Ebay Rods
 

so i have seen many of y'all running the ebay rods with excellent results. It amazes me that an ebay rod can be trusted but there seems to be plenty of proof that they are fine. :party:

So what i would like to know is which ones? When searching i have come across several different sellers and wasnt sure if there is a particular one or branded set to look for?

You just want to make sure the eBay rods come with ARP2000 rod bolts. Some of the cheaper ones do not, and it will be more expensive to buy those later.

this has been discussed to death. aside from the bolts like Lars said they are all either same or very similar and likely made in the same factory

this is one of the few parts you're allowed to use from ebay :)

Careful thing to consider is bolt diameter. Eagle, manley,etc use 3/8" ARP 2000 bolts. Some ebay rods are using 5/16" ARP 2000 bolts. I was advised by a reputable engine builder to find a forged rod with 3/8 bolts instead.

yikes that must be new, they used to all be 3/8 iirc
but yeah, I'd use the 3/8 as well

I couldn't find a generic ebay connecting rod that used a 3/8" arp bolt. Eagle still was the cheapest.

or this and source your own bolts.
Cxracing for Mazda Miata 323 GTX Ford Escort H Beam Connecting Rods | eBay

voila, bolts included
Cxracing for Mazda Miata 323 1 6 1 8 B BP H Beam Rod Rods Bolts | eBay

*edit: doesn't specify arp tho. more searching needed.

Thanks for the input guys. I will keep an eye out of the bolt size, that is great info.

There should just be a sticky of acceptable ebay parts to use, lol.

1- Rods
2- T3 turbo(mk spec)
3- Honda Intake manifold
4- ..........

No ARP tho..


edit: edit to edit your ninja edit since you added that info

it all really depends on your definition of acceptable

the big risk is that QC is basically zero, so you gotta measure/check specs on everything or you can end up with a defective set

Intercooler

Pauter uses 5/16th bolts on their mazda rods since forever. They were the fancy high end ARP bolts though. Something 2000.

Definitely more expensive than ebay rods tho.

[Utag]hi_Im_sean[/utag] were your bolts 3/8?

I seriously doubt anyone here would break even the 5/16 bolts, but if the diff is like 20 bux, why not

An engine builder who builds spec miata engines for some of the top teams and has a lot of experience with miata engines said don't even consider it if your planning on boosting the engine. Maybe it will be fine for NA but bolts are already a weak link in the rod so going from 3/8 to 5/16 would make that the likely failure point. I decided to take his advise.

Like I said, I'd opt for the 3/8 just cause, but I still have yet to see a single street car have one of those fail. Maybe if the car lives at 7k and races all of it's lifetime, but that's not the case for most.

sidebar: the more I get to build other/newer cars, the more I'm just blown away by how cheap Miata parts are.

These have 3/8" ARP fasteners, though they don't seem that much less than Eagle or Manley. Mazda Miata BP B6 1 6 1 8 5 230" 132 84mm H Beam Connecting Rod w ARP2000 Bolts | eBay

This is the first I've heard of 5/16th bolts being a liability unless they are made of some inappropriate material. I've been running my ARP2000 bolts past 7000 rpm and 18 psi for over ten years now.

I concede that I might be wrong where ultra high revving engines are concerned, but I don't think a BP with a stock crank is going to be capable of snapping ARP2000 5/16ths bolts.

BTW, the 5/16th inch bolts use 3/8th inch sockets. The 3/8ths use 7/16ths sockets.

I went from racing old EF civics, to a WRX, and now a Miata. The amount of fast you can go to how much money comes out of your pocket is highly in favor of the Miata. I have less in my Miata than almost the basic cost of any decent WRX and it is much faster than a WRX or even an STI in almost every aspect (an STI might beat me in the 1/8th mile and minus the whole off road thing). If you can get past the aesthetic and stigma of owning/driving a Miata there is really no better option in the price/performance category.

My A-beam Carrillos use 5/16" bolts, so there's nothing wrong with that size in principle. All else being equal, if it's got the strength you need (and these are supposed to be good to 400+ at the wheels), the 5/16" version is going to be lighter.

--Ian