1.0 pistons in a 1.3

[chickenwaahoo]

I see this has been covered a few times before, but does anyone have this mod running and by any chance was the compression ratio measured / calculated while the engine was apart. Also whats the valve / piston clearance like?

Are all 1.0 pistons flat tops?

 

[Alienfish360]

1.0 Pistons are flat top.

Chances are the valves won't hit the piston.

However you will largely raise the compression ratio. I can't see any advantages to do this when you can just get your head skimmed to do it.

 

[chickenwaahoo]

I'm just weighing up various options at momo. When the head is skimmed enough to raise the cr up to where I want it, the cam timing starts becomming an issue.

 

[Alienfish360]

You have more flexibility and control of attainable compression ratio by skimming the head. As the engineer will be able to do as you request. Where as whacking CG10 pistons in the CG13 will only give you 1 of 2 possibilites.

 

[whipit]

I think that is what hes asking, what are the possiblities??

 

[Craig]

I vaguely remember figures of ~10.5:1 being bandied about, but htos may have been with a thinner gasket, they also had a picture of their piston with a nice valve-shaped mark in it, I would guess that you could get away with it if you were running the standard headgasket and didn't raise the rev limit.

 

[chickenwaahoo]

Have seen figures of 10.2 & 10.5 talked about on here & micraholics, guess I'll just have find a 1.0 engine, rip the pistons out, get them on my rods, installed & start measuring! Easy :grinning:

 

[Swiper]

Have seen figures of 10.2 & 10.5 talked about on here & micraholics, guess I'll just have find a 1.0 engine, rip the pistons out, get them on my rods, installed & start measuring! Easy :grinning:

make sure the pistons are the correct size for your engine. they have different grades for different sizes i.e. 1-4 i think. the four digit code is stamped into the front, underside of block, gearbox end. and there is a number stamped into the top of the pistons aswell. pics to follow.
but i've heard that the engine doesn't last very long running these pistons in them, but i'm not sure!

 

[Craig]

As long as the pistons haven't been replaced, I see no reason why the grading should be different TBH

I have a set of 1l pistons and rods if you're interested?

 

[Swiper]

As long as the pistons haven't been replaced, I see no reason why the grading should be different TBH

I have a set of 1l pistons and rods if you're interested?

they do vary from engine to engine. i wouldn't like to risk it!

 

[Swiper]

as you can see in the pics if you maximise the photo, the red circled numbers are for the piston/bore size (these obviously have to match the grade stamped into piston top) (the blue circled numbers are for the crank bearings). the haynes manual gives the dimensions for each of the grades iirc.

 

[chickenwaahoo]

Its a little worrying, cause if the '2' on my pistons is the grade, I've got three 2's and a 1! Do they mix sizes on engines, I can't see from the photo if yours are all 2's.
My block is away being honed, so I can't check what its meant to have. However, the engine did have non-original sealant on most of the gaskets so I'm pretty sure the internals have been worked on before.
Craig, where are you and what do you want for the pistons?

 

[Craig]

I am either in southampton or watford, was thinking £40 for the pistpns?

 

[Swiper]

Its a little worrying, cause if the '2' on my pistons is the grade, I've got three 2's and a 1! Do they mix sizes on engines, I can't see from the photo if yours are all 2's.
My block is away being honed, so I can't check what its meant to have. However, the engine did have non-original sealant on most of the gaskets so I'm pretty sure the internals have been worked on before.
Craig, where are you and what do you want for the pistons?

i've only looked at the grades on three engines, and they've all had same grade pistons in each block, 2X '2' and a '1'. but not sure if they mixed and matched.
i've seen complete cg10s go on ebay for less than £30, so i'd say £40 just for pistons is expensive.

 

[asdame]

Its a little worrying, cause if the '2' on my pistons is the grade, I've got three 2's and a 1! Do they mix sizes on engines, I can't see from the photo if yours are all 2's.
My block is away being honed, so I can't check what its meant to have. However, the engine did have non-original sealant on most of the gaskets so I'm pretty sure the internals have been worked on before.
Craig, where are you and what do you want for the pistons?

hey
i've just taken out me pistons for a clean and they too have three #2's and a #1 grade so it's normal i guess.

 

[Craig]

I'd pay an extra tenner not to have to strip it down and end up with a load of bits of engine in my garage

 

[chickenwaahoo]

Cheers for the offer mate, but could do with other spare parts too, so I guess I'll look out for a whole engine.

 

[Antony]

you could put the cg10 pistons in and have them pocketed to sort the valve clearance out.

then run it on GSXR carbs, or ITB's, raise the rev limit using some means..lol and whilst your at it, have the head gas flowed, re-shape the combustion chambers to suite the engine.... balance the rods and have the pistons "skirted" (if you dont know what that means it means taking the bottom of the piston skirt off making the overall piston height lower, decreasing movable mass"
and you should have an engine that will produce a good glob of power....and sound awesome!!!!

probs about 140bhp+ and if posible >>>10,000rpm, (seen it on carbs in car and car conversions so its possible)

good luck

 

[Swiper]

you could put the cg10 pistons in and have them pocketed to sort the valve clearance out

this wouldn't be needed with standard cams, providind not too much has been skimmed off head or block.

 

[chickenwaahoo]

Looking at most of the cams on show at Autosport, it looks as if manufactures are going away from big lift and are now doing big duration. Cam lobes are looking like the ends of giants thumbs now! I presume this has something to do with lighter valve trains and the ability to keep emissions down with better fuel control that modern fi systems have.