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Thinking of 4g52

Posted: Sat Aug 04, 2018 12:58 pm
by barana
Gray all thinking of a 4g52 head. On my 54 for boosting. How much do they go for?

Re: Thinking of 4g52

Posted: Sat Aug 04, 2018 9:52 pm
by Scorpma82
May I ask what benefits the '52 head gives over the '54??

Seems a bit of any unusual choice

Re: Thinking of 4g52

Posted: Sat Aug 04, 2018 10:55 pm
by barana
I've read on these forums that it has a smaller combustion chamber to raise the compression up to somewhere near 11.5:1

Ah I see the confusion I've said blown instead of direct petrol injection. Apologies. Will edit.

Re: Thinking of 4g52

Posted: Sat Aug 04, 2018 10:56 pm
by barana
Hmm can't edit.

Re: Thinking of 4g52

Posted: Sun Aug 05, 2018 9:58 pm
by Scorpma82
I didnt think the size of the combustion chamber Had a direct effect on the compression...that usually deck height and piston design.......Astron I '54's run dished pistons whereas the Astron II '54 has flat-top pistons, squaring off the deck and increasing compression

Re: Thinking of 4g52

Posted: Mon Aug 06, 2018 2:49 pm
by barana
Heh certainly, otherwise domed pistons would be useless. And diesel engines that have no significant in head combustion chamber couldn't achieve 22:1 as they do.
Its well known in the holden world that if you want a high compression holden 6 you use a 138-161 red head on a 179-202 engine as it uses smaller combustion chambers.
This same concept has been mentioned by people on this forum with 52 head on 54 block.

Re: Thinking of 4g52

Posted: Mon Aug 06, 2018 10:37 pm
by Scorpma82
Personally..for simplicity reasoning...id tickle the original '54 head to increase the compression

Re: Thinking of 4g52

Posted: Wed Aug 08, 2018 9:14 am
by barana
Fair nuff

I still want to see if anyone knows what they go for...

Re: Thinking of 4g52

Posted: Sat Aug 11, 2018 10:17 pm
by Scorpma82
I doubt they go for more than scrap tbh.....there was never really anything rare, special or limited about them (apart from the handful of DOHC heads that were made in Japan.)

If a mate has a spare head around.....a slab of there fav drink is usually a fair exchange

Re: Thinking of 4g52

Posted: Sun Aug 12, 2018 6:25 pm
by barana
OK, ta m8.