I really thinkg before we do that we need Stealths gear sent to Cjerigan, and let him do the hardness testing (20 minutes). Once he does that and sends us some results and pictures we should be able to guess what they did originally.

I have my materials book and we can figure out (estimate) what we will get with the different treatments. Because not only are there different treatments the timing of each treatment will give us different results, IE cryo treating for 15mins then quenching, or 30 minutes and air cooled all give different results.

Thats my vote unless people are in a huge hurry, i think its the best route. If we get more gears itll be nice for testing, but I think we need a base line of stock or were just shooting in the dark.

What is your preferred method of cutting the gear to test the inside of the gear?

EDM ideally, but waterjet, this might be something to ask the prof. I dont know how true the piece needs to be. A bandsaw with liquid cooling and then very slowly with alot of oil mill it true.

I don't have access to EDM or waterjet but a bandsaw and mill I can handle. If you wanted to waterjet samples to be tested then I can just take the samples in to test them. They really don't have to be big at all. If you wanted to cut a gear up into 8 pieces and test your cryo theory ahead of time I could test them all at once.

that can work, assuming we dont end up doing through hardening

Good lord, man, did I accidentally fuck your mother while shitting on your sister's head in a previous life? Would you just leave the personal attacks out of the threads, or can you not help yourself?

I said cast but yea, a billet piece. A billet is just a piece of metal, made form a casting. I was just saying a cast or billet piece as opposed to a powdered metal piece is a lot stronger.

Most of my numbers are from memory when taking machine shop back in high school. Powdered metal parts are generally 1/3 the strength of a part made from a billet made part. When properly alloyed and heat treated, their stregth can increase to about 1/2 the strength of a piece machined from a billet. One exception to this is alluminum, as certain alloys of alluminum can be used to make sintered metals that are almost as strong as a billet piece.

Of course, the main reason companies use powder metalurgy is to reduce cost, so the odds of these gears being properly alloyed for strength is slim. The fact is, these gears don't need to be very strong on a stock miata.

As far as crankshaft flex increasing exponentially, I don't have any proof or books to cite. However, I'm fairly certain that is the case. As piston speed increases, the force being put on the rod journals in increasing by One half the mass times the square of the velocity. If you increase piston speed by a factor of 2, then the force increases by a factor of 4. If there's 4 units of force acting on the journals at 3K RPM's, then there will be 16 units of force acting on the crank at 6K RPM's.

Perhaps reducing crank flex with the use of ligher rods and pistons would be a better way to increase the durability of these gears.


Edit: I think it may be better to use the same gear for all the testing. If you use different gears, from diff year model cars, the structure and properties of the gears may indeed be different. We don't really know that the same manufacturer made these gears for all the years it was used nor do we know they didn't change anything about them midway through production. Just pointing out our results would probably be more accurate if we take the same gear inot pieces and test various methods all on the same piece.

Edit Agian: A billet is a broad definition of a piece of metal, and it includes both casted metals and sintered metals.

Well then if we had (2) gears, they could be cut up into larger, more managable pieces to test out the various procedures, then you could have nice big pieces to work with. If I have to cut the gears into sections, it's getting done with zis wheel or something, so the ends will be worthless.
So if stealth and whaam come through, we're golden me thinks.

fix the source?
 

if crank flex is truly causing the problem, then perhaps
- reducing it by using a bigger crank damper (eg a *heavier* flywheel, like those torque monster turbodiesels),
-or maybe even WI (smoother torque spikes) would help instead.

Just throwin' stuff out there...

i will provide the gears of my motor that i want to build later on, a new oil pump was going on it anyways...so im there, just need to get them off the motor

also, a friend gave me this JDM magazine a while ago and while skimming through it i saw something that reduces crank flex, ill try to look at it tonight and see if i can get some pics...anyone know what im talking about?

Bumping a dead thread, for shot peening the sintered oil pump gears:

http://www.shotpeener.com/library/spc/1984106.htm

I'll add another piece of potentially useful information... Sorry for the bump, but I believe we need an alternative approach to oil pump failures. I'm not going to buy a fricken pump for $300 some bucks or whatever it currently is, I can get a good running used engine for that! lol.

http://www.motoiq.com/magazine_artic...eprinting.aspx

Billet gears or complete pump packages: http://www.boundaryengineering.com/drupal/node/7 If you don't want to pay that, don't build an engine. There's no choice but to pay to play with parts such as this.

Omg, why the necro posts. Shot peening and blueprinting won't do dick to stock your gears from exploding at high rpm or power levels.

lol!!!!!!!!21111234!1!


maybe you are jobless and live in your garage and have the several hours to find and retreive a spare motor and then another spare several hours to replace the motor but some of us would rather spend the money one time and go fall asleep on the couch.