Hi K11 gurus. i have cg/cga questions?

[Machi san]

Hi peeps,

Got some questions that I have been researching over the last couple weeks, based on thoughts of possible upgrades.

Right here goes, as some of you know I have fitted a cg13de into my k10 prefacelift. It is running twin downdraught webers and a k10 electronic dizzy.

Iam in talks with my local tuner about head work. I will be giving the head a little clean up and mild port myself. My tune shop will make sure my works all good and then give it a 3 angle valve/valve seat job and probably a decent size skim.

Autosprint will be doing some cams for me with any luck.

Now, I want a bit more from my setup and have been pondering different ideas. Can people brain storm some pros and cons for the following:

Cga13de instead of cg13de?

Or

Cg10de stroked too 1312cc?


Also:

If I were to pick my self up a cga13, will I be able to use my modded k10 dizzy in the cga13 head?
If not can I swap a cam from a cg13 into it too make it work?
Can I fit the whole head from my cg13 onto a cga13?
Do cga13 use same inlet and exhaust manifold bolt patterns?


Also:

What is a safe rev limit for the stock cg13de bottom end?

And

The cga13 bottom end?

I wouldn't mind an engine that'll rev too 8k but iam sure I have heard that 7.5k is the safe limit without some balancing work.

Any details on work, too make the cg or cga rev higher?

At what stage do the hydraulic tappets need changing for solid?

Iam pretty sure my swift gti engine in my mini will rev too 8600 before the tappets start to bounce/lock out.

I do appologise for all these questions and iam sorry I have had to ask, I suck at searching on this forum lol

Cheers dudes
Kev

 

[frank]

the cga head has no hole for the dizzy eh kev, and i had a cg head on my cga block
i ended up refitting the stock exhaust cam (for more grunt and better mpg)
the a/s inlet cam with 11:1 c/r or more is the best mod ever
the tappets are solid, and personally i would keep it below 7.5 rpm :grinning:

 

[Machi san]

the cga head has no hole for the dizzy eh kev, and i had a cg head on my cga block
i ended up refitting the stock exhaust cam (for more grunt and better mpg)
the a/s inlet cam with 11:1 c/r or more is the best mod ever
the tappets are solid, and personally i would keep it below 7.5 rpm :grinning:

Frank, you really are a ledgend

So a winning recipe for me would be:

*Cga bottom end
*Cg head (with a little bit of work)
*A/s cams (probably go with both in and out because my car is light and I like revs, also don't want too much torque because of small casing gearbox)
*11:1 or more compression
*7.5k rev limit



Is there a rule of thumb for head skimming, to achieve 11:1 or 11.5:1??
How much can you go before pistons collide with valves?? (Obviously this will alter if I go for higher lift cams)

Thanks again frank :thumbs:
Kev

 

[frank]

np kev :grinning:
the 1.0 pistons in a 1.3 block is a neater solution really (because the 2mm headskim makes the lower chain pretty slack)
i get the combustion chamber and h/g volume to about 26cc, and the 1.3 piston dish to 7cc, and i get the c/r of the 1.0 piston in a 1.3 block to about 12:1 (there are c/r calculators availiable online eh)
and i get the 2mm skim on a 1.3 to about 11.5:1
and the valvelift wont affect piston contact, its more the duration, so dont worry about any contact with the 260 deg/10mm lift a/s cams

 

[martinb]

That just sounded like a mathematical equation lol

You know too much Frank, are you a mechanic by trade, sorry for thread hi jack keV

 

[Low Rider]

We measured 8.1cc for the cg13 piston bowl frank, (cc'd). Not cc'd the head yet but the gaskets are 1.2mm nominally but is more like 1.15mm torqued up, (NME specs). Doesn't make too much of a difference but on a stock head, stock gasket and CG10 pistons you're looking around 11.85:1 static compression and a tad higher, (11.87:1), assuming a minimum head skim of say 0.05mm for flatness if the head is in order.

 

[Machi san]

Cg10 pistons in a cga13 :suspect: ??!!

Aren't cg10 and cg13 the same bore size? But cga is bigger bore and stroke??

Are there any piston options for cga to get the compression higher?

I have been on the phone to autosprint, little more money than I expected. Iam sure I read on they're website there grinds were 80per cam. I got quoted 200 which seems ok

 

[frank]

the 1.0 pistons are flat-top eh kev, the cga piston has a very big dish, and yes its 1mm bigger
and yes the a/s cams should be £80 + vat each
(coilpack 1.0, 1.3 and cga in pic)

 

[Machi san]

Can I use the cg10 conrods as well?

Also can I send cg10 camshafts to AS and get the same grind carried out?

Just trying to figure out my best option without buying too many engines too strip

Maybe I should get a cg10 and pop a cga crank in for longer stroke. Then get my cg13 head and cams worked over, then fit them when they're ready.

Anyone got any bits for me ???

I am after

Cg10 pistons and rods
Cg camshafts
Cga crank maybe
Could do with a cg13 head to work with as well

Cheers
Kev

 

[Machi san]

Also how much can the cg block be bored out by? Will it take cga pistons? Can you get cga overbore pistons and fit them?

Cheers again
Kev

 

[frank]

Also how much can the cg block be bored out by? Will it take cga pistons? Can you get cga overbore pistons and fit them?

Cheers again
Kev

the liners are only 2mm thick in the cg block kev (i,ve never busted a cga block to check theirs)
but they all use the same head gasket tho
cga3 pistons have such a huge dish, and are,nt ideal for n/a really
GA14 pistons with GA16 rods might be an option ?

 

[Machi san]

Thanks for the info frank I think ill stick with cg13 block and crank with cg10 pistons

Got another question lol

I have been offered a cheap cg10!

Iam going to be using the pistons, do I need to use the cg13 conrods?

Is the head the same? Has it got the same size valves and ports?

Can a/s regrind cg10 cams to the cg13 profile that you suggested?

Thanks in advance

 

[frank]

the cg10 rods are about 1/2 inch too long kev
yes the heads are the same
and the 1.0 cams have 2mm less lift so you cant get a 10mm lift profile from them (only 8mm)