Conversion to Non-Interference Engine

[Billman]

what is the height of the piston outside the dish?

Can someone who has cut a piston tell us how thick is the piston under the valve posckets deeper section?

[Josh-stateside]

Here's the thread from Motorgeek (search terms highlighted):

http://www.motorgeek.com/phpBB2/viewtopic.php?t=132&highlight=copper+head+gasket

Javad's gasket is .070" thick, so maybe that will help answer the question?

About $150 is what Javad wrote in the thread.

THe important note is that he had the block O-ringed. That's the key to copper headgaskets. Well and ARP studs too.

[Mark Halligan]

Here is a picture of a JE piston I have recently been sent, this has a valve pocket machined 1.5mm deeper than standard, they actually look deeper.

I wont be using this set I just received, wrong bore size........long story.

But the next set should be the same and I will test (carefully) when rebuilding if it does make it non interference, will be nice if it does.

[Mark Halligan]

From another angle:

[Pisobiker]

Mark, are you plannintg to change the pistons on your engine?
Didn't your engine rebuild already come to an end? did I miss something here?

[Mark Halligan]

did I miss something here?

Not if you could my current pistons slapping Marco, the clearances were not right.........anyway, it gives me the excuse for trying a few different things too, and the new pistons will be slightly different spec than the last set.

But getting back to the thread it will be interesting to see if they do make it non interference, although I am using the higher lift 7A cams for now and it will depend on what if anything I do with the head gasket.

I'll report back when I know.

Mark.

[Billman]

what is the height of the piston outside the dish?

Can someone who has cut a piston tell us how thick is the piston under the valve posckets deeper section?

I Quote on my post! Thats nice? Anyone???

@Mark Halligan

We are waiting for your experience!

[RSCoupe]

I wont be using this set I just received, wrong bore size........long story.

Mark,

What bore size are they?

[Mark Halligan]

Mark,

What bore size are they?

They are 81.5mm, but they need to go into my spare block that has a bit of damage to one of the bores so I am going a touch larger on it.

[RSCoupe]

They are 81.5mm, but they need to go into my spare block that has a bit of damage to one of the bores so I am going a touch larger on it.

Thanks Mark. I was hoping that they really made a mistake and sent you 83mm, which is what I need.

[cooperquattro]

abit of a revival!!
does anyone know what the effects will be in using 2 gakets(or rather 1 and 1/2)to what the valve timing will be??
i mean if the block length is increased(with the added headgasket)then surely the valve timing will be retarded as the timing marks wont line up perfectly..
also will this extra length have any adverse effect with the cam sync(hall sender to crank vr)??

[Billman]

The block length stays the same. The combustion chamber volume changes. The difference in timing because of the height is not significant.

[cooperquattro]

so just the increase of volume then no other factors??
what effects does more or less volume in the combustion chamber have??thanks

[prj]

Thicker gasket means lower compression ratio and worse squish.

[cooperquattro]

ok i know about c/r but the squish is the area i am refering to..larger volume/squish = ????? how does this relate to power,fueling etc??