L18 block questions

[Giljr2]

L engines are usually ID'd behind the dipstick handle just below the head. The head ID is to the front between #1 and #2 spark plugs just above the block.

yes i remember seeing it and i wrote it down and posted it but once again it is 

L18 490560 W

that is what is displayed 

[Giljr2]

i was wanting also to ask i i haves a rustomieum thing that i brushed on that killed rust and turned black when rust was killed 

wanted to see what you guys thought on that? or any ideas you guys have on killing rust

[datzenmike]

L18 is all you kneed to know really. The rest might tell what year or model vehicle it was used in but again L18 is an L18 for parts and such.

 

L18s are 85mm bore so 86mm would be 280z/zx piston size.

 

Flattop pistons would be non turbo use.

[wayno]

is lightning the flywheel a good idea? i want to make this build as best as it can, as its out of the car i want to do this build right

also i need bolt because i believe the head-bolts are torque to yield? and are one time use?

The guy said lightening the flywheel will help the engine meet it's true potential, I am going to start by re-curving the distributor just to see if I can drive it without it knocking.

All L series head bolts are reusable, at least if in good condition, if badly rusted find replacements or buy an L series head stud kit.

[datzenmike]

The flywheel stores kinetic energy in the form of a spinning mass. This helps to get a heavy truck mass moving easier from a stop. I'm only saying that if you remove too much mass, you will have to rev the engine higher and slip the clutch more to get moving on every start. Pound for pound a smaller engine or one used in a heavier vehicle will have a heavier flywheel.

 

A lighter flywheel has less mass to absorb spinning energy from the engine and this energy can be used to move the vehicle.... but only if already in motion. I have weighed 200mm 225mm and 240mm flywheels some are 29 pounds some are 21 pounds. I've only seen these two weights used. Twenty one pound are six cylinder or light car 4 cylinder. Twenty nine are 4 cylinder truck flywheels.

 

Weigh it and see. If 21 pound I wouldn't go lower in a truck. I definitely wouldn't if only driven in stop and go, in town traffic. If you have the fully counter-weighted crank there's an extra 5 pounds of spinning weight. If 29 pounds I would go lower.

 

Look on the engine side of the flywheel. If flat  across they are 29 pound. If scalloped (below) they are 21 pound.

 

 

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[Giljr2]

The flywheel stores kinetic energy in the form of a spinning mass. This helps to get a heavy truck mass moving easier from a stop. I'm only saying that if you remove too much mass, you will have to rev the engine higher and slip the clutch more to get moving on every start. Pound for pound a smaller engine or one used in a heavier vehicle will have a heavier flywheel.

 

A lighter flywheel has less mass to absorb spinning energy from the engine and this energy can be used to move the vehicle.... but only if already in motion. I have weighed 200mm 225mm and 240mm flywheels some are 29 pounds some are 21 pounds. I've only seen these two weights used. Twenty one pound are six cylinder or light car 4 cylinder. Twenty nine are 4 cylinder truck flywheels.

 

Weigh it and see. If 21 pound I wouldn't go lower in a truck. I definitely wouldn't if only driven in stop and go, in town traffic. If you have the fully counter-weighted crank there's an extra 5 pounds of spinning weight. If 29 pounds I would go lower.

 

Look on the engine side of the flywheel. If flat  across they are 29 pound. If scalloped (below) they are 21 pound.

 

 

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so if its 29 Lbs i can shave it to 21 Lbs? but if it'd 21 Lbs don't do anything? when i took it off it felt pretty heavy haha ill weigh it tomorrow! its 10:30Pm here so ill check it in the am when i go into my shop! 

idk how to check if i have a counter weighted crank?

[wayno]

WOW, I never noticed this before, I have a scalloped flywheel with a 240mm clutch cover/disc, I would have put that one on if I had noticed, I use 240mm flywheels on all my trucks.

I also have a really heavy flywheel with a 225mm clutch cover/disc, it even looks heavy, but all these flywheels have the clutch covers/discs installed on them so they don't get lost, so I cannot weigh them without taking them apart, and that really is not on my top 10 list right now.

 

 

 

 

[datzenmike]

It's arguable. You could probably go lower than 21 pounds but once cut you can't put it back if you don't like it. Your 620 is at least 500 pounds heavier than a 510 car. Running a seriously lightened flywheel is for race cars that don't stop often. In fact you don't even need a flywheel other than for a clutch surface in a race car. Some NASCAR flywheels are 7 pounds!!!... basically a pie plate with a starter ring on it.

[datzenmike]

 

Yes! I also have a 21 and  29 pound 240mm flywheels. All Z24s and KA truck engines had 240mm wheels. Car KAs had 225mm. I have no idea what they are off of.

[G-Duax]

I run an OS Giken 7-lb flywheel with a twin plate all metal clutch on my 620.

It's like an on/off switch.

I've leaned to drive it just fine, but few others can.

I call it theft prevention   :)

 

 

The place that does my state inspections doesn't even try any longer, they just check the lights, and hand me the receipt. 

Back when I first started playing with L4s, I machined one down to 20-lbs, and even that was a big improvement.

[Stoffregen Motorsports]

what do u mean by fully counter weighted? and it is! took it all apart and took it to an engine shop and they said its bored 40 over with 280z flat top pistons

and why move it? it has headers already and it was left in the same place

The crank in the pic shows that it has counterweights on only half of the crank throws. The early L18 cranks had counterweights on all of the crank throws. It makes for a smoother running engine.

 

I can't tell from the pic, but in most cases, those Z blocks had an angled pad of material on which the ID was stamped, and the angle makes it impossible to fit a header (without mods). If you say that it does fit, then ok.

 

Why move the dipstick? For easier access and a more appropriate appearance. L motors had them on the pass (right) side.

[Stoffregen Motorsports]

I run an OS Giken 7-lb flywheel with a twin plate all metal clutch on my 620.

It's like an on/off switch.

I've leaned to drive it just fine, but few others can.

I call it theft prevention   :)

 

 

The place that does my state inspections doesn't even try any longer, they just check the lights, and hand me the receipt. 

Back when I first started playing with L4s, I machined one down to 20-lbs, and even that was a big improvement.

Those multi disc clutches are definitely hard to drive. If you've got it figured out...cool.

[G-Duax]

The thing is, that from just barely starting to engage, to 100% hooked up is only about 3/16" of pedal movement, if that.

Once that sunk into my old feeble brain cells, things got a lot easier. 

 

I'm thinking a smaller bore master cylinder would help a bunch.

When the old engine comes out, it's getting a Quartermaster hydraulic throw-out.

Now you are supposed to use a 3/4" master with them, but I'm going to leave the original 5/8" in the truck, and see how that works.

Because, I still stall it once in a while when 50 years of manual clutch experience overrides the newly learned skill.

 

[Stoffregen Motorsports]

Those throwout bearing assemblies are known for being hard to bleed and also for not returning allt he way, all of the time. I know it's a race proven design, but it is not maintenance free.

 

Give yourself a head start and extend the bleeder on a AN hose so you can reach it when you need to bleed it.

[wayno]

So your supposed to point that at the hole where the arm normally comes out?

Have they ever jammed and spun inside the bell housing or does it connect to the arm ball like the arm does?

[G-Duax]

The top hose in that picture is the bleeder hose. Had to do that so the bleed port was on top.

Took forever to find that damn fitting :(

 

Wayno, yes on this one, I pointed it out the original clutch fork hole, and locates on the original ball location.

But it had to be cut down, and a shcs takes the place of the ball.

 

 

Also, the ID of the US trans intended throw-out was too large to fit the 71B snout, so it was sleeved.

The throw-out was used, off eBay, so it was completely disassembled, had new seals, and a fresh bearing installed.

Weird thing is, Quartermaster used a metric bearing commonly found on Toyotas.

Pretty sure that if the bearing ever goes bad, that I will hear it before it ever comes close to locking up.

 

I'm doing an S15-R 6-speed into a Toyota right now, and using the same throw-out.

But because the 6-speed snout isn't hard chromed like the 71B, just bare aluminum, so I'm bonding a steel sleeve over it, instead of in the bore of the throw-out.

Since the Toyota conversion is using the Toyota auto bell housing, I can just about point it any direction.