Check out the specs on the ACL website, they have a 7.5cc dome and state a comp ratio of 10:1 @ 57.5cc.
They're probably going to be used in my next project for more comp.
Posted 25 May 2014 - 07:09 PM
Check out the specs on the ACL website, they have a 7.5cc dome and state a comp ratio of 10:1 @ 57.5cc.
They're probably going to be used in my next project for more comp.
Posted 25 May 2014 - 07:13 PM
Excellent Jonesy,
we need pictures too
Posted 25 May 2014 - 11:31 PM
Posted 25 May 2014 - 11:39 PM
Edited by rodomo, 25 May 2014 - 11:40 PM.
Posted 25 May 2014 - 11:48 PM
If you want a good motor why not just take OJ's advice from his excellent thread instead of trying to reinvent the wheel ?
Posted 26 May 2014 - 08:40 AM
Thank-you Kevin, Rob and Mark,
I did see how long the skirt was, but never thought about how heavy they were or even the milling of the Head,
so that would make those Pistons cost $3000 in the End.
Now to look into the ROSS DOME Pistons.
Oldjohhno and I didn't Invent the Holden Red Six Motor, and it is how they Spin the Wheels. Dave I
The Quest of a 14:1 Dynamic Compression Motor is getting Closer
Posted 28 May 2014 - 11:33 PM
Posted 29 May 2014 - 11:55 AM
Posted 29 May 2014 - 12:19 PM
Thank's for the Piston Information Jonesy,
Tonight I will put some more info up Here that Rob supplied,
and the Seller got back to me about the Weslite Pistons,
and they are 800 grams each with Pin. Dave I
800 grams.That's roughly 300 grams too heavy. Might be Ok in a slow reving truck engine.
Posted 29 May 2014 - 12:29 PM
Posted 29 May 2014 - 03:32 PM
how much gain @14:1 over 13:1 will there be Dave? is it really worth pursuing? Is it really do-able?
just wondered out loud,mervx
Posted 29 May 2014 - 05:10 PM
how much gain @14:1 over 13:1 will there be Dave? is it really worth pursuing? Is it really do-able?
just wondered out loud,mervx
Exactly.
Gains from increasing the CR get progressively smaller. In other words you gain a lot more by going from 10:1 to 11:1 than you do from 13:1 to 14:1. And in my opinion breathing and a good burn trump CR every time. So while I'd have no qualms running 14:1, it'd have to be on the condition that it had no negative impact at all on these other more important factors.
If it meant it increased the burn time even a little bit I'd gladly sacrifice some CR. Likewise if it meant I lost a few CFM I'd happily trade off some compression, or if I had to compromise the tune in order to avoid deto then again I wouldn't be able dump the compression quickly enough.
That car back in the 70's that smoked the tyres from a 180mph roll-on (or whatever it did) didn't run well because it had 14:1; it did it because it had a good package and compression is only a part of that package. So by all means go for 14:1 but realize that if you have to run ugly pistons or compromise more important factors to do so then you're probably not getting as much power as you could. Also note that if an engine responds well to unusually high cranking pressures then it's often just a indicator of poor breathing.
Posted 29 May 2014 - 05:41 PM
Posted 29 May 2014 - 06:55 PM
Posted 29 May 2014 - 07:52 PM
Evening Hip6,
As usual,
I am curious to see what the difference is to what I had, and to what 14:1 can do,
mainly to see what the compression per pot is, but as the Title say's,
I though it was a matter of getting 14:1 pistons, and that was that,
but as we now know, you cannot just go and buy them. Dave I
Why would you need 14:1 if you had one of the fastest toranas in Newcastle in the early 80's?
Just asking....
still have the same Red 6 Head
Posted 29 May 2014 - 08:07 PM
Posted 29 May 2014 - 08:48 PM
Why would you need 14:1 if you had one of the fastest toranas in Newcastle in the early 80's?
Just asking....
Posted 29 May 2014 - 08:50 PM
this is the link Rob gave me,
and the weight of a 10:1 piston and pin is 578 grams:-
http://www.aclperfor...u/6MKRY9118.htm
and here is the side shot of the 800 gram piston and pin:-
$_0.JPG 18.02K 2 downloads
Posted 29 May 2014 - 08:58 PM
I would certainly choose a drop of 222 grams reciprocating weight over a point of compession any day of the week....
Posted 29 May 2014 - 10:07 PM
Posted 29 May 2014 - 11:27 PM
Posted 29 May 2014 - 11:33 PM
That one looks good Jonesy,
Look's modern too
maybe 600 grams with pin
Posted 29 May 2014 - 11:36 PM
Posted 31 May 2014 - 02:19 PM
I still think you're taking the wrong approach.
The obvious solution is to fit a Starfire head. I seem to remember Planckman Racing pioneering this conversion in the early eighties.
Place your short motor in the deep freeze for a couple of weeks. Pack around it with packets of frozen vegetables to enhance the chill factor.
When you are ready to assemble simply preheat your oven (fan forced is best) to around 500C then bake the Starfire head until it begins to soften around the edges, remove, then place on the still frozen block and quickly bolt into place.
Voila. You should have somewhere around 14:1 without the need for expensive and difficult to obtain custom pistons.
Posted 31 May 2014 - 07:41 PM
I still think you're taking the wrong approach.
The obvious solution is to fit a Starfire head. I seem to remember Planckman Racing pioneering this conversion in the early eighties.
Place your short motor in the deep freeze for a couple of weeks. Pack around it with packets of frozen vegetables to enhance the chill factor.
When you are ready to assemble simply preheat your oven (fan forced is best) to around 500C then bake the Starfire head until it begins to soften around the edges, remove, then place on the still frozen block and quickly bolt into place.
Voila. You should have somewhere around 14:1 without the need for expensive and difficult to obtain custom pistons.
And don't forget to brush the mating surfaces with egg white to ensure a good seal.
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