Deck my block? Quench will be .066 like this. How much affect on compression?
Thread Starter
Registered User
Joined: Oct 2002
Posts: 2,168
From: AACO, MD
Deck my block? Quench will be .066 like this. How much affect on compression?
Got my crank and pistsons in today. Still waitin on my Rods. Anyways, from what I understand, these Scat rotating assemblies put the piston down .025" in the hole. Compressed Head Gasket thickness is .041". That is a quench area of .066". That is a bit excessive, no? From what I remember reading, decking it to. 005 OUT w/ a quench of ~.036" will be optimal.
My concern is compression and detonation. Stock CR is what, 10.4:1 ? With these SRP Flat top pistons, and then milling the heads (aluminum) enough to clean them up, how much more is decking the block .025" going to raise my compression?
I need it to be able to run off 93 Octane.
On that same note, if you have a reccomendation on a good head gasket without breaking the bank let's hear it.
Builder says for this being a street engine it's not necessary to deck the block. But from what I think I remember kim saying, with a tighter quench like .036" I'd be less prone to detonation. Too MUCH compression will cause detonation too no?
Let's hear it! BTW it will cost ~ $100 to deck the block.
My concern is compression and detonation. Stock CR is what, 10.4:1 ? With these SRP Flat top pistons, and then milling the heads (aluminum) enough to clean them up, how much more is decking the block .025" going to raise my compression?
I need it to be able to run off 93 Octane.
On that same note, if you have a reccomendation on a good head gasket without breaking the bank let's hear it.
Builder says for this being a street engine it's not necessary to deck the block. But from what I think I remember kim saying, with a tighter quench like .036" I'd be less prone to detonation. Too MUCH compression will cause detonation too no?
Let's hear it! BTW it will cost ~ $100 to deck the block.
Last edited by Dave88LX; Jun 10, 2003 at 08:30 PM.
Thread Starter
Registered User
Joined: Oct 2002
Posts: 2,168
From: AACO, MD
Here is the thread I was referring to:
http://www.corral.net/forums/showthr...ghlight=quench
Why does a larger quench area increase the risk of detonation?
http://www.corral.net/forums/showthr...ghlight=quench
Outside the valve relief area most pistons have no EXTRA material in the dome, too much weight. SO cutting/milling the piston top is BAD. On a quality steel ROD, I would not push .025 minimum head to piston clearance. On a cheap steel rod, I would like .030.
Ideal quench is between .045 and .035. Anything bigger and quench doesnt happen, its a detonation prone pig, anything tighter and you risk piston to head impact... .025 is absolute minimum, and then only with something of excellant quality on the rod.
Ideal quench is between .045 and .035. Anything bigger and quench doesnt happen, its a detonation prone pig, anything tighter and you risk piston to head impact... .025 is absolute minimum, and then only with something of excellant quality on the rod.
Why does a larger quench area increase the risk of detonation?
You dont end up with the air/fuel mixture pushed out of/turbulent in that area. It remains trapped. As the flame front approaches the expansion of the burnt gases from the combustion chamber area compresses that unburnt gas to much more than any designed combustion pressure, and it detonates versus burn linear.
When the quench is right, the compression of the piston, pushes most of those air/fuel molecuels into the combustion chamber area where we want them.
When the quench is right, the compression of the piston, pushes most of those air/fuel molecuels into the combustion chamber area where we want them.
Last edited by Dave88LX; Jun 10, 2003 at 08:17 PM.
Thread
Thread Starter
Forum
Replies
Last Post
stockssn2o
Parts For Sale
14
May 25, 2015 08:54 AM
11racing
Classic Engine Tech
0
Dec 26, 2014 05:40 PM