Turns out the conrods I was looking at are the smaller 8mm bolts and not the 9mm I had hoped.
 
Does anyone know if I changed to ARP bolts would there be any issues using the smaller bolts?
 
The car won't be an all out racer but I hope to see some track time in the future and plan to keep the max revs to 7500.
 
Cheers,
 
Matt
 

Please tell me you're not going to go down that road.....
 
Have you priced the machining and pistons you're going to need to make it all work?
 
Cheers
Woz

Woz, not sure what road that is? 
 
I am just in the process of gathering as much info together as I can before I decide what direction to take with my engine build.
 
I am trying to get the best bang for dollar as I am building to a budget.  Stroking to me seems a good way to go.  As I understand it, the added torque down low allows for a less peaky engine power output so you don't need to rev it's guts out to get the power required.  Obviously, there are many variables inc , cam, CR, Induction etc.. but I was just curious to see how one would go about it. 
 
I have been quoted around $350 to have the crank stroked and around $200 for the rod machining.  So with datto rods ($65) and VW cast pistons (around $150) I'll have a stroked bottom end for around $850.
 
Having said all of that I am now looking at Crower 5.7inch rods with some Ross Forged Pistons which will cost similar to the above scenario and will be a lot less work to build and be a much stronger & stable package.
 
So I am just trying to learn as much as I can before I start handing out money.
 
Cheers,
 
Matt
 
 
 
 

Matt75

Woz, not sure what road that is? 

I am just in the process of gathering as much info together as I can before I decide what direction to take with my engine build.

I am trying to get the best bang for dollar as I am building to a budget.  Stroking to me seems a good way to go.  As I understand it, the added torque down low allows for a less peaky engine power output so you don't need to rev it's guts out to get the power required.  Obviously, there are many variables inc , cam, CR, Induction etc.. but I was just curious to see how one would go about it. 

I have been quoted around $350 to have the crank stroked and around $200 for the rod machining.  So with datto rods ($65) and VW cast pistons (around $150) I'll have a stroked bottom end for around $850.

Having said all of that I am now looking at Crower 5.7inch rods with some Ross Forged Pistons which will cost similar to the above scenario and will be a lot less work to build and be a much stronger & stable package.

So I am just trying to learn as much as I can before I start handing out money.

Cheers,

Matt

 
Stroking it isn't worth the effort.  Puts you into the next class, and not worth the effort power wise.  More torque, but won't rev.
 
(datto rods)
crank machine to fit rods $350
rod machine                     $200
rods                                 $65 (you really should be using the 9mm ones anyway)
Pistons                            $150 (are you sure? that doesnt seem right to me, and do they require mods to fit?)
ARP Bolts                         $100
 
total of that is                 $865
 
You also need to factor in resizing the rod if you're serious about it, which will be extra, and I think you'll find the prices you have above will blow out, quick smart.  Have you check exactly what need to be machined to fit this combo in?  You need to machine the big end, and the pin end of the conrod, $200 seems awefully cheap, and so do those pistons.  I'd be checking the prices.
 
The 5.7" rod combo is far too long.  Although it fits it completely upsets the rod ratio, so don't do that.
 
I'd imagine that a rod and piston set ready to bolt in is about $1300-1400?  correct me?  and it bolts straight in? Forged versus cast pistons?
 
Trust me, when its all said and doen the piston and rod package is the way to go, and you'll never have to touch it again if you do it right.
 
Cheers
Woz
 
 
 

Have you read the June issue of Classic Ford where they build a 2.2L pinto using an offset crank, Chrysler Voyager pistons and Zetec rods?

Woz, I agree with everything you are saying but I am just out to learn as much as I can.
 
I don't want to pay $1,400 - $1,600 as I think I can get it done for a lot cheaper than this.
 
The Rod machining price was inclusive of the resizing to fit the piston pins as well as surface grinding the big end too. 
 
I have done a great deal of research into the stroker engine and feel confident I know what is required to do it in theory but have no real world experience to back it up only what others I trust have told me.
 
After researching a lot I think I will head down the forged piston path as i would be silly not to as the pros outweigh the cons by a great deal.
 
What in your experience is wrong with the 5.7 rods as i thought this would have a much better ratio than standard? 
 
The theory (or so I have read) is that the piston stays longer at top dead centre and thus produces more power. Also there is less side loading which reduces frictional losses.  
 
Cheers
 
Matt
 
 

true about the longer rod staying at TDC, but then if it stays at TDC for longer you have less time for the piston to get to BDC giving you a greater piston acceleration, there is much debate about the theory....
 
i think you forgot about the balancing of the rods after they are machined, then the balancing of the whole assembly and also the decking of the block and piston rings, new bearings. etc.
 
i think when i went down the datsun rod path matt, i didnt get much change from $2K, but it was a while ago now, im sure i have the receipt somewhere.....
it is a lot of stuffing around for little gain.
if i were looking at it again i think i would do it like wozzah is suggesting with a bolt in rod and piston package.
 
Gazz

Hi Gazz,
 
Theories are like A holes, everyone has one.   
 
The balancing costs and decking of the block etc would probably be the same for any engine rebuild wouldn't it?
 
It seems no one in OZ does the stroker thing but the Poms love it.  It's very interesting to hear both sides of the argument though.
 
Cheers,
 
Matt
 
 
 
 
 

Matt75

It seems no one in OZ does the stroker thing but the Poms love it.  It's very interesting to hear both sides of the argument though.

 Yeah, but those Poms like some pretty ordinary stuff sometimes

Matt75

Woz, I agree with everything you are saying but I am just out to learn as much as I can.

I don't want to pay $1,400 - $1,600 as I think I can get it done for a lot cheaper than this.

The Rod machining price was inclusive of the resizing to fit the piston pins as well as surface grinding the big end too. 

I have done a great deal of research into the stroker engine and feel confident I know what is required to do it in theory but have no real world experience to back it up only what others I trust have told me.

After researching a lot I think I will head down the forged piston path as i would be silly not to as the pros outweigh the cons by a great deal.

What in your experience is wrong with the 5.7 rods as i thought this would have a much better ratio than standard? 

The theory (or so I have read) is that the piston stays longer at top dead centre and thus produces more power. Also there is less side loading which reduces frictional losses.  

Cheers

Matt

 
Research what the costs are a little further, as the prices you have don't seem right, in particular the piston prices.  Did the price of the rods allow for the machining that needs to be done on the big end? not just the resizing?
 
If you break down your L16 rod costs the you have been quoted (rods $65+ machining $200 + ARP's $100) its $365
A set of half decent rods off the shelf is $495
So there is only $130 difference in the price of your conrods which will be soaked up in 5 seconds in crank machining if you use the Datsun rods.
 
Any decent forged piston is going to be $800-900, regardless of what rods you use, the price of the pistons won't change whether you use datsun rods or a forged rod.
 
Either way you are going to be spending the money whether you want to or not.  10 years ago I would have said go with the Datsun combo, because at that time there was very little available at a reasonable cost.  Not so now, plenty available and at $1300-1400 it's not expensive.
 
Crank machining is ultra important if you are going to stroke it.  There are a handfull of people around that do the job properly, so i'd be very careful with what you are quoted, and how the job is done.  I would be getting quotes off the likes of Crankshaft Rebuilders or Saliba's for a realistic figure and the job done properly.
 
In regard to the rod length, yes, a longer rod is desirable.  However, at 5.7" the rod is far too long.  The effects in piston acceleration and going too long in the rod has a less than desirable result in how the air is drawn into the cylinder.   Cylinder head and cam designs play a key role in exactly what rod ratio is ideal. 
 
Cheers
Warren