mx5cartalk.com

All,

I was trolling ebay yesterday looking for something else and stumbled on these.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=005&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=150104339700&rd=1,1

They weigh 528gm each. The Carrillo H beam rods are 440gm each.

Quoted shipping to Oz is $81USD.

Nice find...

Interesting, though have you been able to find much about them? They're a bit of an unknown quantity really.

For turbo applications you should be looking at I-beams, not H-beams.
H-beams are a legacy from the Chev-Ford V8 era (ok, I know they still exist) and although they will enable you to run more boost they won't handle 2 Bar continuously and even though they may not break, they will bend.

Simple motto, H for NA and I for FI.

They may do for a 1.6 with a small turbo but push serious power and your block would be ventilated, I think you'd find.
Even Carilla state that H-beams are not recomended for turbo applications. Imo look around for some Argo Familia rods, they can be sourced cheaply (~AU$200 each) and will be good for 450kW at the fly.

FYI Argo I-beems are 560g +- 0.005 grams and are a forged Titanium blend.
If your spending $$$$ on a rebuild you might as well do it properly, hey

Woo

Simple motto, H for NA

Seems just right for me..

The manufacturer website?

Interestingly does not seem to list Mazda bits, so may not be the manufacturer.

http://www.catpep.com/default1.htm

Woo - are you sure you've got that right.... and not arse about.....

http://www.flyinmiata.com/index.php?dep ... r=04-66000

Yes I'm sure CT.

I wasn't knocking the H-beams at all.... they are great for upto 28 psi (2 bar) as they can be made really light (as the FM link describes)

They (H) are ideal for large displacement low(er) compression V8s with loads of torque, but they tend to bend at high revs and force feeding when making making big power from what I've experienced.
The forces involved with FI are really big as I'm sure you realise and with the new rod designs/materials we are now able to remove that weakness from the system (now I just have to overcome valve float at 8500 rpm but thats another story).

I've found (as many other have) that boost is addictive and as soon as you get used to 2 bar you look at 2.5 then a 120 shot of nitrous, then avgas etc. One less rebuild will pay for the better rods imo

Thanks Woo - bit of news to me but life's like that - always something new to learn.

BTW CT I was talking about I beams not A beams as FM quote.
The hierachy is, from weakest to strongest
A
H
I
S(olid)
T(ubular)

The weight hierachy is, from heaviest to lightest
S
T
I
A
H

The 1.8 (and I assume 1.6) come stock with lightweight H beams

I suppose it depends on the work the motor will be doing as to what you choose

It's cool CT, rebuilding this motor of mine I'm learning new things everyday

Woo wrote:It's cool CT, rebuilding this motor of mine I'm learning new things everyday

'

Yep, going from a mental NA engine to the turbo thing has been a decent curve for me too. I'm not sure I've ever seen pics of I beams - I had assumed they were the same as A beams which I used in my old NA race motor maybe explaining my confusion. I'm in the market for turbo rods at the moment so I might call argo and see what they reckon.

Here is a pic of the I beams CT, you will note that the sides are parallel compared to the stock rods.
I said they were H beams stock, clearly I was incorrect as Sabre's pic shows they are A beams.





The only disadvantage is they are quiet heavy at 560g

Try http://www.argorace.com.au or phone 02 4934 7099, they are in Swan st Morpeth number 84 ask for Phil or Adam

Woo

What about 4 bolt mains type rods?
Are they available for a 5?

Would they be of any advantage in a small motor?
I know they are used very successfully on big V8's, and I believe they even have 6 bolt mains available now.

Benny the '4 bolts' refer to the main bearings, not the big end bearings. Only reason they use them is because of the relative flexibility of the V8 block - the base of the block is a big open space compared to an inline 4cyl block, plus the diameter of the crankshaft is bigger. All these combine to allow lots of movement in a V8 bottom end at high revs, resulting in the bearings moving and destroying cranks or worse. A second pair of bolts into the main bearing caps, generally from the sides, helps to limit this movement. Stud girdles are often used for the same purpose (big flat plate with lots of holes that ties all the main bearing caps together). I remember working with a crowd that made stud girdles for race motors - unfortunately they didn't do their metallurgy sums very well and the girdles expanded faster than the block with heat resulting in some catastrophic engine blowups! In a stiff little 4cyl block these are not common problems, but can still be addressed the same way if they occur.