[ypzilon]

I don’t like the idea of using two head gaskets and I don’t have the money to four low-comp pistons, so I think I have to mill my cylinder head.
Does anybody know where Ill can cut out the 6cc I want to get rid of?
/Ted Duell
-Arthur Dent also drives a golf gti!

 

[rocco2nr]

Re: Reducing comp on the 16v-head? (ypzilon)

why not dish the pistons? [email protected] dished mine for 9.2:1 (PL pistons), i can tell you the specs if you have access to a lathe...

 

[ypzilon]

Re: Reducing comp on the 16v-head? (rocco2nr)

The advantage of milling the head is said to be better cooling and smaller knock tendencies.
But how much pressure could the pistons take after being dished?
"Access to a lathe" means?

 

[psi]

Re: Reducing comp on the 16v-head? (ypzilon)

You could also use valve clearenced 1.8 10:1 pistons.That will give you about 8:1 comp.

 

[ypzilon]

Re: Reducing comp on the 16v-head? (psi)

Isn't it 10:1 pistons I've got now?

 

[mk1classic]

Re: Reducing comp on the 16v-head? (ypzilon)

quote:[HR][/HR]Isn't it 10:1 pistons I've got now?[HR][/HR]​

I think psi meant 1.8L 8v 10:1 pistons. Is that right ChuckB ?
rocco2nr, could you give us the specs of your dished pistons?

 

[nscirocco]

Re: Reducing comp on the 16v-head? (rocco2nr)

quote:[HR][/HR]why not dish the pistons? [email protected] dished mine for 9.2:1 (PL pistons), i can tell you the specs if you have access to a lathe...[HR][/HR]​

i wouldn't mind knowing the specs, if you don't mind...
i have a lathe at home and a spare PL engine

-nigel.

 

[rocco2nr]

Re: Reducing comp on the 16v-head? (nscirocco)

the dish is 2.35" in diameter and approximately .060" deep. it is radiused at the bottom (evidence that it a lathe was used)
apparently yields 9.2:1 compression.

 

[ypzilon]

Re: Reducing comp on the 16v-head? (rocco2nr)

rocco2nr:
What is your boost level with that mod on the pistons?
How long have they survived?
How much boost could the pistons take with that decreased strength?


[Modified by ypzilon, 7:46 AM 12-4-2001]

 

[killa]

Re: Reducing comp on the 16v-head? (ypzilon)

quote:[HR][/HR]I don’t like the idea of using two head gaskets and I don’t have the money to four low-comp pistons, so I think I have to mill my cylinder head.
Does anybody know where Ill can cut out the 6cc I want to get rid of?
/Ted Duell
-Arthur Dent also drives a golf gti![HR][/HR]​

You DONT want to mill your cylhead, that'll take away cc's and you want to add cc's to you chamber, otherwise you'll raise the compression ratio.
Paul

 

[ypzilon]

Re: Reducing comp on the 16v-head? (killa)

Paul:
Maybe a confusion of tongues, I want to remove ccs of aluminium from the head. The cylinder volume will be the same but the combustion camber will be bigger, and I'll get lower compression...