[EVO440]

Hi guys, I need some help with the pistons below. Can i fit these in my Evo 4 block?

http://www.slowboyracing.com/more.php?id=2537&mods=32-3130

 

[thetyrant]

They will fit ( after reboring) but are 4th oversize if you go for 87mm version, stock bore is 85mm and normal is to bore stock engine to 85.5mm, which is first oversize ! has the car been rebored a few times already or got bad bore damage ?

Cheers
Ian

 

[dlgis]

I wasnt even aware you could go to 87mm on the Evo block and was once told by an engine builder that 86.5mm was cutting it a bit fine! - dont know how true that is


Darryl

 

[Wreckleford]

The 4g64 has the same bore spacing as the 4g63 (and is supposedly the same block casting but they don't machine the deck height as low), and comes from the factory with 86.5mm pistons. One step oversized would come to 87mm, so I son't think it would be a problem to run 87mm pistons in a 63 block. However, if you do, you are not leaving much room for overvboring in the future.

 

[EVO440]

I was looking at using these pistons because a few months ago i took my car to a (mechanic) to put in a new clutch and when i got the car back i noticed that there was a slight knock in the engine and the engine was cutting like it's running on 3 cylinders and the all of a sudden there was a bang and the car lost power and wouldnt start i took out the spark plugs and found that one of them was totally smashed i looked into the sprk plug hole and on the piston was a small piece of metal like a piece from a washer then we took of the cylinder head and found 5 more pieces 4 of them were in each bore and scrath the bore walls and the other piece was stuck in the head so now i have to rebore the block but i have to go for either 86 or 87 mm pistons is because my block has allready been rebored to 85.5. What bore would you guys think would be good i relly don't want to lose any strentgh from the block by cutting it to much please help me

 

[Wreckleford]

The same page you posted, they have hte pisotns in various sizes form standard up to 87mm. Just clock on the size part and the list comes up.

If you are running an original early Evo IV engine, I suggest you change the engine for a V or up engine as yours might crankwalk. If you rebuild your engine, find out how much it needs to be bored to in order to take out the scratches and then choose your piston size.

 

[EVO440]

Ok but what do you mean by crankwalk

 

[Wreckleford]

Do a search, but in short it is thrust bearing failure which will lead to catastrophic engine failure if it is not detected in time. Nobody seems to have a cure for it either.

 

[EVO440]

oh man that is bad i wouldnt want that to happen thanks alot for your help

 

[thetyrant]

No you wouldnt...not pretty!

ian