32 replies to this topic

[spikyrob]

The stig speaks the truth, i have access to and work on CNC machines all day, once they are set, they are set, and the only limitation is your speed and feed rates, error usually only comes about in the form of wear on tools or if the machine has had a tool crashed into it, of which is microns for wear and a lot if it has been crashed! IMO the tolerences on the bores and other dimensions will probably be in the region of +/- 0.03mm i'd guess the machining time would be roughly 20-30 minutes per rod, then costs for hardening, shot peening and x-rays etc, at the standard rate of £50 per hour on machining time it works out at £100 per set, plus roughly £20 per billet so total cost by my ROUGH reckoning would be around £230 - £250 per set all in.

THAT IS IN MY PERSONAL OPINION

THIS IS FACT

All it takes to make a different size big/small end or length of rod is a couple of position changes or offsets! which is why companies like arrow or specialist components usually make a few different sizes for the most popular of engines, ford/vauxhall engines are commonly used in caterhams and other kit cars which are mainly track day cars so the extra strength/reliability is wanted.

The only reason for their excessive markup is that they know people and race/rally teams etc are willing to pay the inflated prices!

jonspeed is simply doing as the stig says, selling large quantities at a much lower price and its about time too!

[Sprocket]

Interesting outlook.

However, i live by the old adage ; Its quality, not quantity, that counts

And, yes, this is my opinion, of one man, so should considered as that only

As for comments on 'Chinese' products, I stand by what i said

[ginigwunkle]

johnspeed sell these on there site for 600+ so the ebay has a lot to do with the price drop......

as with most dealers making extra income through ebay......they knock a bit off the ususal price.

ill be looking at these in a couple of months, like to hear from people who have used them...

[Jammy]

The Arrow rods, and these Jonspeed items. Are they both made from the same grade metal?

[spikyrob]

aha! arrow use double air remelt steel which is a more pure steel, although it is IMO overengineering to even consider using a steel as pure as this in an engine which does not require it, it is naturally harder and therefore is harder to machine, it will wear slot drills and end mills out faster than EN21T

i'll find out the significant differences in a minute when i get the data sheets and prices

[haz]

tell you what, if id spent 800 on rods and theres an eqivelent just come on the market for 400, id be doing my best to justify why my 800quid rods are better than the 'chinese' rods... eh sproket?

will be interesting to know the significance of the different material compositions, especially fatigue life

[ginigwunkle]

surely they are tested and are at a certain standard to be able to sell them?

the materials as said will be interesting to know!

[spikyrob]

Right, i'v had enough, i cannot find any material data sheets for EN21T or even EN21, closest is EN19 or EN24, either way imo double air remelt steel is all round a better material except it is much harder when supplied.

Haz: its like justifying buying KAD calipers over minisport or minispares calipers lol

Ginigwunkle: unfortunately i am unaware of such testing standard, its up to buyer faith and trading standards, however any company that sells an inferior product will eventually be shooting themselves in the foot.

[Jammy]

There are no standard they would have to comply with in order to sell something. By law it has to be fit for purpose. If it isn't then it probably means a lengthy battle through the courts for the customer, and a record being made with Trading Standards. If enough people complained the TS might eventually do something about it.

Of course I believe they could voluntarily apply for certain standard marks I guess?

[Sprocket]

Well if we are looking to save some money, Why pay £400 when you can get them cheaper still!?

http://cgi.ebay.co.u...DVWQQrdZ1QQcmdZ

As for strength, I know that my rods will survive for extended periods at 9krpm for many a mile without worry of failure. can the same be said of these lesser grade items? Thats what i paid for and i am happy with it

Its like when one manufacturer produces a flywheel in EN24T and another produces a similarly identical flywheel in a lesser grade EN21T and sells it for less. Now forgetting the cost for the moment, the question you have to ask is why one manufacturer decides to use a lesser grade steel than the other.

Attention to detail

This is all perspective, as im looking at this from a point of view that my engine needs to survive 9krpm. Not many people will build an engine to that spec and the lesser grade parts will most likely be perfectly adequate.

The point is, these rods are not manufacturd in the same manner as the likes of Specialist Components, Swiftune, MED, SH Engineering, Carillo, to name a few, therefore cannot be compared.

[mini13]

I would not touch these rods with a barge pole, not in EN21 anyway.

Why?

they are billet.

Std rods, S rods, and any rod worth their salt are forged.

ask yourself how many G's are the pistons pull at high rpm, and then consider if you want a rod where the grain of the steel follows the length of the rod and then splits around the crank or not.

Edited by mini13, 02 April 2008 - 08:33 PM.

[Sprocket]

tell you what, if id spent 800 on rods and theres an eqivelent just come on the market for 400, id be doing my best to justify why my 800quid rods are better than the 'chinese' rods... eh sproket?

will be interesting to know the significance of the different material compositions, especially fatigue life

Thats just it, they are not 'equivelant', thank you for your sarcasm, but no thanks

[Jake Blues]

As for comments on 'Chinese' products, I stand by what i said

But you said the Jonspeed items on sale on e-bay were Chinese in origin...that is not true.

[Sprocket]

As for comments on 'Chinese' products, I stand by what i said

But you said the Jonspeed items on sale on e-bay were Chinese in origin...that is not true.

Easy to take things out of context when you omit certain information

Fair enough that the Johnspeed Minis rods are made in GB

[Oldskoolbaby]

If I'm honest I can't really see the point in the "cheap H section rods". Don't get me wrong, they may be very good, but the reason people like myself and others buy components that are a few hundered pounds more expensive than cheaper equivelents is because you want to fit and forget. When you've spent a fair few thousand building an engine the last thing you want is a cheap component letting go and destroying every thing around it and lets just remember, that includes the gearbox on a mini.

A faulty rod or one thats not up to the job can in the worst case go through the block, into the box, let the piston smash buggery out of the expensive race spec cylinder head you've had fitted, mangle the crank you may have spent a fortune on. For the sake of a couple of hundered quid, get something you know is 100% upto the job. Arrow, Corrilo etc have obviously spent many hours developing and testing such components so when people buy them, they can say to them it will do so many revs, with so much bhp for so many hours or minutes. On the other hand you could have some body say to you "well it coped with the 150bhp we threw at them last weekend...." No thank you. I know where my money would be going