Team Camaro Tech banner

1 - 9 of 9 Posts

·
Registered
Joined
·
656 Posts
Discussion Starter #1
I know the importance of a qood quench area. My problem is with soup bowl blower/turbo pistons, does quench still work. A negative 34cc bowl top piston just doesn't seem like it would be effective to set a tight quench. Any thoughts?
 

·
Registered
Joined
·
2,614 Posts
What shap are the chambers on the heads? What shap is the top of the piston? I know the D-shape reverse dome pistons still benafit from proper quench.

As for the stock dished pistons. I wouldn't push it.
 

·
Registered
Joined
·
656 Posts
Discussion Starter #3 (Edited)
The pistons are Ross forged soup bowl, not D-shaped or inverted dome. The chambers are wedge heart shaped. They are Dart 215cc Iron Eagle.
These pistons are 9.0 CR for a 420sbc with a 177 miniblower. I got a 3.875 crank, 6" Rods, and the pistons have a 1.088 CH. This brings me to a 9.0255 deck height. I am thinking that a thicker head gasket would work better in this case than a tight quench.
 

·
Registered
Joined
·
10,475 Posts
You don't have a quench with a dog dish (soup bowl) piston. The "D" dish would be nice if you can find one for your needs. I am using a piston just like the one pictured above, but with your cubic inches you probably can't get the compression you want with a "D" dish.
 

·
Registered
Joined
·
656 Posts
Discussion Starter #5
I can't get any kind of inverted dome type in the CR needed. I guess I lose the benefits of a tight quench area? Any other ways to help control detonation? I polished the chambers to eliminate hot spots.
 

·
Banned
Joined
·
21,341 Posts
400 piston info, only for reference!

I finally figured out I have L2410F's in my 406 b/c of my double-hump heads.

They are the full bowl, four notch TRW's that have the 3/16" to 1/4" chamfer around the outer edge that is "supposed" to help blow the new gases out of the open area behind the quench ring area. They do have about a 3/16" quench ring around them.

NOT the best in the world, imho, but I got them before I knew anything about this stuff way back there due to my -461 double-hump heads.

Forged stock type TRW 400 pistons with four valve notches are as follows:

1970 = L2352F, .088" deep full dish, very slight chamfer;

1971 to 1973 = L2376F, .160" deep dish, slight chamfer; and

1974 and new = L2410F, .185" deep dish, big chamfer.

If I had it to do over again, I would run "D" shape dishes like is being discussed here.

Hope this is of interest to somebody..

pdq67
 

·
Registered
Joined
·
4,837 Posts
I chose to attack the problem from the other direction. I have a 406 with flat tops. That puts the combustion chamber in the head instead of in the dish of the piston. With zero deck I get good squish from my quench area to promote turbulence which reduces pre-ignition. It requires me to run a 72cc aluminum head for 11.2:1 but it gives me what I think is the best compromise.

Larger Dave
 

·
Banned
Joined
·
21,341 Posts
L. Dave,

This is why I have said several times that stock 76 to 80+ cc, 400 heads worked over with big valves is darn good value for the money on a mild 406 STREET motor!

pdq67
 

·
Registered
Joined
·
656 Posts
Discussion Starter #9
pdq67 said:
400 piston info, only for reference!

I finally figured out I have L2410F's in my 406 b/c of my double-hump heads.

They are the full bowl, four notch TRW's that have the 3/16" to 1/4" chamfer around the outer edge that is "supposed" to help blow the new gases out of the open area behind the quench ring area. They do have about a 3/16" quench ring around them.

NOT the best in the world, imho, but I got them before I knew anything about this stuff way back there due to my -461 double-hump heads.

Forged stock type TRW 400 pistons with four valve notches are as follows:

1970 = L2352F, .088" deep full dish, very slight chamfer;

1971 to 1973 = L2376F, .160" deep dish, slight chamfer; and

1974 and new = L2410F, .185" deep dish, big chamfer.

If I had it to do over again, I would run "D" shape dishes like is being discussed here.

Hope this is of interest to somebody..

pdq67

Ross told me they can't build my pistons D-shaped or inverted dome because of my compression height. But they did say that a 34cc dish with a large chamfer around the edges would reap some benefits of a good quench area.
 
1 - 9 of 9 Posts
Top