Difference between l26 and l28

[Josh Slade]

Hi there,

Sorry if this has been asked before, i genuinely can't seem to find any info on it, maybe i'm searching wrong

What are the differences between these two engines? I think i heard somewhere that the only difference was crank shaft, so a swap in crank shaft is all you need to turn it into a 2.8... did i hear correctly?

What other differences are there?

Thank you

 

[atomman]

from memory the crankshaft is the same in the 260 as 280 its the bore that's bigger to make it 2.8 , 86mm in the 2.8 vrs 83mm in the 2.6

 

[AliK]

Wot he said ^^^

Obviously they had a variety of heads and therefore compression ratios but the stroke is the same.

The cylinder walls are thicker so an L28 can be bored safely further than the L26.

 

[yellowz]

The cylinder walls are thicker so an L28 can be bored safely further than the L26.

I thought that would be the other way round?

 

[Albrecht]

I thought that would be the other way round?

Different engine block castings with different internal cores.

Generally speaking:
L24 = E30, E31 then P30 casting codes.
L26 = P30 casting code.
L28 = N42 then F54 casting codes.

 

[Rob Gaskin]

Well yes the bore is different but so are the valves. Cam oiling? AFAIK the block of a L28 has two groups of 3 cylinders in the casting, the L24 has 6 separate cylinders - not sure about the L26.

 

[status]

I’ve got a 3.2 for my 260 but I heard they can be bored to 3.4 or 3.5 correct me someone

 

[jonbills]

I’ve got a 3.2 for my 260 but I heard they can be bored to 3.4 or 3.5 correct me someone

they can be stroked and bored to 3.4 or 3.5, if you do about £10k of other work to it.

 

[status]

Lot of dosh to fork out

 

[Albrecht]

AFAIK the block of a L28 has two groups of 3 cylinders in the casting, the L24 has 6 separate cylinders - not sure about the L26.

Two types of L28 (petrol) block castings - N42 and F54 - differ from each other in casting core design. One has solid webs between the cylinders, and the other has open webs to allow more coolant flow around the cylinders.

 

[yellowz]

Just another school day................

 

[vipergts]

Great knowledge.

I only went 2.9 with my L28. So much more scope

 

[AliK]

Great knowledge.

I only went 2.9 with my L28. So much more scope

Yes but at least you have margin for any potential problems in the future! Open trumpets it is then!

 

[Josh Slade]

How far do you think it's possible to bore out an L26? would 3 litres be possible?

 

[jonbills]

no, 2.8 is about it.

 

[AliK]

Even at 2.8 the walls are getting awfully thin. Rob Gaskin did however run a track car like that for years so you do that at your own risk I guess.

 

[richiep]

You could theoretically get it sleeved and bored in those fresh sleeves to get 3.0, but that is an order of magnitude more expensive. Sourcing an L28 and starting from that is much more practical and cost-effective.

As for the above points about 3.4, 3.5L, that’s epic money and effort. That’s boring with sleeves to get 90-91mm bore, and offset grinding or entirely custom crank to get 86+mm stroke (LD28 crank being 83mm). That necessitates custom rods, pistons, etc. Plus a million other precise details and care and attention needing to be applied that most people haven’t got the money, skills, or attention spans to deal with!

 

[jonbills]

you need 90 stroke to go with the 91 bore to get to 3.4.

 

[Alphabettispaghetti]

I've been quoted £60 per sleeve + £30 per sleeve for fitting.

 

[Albrecht]

Worth bearing in mind that elephants have bigger appetites than zebras. If you were to go to all the trouble of 3.4 litres you'd be needing to feed it through 48 or 50mm of induction at least, and not much point having the capacity without a head that can do it justice. Big Domino-Effect on systems and drivetrain too.