The Limit of AGG Rods? / Where to get Steel rods from?

Some will know im building a diesel cranked AGG based 2l 8v on itbs and Megasquirt. Im looking at possibly using a 288 cam or maybe even longer depending on the limit of the hyd tappets, but im going to make it rev a bit further than std, to get more from it. and im worried by the rods, diesel crank, std rods and lots of revs, what breaks first

Where is the best place to get steel rods from? i know that with the $ vs at the minute its a good time to buy from the US.

 

I run some balanced standard 144mm AGU rods with 20mm pins up to 7700rpm with ~500g pistons and a 86.4mm crank.

 

I doubt you'll see peak power much past 6,500 rpm with that spec, probably a bit under, so there wont be much point reving past 7k-ish, maybe 7,2... as power will be dropping off sharply by then.

The standard crank, rods and pistons will be fine at that rpm level (wer'nt you getting some forged pistons ?). As Ray above, the standard crank is very strong.. I run a standard unbalanced (apart from factory balance) 1800 crank to 9k. Though I woudnt run a long stroke crank that far (you'd never need to anyway), I think Martin (Hotgolf) runs his diesel crank to 8k-ish, so you wont need to worry really at your sort of rpm.

Rods are good too, again, for the rpm needed a standard rod will be fine. I'd be happy to use the std 144mm rod to 8k, plus a bit, in short bursts (hillclimb/sprint use) though I'd imagine your using 159's ?.. they'll be fine to about 7,800 occasionally, a bit less regularly, so again, fine for your application.

I'd fit ARP rod bolts as a precaution in any of them that were going to get regular abuse, so thats worth looking at.

Standard good quality pistons take a fair bit as well... I've just stripped an 8v hillclimb engine thats been running to 7.5k regularly with over 12:1 compression using KS cast pistons that have been machined down to within MM's of their life.. the top ring is only 0.165 thou from the crown !.. and there's no sign of a problem.

Eurospec have a good range of rods if you wanted to play safe, but I really would'nt spend the money if you dont plan on exeeding any of the above.

Take a look here... http://www.eurospecsport.com/

 

My concerin is about the extra rod angle due to the crank, im not too woried by the pistons, yes im still trying to sort some out but Im going too build up the engine and get it running then use my old 2e block for the new pistons. and fit that some time next year, Im determined to get this engine in a xmas as its been 18 months in the planning and collecting parts.
My uncle who work for omega is mega busy with dealing with KTM and getting elite engine systems up and running. he was saying that they are working on fitting F1 air valves to a porsche engine.

Are the 8v rods same as 16v?

 

whats the limit of the hyd tappets?

 

The rod angle is no prob at all bud, its 1.66 (159 divided by 95.5), the same as a stock 1800 combination (144 divided by 86.4). It's when you drop below 1.6-1.5 problems can arise with higher cylinder wall loadings. The stock 2ltr ratio is better @ 1.71, but your splitting hairs, and only in full on engines really anyway.

 

so no real need to part with 240 + postage then.

 

AGG ones are the same as ABF ones. 2E ones, which I use for my application are a bit meatier.
You should not have a problem as said by mrhillclimber revving an 8v to the same limits as a tall block 16v. If it would get there! If running past 7500rpm then I would look into better fasteners. But under that you will be fine.

 

Aren't the 2E rods forged?

 

If you're going to buy ARP's, may as well by the Scat Steel rods with ARP bolts. You'll get a set for around 220 delivered, only 100 more than a set of bolts, and you're getting a set of rods!

The 8v isn't going to be producing power that far up, even Wills 8v with crossflow head ITB's and 300 deg. schrick cam wasn't producing after 7500rpm from what I remember, so the standard rods should be ok.

My diesel crank is hitting 8400 limiter no probs. Pointless though, powers dropping off at 7k lol

 

Im not saying that it will be producing power just that if i rev it more than std i dont want rods breaking on me, I guess when im setting the limiter it will depend on the cam that im using really.


where can i get some from HG? might buy some for an early xmas present to the wife, , if they are that cheap!

 

Power wont break std. rods...

Rods only break when your revving an engine over its normal operating limits becasue they are trying to stretch themselves,

ARP's as a precaution would be a good idea, but no need to go overkill with forged rods..

 

I will be revving it beyond std 8v figures and with the long stroke crank that was why i was concerned, plus steel rods may save some more weight!

 

If your power peaks at say 6k, it'll be dropping fairly fast by mid 6's, so I would imagine you'll rev to 7k "absolute" tops ? If thats the case, std crank & rods are more than fine, maybe with new genuine rod bolts as a precaution or ARPs in case you upgrade the power/revs at a later date.

 

I may buy some rods anyway, like hotgolf said for the price of ARPs i can have a set of rods for an extra hundred quid.

BUT WHERE TO BUY SCAT RODS FROM!!!

 

You should save that hundred quid. Put it in the bank for the "but Daddy, I NEED a pony" conversation.

 

the rod angle worries come from guys on vortex diesel cranking 9a blocks, in a tallblock there's no issue

 

she already asked for a white mk1 GTI for Xmas!! altho the Mrs isnt buying that one! yet! She has told her that she can have the driver, as it has a stop and a go pedal. so she wont have to worry about gears yet!

 

Spend the extra hundred quid on big inlet valves, give that 2.1 some air !