eBay Cool Head - 1970 170 on eBay
- Thread starter TrickSix
- Start date
Here is a good article on quench.
The only thing I will add is that the quish velocity increases exponentially as the quench distance decreases.
If you are wondering how tight you can go, If you are at .020'' and you are shifting at 7500 and you miss the shift and it goes to 8000 the number one piston will just dust the head, showing light rub marks, so that is too tight for the combo.
I prefer to only cut the block only enough to make flat, it is thin to start with and work the rod and or piston to get the desired deck height. These rods are short making the rod ratio bad ,a longer rod is good and a shorter piston helps by being lighter. of course it costs more sometimes it not so bad if the parts you have are messed up to start with and careful planning can make it work out.
I prefer to only cut the block only enough to make flat, it is thin to start with and work the rod and or piston to get the desired deck height. These rods are short making the rod ratio bad ,a longer rod is good and a shorter piston helps by being lighter. of course it costs more sometimes it not so bad if the parts you have are messed up to start with and careful planning can make it work out.
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Good article! I have learned more about quench than ever
. I’d like a conversation with the guy that came up with the term though 
In the article it states: “Quench should never be less than .035-inches. As Hupertz points out, the quench distance should be increased if the piston has enough rock at TDC to protrude above the deck“. Do you mean 0.035” to 0.05” …. Oh! I think you mean the 0.05 only is the max. 0.035 is the minimum. That makes it jiveQuench is the technical term for both descriptions, and 'squish' is a common slang for quench. You are correct of the proximity and effects (literally quenching and limiting initial burn radius from the plug), with common street engines of our description striving for roughly 0.035" to 0.05" max piston-to-head clearance, in order to minimize end gasses that lead to detonation on det-limited fuels.
A chamber does not care about pressure from atmospheric (NA) or boost for burn, and there is no special benefit from it due to that. Non-quench is more prone to detonation no matter the pressure or density, as exhibited by hemi and open-chamber examples. There are design preferences for certain chamber shapes (e.g., hemispherical to allow high valve angles and/or central spark plug location), but they are not applicable to our designs. To some degree, "it is what it is" at this point.
sorry, showin up late in final period.
All above just a bit above my cutting edge (I get schooled again, thnx) BUT...
the head is offered by 1) a well known bronk guy; 2) some1 who often prices high.
1) = they (this shop I assume, strongly; most bronk guys) mostly dump the 6 for 8. Pretty much
a toss out for him (still his hi $). 2) = same so
double the cost add ons for this head.
All above just a bit above my cutting edge (I get schooled again, thnx) BUT...
the head is offered by 1) a well known bronk guy; 2) some1 who often prices high.
1) = they (this shop I assume, strongly; most bronk guys) mostly dump the 6 for 8. Pretty much
a toss out for him (still his hi $). 2) = same so
double the cost add ons for this head.
PSIG
Famous Member
Heh, good stuff already. My previous response that didn't post:
Partly, and how far in our out of the cylinder the top of the piston is (deck height). A common method for generic engines is to machine for actual piston height to achieve zero deck height ("zero deck") and let the head gasket set the quench - if the gasket is within the target range. If not, any of the factors for how high the piston top sits at TDC, or the gasket thickness, can be altered; e.g., piston compression height, rod length, etc, to arrive at target quench range. This is best calculated in build planning before buying parts or machining.
Sorry to get carried away and off topic
.I do know now that this head for sale is one of the better ones for quench! It goes back to how much you want to spend to go fast
Yes it is true, but now people know what this head is about, which is a good thing, an informed buyer.
PSIG
Famous Member
Agreed. Moderator - this entire thread should be moved, as the OP did not post something he is selling. It was a timely find notification, the OP is not the contact nor responsible party, should be re-titled for content ("170 head compression & quench"?) and placed in the appropriate sub-forum, IMO. The conversation expanded because the OP is not selling this head, is conversational, and should not be limited by forum placement.
