cg10de pistons in cg13de

[Craig]

you would have to use 1.3 crank and rods with 1.0 pistons,
if you put 1.0 rods on a 1.3 crank, valve to piston clearance wouldn't be a problem because you would posibly snap the rods or crank when the pistons come into contact with the head

You know this for a fact?
Craig

 

[whipit]

We shall find out as soon as i get my hands on this 1.3. Just waiting for welly to nick the bits off that he wants.
As far as i can see the dish in the piston is not there to stop any valve to piston interference. Anyway if i blow it up ive got a spare head, block and run around micra. Providing i dont damage the crank im not too fussed.

 

[Craig]

Well, when you strip it down, make sure that you not e how close to the deck height that the pston goes in the 1.3 - I still might beat you to this engine mix though

 

[Swiper]

You know this for a fact?
Craig

i know that you cant put 1.0 rods on a 1.3 crank as the rods are too long, if the piston doesn't hit the head, then the rings would come out of the block.
and i know the pistons are approx the same height, just the 1.0 pistons are flat. thus giving a higher comp ratio.

Well, when you strip it down, make sure that you not e how close to the deck height that the pston goes in the 1.3 - I still might beat you to this engine mix though

the piston goes right up to the deck height on both 1.0 and 1.3. i can confirm this as i've had both stripped down. the longer throw of the crank and shorter rod on the 1.3 still gives the same piston height as the shorter throw and longer rod of the 1.0.

 

[whipit]

Well, when you strip it down, make sure that you not e how close to the deck height that the pston goes in the 1.3 - I still might beat you to this engine mix though

Go for it, save me some of the trouble. :laugh:

 

[Craig]

i know that you cant put 1.0 rods on a 1.3 crank as the rods are too long, if the piston doesn't hit the head, then the rings would come out of the block.
and i know the pistons are approx the same height, just the 1.0 pistons are flat. thus giving a higher comp ratio.



the piston goes right up to the deck height on both 1.0 and 1.3. i can confirm this as i've had both stripped down. the longer throw of the crank and shorter rod on the 1.3 still gives the same piston height as the shorter throw and longer rod of the 1.0.

Oh well, thanks for the info, I will prob still put the flat-tops in when I re-con anyway.
Craig

 

[whipit]

Still be interesting to see just how close the valves get to the pistons on standard cams. Be a good calculation on how much you can skim off, even recalculate for when using higher lifting valves.

 

[Soixantaine]

Conclusions(?)

Did you guys come to any conclusions regarding using 1.0L pistons in a 1.3L to gain a higher compression ratio? I've got my scrapyard 1.3 down to the bare bones and can see that the dish (approximately 5mm) in the piston has nothing to do with valve clearance, or even the spark plug electrode. If the pistons are exactly the same (and the 1.0L rods longer) in all measurments, except for the dish, then the dish in the 1.3 piston would serve no purpose except, as someone said, to lower the compression ratio(!). So, if they are the same, using 1.0L pistons, pocketed, or notched, at the outer edges to clear the valves would be feasable and would result in bump in the compression ratio. (However, if they are the same, except for the dish, why didn't Nissan feel the need to pocket them? The dish having nothing to do with valve clearance as the valves would only contact the piston at the outer edge, not in the middle of the piston where the dish is deepest.)

The 1.3 piston is 52mm high from skirt to top. From the approximate centre of the piston pin to the piston top is 27.7mm. The rod length, from the centre of the crank throw to the centre of the piston pin is, approximately 120mm.

If someone has a 1.0L piston and rod to hand, I would really appreciate the measurements. If the 1.0L piston is do-able then I can start looking out for a 1.0L engine from my scrapyard as I'd like to make the swap.


S

 

[Craig]

At TDC, where were the pistons located?

Is what I got from 1l

 

[Soixantaine]

Careless of me to overlook that. Didn't come to the top of the block, if I remember, maybe 6mm or so. Based on your drawing, however, it would seem that the pistons are not identical. Just to reiterate, I get 44.5mm, skirt to top, at the my piston's narrowest and 52mm at its widest. The bore is 71mm, same on both. Rod length, "centre to center," is 120mm on a 1.3L.

I need to get my hands on a 1.0L piston and rod assembly.

Thanks for your input.

S

 

[Soixantaine]

More pics

Can't really tell if any are TDC but thought I'd post these anyway. Think I'll put the crank and one piston back in and check the "squish."

S

 

[NeX]

just out of interest why are you trying to up the compression?

 

[Antony]

in the imortal words of jeremy clarkson
POWEEEERRR....

 

[Soixantaine]

Exactly!

S

 

[NeX]

but surely, the bigger explosion that you get from higher compression with be counter acted by the resistance of having to make it compressed. the pistions will be slowed down as they come up by the resistance of the compression and then speed up when they drop back down because of the larger explosion. so surely its gonna be about even. and wont you loose cylinder capacity if you loose the dish, surely you want more displacement rather than compression

 

[Soixantaine]

Try googling
www.popularhotrodding.com/tech/0311_phr_compression_ratio_tech? for a better explanation then I could ever give you.

S

 

[NeX]

Try googling
www.popularhotrodding.com/tech/0311_phr_compression_ratio_tech? for a better explanation then I could ever give you.

S

ahh cool ok looks like a stronger head gasket is a must tho