engine build

[CMF_frank2]

a bit of a hybrid CG
CGA crank and rods in a coilpack CG10 block, and a pre-coilpack head.
the 2 donor engines....

 

[CMF_frank2]

block assembled, 2 headgaskets will be needed for the time being

 

[CMF_frank2]

the CGA3 engine turned out to have shimless buckets and longer valvestems

 

[CMF_frank2]

coilpack (post 2000) piston (on the right), oval skirted (slipper type) with skinny rings, and a higher topring (thinner ringland, no good for boost i guess)

 

[CMF_frank2]

another piston pic
and i,ve been trying to work out the C/R with only 1 head gasket.
i calculate the CG10 chamber size at 29cc (incl gasket)
and the CG13 at 37cc (ie, the extra 8cc of piston dish)
so i get that to 11.9 C/R for a CG13 crank with CG10 pistons
and 14.1 C/R for the 1311cc CGA crank and CG10 pistons

 

[CMF_mycra]

frank is it better to use cg10 crank pulley on cg13? is lighter right...wont throw off balance?

 

[CMF_frank2]

mycra WROTE:

"frank is it better to use cg10 crank pulley on cg13? is lighter right...wont throw off balance?

they,re a lot lighter eh mycra, but i prefer to keep the harmonic dampened one personally
and its only 1kg from a small diameter, i guess another 200 grams removed from the flywheel would have the same effect
while i,m doing an engine swap anyway this week, i,m gonna try out a spare 1.0 engine
this one has a 2mm skimmed head with weldfilled area,s in the chambers

 

[CMF_mycra]

increase compressing hey... so the cg10 hb is only 200g lighter and the cg13 hb is dampened so heavier?

 

[CMF_frank2]

no mycra, the pulley is 1/2 the weight look, but that extra 1kg is on such a small diameter, and shaving a lot less than 1kg from the bigger flywheel would be a better option imo.
and the damper may have been fitted to avoid excessive chainwear/crankwhip or whatever from the longer throw 1.3 crank

 

[CMF_mycra]

fair enough... thanks for the photo frank. if it was you, would you fit that lighter pulley on?

 

[CMF_sikK11]

No I doubt he would. From what he is saying he thinks there is better reasons to keep the 1.3 one on there. He would just
Remove 200g from the flywheel instead as he believes that would give a better result then THe 1kg off the pulley.

 

[CMF_mycra]

oh **** i bought it already....

 

[CMF_frank2]

well we,ve tried out the high comp 1.0 engine for a few days
and tested the hybrid clutch, 1.0 spline and centre and 1.3 friction plate (bevelled down to 170mm dia on the pressure plate side)