frenkienstien l18? is there a way?

[G-Duax]

Holy 10 year old thread has risen from the grave...

 

[datzenmike]

1 hour ago, slowlearner said:

 

 

or 

 

http://lescollinsracing.com/engine/projects-engine/2-4-4cyl-l-series

 

I'm interested to see it's an L18 block. Not sure how they do it though.

 

Last fall I threw together an old U67 head onto a good running Z24 bottom. It's out in the shed tarped up. I ported the head and un-shrouded the valves because the bore is 3mm wider and the compression is going to be too high anyway. Just stock parts nothing exotic. Won't make 225 but if an L20B is 93 hp then scaled up that's about 112hp (on a good day) It will have an L16 cast iron header and modified 240sxdown pipe and R-1 carbs. So maybe 125 with luck. This is something anyone could do. I also have a .480" lift cam I might try. It may never happen but I had a ball doing it and dreaming about it.

[slowlearner]

Z24 bottom end into an L18?

[wayno]

1 hour ago, slowlearner said:

Z24 bottom end into an L18?

 

He put a L20b head on to a Z24 block.

 

Those engines you posted links to are highly modified engines that could likely cost thousands, the L18 with the L head is likely not all that street-able, and the one with the KA head would likely take an expert to build, and again with them HP numbers and RPMs it's not all that street-able, what I mean is who the hell drives around on the streets at 7000 to 9000rpms to take advantage of the engine.

 

Read this thread about modifying engines.

 

[datzenmike]

8 hours ago, slowlearner said:

Z24 bottom end into an L18?

 

With stock parts a Z24's red line is 6,500 RPMs. This is the limit of reliable revving. To go to 7K (reliably) you would need special rods and fasteners. I severely doubt that many Z24 ever rev much over 5K because of the stock head design. With unlimited breathing the Z24 should make about as much power (+- 140 hp) as the KA engines as they both have the same bore and stroke.

[datzenmike]

On 1/2/2020 at 6:45 PM, slowlearner said:

 

 

http://lescollinsracing.com/engine/projects-engine/l-series-4v

 

 

 

I'm interested to see it's an L18 block. Not sure how they do it though.

 

Well it's an L18 (1.8 L) made out to 2 liter. The L18 and L20B have the same bore and there are practical limits to over boring an engine just to increase displacement. The next easiest thing is lengthening the stroke and using shorter rods and OMG... an L20B crank in an L18 would make 2 liters!!!!  You can't use L20B rods because the block is 20mm shorter but you could find other pistons with a shorter pin height. L series pin height is 38.1mm while Z20E are 31.75mm and 86mm wide. 

 

L18 block bored to 86mm and use 1mm oversize Z20E flattops and L20B crank.... You would need a 133.1mm long rod OMG (again) L16 rods are 133mm!!! So what would the displacement be?  Well 1996cc all with Datsun stock parts. The down side is the KA24DE combustion chambers are  47cc and the compression would be only near 9.

 

 

Rod / stroke is 1.54 while an L20B is 1.69 and L16 is 1.86! Why would they go for the shorter deck height??????

.

[slowlearner]

33 minutes ago, datzenmike said:

 

Well it's an L18 (1.8 L) made out to 2 liter. The L18 and L20B have the same bore and there are practical limits to over boring an engine just to increase displacement. The next easiest thing is lengthening the stroke and using shorter rods and OMG... an L20B crank in an L18 would make 2 liters!!!!  You can't use L20B rods because the block is 20mm shorter but you could find other pistons with a shorter pin height. L series pin height is 38.1mm while Z20E are 31.75mm and 86mm wide. 

 

L18 block bored to 86mm and use 1mm oversize Z20E flattops and L20B crank.... You would need a 133.1mm long rod OMG (again) L16 rods are 133mm!!! So what would the displacement be?  Well 1996cc all with Datsun stock parts. The down side is the KA24DE combustion chambers are  47cc and the compression would be only near 9.

 

 

Rod / stroke is 1.54 while an L20B is 1.69 and L16 is 1.86! Why would they go for the shorter deck height??????

.

 

At which point, you may as well throw an SR20DE in it. Right? The only reason I can see why you'd want to build this motor is a racing class that specifies the L18 block for some homologation reasons. Or you're trying avoid the extra inch of deck height from the L20B block. Hmm. Cubic $$$$$.

[datzenmike]

Popular wisdom says longer rods for higher revving not shorter. Of course a custom piston was used so the pin height could have been less but only by a few mm and this wouldn't have altered the ratio much. Maybe the crank journals were turned down to lengthen the rod also.