TheNeedForZ

What really amazes me is the strength of the tree. If I hadn't seen this video I would bet 100$ that tree won't stand an impact like that.

Hey I think you gentlemen nailed it. I talked to a professor that teaches in my mechanics class. I gave him the assumption of frictionless, airless system. He thought about it(drew some pictures with his hands in the air) and said yes, the crank/rod/piston will go on forever if there is no losses. I then asked him the same question : "the rod tension/compression isn't always parallel to the tangential direction of crank throw, will the energy transfer be 100%?" He said since it is a system with no frictional losses, angularity of the rod has nothing to do with delivery of energy, energy will be 100% transferred. You know, I used to think kinetic energy that goes into reciprocating weight is completely wasted once it hit TDC and BDC. and that reducing the reciprocating mass will give me a major LEAP in efficiency. I guess not. Well I can still have accelerated horsepower I guess. of course, even got all the bonus marks too!!

Yes LSD, and Viscous type. You should put this in the drivetrain forum.

also bore size. KA24 = 89mm, L28 = 86mm

yeah all cars do that after shutting down hot.

Thanks for the help guys Here's why I wouldn't worry about shear load : There is a gap between the rod pin boss and piston pin boss. --------|..|------------|..|-------- ----------------------------------- .piston pin . ----------------------------------- --------|..|------------|..|-------- piston........rod pin boss.....piston pin boss...........................pin boss So if the pin is overloaded, it will bend before it is sheared. Since aftermarket titanium pin makers use the "same dimension" approach without problem, I will not have problems(bending or breakage) as long as I use the same approach.

Hey in the end we all turn into dirt, so why don't you stop going to work tomorrow?

Let me simplify the question to get rid of some elements : Assume there is no air, and no friction, connecting rod have no mass but is rigid. There is no power produced from engine so no external force from burning gas or compression. The system is only a piston(with mass)inside a frictionless cylinder, connected to massless rigid rod, connected to a crankshaft with mass. If the crankshaft is given a initial rotational speed, is the energy inside the system conserved? Cyrus, You pointed out the piston and crank have a mutual relationship in which one accelerates/decelerates another and vice versa in different crankshaft position. Question is, is the energy exchange 100% efficient even though the direction of rod tension/compression force isn't always parallel to the tangential direction of the journal or direction of piston travel?

hahaha elbow grease,hahaha OUT OF STOCK hahaha

well dr_hunt wasn't really asking "why do they make ti rods", he was just trying to make a point to AK-Z, who doesn't know titanium engine parts exists. In fact Diablo, some modern Ferrari's and Porsche GT3 all have titanium con rods, not to mention race cars. The purpose of the coating is NOT for wear resistance. It is to prevent titanium from friction welding with other metal. People that use free floating steel pins never needed any wear resistance because the pin is oiled and is free to move inside the rod and pin bosses to change the load bearing surface. Ditto for titanium wrist pins. The ti alloy I bought(in fact I won the auction just hours ago) is 6AL4V so it is not a pure element. I never said anything about making ti rods, I said I am going to make piston pins. Shear load has nothing to do with piston pins or con rods. Ti has lower shear resistance than HSS...I dunno if this is useful to me, but I'll keep that in mind. At least I learned something so thanks for that. Since you attended metallurgy, can you help me out and tell me something about 6Al4V titanium? compare it to steel that might be used in stock piston pins? Thanks

Thanks for the info buddy!

Here's what I did Full car media blast = 1200$ CDN (should be cheaper down in US) Full car painted with RustBullet(this is better than POR15) paint 372$CDN +labour 600$CDN Bodywork is still in progress.

If the sheet metal under bondo is vulnerable enough to be wacked out of shape by wire wheels then it is not worth protecting in the first place. It ought to be cut out and replaced. Paint stripper is not an acid, it is alkaline mixed with methyl alcohol and gelled.

dude, do you even know what a wire wheel is? It's not going to "possibally" damage the metal.

I asked for places that can do nitride coating or casidium coating on titanium. Please keep the hearsay to a minimum.

The question is "what happens to kinetic energy invested into the reciprocating weight(piston, rings,pin,small end) inside an engine?" Energy put into rotating weight like crank journals and big end of rod carries around in a circle. An object can spin forever in airless space so it makes sense to say energy inside rotating weight is conserved until friction robs it all. But what about energy put into reciprocating mass? In every cycle, the piston is accelerated twice and stopped to a complete halt twice. What happens to the kinetic energy inside the pistons? Is it totally lost or some of it actually goes back into the rotating assembly? If so then how much? Thanks

bump

Before you pull out those pistons ask your machine shop :how much does it cost to press out six KA24 piston pins WITHOUT DAMAGING the pstons? I gave my L26 rods/pistons to my machine shop to pressed out the pins. I asked for an estimate, they said : 28$CDN for EACH if I want to keep the pistons undamaged, 40$CDN for all six if I don't care about damaging the pistons. I said I don't care and the pistons were indeed damaged in the process. They charged me based on actual hours spent so I was only charged 22$CDN If the shop charges you a lot to press out the pins without damaging the pistons, then you wouldn't save much by going with used pistons.

Early NA L28 had dished pistons. Later NA L28 had flat tops

Well eBay people always think they have 240Z rods when they list them, but when I receive their stuff they always turn out to be something else. Thanks to them I now have not only 240Z rods but 260Z and 280Z rods as well. They are pretty much useless to me. 260Z and 280Z rods...are different in strength I am pretty sure(yep, you heard me, the 260Z rods are always lighter than the 280Z ones despite having the same parts number) I am interested in doing failure test on these rods. Wonder where can I find compression/tensile load test machines? The university I am about to go to might have one but I am not sure.

well the whole engine is still behind the front wheel axle

Did the shop add shims under the cam towers after the head shave? For every 1mm (0.040") you shave off the head, the cam is retarded 1.91 degrees relative to crankshaft. Of course the chain may have some slack to it in the first place that adds even more retard to give you problem. Check for vacuum leak and electrical connections first, sooo many engine problems turn out to be those small problems.

NA block will do fine, of course you have to use L28 block. Some NA blocks are even stronger than the turbo blocks. 75,76 N42 blocks are said to have a higher nickel content.

I get static shock all the time. Whether it's getting out of the car or opening a door at school. The solution I came up with is to flick the door with your finger before you open it. The electricity goes thru your fingernail and you won't feel a thing. That has always worked for me.

Joke alert! That was part of the dialog from a Dodge Magnum commercial.