waste fuel) was frowned upon to the extent that the government became involved.

So, are you saying that it was consumer pressure for less fuel-guzzling cars or political pressure, ie MITI wishing perhaps to reduce or at best stabilise foreign currency debt by ‘encouraging’ the Japanese motoring manufacturers to produce less thirsty/more efficient cars (read engines) ? Not harming them with their exports to markets also crying out for more economical cars – some publicity in the States by Nissan ‘Datsun saves’ ?

Is this when and why the 2000cc tax-laws were introduced ?

I can't say anything on the 1980s and '90s racing competition from Nissan - I'm not clued up enough but didn't the other Japanese manufacturers go racing and rallying despite being under the same political restraints ?