OlderThanMe

NOS Datsun Competition head that I just purchased.

In March 2010, I designed an L4 shortblock using some off the shelf 86mm pistons, 96mm throw crank, 152.5mm (6")rods. Finding 6" rods is "impossible" so I shelved the idea. Bought myself the lightest weight Datsun I could find, a 1981 Datsun 210 with a 40RWHP A14 engine and a 4 linked 3.90:1 H145 rear end. Car has a basically damage and rust free chassis(other than some slight hail damage on the roof and slight rust on the bottom of the doors but it is 8000X better than my 260Z was. Owner said it was running but when I got there it would turn over and cough but not start. Gave $640 for the car since it was rust and damage free as far as I was concerned. Got it running with a shot of carb cleaner in the vent tube of the nikki carb and I am enjoying the 32-35mpg that the car offers. paint polished up pretty well(I'm a race car technician, hence the vehicle in the background) First upgrades/modifications new complete clutch kit: $53 Sylvania silverstar headlights: $40 240Z taillights nearly fit into the stock taillight holes so they are put in(still need to be properly mounted... I just spliced the 240Z taillight harness with the stock 210 harness to adapt it to the stock 210 body harness. 1g talon seats mounted basically to the floor 280zx Iron cross wheels with 185/65R14 Douglas all season tires. Found myself with a Z20E with the good rods and bought all the other stuff I needed to assemble the shortblock. deburred and smoothed the interior of the block(~30 hours of work with as many different carbide bits as I needed) before: deburred the main caps too block back from the machine shop painted main studs bottom end components ready for assembly(200+ hours later) wrist pins installed with lock rings bottom end together nothing really special about this engine build....just a typical off the shelf bottom end that should be good for setting up the top end stuff. something stupid I bought. Something stupid I built out of OEM Nissan parts but I doubt I'm going to use it... you can see 60% of the back of the valve just looking through the wide open 45mm throttle plate.

Almost makes you think the second one would work, doesn't it?

Nope. The critical plane contacts the main and rod journals at one point each. Also mind you that I have 34mm for each cheek pad. Yours look offset to one side with different cheek pads. (I'm hoping that your motor is based like that) It also looks like you cut into the main and rod journals too with your critical plane? What are the rounded parts at the upper and lower portions? Are they radii on the journal? OTM

Alright... now lets get rid of any stress risers(sharp corners...) and then maximize your critical section area. Use that information I gave you and plug some numbers to figure out if it will hold up to your expected horsepower levels. Although 59in^2 sounds like you had an error somewhere in your conversion math. 6"X6" only yields an area of 36in^2 and your cross section isn't that big. Just as a comparison, my design has a cross section of 2249.2mm^2.

Proxlamus posted this link in his ITB fabrication thread... http://www.velocity-of-sound.com/velocity_of_sound/calculator3.htm

OMG Tim!!!! lol Gollum, for a N/A motor, long nuners are good for torque. Have you figured out the helmholtz numbers for your peak pressure? It wouldn't be that hard to make a variable intake with a design like that........ two plenums etc...

I had a time doing this on an LD28.... I stripped everything off the motor down to the shortblock with the pan off(the world's nastiest black mess). I then crammed a wooden hammer handle in behind the #1 connecting rod and proceded to snap the hammer in two. Then I got a 2" diameter pine dowel and crammed it in there. With a cheater & breaker bar I was able to release the bolt. It still destroyed the dowel... Be sure to use a soft dowel as not to marr any internal parts. I've pulled an L24 apart in a matter of about 60 minutes to get the rods in a JY(motor still in car) but that LD28 took 3 days to pull apart on an engine stand!!!!

First of all, Is this on an S30, S130, or Z31? I'll assume S30. Philbert, I do not believe that any Z car came from the factory with louvers. I suppose it may have been a dealer option somewhere, but not factory. I'll try to find a pic of how the louvers were setup on my Z. I still have the hatch so I can get pics of the 8 hole locations.

The other day I was driving to school with the windows down in my truck..... My right hand was on my thigh and I begin to feel something. Next thing I know a yellowjacket crammed his stinger into my fingernail and slid along until he rammed it into the quick of my thumbnail. I flung it into the cupholder and crammed a Dairy Queen cup on top of it to restrain it as it had not completely died from my attacks. It may only be one little yellowjacket, but it freaking hurt more than most any other sting I've had. OTM

http://www.presleynono.com/

Your not alone there...lol

I second that!

How come EVERYTHING is in Stone Mountain, Ga? lol! The city is a whole 1.3 square miles.(10 miles from me)

LD28 intakes are around 34-36mm(mostly 36mm) and it could be adapted pretty easily if you want to go that route.

Its a rendering that I made the other day. I want to learn more of the animation stuff but I still stink at it. lol

Gollum, Have you measured your critical area in your crankshaft? Its from the bottom of the rod journal to the top of the main journal. The max stress of the crankshaft moves through this plane. ala critical plane: OTM

Thats awesome sounding with the inserts in the exhaust. Imagine what it could do with some upgraded camshafts!!! Sounds wicked.

Anybody know an exact figure on the angle of the valves on an L head? My rough measurements were came up around 14 or 15 degrees but I want some solid numbers.

The problem isn't finding someone to make the crank, the only problem is finishing a crankshaft design and sending it to your choice crankshaft manufacturer. And about $2000-$3500 depending on your crankshaft design and how intricate it is.

Instead of leaning the valves over why not just raise the ports up? It seems much easier to mess with ports than to mess with valvetrain geometry.

Well I've seen a couple oil pan drain plugs that have the magnets on them. Really helps keep crud out of the oil if you are munching something in the motor. I suppose you could epoxy a rare earth magnet to the fill plug if you can't find the particular plug. L6 drain plugs have a M16.4-1.33 thread(SAE?) with a 21mm head if that helps looking for a generic part.

You are almost there, but 180 degrees in the wrong direction. The more the rod journal and main journal overlap, the more rotational strength there will be. Severe bearing wear is more related to counterweight than stroke, but it does have some effect. Think of it as a simple beam problem rather than a complex crankshaft, just for a minute. Think of a pair of beams joined t look like a "T". The top part is at the centerline of the crankshaft and the vertical part represents the stroke. For the same amount of force applied to the bottom of the vertical element of the T, a shorter vertical element will apply less twisting forces on the horizontal element. What I was saying about bearing journal overlap is that the more solid metal that runs the length of the crankshaft, the more stout the crankshaft is, thus improving crankshaft lifespan and less axial twisting.(thus bearing wear too) A ballpark figure for the amount of twist in a crankshaft while running is around .03 degrees.

I have all of the parts to put that setup together, and have assembled it on the engine once. Mind you that its not 100% bolt on but you have to grind some tabs off of the runners for it to fit but other than that it is easy.