To Quench or Not to Quench?

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Just did a calc W/standard 3.445" bore 2.2L pistons & at .062" quench it drops CR to 11.99:1.

3.445/2 = 1.723 X 1.723 = 2.97 X 3.14 = 9.33 X 4.175 = 38.9 co in /.061 = 637.7cc

637.7 + 58 = 695.7/58m = 11.99:1 CR

Total displacement is 233 cu in.

I think if I utilize concave head valves & pay attention to other details I can drop CR even further. If I can get another 6cc of combustion chamber voluume W/O increasing quench height, I can get to just below 11.0:1 or perhaps a bit lower.

At that CR think I could run 93 octane W/cold plugs & a 160° TSTAT & still use aggressive ignition timing.

I probably could still run nitrous if I can somehow program in 4° of spark retard W/electronic ignition.
 
/6 Matt said:
Shoot, I'm learning things too! I didn't know you could have the crown of the piston come out the block!
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It's the top ring ya have to worry about.

If that comes out da block bad things happen.

Actually I need to check on minimums but modern OEM pistons have the top ring VERY close to the top deck. The OEM top rings probably run closer to the deck than what my dreamed up stroker \6 will.

They do this for emissions standards as the gap around the piston above the top ring that is down in the bore makes for nasty unburned hydrocarbons.

This has it's drawbacks as now the top ringland is a weak spot because it is very thin.

In 5 years of running & pioneerimg performave mods for the Gen III Hemis the only common (catastrophic) engine failure we saw was broken top ring lands. This was usually due to poor tuning W/nitrous or A/F mixture too lean in N/A applications. The top ring grabbed or detonation hammered the ringland & the results were little pieces of ringland in the combustion chamber. I even saw 1 guy drive home several hundred miles after such a failure as most of the ringland remained to keep the ring contained.

The only thing that clued him in that something was wrong was an intermitant miss on the pass & the smashed electrode on one of the plugs after the pass. When a bore scope was inserted the broken ringland was seen. Fortunately, the chunks blew out the exhaust W/O causing further havoc.

It is now recommended that W/OEM pistons in the 5.7 that the ring gap be increaed for F/I or spraying. This was in a Mopar Muscle or some other magazine where they were exploring the upper UPPER limits of the stock 5.7 block. I ws making about 700 crank HP on the 175 shot.

My engine was very detonation resistant & I ran 175 shots W/O pulling timing from my N/A tunes. No KR until 4th gear & then it was in the neighborhood of 4°.

Aftermarket pistons don't have to meet emission standards so the top ring land is made much thicker then OEM for strength.

This allows the piston crown to come out of the block W/O any bad things happening as long as the top ring stays far enough down.
 
RustyRatRod said:
HEMI. duhhhhhhh


LOL
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Wow.... I feel dumb now. I have nothing to say to that lol!

PowerWagon896 said:
It's the top ring ya have to worry about.

If that comes out da block bad things happen.

Actually I need to check on minimums but modern OEM pistons have the top ring VERY close to the top deck. The OEM top rings probably run closer to the deck than what my dreamed up stroker \6 will.

They do this for emissions standards as the gap around the piston above the top ring that is down in the bore makes for nasty unburned hydrocarbons.

This has it's drawbacks as now the top ringland is a weak spot because it is very thin.

In 5 years of running & pioneerimg performave mods for the Gen III Hemis the only common (catastrophic) engine failure we saw was broken top ring lands. This was usually due to poor tuning W/nitrous or A/F mixture too lean in N/A applications. The top ring grabbed or detonation hammered the ringland & the results were little pieces of ringland in the combustion chamber. I even saw 1 guy drive home several hundred miles after such a failure as most of the ringland remained to keep the ring contained.

The only thing that clued him in that something was wrong was an intermitant miss on the pass & the smashed electrode on one of the plugs after the pass. When a bore scope was inserted the broken ringland was seen. Fortunately, the chunks blew out the exhaust W/O causing further havoc.

It is now recommended that W/OEM pistons in the 5.7 that the ring gap be increaed for F/I or spraying. This was in a Mopar Muscle or some other magazine where they were exploring the upper UPPER limits of the stock 5.7 block. I ws making about 700 crank HP on the 175 shot.

My engine was very detonation resistant & I ran 175 shots W/O pulling timing from my N/A tunes. No KR until 4th gear & then it was in the neighborhood of 4°.

Aftermarket pistons don't have to meet emission standards so the top ring land is made much thicker then OEM for strength.

This allows the piston crown to come out of the block W/O any bad things happening as long as the top ring stays far enough down.
Click to expand...
Interesting....
 
/6 Matt said:
This is the snow performance kit I would reccomend for you car. I've heard lots of great reviews on snow. http://www.snowperformance.net/stage-2-boost-cooler-muscle-car-n-a.html

The kit advertises you can use pump gas on a 10:1-14.5:1 CR ratio and I believe that the large coverage there is due to cam selection. Stock cams will detonate with this kit closer to 10:1 and wild one will be covered closer to 14.5:1.
Click to expand...

I appreciate your help & I do understand the benefits of WM.

Problem is I have a pump from Snow (JOB) Performace under my work bench that locked up because it was nothing more than an RV water pump & the methanol ate up the internals. I have the solenoids & jets. the whole shootin' match.

Forgive me if I don't take much of what Snow Job Performance says seriously & their "kit" is ridiculously overpriced for what the individual components cost.

I was hoping you had some input on how to put something together W/available compnents that are far less expensive than the Snow Job kit.. .

Like this?

http://www.turbomirage.com/water.html
 
/6 Matt said:
Wow.... I feel dumb now. I have nothing to say to that lol!

Interesting....
Click to expand...

No need for that. Gawd, all the times I've felt dumb learnin about new stuff. The Hemi isn't the only positive deck engine by a long shot. The 68-71 340 was too. There are many others, but I'm too dumb to cite them LMAO
 
I just found a pair of 75-78 vintage \6 heads casting #3698447 just a few miles from the house.

One of them still had the rocker cover on it & when we opened it up it was clean inside.

I can buy 1 for $75 or both for $100.
 
PowerWagon896 said:
I just found a pair of 75-78 vintage \6 heads casting #3698447 just a few miles from the house.

One of them still had the rocker cover on it & when we opened it up it was clean inside.

I can buy 1 for $75 or both for $100.
Click to expand...


Is there really a decision here? lol
 
RustyRatRod said:
Is there really a decision here? lol
Click to expand...

No, but I had to come home to check the #s as I didn't have the casting # writen down.:eek:ops:

I'll stop buy later & tell him to hang on to them till my SS check comes in. This is a very rural setting so he won't have a problem W/that I'm sure.

I'm heading to another scrap yard in the woods that is supposed to have some mid '70s pickups.

Maybe I can score an 8 3/4 housing today too.

On another note: I just got off the phone W/Kieth Black tech & the combo will come out to 11.75:1 CR W/.055" quench.

He suggested that I level out the slanted profile of the -.18cc cup to gain about 10cc volume in the dish. That will bring the CR down to 10:1.

The crown of the piston is .385 thick & the deepest part on the cup is .200" deep.

Lots of room to experiment so I think I might go for .040" quench & -30cc total cup volume to maintain 10:1 CR.

He said that hypereutectic pistons reflect heat into the combustion chamber so 10.5:1 would be a bit high.

Also, he said that N2O would be OK as long as I had enough ring gap on the top ring. .0085" per inch of bore.

The top ring land is something like .221 thick so a +.070"positive deck application should be fine.

For those doubting that positive deck is viable solution, here is a \6 that seems to be using a rather substantial + deck application. In fact, those look an awful lot like KB168 piston crowns.

 
That's a serious positive deck motor. lol
 
PowerWagon896 said:
Maybe I can score an 8 3/4 housing today too.
Click to expand...

I went out & checked some local junk yards this afternoon.

I got a lead on a guy that was supposed to have a bunch of classic cars.

It was a bit of a drive but it was all country driving & it was a beautiful day I missed the place on the way out, after driving about 14 miles I knew I had passed it so I turned around. I barely caught sight of the barnyard full of classic cars, most of them had various ends sticking out from inder [plastic tarps.

I parked the car on the shoulder (the drive was blocked off) & hobbled over to a sheetmetal barn where a guy was working on a backoe. As I made my way over, I passed a '56 ford, a '67 Cutlass coupe & a the nose of a big old 1960ish Pontaic sticking out from under a tarp.

No Mopars! I wasn't feeling lucky & thought that it was a waste of time. I akse him if he had any Mopar parts & he asked me what I was looking for. I told him.

"All I have is a bare housing from a "B" body" he said.

I couldn't beleive it! There laying neatly tucked up against the side of the barn was a clean 8 3/4" housing stripped of everthimg but the studs. It wasn't even rusty & had a coat of weathered, but intact satin black paint.

I couldn't believe it an 8 3/4" "B" body housing!

"How much" I asked.

"I'll take $40" he said.

$40 freakin' dollars! Can you believe that?

It's from a '69 if that makes any difference.

According to Mopar Muscle, the "B" housing can be used in the "A" body W/offset wheels.

http://www.moparmusclemagazine.com/...404_8_3_4_rear_axle_housing_swap/viewall.html

I'm going to read up on this. If I can use the housing W/O narrowing it I will look for a Surgrip carrier, preferably a 4.10.

I need to find some spec's on the bare housing so I can check it out when I go back to get it.
 
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