4g32 to 70 thou oversize

[Splatmarker]

I have a worn out 4g32 block alreay at 60 thou oversize, rather than sleeving it we want to take it to 70 thou over. Does anyone now if it is possible to get flattop pistons any make that will fit. We would really like to up the compression ratio from the std 8.5.

[shuggy]

haha now you will have a 5.8 liter saturn
yes exadurating i know

sorry have no idea on this topic but interested in the outcome - you might just have to find a piston from another engine with the diametre you need?

[HoonBoy]

Look at 4G37 pistons, stock bore is 80.6mm compared to 76.9mm for 4G32. It's common to build a 1770cc 4G32 for a bit more grunt.

[Splatmarker]

Thanks Hoonboy, I spoke to my mate in the engine shop he is stoked and will check it out on Monday. Hows that green lancer going, I,ve been meaning to get onto your site and check out how your engine transplant id going.

[HoonBoy]

Slowly, very very slowly. Won't be any significant progress this year, too busy with the LC Lancer and other stuff.

[mbrallying]

I took mine out to fit 37 pistons

Bored fine...but... couldn't end up getting good pistons. The only 37 pistons I could get had a 2mm dome top which we had machined down flat. Engine went hard but only lasted about 1000ks before it broke a piston, I think due to the brand more than anything else. We just couldn't get good quality ones.

If you could get quality pistons there is no problem taking the bores out that far!!!

I gave up on 1600s and built a $1000 2.6 that makes 120bhp. Heaps better value.

[Splatmarker]

Checkedout those 4g37 pistons today; all dome tops !! I dare say the milling caused the piston failure maybe. We are now looking at daewoo and hyindai pistons to see if and fit the gudgeon pins and height.

[gus75]

Just checked my invoice from my builder and it says mine is 1.5 over.. Pretty sure he used a starion dome top.(it was a good 5 years ago it was built). Ill try to see if he can remember.

He had a heap of problems with the pins more than anything.
Its running 10.5/1 110hp atw.

Got all the specs if anyone is interested, i don't understand them:) but it goes good...

[mbrallying]

The piston actually broke on the edge of the crown down to the ring land. Not on top where it was machined. Although as soon as it happened I thought sheeeeet its broke that piston where it was milled. I was surprised to find what actually happened

[Splatmarker]

Gus, I would be very interested in seeing those specs.
We have gone with a toyota s20 pistons which should take the compression around to 10.1 we hope and a capacity of 1760cc.
Is the flywheel from a belt drive 1600 the same as chain drive one ? Once I get that sorted everything is off to the balancing shop. GIDDYUP.
Heads good, re seat the vavles, double valve springs to boot !!

[gus75]

http://img69.imageshack.us/img69/6476/img4993.jpg

I'm useless at teh upload....
Sorry for the crap quality. Ill try and scan it tomorrow.

[Splatmarker]

All good Gus, i opened in photoshop and zoomed in