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Bore spacing on L4 versus SR
http://ozdat.com.au/forum/viewtopic.php?t=30642		 Page 1 of 2
Author:  d [ Fri Feb 08, 2013 4:30 pm ]
Post subject:  Bore spacing on L4 versus SR
L20b = 95.2mm vs SR20De = 97mm

Just theoretically speaking what if an L series head ca be made to fit an SR20de bottom end with a lot of work obviously.
Not for anything better of course but something uniquely different and much lighter weight than a cast iron 8v L4.
(This idea is just he opposite of KA24de headed L series build up but with the bonus of lighter weight and older school look up top :) )

eg.

Bare block weights with main caps
L16 37kg
L18 45kg (siamesed)
L20 50kg
SR 22kg

Head weights
L20B A87 16kg vs SR20DE 28kg

L16 block weight minus SR20 = 15kg saving
SR20DE head weight minus L20B = 12kg saving

At least 25-27kg saving all up for an 8V or 12kg lighter than SR20DE 6v
SRL20B
Author:  180BSSSt [ Fri Feb 08, 2013 5:34 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
I can see why you'd want to do this to get it all as light as possible (although turbo A15 or Hyabusa motors are alternatives).

One small detail is I think the bore spacing is slightly greater between cylinders 2 & 3. I remember this from the build thread of the bloke in the USA who built a 24 valve L6 for his Z- he needed 3 chunks of KA34DE cylinder head (2 cylinders each) to make it fit.

Cheers!
Author:  d [ Sun Feb 10, 2013 12:51 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
Well definitely a wack job idea for so much effort but for the bores using common
Darton sleeves, an SRs can go to 92mm so offset boring to 89mm is possible.
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darton sleeved SRL.jpg [ 72.21 KiB | Viewed 8180 times ]
http://www.sr20-forum.com/mazworx/26658 ... ecial.html

The water galleries line up, block the front head oil and side pressure feed galleries
and use the middle one re-tapped through the side mount next to the middle stud
and drill another hole on top of deck to meet the side entry.

Weld up these areas in green, tap the drain holes and remove unwanted protusion ridges
surrounds on oil drain areas (not illustrated) then oil feed mods as pictured in red
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SRL mods.jpg [ 274.14 KiB | Viewed 8180 times ]
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comparo.jpg [ 403.62 KiB | Viewed 8180 times ]
Author:  datzenmike [ Sun Feb 10, 2013 1:22 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
You would have built a 30 kg lighter L20B using as SR block and it would perform like an L20B. No one will know unless you tell them.
Author:  d [ Sun Feb 10, 2013 6:29 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
Cant fool aficionados like yourself Mike but painted or powder coated flat black could help :)
Author:  dangero [ Mon Feb 11, 2013 5:21 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
by the time you have had all the work done, you could have spent the $3,000 it would cost in parts and labor on an L series head to get the most out of it and offset the weight difference with more power :)

I do still like the idea, A cheaper and possibly cooler option would be to have a L series block cast in aluminum and machined. I know it sounds ridiculous but you could use L series EVERYTHING and the it would be the only aluminum l series block :)
Author:  d [ Tue Feb 12, 2013 12:49 am ]
Post subject:  Re: Bore spacing on L4 versus SR
dangero wrote:
by the time you have had all the work done, you could have spent the $3,000 it would cost in parts and labor on an L series head to get the most out of it and offset the weight difference with more power :)

I do still like the idea, A cheaper and possibly cooler option would be to have a L series block cast in aluminum and machined. I know it sounds ridiculous but you could use L series EVERYTHING and the it would be the only aluminum l series block :)
All good points thats for sure can still find some worked stuff for cheap up top
Its going to be a Z like head (na20) I figured the only real dramas are:
2 and 3 big ends and what to do for rods?
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SR20 crankpins.jpg [ 106.42 KiB | Viewed 8113 times ]
Sleeving with offset boring and custom HG.
Deck welding on block, block, drill and tap for new head studs
modded head timing cover as the SR bottom end lends all else quite well.
eg. timing case, water pump and oil pump can be left as is
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sr block-oilpump.jpg [ 69.2 KiB | Viewed 8114 times ]
Here is what it could look like with slightly modified front cover using sr single chain
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SRL20B.jpg [ 83.79 KiB | Viewed 8113 times ]
Author:  datzenmike [ Tue Feb 12, 2013 6:18 am ]
Post subject:  Re: Bore spacing on L4 versus SR
Wow, you're been thinking about this. Transmission?? Distributor??
Author:  d [ Tue Feb 12, 2013 11:40 am ]
Post subject:  Re: Bore spacing on L4 versus SR
Stumpy 71C 5 speed from D21 with S14 gearset

Megajolt jnr distributorless ignition cheap as chips, gone the days of pricey electromotive!
http://www.autosportlabs.com/megajolte-p-41.html

Head prefer lower height NA20 - using cheap U67 to line it all up at first.
(NA20 is like a kidney shaped Z series head takes Z18et turbo manis)
http://datsun1200.com/uploads/photos/24258.jpg
roller rocker top to reduce friction unlike earlier Z heads
http://datsun1200.com/uploads/photos/24251.jpg
might be in luck with the Na20 head as it looks like bore spacing is better
between 2 and 3 cylinders by looking at the gasket maybe 1.5mm only
http://sell.lulusoso.com/upload/2012033 ... ngines.jpg
part no: 11044 - http://old.japancars.ru/cat/nissan/seci ... 409&s=0.75
stock pistons http://www.alibaba.com/product-gs/55353 ... 85G00.html
Author:  datzenmike [ Tue Feb 12, 2013 1:56 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
This is soo cool. Have never even heard of the NA20 head. We went from the Z series directly to the KAE and DE. Closed chamber head like the L series. Roller rocker. Will it fit the older Z series motor?
Author:  d [ Wed Feb 13, 2013 11:20 am ]
Post subject:  Re: Bore spacing on L4 versus SR
I didnt either until about a year ago then freaked out that it was based on the NapZ.
Oz Nissan went same way pretty much while other countries got them even LPG ones.
Should fit for sure but suit a turbo application more than NA due to shallow inlet design
like the Z as it was designed also as a pro-swirl head but with better pollution control
for Japans standards not to mention very healthy torque curve for such a horribly
manifolded engine with big exhaust pump and tubes blocking gas flow still managed
100 PS (74 kW) at 5,000 rpm complete with air con, power steering, pollution cam but
good economy and later Chinese made head on link supposedly is even better revised
version is higher compression again compared to Jp cast big kidney chambered head.
http://www.alibaba.com/product-gs/54042 ... _head.html
Author:  datzenmike [ Wed Feb 13, 2013 2:23 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
There's a guy here who is looking to tubo a Z24. Hope he keeps at it rather than swapping an L head on. I think he modified a KA-E turbo exhaust manifold to fit a modified Z head.
Author:  d [ Sat May 04, 2013 4:18 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
http://www.youtube.com/watch?v=rPfQq7PeXYA

here is an interesting project to emulate the original super touring version of the H22
if you notice the head gasket match up and block welding Im now wondering if for
something theoretically possible could a KA24DE head be made to fit an SR20DE in
a similar way in order to have a narrower engine with the better flowing cam over
bucket head, light alloy bullet proof bottom end and freaking hybrid craziness.

Also interesting to see the front top timing case unbolts which would allow a simpler
custom box unit without the dizzie, using crank fire ignition adjustable sprockets.
Easier removable adjustment window & easier to match bottom SR timing case section.
This will allow also shortening the length of the engine by modding the length of the
rocker cover, custom top and bottom timing case, idler gear removed for dizzie and
side fed marine mech or electric style waterpump. Alot of work to fit an L series into
a 1000 bay, at least some options for the curious and able (just need the latter).

[ img ]
Author:  180BSSSt [ Sun May 05, 2013 9:05 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
d, have a look at a FWD Bluebird KA24DE for some of the difficult bits on your wish-list. They have a front cover with no provision for a distributor as their distributor runs out the other end of the rocker cover (If you buy a Bluebird head I can turn you up a plug if you want). They also have a separate belt driven water pump (like a Magna).

Cheers!
Author:  d [ Sun May 05, 2013 10:54 pm ]
Post subject:  Re: Bore spacing on L4 versus SR
Thats really good info on the belt driven water pump thank you! also forgot about the dizzie at the back on the only available ka24de fwd bluebirds here Ive been looking at so many US threads forgot totally! I will see what size plug the head needs and thank you again for the offer I might be able to get away with one of these Swirl Flap Blanking Plates available in several sizes.
http://www.ebay.com.au/itm/22mm-Swirl-F ... 231c8f9150
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