Don Terrill’s Speed-Talk

So I've read some articles, and seen the posts here regarding cutting the hcannels radiating out from the plug area thru the head's quench area. I'm currently playing with (still in mockup and fitting actually) on a BB Mopar 4.38 bore engine, uzing quench dome pistons and opwn chamber heads. These heads are huge (now 89cc, soon to be slightly larger when they are shaped and polished) and will be milled when everything is done to get .035 quench on the piston's quend dome and the chamber roof. These pistons (KB) leave a lot of dead space behind the qunech dome, and I'm considering some osrt of channel in the dome to get flame behind it. With the bigger bore std Fel Pro gasket and the dome, theres a lot of volume back there I'd rather not give up to poor burning. This is my first time using these, might be my last depending..lol. So, are there thoughts in the positive or negative to doing something similar to the chamber mods? I would think piston rock is pretty minimal because of the tight wall clearances, which is what prompted my thought.

Check out http://www.somender-singh.com/ It seems that the jury is still out on this one. Lots of folks claim they have noticed improvements but no dyno quantification yet. This thread has some limited info:viewtopic.php?t=4069. These grooves were on the heads of a Mustang drag car in first place in it's class about four years ago. I was told that they only worked because of the fuel being used. I believe otherwise. You'll notice that out of all of the professional head designers and porters that post here, none are respoding to these topics. This leads me to believe there is something to it.

As a matter of fact MOST of the folks who reply to what seems like nearly every other post on this forum are leaving this one alone. I wonder why. Where did everyone go?

Twinscrew wrote:As a matter of fact MOST of the folks who reply to what seems like nearly every other post on this forum are leaving this one alone. I wonder why. Where did everyone go?

If you do a search here there are multiple threads and hundreds of posts and comments. I think it has been pretty well covered til someone has new info/dyno numbers etc. Search "automotive breath" who posts here a lot and seems to have most experience. If you just search Singh, I see 7 threads and about 400 comments. There are more.

Twinscrew wrote:Check out http://www.somender-singh.com/ It seems that the jury is still out on this one. Lots of folks claim they have noticed improvements but no dyno quantification yet. This thread has some limited info:viewtopic.php?t=4069. These grooves were on the heads of a Mustang drag car in first place in it's class about four years ago. I was told that they only worked because of the fuel being used. I believe otherwise. You'll notice that out of all of the professional head designers and porters that post here, none are respoding to these topics. This leads me to believe there is something to it.

Maybe it's because the grooves have done nothing for them in testing, and there is no evidence to suggest otherwise... no hard, scientific evidence...

I think it would be a very bad idea to cut the grooves in the pistons...

Often it comes down to "monkey see, monkey do!"

Is this done in nascar cup engines or nhra prostock? NOPE

Playing Devil's Advocate for a minute,the "benefit" of
these grooves may relate more to lower rpm than would
concern a pro stock or nascar engine builder.

Or.....

jacksoni wrote:...I think it has been pretty well covered til someone has new info/dyno numbers etc. Search "automotive breath" who posts here a lot and seems to have most experience....

I agree, for now it covered fairly well. It's getting to where I'm answering the same questions over again. I have been as honest and informative as possible, with out more people here to discuss their experiences with this, it gets kind of boring. Aside from SWR, MPGMike and my self, I don't remember anyone here that claims to have experience, only opinions, in time this will change.

Twinscrew wrote: This leads me to believe there is something to it.

Or nothing to it, . . .. ..


Curtis

cboggs wrote:

Twinscrew wrote: This leads me to believe there is something to it.

Or nothing to it, . . .. ..

Curtis

Curtis, I have the utmost respect for you, your experience and accomplishments.

I have been very honest and straight forward describing the modified engines. I have been contacted by hundreds of people around the world for guidance, if I'm missing something; I like to know about it.

Do you not believe what I'm saying or rather just think I'm using this as crutch to hide problems?

What is your response based on; do you have any experience with this? Are you able to realize the same benefits by other means?

Squish grooves/jets can be applied to either the cylinder head or piston. With the piston grooves/jets it's in engines that normally have a flat (no chamber) cylinder head like the Ford "Kent" I4 engine.

SAE paper 1999-01-3664 is a good example. There are other papers in the SAE/IMECHE/ASME jornals on this.

The above paper was in "Design of Racing and High-Performance Engines - 1998-2003" published by the SAE.

Stef

Stef wrote:Squish grooves/jets can be applied to either the cylinder head or piston. With the piston grooves/jets it's in engines that normally have a flat (no chamber) cylinder head like the Ford "Kent" I4 engine.

SAE paper 1999-01-3664 is a good example. There are other papers in the SAE/IMECHE/ASME jornals on this.

The above paper was in "Design of Racing and High-Performance Engines - 1998-2003" published by the SAE.

Stef

Thanks for the information and reference to the book.

Do you have experience with squish jets?


Ford Kent 1600

You can download SAE paper 1999-01-3664 here for $12 US


http://www.sae.org/servlets/productDeta ... 99-01-3664

beth wrote:You can download SAE paper 1999-01-3664 here for $12 US

Thanks, I'm working on getting a copy of the book, it sounds like good stuff.

Unkl Ian wrote:Playing Devil's Advocate for a minute,the "benefit" of
these grooves may relate more to lower rpm than would
concern a pro stock or nascar engine builder.

Or.....

...the professional teams are realizing similar benefits by a different means.