Combustion chamber shapes (w/ pictures) 2

[NickB]

Found a picture showing a Chrysler 2.2/2.5 head beside a Viper head, and surprisingly, there's not a whole lot different in the combustion chamber. The obvious difference is the shape of the shamber opposite the valves. Not so obvious is the valve angle. The valve stems on the 2.2 are about 5 degrees off the bore axis. On the viper, it looks more like 25. The little notch in the point of the heart between the valves on the 2.2 head is very shallow, only .050" or so.

The fifty dollar question (about what my spare 2.2 head is worth) is would it be worth anything (for flow or combustion) to rework the chamber similar to the vipers, and get rid of that ramp at the one side of the 2.2 head? I'll also be unshrouding the valves, but i'll keep the heart shape. The head sufrace will be milled to raise compression a little past stock after all teh metal removal, so the flat spots should disappear into the head surface. The pistons have a dish, the top edge is about .4" wide, so i could see some benefit from quench area at the top of the chamber, and the bottom where it would be filled in like the viper.

Which would flow better?

Which would more likely be less prone to detonation?

Which would give a better combustion process?

 

[NickB]

OOPS, here's the link:

http://members.rogers.com/turbolag/viper 002.jpg

 

[MaxRaceSoftware]

Which would flow better?

Which would more likely be less prone to detonation?

Which would give a better combustion process?
=======================================================

Nick ,
1-Obviously , the Dodge Viper head
2-Same as 1
3-Same as 1 , but depends upon some factors

Do you see where the Viper's Intake port starts off
in the middle/centered on the chamber ????

It then directs its mixture "away" from the open
exhaust valve during overlap

The 2.2 head has to use a "RAMP" because the "BIAS"
is not so pronounced !!!

The 2.2 head's Intake Port starts off almost directly in a straight path with NOT as much BIAS away from the exhaust valve, so they use a RAMP to keep mixture moving where they want to and to naturally enhance mixture spiral/swirl effect

Another problem with the 2.2 heads is the "ditch" you mentioned between the 2 valves near the quench/deck area
On the Intake side = you need this built up to enhance flow
to turn

On the Exhaust side you this built up to let more Exhaust Flow enter into the seat area from chamber into port

this will HURT FLOW both on Intake and Exhaust

You have a lot of valve guide material surrounding the
Bronze guide in the way , that needs a lot of reshaping

The Intake and Exhaust bowls are not deep enough

The Intake Bowl is too-BIASED to swirl mixture at seat area
for real HP/Torque gains in Hi-Performance apps

You have greatly reduced Squish/Quench Areas in the 2.2
-VS- the Viper , which will make the 2.2 a little prone to detonation more than the Viper

The Viper head is more like a Chevy LS-1 or LS-6 layout
in some respects , and the 2.2 's chamber has a hint of
LS-1 mixture direction ramp




Larry Meaux (meauxracing@mindspring.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers

http://www.mindspring.com/~meauxracing/

Support Israel - Genesis 12:3

 

[MaxRaceSoftware]

The Viper head is more like a Chevy LS-1 or LS-6 layout
in some respects , and the 2.2 's chamber has a hint of
LS-1 mixture direction ramp
---------------------------------------------------

should have read =
The Viper head is more like a Chevy LS-1 or LS-6 layout
in some respects , and the LS-1 chamber has a hint of
Chrysler 2.2 mixture direction ramp

Nick the only reasons i see for the ditch was to
HURT crossover flow during overlap period
and maybe speed up combustion








Larry Meaux (meauxracing@mindspring.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers

http://www.mindspring.com/~meauxracing/

Support Israel - Genesis 12:3

 

[NickB]

Ok, i understood some of that

Can i taper the floor of the intake port down towards the outside of the cylinder to get a better 'bias' in the intake port? I know it won't be as good as changing the overall direction of the port to that of the viper head, but sicne i can't do that, i figure it could be the nex best thing?

If i can change the bias like that, i think what you're saying (basically) is that i should try fill in the lower part of the chamber below the intake valve so the chamber has the same outine at the head surface as the viper?

"Another problem with the 2.2 heads is the "ditch" you mentioned between the 2 valves near the quench/deck area
On the Intake side = you need this built up to enhance flow
to turn

On the Exhaust side you this built up to let more Exhaust Flow enter into the seat area from chamber into port

this will HURT FLOW both on Intake and Exhaust"

Sorry, but i didn't catch what you meant there. Is the protrusion between the valves in the top part of the chamber good, or bad? First you said built up to enhance flow, then you say it will hurt flow on both.... Thanks for always being patient with my questions, you're a great help!!

About how big should i make the bowls? How do you know what's big enough?

 

[NickB]

"Nick the only reasons i see for the ditch was to
HURT crossover flow during overlap period
and maybe speed up combustion"

These heads were referred to as the "fast burn" heads. The older style had a bathtub shaped open chamber, nothing special looking at all.

The stock cam has zero overlap, i can't see why they would put it there to hurt overlap flow. I'm not disagreeing with you, it certainly looks to me like it will hurt overlap flow.

 

[MaxRaceSoftware]

Sorry, but i didn't catch what you meant there. Is the protrusion between the valves in the top part of the chamber good, or bad?
======================================================

its a BAD-effect ! ..as far as trying to make
really maxed HP efforts.

the "ditch" hurts Intake flow coming into cylinder
because air can't stay attached..theres no more TURN
or radius length left to help turn mixture into cylinder , so there will always be a reduction in airflow there .

on the Exhaust-side....the ditch is in the way because of the damming-ledge-effect reducing airflow trying to turn into Exh bowl

=======================================
These heads were referred to as the "fast burn" heads. The older style had a bathtub shaped open chamber, nothing special looking at all.

The stock cam has zero overlap, i can't see why they would put it there to hurt overlap flow. I'm not disagreeing with you, it certainly looks to me like it will hurt overlap flow.
===========================================

Nick, like you mentioned ..its supposedly also known as a
"Fast-Burn" chamber ,....so the "ditch" agrees with the theory

also the "ditch" agrees with what they did with stock Camshaft overlap period ,...and the ditch helps to reduce effective-overlap period !!!

so both aspects are in agreement !

===============================================

First you said built up to enhance flow, then you say it will hurt flow on both.... Thanks for always being patient with my questions, you're a great help!!

Nick... Yes i moved that LINE down and forgot to paste it back where it should have been ..sorry for confusion ,
but it should have read =

Another problem with the 2.2 heads is the "ditch" you mentioned between the 2 valves near the quench/deck area
this will HURT FLOW both on Intake and Exhaust

On the Intake side = you need this built up to enhance flow
to turn

On the Exhaust side you need this built up to let more Exhaust Flow enter into the seat area from chamber into port






Larry Meaux (meauxracing@mindspring.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers

http://www.mindspring.com/~meauxracing/

Support Israel - Genesis 12:3

 

[MaxRaceSoftware]

Can i taper the floor of the intake port down towards the outside of the cylinder to get a better 'bias' in the intake port? I know it won't be as good as changing the overall direction of the port to that of the viper head, but sicne i can't do that, i figure it could be the nex best thing?

If i can change the bias like that, i think what you're saying (basically) is that i should try fill in the lower part of the chamber below the intake valve so the chamber has the same outine at the head surface as the viper?
=======================================================

Nick, you would have to WELD in the chamber to add aluminum
to BUILD-UP the ditch ..but the heat from welding would
"kill" the seat inserts press-fit (distortion)


to do the kind of welding you are talking about , you will loose the "Heat-Treating" on the surrounding areas
..it will have to be done by the very best welder
with the correct equipment , then possibly sending it back to reheat treat


the 2.2 's chamber looks pretty good as far as UNSHROUDING
for airflow goes

you need to concentrate on the valve job, bowl-areas, and ports more than worrying about the chamber

i wouldn't try to BIAS the intake port on the 2.2
head , the chamber already will take care of that

there is so much to do in the valve-job,bowl-areas-, and ports to gain a lot of Torque/HP
Larry Meaux (meauxracing@mindspring.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers

http://www.mindspring.com/~meauxracing/

Support Israel - Genesis 12:3

 

[NickB]

Ok, i'm getting a better idea what to do here. I've got a scrap head i cut apart a while back, and i unshrouded the valves on one of the chambers to see how much more space i could get around the valves. I was able topretty much trace around the outside of the valve seats with the end of a round nose 1/2" burr. The chamber still has the same shape, but it's opened a lot of pace around the sides of the valves that were preiously closed in. It also moved the point further back and out of the way.

You make a very good point about the welding. I've got TIG equipment, but i can't get the heat-treat done, and i don't want to have to get everything re-machined for new seats and such.

I hadn't thought that they would use the ditch in combination with the zero overlap cam. The head was originally ofered in the mid 80's, and the cam's did have some overlap at that time. I'm actually running one f the overlap cams in it now.

I'll post a few pics of the cutaway views of the ports. They look pretty horrible to me. The intake necks down a lot in the middle, and the roof angle doesn't match the intake runner roof angle. There is enough metal above the roof to match it though, and keep the same runner area down to the valve seat. If i post some pics, and draw in what i was thinking of doing, could you point me in the right direction?

Another interesting thing, in every one of these heads i've seen (i have a really good view of it on one cut piece) the valve seat on the intake port is always off center from the port by about 3/16". Since this is on every head i've seen, i'm guessing they did it to enhance swirl?

 

[NickB]

I just wish i could find some way of helping all you guys after all the help you give me