Flusher

  • Karma: +84/-0
Re: argh cant decide on engine build...
« Reply #25 on: March 19, 2016, 10:43:44 AM »
Too much quench distance? Maybe I'll just zero deck the block and run 22cc dished pistons.

And now back to our regularly scheduled programming...

I know a full-dish with a smaller combustion chamber will make more power.  This is opposed to a flat top or a dish with a shape that mirrors the combustion chamber.

I have a theory why this is (to some extent).  What I am trying to wrap my head around is:  A full-dish opens up some of quench area, why doesn't this contribute to detonation?
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"I want to roll with my brother Joe" - Joe Bateman - January 29, 1950 ~ November 27, 2013

LakesOnly

  • Karma: +15/-0
Re: argh cant decide on engine build...
« Reply #26 on: March 19, 2016, 09:33:44 PM »
I was looking at having the block decked but keeping the pistons. 020 below deck.  And running 15cc dish pistons.  As well as a .040 compressed head gasket thickness.
The effectiveness of quench can be a bit counter-intuitive at first, and so I can understand how it might seem that leaving the pistons in the hole woudl lower compression and thereby reduce detonation, but the resulting lack of quench actually makes detonation more likely.  And so conversely, while zero-decking the block may increase compression ratio the simultaneous increase in quench effectiveness greatly surpasses the modest compression increase.

If my calculations are correct that should bring it to around 10:1.  I wouldn't mind splashing some 100ll into it.  Or even keeping race fuel on hand to add in at every fill up.
OEM early heads are typically 77cc's from the factory; with the addition of large valves the chamber volume drops to about 74cc typical.  Any chance you're porting the heads yourself?  If so, perhaps you can grind/shape/polish the combustion chambers and get about 5ccs back into them, to about 78-79ccs.  If so, then c/r would drop to about 10.1:1 with the Icon pistons I mentioned earlier.  Might be a long way to get there but if you're motivated/enthusiastic about doing your own stuff like I am then it's not so bad.  PS: Check the heads for flatness and if they don't need surfacing then bypass that step since it lowers chamber volume as well.
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Outlawmayhem

  • Karma: +4/-0
Re: argh cant decide on engine build...
« Reply #27 on: March 19, 2016, 09:42:59 PM »
The effectiveness of quench can be a bit counter-intuitive at first, and so I can understand how it might seem that leaving the pistons in the hole woudl lower compression and thereby reduce detonation, but the resulting lack of quench actually makes detonation more likely.  And so conversely, while zero-decking the block may increase compression ratio the simultaneous increase in quench effectiveness greatly surpasses the modest compression increase.
OEM early heads are typically 77cc's from the factory; with the addition of large valves the chamber volume drops to about 74cc typical.  Any chance you're porting the heads yourself?  If so, perhaps you can grind/shape/polish the combustion chambers and get about 5ccs back into them, to about 78-79ccs.  If so, then c/r would drop to about 10.1:1 with the Icon pistons I mentioned earlier.  Might be a long way to get there but if you're motivated/enthusiastic about doing your own stuff like I am then it's not so bad.  PS: Check the heads for flatness and if they don't need surfacing then bypass that step since it lowers chamber volume as well.

I've never ported and polished heads before.  I'd like to do it myself but I figure I would have it done while I get the bigger valves put in em.
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Outlawmayhem

  • Karma: +4/-0
Re: argh cant decide on engine build...
« Reply #28 on: March 20, 2016, 09:21:07 PM »
Well looks like Ill be building a motor alot sooner than I thought.  Crank is moving up and down and engine is knocking. 
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FordLover

  • Karma: +72/-0
Re: argh cant decide on engine build...
« Reply #29 on: March 21, 2016, 11:04:27 AM »
What were you doing when it gave out? See oil pressure drop?
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Outlawmayhem

  • Karma: +4/-0
Re: argh cant decide on engine build...
« Reply #30 on: March 21, 2016, 11:09:34 AM »
What were you doing when it gave out? See oil pressure drop?

My oil pressure gauge isn't working so no clue if it dropped out.  Wasn't pushing it too hard.  Was going 41mph on GPS the tach said 2300rpm but I'm thinking it was more like 3800. I'm thinking i lost oil pressure. 
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FordLover

  • Karma: +72/-0
Re: argh cant decide on engine build...
« Reply #31 on: March 21, 2016, 11:20:43 AM »
For the next engine I am going to need you to have working gauges....mmmmmkay? Lol
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Outlawmayhem

  • Karma: +4/-0
Re: argh cant decide on engine build...
« Reply #32 on: March 21, 2016, 11:29:43 AM »
For the next engine I am going to need you to have working gauges....mmmmmkay? Lol

That's the plan.  I'm going to rewire the boat while I have the engine and interior out. 
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Outlawmayhem

  • Karma: +4/-0
Re: argh cant decide on engine build...
« Reply #33 on: March 30, 2016, 08:25:47 PM »
Okay so I got the heads off the d1 block.  I'm going to definately need to take the block and have it taken 30 over.  Cylinders all pretty much rusted to the point the engine won't rotate.  I'm hoping the crank and Rods are okay.  I can see some rust on the cam but that's getting replaced. 

Noticed the pistons are half dish.  Running those with c9 heads should net me around 9:1 compression and flat tops 10:1?

Thinking this cam http://m.summitracing.com/parts/cca-k34-232-4

With a little port and Polish on the c9 heads.  And either the edelbrock Victor intake or the offy tunnel ram I have with dual quads on it. 
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Squirrel Master

  • Karma: +7/-0
Re: argh cant decide on engine build...
« Reply #34 on: March 31, 2016, 03:14:52 PM »
I have a 460 zero deck 22 dish pistons 30 over a mild cam 108 loobe separation I am 231 at 50 I believe and 256 overall lift and I have dove heads ported and polished larger valves and when they ported it they opened it up the chamber up too much so my chamber is 83cc I made 470 horse with 525 foot pounds of torque starting at 2800 RPM


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  • Boat #1: 1976 Sleekcraft Kauia
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"most important... WHEN IN DOUBT, THROTTLE OUT!!!"  Crewchief22

Outlawmayhem

  • Karma: +4/-0
Re: argh cant decide on engine build...
« Reply #35 on: March 31, 2016, 06:04:54 PM »
I have a 460 zero deck 22 dish pistons 30 over a mild cam 108 loobe separation I am 231 at 50 I believe and 256 overall lift and I have dove heads ported and polished larger valves and when they ported it they opened it up the chamber up too much so my chamber is 83cc I made 470 horse with 525 foot pounds of torque starting at 2800 RPM


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Damm nice.  I need to put this motor together on the quickness summer is coming
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Outlawmayhem

  • Karma: +4/-0
Re: argh cant decide on engine build...
« Reply #36 on: April 21, 2016, 11:12:54 AM »
For the next engine I am going to need you to have working gauges....mmmmmkay? Lol

Well there's the main bearing. Found the oil pump shaft in the pan.  Not sure how it got there. 
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