Quench "flame channels" in piston vs. head quench

[andrew]

So many people talk of dyno testing to prove benefits. From what I read, that’s not the ideal approach. Without comprehensive knowledge of controlling cylinder pressure and engine detonation limits it’s easy to walk away very disappointed.

[mpgmike]

- 2000 Ford Ranger 2.5; from 21 mpg to 27 mpg and had the power of the 3.0 V-6

Mike
www.PowreHaus.com

All this from grooves only or is this from the portwork done as well? I see a significant amount of porting done in the pictures of the ranger head and that would invalidate your performance claims if included as part of your back to back testing.

I own a vehicle with that same engine and am to the point where I want to test this myself on a dyno to put this to rest or be another believer. Please elaborate on your testing!

Bo

I did minor clean-up around the guides and under the seats in the bowls, but very minor. If you compare the pic of the Powre Haus 2.5 combustion chamber to a standard one you will see that there is a significant amount of reshaping in there. 95% of all the mods took place in the combustion chamber on this engine, and the other 5% were bowls. The head was milled (from memory) 0.035" to compensate for the material removed from the CC.

The theory on this particular head was to treat it as 2 seperate combustion chambers with 2 seperate spark plugs, then have the 2 flame fronts converge harmonously. Obviously I'm playing Smokey by guessing at what actually happened, but the performance and mileage were on par with targets.

Mike

[Unkl Ian]

So many people talk of dyno testing to prove benefits. From what I read, that’s not the ideal approach. Without comprehensive knowledge of controlling cylinder pressure and engine detonation limits it’s easy to walk away very disappointed.

If there is a "definate" improvement,they must be
a way to measure that improvement.

[andrew]

I’m not saying it can’t be measured the maximum benefits come from a combination of modifications.

I have a friend that lived in India for some time. He talks of the shop that has been grooving heads there for 10 years. They do a lot more than just grooves. The camshaft is re-cut. The valve timing is altered. The air fuel ratio is changed. The compression is raised to a point where the engine would self destruct with out the grooves. When they are finished the car doesnt need a transmission.

[Unkl Ian]

Can anyone percisely plot cylinder pressure vs crank rotation
(in degrees) ?

Then compare the pressure curve,before and after,
with the only change being the added grooves.

[andrew]

I would think the changes in cylinder pressure would come from the increase in compression and camshaft modifications not the grooves.

[Unkl Ian]

If the grooves influence combustion,by altering the quench effect,
I'm guessing it would show up in the combustion pressure curve.

If it's real,there must be a way to measure the result.

[Masher Manufacturing]

I've got a 2.3 Ford OHC Lima apart and can try some head grooves if we can come up with a configuration to try. This is similar to the 2.5 Ford listed in other posts. My engine has come apart to replace cracked skirt pistons, common on these motors.

The short block is a 2.3 and the closed chamber head is from a 2.0 ( not the German 2.0 but the Lima 2.0 in Rangers ) as a result the compression is much higher than the stock ~ 8.5. The chamber looks like the one in the prior 2.5 post as well except is has only one plug. The cam, carb are stock, the ex manifold is a stock cast iron header shape that probably is pretty good.

I don't have any dyno data but know the truck typically gets 20 mpg and must run on 92 fuel.

As a side note, the stock dual plug 2.5 Ford shuts off the extra plugs under full throttle usage. Some Porsche 911 motors run both plus all the time, mid 80's Nissan 4s used dual plugs but I don't know if they are constant or not.

[automotive breath]

Can you post a picture of the cylinder head and piston top?

[Masher Manufacturing]

I will see if my camera will talk to my computer, lately they have been ignoring each other.

The piston tops are flat with two valve notches ( one on each side )

The comb chamber is sort of heart shaped with a rounded bottom and not too pointed top. Since the 2.0 head is on a 2.3 bore, there is a ~ 1/4" squish band completely around the rest of the chamber.

I don't know what the quench distance as the pistons are at the shop getting pressed.

[automotive breath]

I thought this might intrest some, this written by one of the top EMC teams is from another forum.

I have been doing this for about 2 years now...

...and long story short, it works.

The increases in low end torque and stable low speed flame propogation are valid and is the increase in detonation resistance. Idle vacuum increases a bit too.

There are not really any HP benefits at the top of the RPM window but more so at the bottom and mid range.

I used them at EMC this year and two years ago with good results, our combo was pulled down to 1,900 RPM at WOT with an 1150 dominator with out missing a beat. No detonation at 10.5 to 1 nor 12.5 to 1 on pump premium

[putztastics]

There are not really any HP benefits at the top of the RPM window but more so at the bottom and mid range.

Interesting, that is exactly what my dyno testing showed.

[peerless]

Ok I am going to jump in here on this subject. I happen to have a BMW 2.8L I am building. I am still in the clean up and polishing stage of the head. I have thought about including these grooves but not sure how to place them for maximum effect.

It seems some have positive things to say, and I have heard no negatives regarding poor performance. So I am game if someone would like to comment on how best to place the grooves in my cyl head.

85mm bore, Forged pistons 10:1CR (9:1CR stock) The piston notch faces intake valve

[automotive breath]

Robert,
I would approach this the way I do BBC heads.

Two grooves in the squish pad both pointing just to the exhaust valve side of the spark plug.
Stay 0.060" (1.5mm) away from the gasket surface.

Check the deck thickness before you decide groove depth; 0.040" to 0.060" is deep enough,
deeper as it gets to the chamber. Remember theres water down there.

I cut the grooves with a 1/16" ball end mill then widen with a file into the chamber.

[mpgmike]

AB, I find it interesting that you changed from Somender's original "point the groove directly at the spark plug" to pointing it next to the spark plug on the exhaust valve side. That's exactly what I did and I surmise probably for the exact same reasons.

Mike