when whitesedan and l18_b110's L powered dattos gets going we will settle the l vs. a debate once and for all!


GO L SERIES!

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I look forward to Harry's exercise as there is an interesting comparison here. For the exercise I have assumed that all L16's have the same dimensions. [I don't have a book on the A10 Stanza's engine]

The 1608cc A series will run a smaller bore & longer stroke than the L series of the same 'nominal' capacity.
A series 79mm x 82mm Bore/stroke for 1608cc
L series 83mm x 73.7mm for 1595cc The downside is that with even a first oversize bore of 0.5mm [83.5mm] it yeilds 1614cc.
With a second oversize of 1mm [84mm] it jumps to 1634cc. I don't know what the allowance is, but that surely must be pushing it.

The L16 has a theoretical advantage in the valve diameter stakes for the similar capacity as a result of the bigger bore but not necessarily an advantage in the rpm stakes as the little A series buggers can rev quite well when called upon.
There is a presumed disadvantage in the torque stakes with the L's shorter stroke too, but presumption is one thing & dyno results can be another.

The L/B210 combo will be a little heavier than the A/B110 competitor but the cavernous engine bay of the 120Y will allow some optimisation of engine positioning if allowed, helping to redress some of the weight/balance issues.

Let slip the dogs of war & let the battle begin. I know I will be watching with great interest.

improved production allows 2% tollerance on capacity, so you can go to 1632cc. But the 120Y will be very much a budget build, so I can get it done pretty quickly. I'm hoping I can find a good block and use the factory L24E hi-comp pistons I have under the bench with just a hone and remain at 1595cc.

it should be alot of fun to come down and play against the A series runners in NSW.

dropped the shell off at the workshop this morning, so its officially underway!

the problem is theres to many engines to choose from the A series is the wat to go (now that I have thinked about it) the performance parts for the L series is a bit....... too much well...... for me anyway!

If I ran at horsepower tracks I'd go with the L18 to keep it old school.(vs twin cam) Personally I like the A series engines. Since you can get near 1600cc out of an A series, I would think that an A15 bored out with a upgraded cam and cleaned up head would make between 110HP and 130HP depending on carb/number style. In fact I'm pretty sure I'm finally going to cave and put an A15 in and use my GX head/carbs and upgrade the camshaft.

For me the fun of 1200's is a keeping them what they were. a fun little car that handled well. If you want to turn one into a weapon then don't hold back...............make it a 500hp mid engine thing.

Tom

Well, I have a calculator & I aint afraid to use it.
The 1mm overbore in an L16 pushes it 2cc over the limit & only the most pedantic would give you grief over that, but the L16 has a really oddball stroke length of 73.7mm. [2.901"]

If it were necessary to grind the crank, even to just the first undersize of 0,25mm [0.010"], then by offset grinding it by just 0.05mm reducing the stroke to 73.6mm will produce a capacity of 1631.5cc when the 84mm bore size is used, which would give the protesting enemy at the gate absolute conniptions. The piston crown will fall short of the deck at TDC by 0.05mm or 0.002" [thinner than a Tally Ho cigarette paper]

A further reduction in stroke to 73.55mm [0.15mm reduction] will produce a capacity of 1630.4 cc leaving a more comfortable margin of 1.6cc. The piston would fall short at TDC by a whopping 0.15mm or 0.003" compared to the stock stroke & this should still be achieveable with a first undersize grind of the crank. [depending on journal condition]

I suspect that this is all accademic however as I doubt that there are very many occasions when racers at this level suffer the indignity of an engine teardown for inspection & scrutiny.
Still, something to think about.

There are many options but realistically small compact and light is best.
I like to look into an engine bay and see good old polished alloy with as little wiring as possible and old technology.

This is why the CA18DE is a good choice with LPG. Economy, power, clean design and 100 year old technology of the twin cam engine. It can be made to look old school by polishing its already available alloy cam cover and a datsun insignia easily adorn it. You can buy one for 120 dollars at Centre road wreckers, similar prices from import wreckers and appearing at normal wreckers and give it a freshen up.

You can run a dizzie but I would prefer to run distributorless ignition with an ignition only computer. A gas research lpg carb can replace the throttle body and the whole inlet manifold can be relieved of all the clutter including grinding the imperfections and polished.

Harry, Could you put a 66m L14 crank in an L18 block and then bore to 88mm for 1606cc? Iff possible the crank would be the hard thing to get but the L18 blocks are the same height as the L16 yet some seem to be able to handle the overbores better?
Also if possible later you could experiment with the Ka24e head for extra midrange the 3 valve head allows, Maybe starting with the Z18 block instead since it for racing and L series based.

I look forward to your racing project yet its such an unfair advantage lugging the 120ys extra weight.
A fair comparison would be the L vs the A in a same weight chassis. Of course the L running gear would make it all heavier but just for eliminating any discrepancies.

i have decided to build up an A series and whether it is a 1400 or 1500 i would like to keep the weight down.Boring it oversize for the extra cudes is on the list plus a weber setup.It not that i dont think the Dellorto isnt ok its just that the webbers are cheaper and easier to come by for me anyway.I can use my existing drivetrain with a heavier clutch.The small amount of mods needed for engine mounting etc is a piece of cake compared to a whole different engine.I just want to thank everyone for their input and advice.I will post pics as it goes