L engine thoughts

[Xnke]

As some may remember out of the thread "Mild Mods for the L24", I have a weakly running L24 out of my '72 that I am going to rebuild. The PO ran it with no air filter for god knows how long, and compression is down to 80-81-78-82-80-80. Since it will probably need to be bored, and when you start cutting cylinders it doesn't matter how much you cut, it all costs the same round here, I might as well up the displacement a bit.

 

Assuming, of course, that I can obtain suitable pistons and rings to fit. This is where I hit my snag. I'd like to use L18 pistons, due to the 85mm diameter, and ~4CC dish. With the E88 head, that means a CR of 8.5:1, (83/87 octane, save that dime a gallon!) and displacement of 2.5L. This puts the bore/stroke ratio at 0.867, and rod/stroke ratio at 1.805. Are these values better or worse than other options, or does it even matter? Stroke it out with L20A rods, and the LD28 crank and you can get close to a 1.00 bore/stroke ratio.

 

Reading through "How to Rebuild Your Datsun OHC Engine", I read that a 2mm overbore is the max for the L series. Does anyone have a maximum overbore size for the L24 engine, or is it the same block as the L28, just with a smaller bore?

 

Again, before the "get an L28 and be done with it" crowd shows up, keep in mind that for the one local L28 that I have been able to source, the guy wants $800 for the engine sans water pump and distributor, and even then it'll have to be rebuilt to run again.

 

Any Kentucky/Tennessee area Z nuts got an L28 engine they'd like to swap for?

[z or bust]

Why not just rebuild it yourself. I knew nothing about the Z engines when i first rebuilt my l28. All i had was that handy book you have as well. Two weeks later I was on the road. I just took an hour each day after i got off work and did a little to it. They really are extremely easy to rebuild and its less money. Also the blocks in the Z cars do not wear as much as you think they would. So you might not even have to worry about boring. If you need to get back on the road a simple re ring and some bearings might do the trick. (plus timing chain set and gaskets). All in all its really not that much to just rebuild.

 

That my .02

[TONY C]

I have a couple good runners complete l28e motors wiring harnesses, everything needed. Knoxville area.

[Xnke]

Z or bust, i am seriously considering rebuilding the L24 that i have, as it's not my first, just my first L series. Built lots of little Honda I4's for the local rice crowd, they bring me the parts and I put them together. Attention to detail is something many would-be engine builders lack, and I've got more than enough to go round, some would say. I have, on two occasions, chromed the interior of the oil pan for some folks, just because the rest of the engine was all chromed-out. Even if no one else ever opens that engine, I know the bling is in there. No worries about the chrome coming loose and killing the bearings, because expected life for one of these bored-out, turbo-eating screamers is only 10-12 months, the way the local kids drive them. But, when you bore the thing out so thin that the cylinder walls crack and pop the head bolts neatly after you fill the cylinders with water at 80MPH, what do you expect?

 

I'm asking because I've been presented with two options: Get a strong running L28e from Tony C. and convert to carbs, (LOVE the classic look and sound) Or rebuild the L24 I've got. Right now, it'd be cheaper to get the L28, but as I've got a generally just tired matching numbers L24 for my car, I am hesitant to swap engines. those numbers mean a lot to my insurance company, I get a big boost in coverage for having the original engine.

[ezzzzzzz]

Keep the original engine on a pallet in the garage. You'll be much happier with the performance of the displacement increase.

[josh817]

Hm I'm having the same problem. My Z has an l28 zxt motor in it with a huge turbo from a Dodge diesel. I'm pretty sure its done for after the way I've been treating it. The kid who sold me the car though also had the "original" motor that was in it. When he did the swap the original was running and everything so we suspect all it needs is bearings and gaskets blah blah blah. But then here comes the humbugger. Keep the l28zxt motor and just carb it (because I want to get rid of the turbo crap) or take the l24, I'm sure both of them are in around the same condition, just a quick rebuild and it'll be good. OR do I do the l24 and then just mix parts like the l28 head on the l24 block etc. Right now my dad is cheering for the l24 but because I'm going to a carb'd motor, I still want a bite to it. I WAS going to stroke it because I think I have everything except the crank and larger pistons but... I just don't know, too many options.