help identifying crank

[infinite_kaos]

So I'm building a 6 bolt stroker, sent my block to the machine shop and had them clean it up and bore .020 over. I also had them order me a 6 bolt 2.4 crank. Well I picked everything up yesterday and while looking at the crank it looks exactly the same as my 2.0 crank.

So is there anyway to identify the difference between the two. I figured the rod end of the crank would be a lot longer but they seem to be almost identical in length.
Any help would be grately appreciated.

 

[BogusSVO]

look on the crank for a casting number, the diffrence between 2.0 and a 2.4 is appox 24 CI, so that comes out to about 6 ci per cylinder.

also the stroke would not be eyeball noctiable...stroke is measured from TDC to BDC so a difrence of .020 from crank main center line to rod pin center line would be .040 of movement of pistion.

 

[Black95awd]

Post a pic of the journal separation and I can tell you. On a 2.0 the rod and mains overlap on a 2.4 they are straight across.

 

[infinite_kaos]

It looks like they overlap just like my 2.0 crank. But there is a slight difference in heigth, maybe an eighth of an inch.

So there's no way to eyeball to tell the difference?

 

[infinite_kaos]

Ok so I put the crank in the black and attatched one stock piston and rod to see what the location on the cylinder the piston would be at to help verify if its a 2.4 crank.

The piston was at the very top of the cylinder at tdc, basically flush with the top of the block. If I remember correctly there was a space there like maybe a quarter inch of sapce between the piston at tdc with the 2.0 crank. So it seems that this is the right crank.

Can anyone help me verify that the piston is not supposed to be flush with the top of the block.

 

[Rob10_99]

I'll go see exactly how far my pistons are at tdc...
Stock crank & stock replacement pistons it's about 1/32nd" under the deck height.

 

[infinite_kaos]

Heres a pic of where the piston is at tdc with the supposed 2.4 crank and a stock piston and rod. This seems pretty high to me, someone please help me verify this.

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[Rob10_99]

Sure looks like its poping out of the bore.
Wheres your stroker setup? put one in to compare?

 

[infinite_kaos]

Well I would but the rods that the stock pistons are on are the rods I'm gonna use for my stroker. I still hav e to get the stock wrist pins pressed out of these rods before I can put the stroker pistons on.

I just thought that some one would be able to tell by looking at it if it was a 2.4 crank by the heigth of the stock pistons.

I could have sworn that the pistons should sit lower at tdc.

 

[donniekak]

Well I would but the rods that the stock pistons are on are the rods I'm gonna use for my stroker. I still hav e to get the stock wrist pins pressed out of these rods before I can put the stroker pistons on.

I just thought that some one would be able to tell by looking at it if it was a 2.4 crank by the heigth of the stock pistons.

I could have sworn that the pistons should sit lower at tdc.

Why would a longer stroke make the piston sit lower? The difference is small, a stroker has the center of the rod journal 6mm further than a standard 2.0 crank from the centerline. To make it easy measure the distance the piston travels from tdc to bdc. I can tell you stock stroke does not put the pistons out past the deck on a 4g63, a 6g72 yes, but not a 4g.

 

[infinite_kaos]

the longer stroke would make the stock piston sit higher, like the piston is sitting now. Its sites a little higher then then the deck of the block. If I were to put the stroker pistons in the piston would sit lower into the cylinder since the wrist pin is set 6mm higher on a stroker piston.

It makes sense if you think about it. If I were to use stock pistons on a 2.4 crank in a 2.0 block the compression ration would ridiculously high, granted the pistons didnt smash into the head.