32 replies to this topic

[JetBLICK]

Can someone of greater knowledge learn me about conrods.

I keep seeing more of these crop up on ebay, cheap 'H' section conrods... whats the deal with these? Because they are suspiciously cheaper than the more common ones. You pay around £700 for a set of these from specialist components, or £800 i think from arrow or MED. These are 1/2 that? Are they really not very good? if not they why?

http://cgi.ebay.co.u...7QQcmdZViewItem

http://cgi.ebay.co.u...1QQcmdZViewItem

Also how much lighter, are H section rods, compared to normal ones? and how much stronger are they? Whilst we're on the subject, what are the limitations of standard conrods and are 's' rods better?

Thanks , Dan

[Sprocket]

One word

Chinese!!


H section rods only come into their own on high reving engines, up to 9krpm. They are indeed lighter than standard A+ rods. Comparing an A+ rod without bolts, the H section rods including bolts are usualy lighter, how much lighter depends on the rod manufacturer. Usualy have a fully floating pin bush.

Balance is also important, end to end and with each other, chinese rods have been seen to be considerably out of balance in both respects, and not just A series rods. And, if the bolts are not genuine ARP, i wouldnt trust them even in a standard engine.

Standard A+ rods are good for 8500rpm in standard form for a short period of time, will need replacing regulary in a race engine and are the lightest standard rod. S rods use a higher grade metal than the A+ rods, making them 'stronger' but have a smaller big end diameter. Innocenti rods are a similar material to the S rods but have the bigger big end diameter, making them the better choice between the two. 1275 rods are strong items, but very heavy, can be lightened, but still end up being heavy. H beam rods are by far the lightest rod still retaining enough strenght to survive anything you can through at them.

Old Chinese proverb; you gets whats you pays for

[ginigwunkle]

these are from jonspeed, i thought they were a reputable dealer?

[JetBLICK]

That sums it up nicely, thanks

[Sprocket]

these are from jonspeed, i thought they were a reputable dealer?

[ginigwunkle]

maybe not then!

[Jake Blues]

Today I visited the engineering unit across the road from Jonspeed to watch the "Chinese" conrods being made. By Brits. In England. Using proper technical drawings. With the correct material. At a fraction of the cost other companies are charging us.
Does this answer the question?!

[miniboo]

lol that third pic does make him look suspisciously chinese lol

the good thing is i see they do 998 rods!!!

[THE STIG]

i to have used the enginnering shop in that well know chinese district known as nuneaton, warwickshire, england,

for a lot of one of stuff

all i am going to say is quoting the line at the top of all tech posts

Don't give out incorrect advice - if you don't know the answer, don't post!

[Sprocket]

Fair enough that the Johnspeed Minis rods are made in GB, but if the quality of their flywheels is anything to go by, I still wouldnt buy them, and i wont be buying another flywheel thats for sure!

Its easy to make something similar but when it comes to attention to detail, thats not so easy, at that price anyway.

[Jake Blues]

That is an opinion...not a factual answer to the question posed by the poster....please note the message in the red box at the top of the page.

[Jammy]

Unless one person has done rigurous analysis on several different makes of conrod then I doubt anyone would be able to provide a completely factual answer. I'm sure the topic starter would like some replies to help him decide what to purchase and so would probably appreciate some opinions from the more experienced technical members of the forum. Of course this is an assumption and I stand ready to be corrected.

[Guess-Works.com]

I'd hardly say £400 is cheap

It's all relative... and no different with many mini parts, take Central oil pickup pipes, the general 'accepted' going rate is about £25, but you can see them advertised on ebay for nearly £35.

[JetBLICK]

I asked the question to establish if, being at a considerably cheaper price than the well known brands, the 'h' section rods would be worth that little bit extra than a set of worked standard rods. Its one thing getting 1/2 price 'H' section con-rods, in reality tho they are still expensive if they turn out to be a load of rubbish.

You've also got to wonder why they are 1/2 the price, especially when this is a product that the company does not specialise in, unlike arrow, where all they make are precision engine components. Then you've got to wonder how much they actually cost to make, if jonspeed (as an example) are selling them at £600rrp, but can afford to sell them at £400 on sale. Whether they're made in china or not, its irrelevant, you still cant help but wonder why so cheap.

That said tho, they may good as a compromise in mildly tuned race motor. Where arrow rods would be OTT, but some of their aspects are more beneficial over a standard con-rod.

[THE STIG]

just because a company does not put a silly mark up on stuff like other companys does not make the product any less as good as one thats twice the price

i would rather sell a 1000 items at £100 than 10 at a £1000

thats how walmart in america has taken over

by selling with a small mark up and selling large numbers not selling stuff in small quantites at high prices