Plaese check this article:

Modified Head

You may also read the FAQ and how to do it by your selfe:

Howto

What do you guys think? Will thet work?

Sounds good to me and worth to give it a try on an spare head.

Frank

Wow, I have never heard of cutting a groove into the head like that. If it works, Might give it a try.

Looks real scarry to me. How close is he to water? What happens when carbon builds up? What about the stress riser created which will lead to cracking?

That's what I was thinking after seeing some of the stuff I learned from Larry. I would be real afraid of water

not something I'd be all that willing to try either First off he wants you to Mill the head down to raise the compression Then turn around and cut at least .005 groove to lower the compression back down by 1cc.

If piston to head is at .070 Or .040 as he said he has run that close. How Close are the valves to piston???? Surely makes me wounder. He also does states You can Hit water If things are not checked Before cutting the groove Hummmmmmm Really makes one wounder doesn't it???????
One Other funny thing I read Is that he wouldn't do a Dyno Test UNLESS someone Else Pays for it??????????????

I have a fire slot cut into my Dome pistons But not something I'd be to willing to do to my heads something about that don't really seem right,and Like french said what about carbon build up in that slot what happens over time there????? carbon is pretty hard. And the compression I would think could very easily crack The head In that V groove you now have cut into the head esp. if for some odd reason it ever Back fired????? Or what if someone desides to add some NOS
Just my 2cent thoughts.

Be afraid of water if you cut through, but a lot of metal at the squish area is reinforced.

I love the idea and I hope that this guy gets a Dyno test donated soon. Don't know how he did it in India with a Dremel, but if there were as many chassis dyno setups have here, I'm sure it would have been done a long time ago. I think it is more of a case where he "can't" do the test UNTIL someone else pays for it, not UNLESS.

Increased compression is really good for efficiency and the faster burn seems to be clean and in addition to the lower operating temp head cracks might be less of a possibility. There is a photo purportedly of a year old groove and there is not only no noticeable carbon buildup, the burn pattern is remarkably complete.

Everything seems to have a blue hue and the claim is that plugs and oil seem to be cleaner than anything the guy has seen. That sounds like a hot burn and NOx is going to be an issue. This is pretty much all one guy, "Automotivebreath" an engine builder in the Tx/La area.

If any mechanic with 30 years experience and race track pictures starts singing praises, it is worth a second look.

to cut grooves like that in a head with a ball mill then finish it up by hand with a hacksaw blade and a triangle file you would take the curve finish out of the base of the cut.?? too replace this with sharp corners and reduced wall thickness i would expect trouble with cracking..

sounds interesting. is anyone willing to try it? if so let us know the outcome. spare heads for these six's are cheap, especially in the unmodified state. it could just be the cost of gaskets and some time. i'd try it but my head is allready modified. i'd hate to cut the groove and then find it did not work on my head. i do have a stock six in a 65 wagon. i would be willing to do it to that. but not in the near future. tom

It all seems to lead to better (complete) combustion by generating a vortex or "swirl" in the combustion chamber. This "Firestorm" spark plug also goes along this road I think:

Firestorm Plugs

I wish they make it to the market one day, sound promising.

Frank

I thought the Firestorm was hype, and read about some PLASMA plugz. Those would be nice.

It looks like Dyno testing is going to happen. At least two people over at Speed Talk have committed to it, and within a week or two , you'll have numbers to go with the pretty pictures.

Who makes the best quality heads for an SBC ?

Just finished up a 300 cc ford. I will provide results as they develop.


[img]http://members.cox.net/dwynne7/Blake%20r1.bmp[/img]

[img]http://members.cox.net/dwynne7/Blake%20r2.bmp[/img]

Brave man!!! Cant wait to hear these results.

Brave? I'm not sure what you mean. I have been grooving about two to three sets of heads a month for the last year. This one's for a friend, it's going in his street truck.

Update on Singh and his Grooves:
Popular Sience Article

Finally he was allowed to bring his engines and hook them to a Benz EC-70 dynamometer with a five-gas analyzer and a Benz gravimetric fuel-measuring device. A week later, he got his results. According to ARAI, at between 2,000 and 2,800 rpm, Singh’s modified engine used between 10 and 42 percent less fuel than its unmodified twin, with no appreciable losses in torque or power. And, as he suspected, it ran cooler too—as much as 16°C cooler.

I still don't believe it, with out running the unmodified heads on engine "A" then pulling the heads, making the cut, and then rerunning the same engine head combination, you are only assuming both engines are twins. The test doesn't count! Even the same engine on different days will produce different results, so comparing two engines doesn't cut it in my opinion. Maybe if they were Nascar built engines worth $75,000 each I would believe it! Joe

Even Two Fully Blue printed engines will run differently. They would run close But each engine built has it's own characteristics.I learned that when I used to run and Build BB chevys.To me it also wasn't worth the extra Bucks spent on having the motors blue printed (if you knew what you did on the first one and it didn't work, What good were the blue prints?) So i would have to pretty much agree with Joe.Even the Quailty of fuel would also make a difference as to the Out come.

The Benz Dynamometer test was on a lwnmower engine. There is another dyno that was done on a Small Block Chevy recently and it showed a 3% torque increase above the best results from the unmodified heads.

Test1: dyno pull with unmodified heads
Test2: dyno pull with grooves only

Still, this doesn't show what the grooved engine is capable of doing. The benefits of higher compression without ping in addition to other low end torque benefits mean this is still a pretty good idea in my book.

I agree it's best to test the same engine on the same day. Test engine, pull and modify the head(s) reinstall and test again. I hope to find an Eddy current load control dyno with an adjustable timing setup so I can see if I’m able to run more or less timing without detonation under load.

The valve job was completed on the L6 head today, It should be running next week.

I agree with your guys and all this
"2 engine/2heads stuff".


But we are talking about 10%-42% better fuel economy.
This are big numbers that are way to huge to talk them away with the 2 engine argument.

Claimed reductions in fuel consumption are extraordinary. When you consider that the internal combustion engine has a thermal efficiency range of 30% - 35% you realize potential for improvements are very real. This means 65% to 70% of what you put in the fuel tank is wasted.

Turbulence from the grooves alone are only part of the equation. It is a known fact that higher compression improves efficiency. If the modification allows increased compression on low octane fuel, claimed improvements can be realized.

Unless there is some physical proof. example
Dyno sheets (tork & horse power gains) some sort of mileage proof. Its all begaining to sound like Here say. This topic has been going on now for at least 4mo.s and the pics are a nice peice of work. but this is all we have seen. So still my 2cents is Not something I'd be willing to do to one of my heads, carbon build up is still always a factor( over time) no matter what the compression is.

Did I read that right, dyno test was done on a lawn mower engine! I can get 40% better fuel milage from my lawn mower by leaning out the mixture! Joe

... the pics are a nice peice of work. but this is all we have seen. So still my 2cents is Not something I'd be willing to do to one of my heads, carbon build up is still always a factor...

I'm not asking you to buy it, believe it or anything of the sort. If you don't believe it works, by all means don't get involved.

On the other hand those who are interested can gain from my experience. I'm studying the modification and educating myself on the changes in my engines performance. Have been modifying engines for over 30 years so grinding on engine parts is nothing new.

I have over 15 engines running with the modification. I can provide details to any one interested in testimonials. If things go as planned I will beable to provide scientific evidence later this year. Until that documentation is available we will depend on testimonials, believe them if you like.

Here's a picture of the combustion chamber from one of the race engines I ran last year.

How deep did you go with the groove?

Perhaps the people at Sissel's Auto, in Covina would be interested in testing this. They do a lot of head work/modification etc.

Good luck.

That looks pretty good. But a race engine doesn't see nearly the amount of carbon build up as a Daily driver. What motor is this? I have to ask that silly question cause I see no Plug? what is the top of the piston look like? How high is the compression On this Race Motor?flat top or pop-up pistons. Inever said i didn't believe it.
But how ever I do realy Have a silly Question Only for the fact that something was said about Gaining Mileage On a Lawn Mower???? How many people you know drive their lawn mowers to work????? LOL I just had to pick at that 1.lol

Normally aspirated 355 CI SBC
AFR 190 heads with 67CC combustion chambers
TRW mini dome pistons - steel rods
Isky solid flat tappet cam 263/268 0.050” - 0.555” lift.
11:1 compression - 0.037” squish clearance
750 Holley - 83 jets square – Victor Jr. intake
RPM range 5200 – 7200
10.65 ET @ 123 MPH at 3000 Lbs

Well it depends on what you have to work with. As with cylinder head porting; the first and most important thing to do is determine where the water jackets are. I like to groove aftermarket heads because the manufacturers add material to the deck, this allows grooving with out worry of weakening the head or hitting the water jacket.

If deck thickness allows I cut the initial groove 0.060” to 0.080” deep. When the deck is thin ( < 0.250”) I cut the initial groove to 0.040” deep. The bottom of the groove is then contoured into the combustion chamber cavity, getting deeper as it approaches the chamber.

This picture illustrates the depth at the cavity.

How does it run?

Can you realy turn the Idle way down til you almost can count the fan blades?

Can yoou realy scoot throu city traffic in 3th?

How about mileage and temperature?

Im up to buy an 61 Chevy Truck as an daily driver.
If the grooving works I´l give it a try.

Frank

I have been able to realize the claimed benefits. Idle speed lower and smother. Reduced engine temperature and improved mileage. I honestly got 23 MPG in my 10:1 compression grooved suburban with conservative driving style, running 87 octane regular!

I haven’t done one with a standard transmission to experience the high gear low RPM claims.

Ok What was the other head That has no spark plug hole Or am I that Blind??? It doesn't apear to have one.

The camera angle does not include the plug.

This should clear up the confusion; the plug hole is the dark spot at the top.

aw ok now I see why it didn't show up in the Other pic

There is a little different slant on this topic at www.realoldspower.com. Go to the site click on forum,go to Hard core race/engine tech and
scroll down to Notching combustion chamber thread. There must be something to this notching
to improve the combustion process.
Gordy

Yeah I see this topic has been Beat just about every where. Starting almost a yr ago. and still nothing much has shown any proof. and to many other changes at the same time. from what I have read. ( over well Over 7 pages on different sites)

all talk about upping the compression at the same
time. No leaving it like it was to see what Gains maybe had or made?? so in all reality it almost
sounds as if your not going to up the compression Not much point in grooving your head??
But I do understand the idea behind doing( or reason for)
But i can agree with many others If this is so much of a big Gain In Power & tork and Fuel saving
Why don't the BIG GUYs do it ( top fuel funny car and so on)So it does Kinda make one wounder????
And Yes i have to agree with many others On them sites One does seem to walk around the answers when asked Nothing straight forward Or proven.
How ever it would be interesting to see What it would change On my new motor after It's seen some track time But ,By the same token I'm not about to spend the time nore the money on another HP head for the same motor. On a stocker yeah maybe
nothing lost there if it didn't work.But I'm not racing a stock motor. And I'm not about to take my daily driver apart.and milling a head or change Pistons just to up the compression It's really telling you that the groove did anything on it's own.

Larry,
I think it would be best if you let more people give it a try before you decide to do it your self. I've been talking to these people at the MPG forum; following their progress.

MPG

I have no problem with leting others try it. It is solely up to that peron/s do what ever they wish. But as I see it and have read You/They are doing more then Just the groove( raiseing the compression) at the same time. so to me This Proves Nothing of the groove itself is all I'm saying.

OPS my type O It's NOT really telling you that the groove did anything on it's own.
You can't change two things at once and say one thing Made the biggest difference.
Now if you had Lets Just say a 10-1 compression and You grooved the head and Only took out .050 and then you milled the head that same .050 to Keep the same 10-1 and You gained Hp and MPGs then Yes I would have to agree The groove did something on it's own. BUT your NOT doing that, so i don't feel your Proving an thing the way i see it.

Larry, I happy we got to this point of the discussion. I agree with you totally. When testing a modification with more than one change at a time it is difficult to determine what change resulted in the benefits.

To simplify things lets talk about one change only. I bought my Suburban new; the 350 engine came with 9:1 compression. If I raised the compression to 10:1 with no other changes; the efficiency would improve as a result of the higher compression; right?

right and with that small amount of increase you should still have been able to run the same fuel.with out any pining or run on.

Ok; now say I raise the compression again this time to 11:1; the efficiency should improve again as a result of the higher compression. This time detonation might set in if I continue to run 87 octane regular; you agree?

That is true. a small Or big Block chevy will not start if the compression is to high for standard 87-93 octane. I know been there done that. BUT I will tell you this will not hold true to our chevy L6s I s was pushing between 13.9-1 to 15-1 as we figured from the CCs on the head. with a 2 staged Pop-up piston. But any how longger story short The Motor would fire up with just a Bump of the Key ONLY and The only problem was is would not shut off . Never heard a sound from the motor other wise. No Ping no nothing. and There WASn't any Marks In the Pistons Or the Valves and I have Photos to prove that. But Make four passes down the track and it would Blow the head gasket by the fourth pass. How ever This was a daily driver On 87 octane and a weekend racer for just over 17yrs. Ran 112 at the track and i got 18 city and 24 hwy with 3:08 gears offey intake and headers with a 600 holley.( and the cam was a crane 583-607 lift)Then I finaly changed the gear set to a 5:13 Not that this would work for everyone Nore would I tell anyone to drive one that way.But it worked for me.
New changes have been made to the new motor But will still be pushing the 13-1? no less then 12-1 with a new bump stick of 691-680 lift and the 5:13s will still be out back Unless that I find it is in need of more :)as for the Pistons The same ones will be used But to with changes They have been floated and a Fire slot has been cut to face the exhaust If i remember right. I will find out and get pics as soon as I go pick the motor back Hoping this week sometime. I plain to pull the head off to get them photos seeing that i didn't get to take them Before they started to balance the setup and put it together.And as many heads I have cut up in the past few yrs I'mnot sure just How much decking is there to cut the groove to start with. and Some people mill these heads as Much as .100 so That wouldn't leave very much left and Would surely endup cracking If it ever was to end up Over heated. cause I have seen this happen to more then one that has been milled .100 and it Sucked the head into the water jacket.

Hey Larry,

From one gearhead to another let me toss this out for your consideration:

As you know when it comes to modified and performance engines it's always about "the combination" That is to say, no one thing is the magic answer.It's how all the mods work in concert with one another.

You yourself have said that Lump porting an inline 6 head as your only mod will not achieve much. Does this mean that Lump porting doesn't work? . . . of course not. When it's done in "Combination" with other mods it will yeild big dividends.

Here's another example: Race fuel when run in a stock motor will typically hurt performance. Does this mean Race fuels don't work? . . . of course not. A stock motor usually does not have enough compression to support proper combustion with Race fuel.

I agree with you that making more than one change at a time is not the best way to test things . . . usually.

I am starting to think however,that this "Groove" modification may be one of those "Piece of the puzzle" type mods whose peak potential is going to be realized in how well it compliments and even maximizes other modifications.

I know I don't post here often so I hope you don't take offense to my input. It's just that,to put it simply, I (and I'm sure you too) have seen the following many times while modifying engines:

This + that = Crap . . . . . BUT

The same:

This + that + a few other thing(s) = Improvement!

Once again . . .It's ALL about "The Combination"


Anyway, JMO . . . for what it's worth !

'Crockett

the only Mod that is needed for the lump is to remove the Boss. But it is also true that by going to a larger valve will also increase the flow gain. and by the same token so will Unshrouding the valve stock Or other wise.
What i wanted to find out Is what Gain is the groove itself With OUT the increase in compression.
I know the theory behind it. It's not really much different then cutting a groove in a pop-up piston to get the spark/Flame to the other side of the dome. as the groove in the squash area is direct the fuel mix back to the flame or to induce a swirl effect in the combustion chamber, not much different then useing a ball cutter to under cut and unshroud a valve to induce a swirl this was done many many years ago i seen this back in the 70s when I first started racing. and It's not anything you see done to a head anymore either. This was the way the machine shop was to have done my head But for what ever reason He didn't or just for got to unshourd it. So now once i get the motor back I will pull the head and disassemble it to finish a cut around my valve guide and to make sure it was unshourded one way or another.And I may go back and raise the port a little more(ceiling wise).
And as for ur2cents we all have it LOL so no harm in adding it. Besides we all have to ,To find the answer we're looking for right.LOL

But something else I have to add, and is due to the factor of rasien the compression as with any combustion engine carbon is always building up and over time it to can require a Much Older motor to need a better octane fuel. But normaly this goes unnoticed because it's not enough change really to warrant it as with each fresh tune-up everything is always reajusted to account for the Age or any carbon build up that maybe going on.Again the old age trick there was to either dribble water or Tranny fluid down the carb to Help BURN off the carbon build up.I don't know for sure how well that really worked But Boy it sure did smoke for them few minutes.LOL But that to was the idea behind a water injection unit was to slow the burn down to make the burn more efficient. And to help improve the MPGs which I did try for a while myself back in the 70s. But i got tired of having to refill it,It never seemed to last as long as a tank of gas. And was always running out before my Tank did LOL.

[ Larry,
Crocket says it all, I was over simplifying to make a point, I hope it wasn’t offensive. Raising compression increases performance, plain and simple, to a point when detonation sets in. If the groove allows more compression then the two combined will allow more power to be made with out raising octane.

The groove alone provides benefits not found with increased compression. I have done this before, groove an engine with out increasing the compression and the performance improves.

The point is if you combine the groove with an increase in compression the true benefits can be realized. The two modifications work together to produce a result that cannot be realized with one or the other.

Hey Larry,

Just to claify the point I was making with my comment about Lump porting. I was making the point that if you took a Chevy 250 I-6 with 1 barrel carb, stock intake, stock cam, stock exhaust and stock ignition and did a Lump port head modification only . The gains would be barely perceptable due to the OVERALL ineffiecency of the Total engine package.

Increasing port flow, improving flow path and runner volume with Lump porting would likely be fruitless if the exhaust and especially the intake (1 barrel carb)were so highly restrictive.

Conversely,the addition of the Lump port modification to an engine that had already been modified with After market intake, larger or mutiple carbs, Headers, increased compression and an Ignition system would see a dramatic difference once the blatantly ineffiecient stock intake runners were modified with lumps to allow these OTHER modifications to realize their full potential.

I was using this example to illustrate that the benefit of a single modification cannot always be fairly judged on it's own individual "Play" but rather it's ability to contribute to the "Team effort" )

I realize that I'm likely just repeating myself but I wasn't sure you got my point about the fairness of judging any single modification on it's own without exploring it's ability to "enhance" other modifications.

Again . . . . it's all about "The Combination"


Automotive Breath said:


This is key bit of infomation in regard to the current discussion surrounding the issue of compression because as I see it grooving alone would decrease compression due to increased (minimal albiet) chamber volume.

Presuming the info Automotive Breath has provided is correct your question about the result of "groove only" resulting in increased performance has been answered Larry.

I find it interesting that although we are all in agreement that INCREASING compression improves performance, that it appears that the benefit the groove provides seems to out weigh the negative effect on performance that the DECREASE in compression resulting from the grooving operation (increased chamber volume) would usually net.


'Crockett

Earlier I posted pictures of SBC AFR heads; I have been running these heads for about five or six years in my Camaros.

I first had them on a flat top 355 that resulted in 10:1 compression. The performance was OK but not what I expected from a quality head, ¼ mile time in the high 11’s at 115 mph.(no grooves)

Later I swapped to a set of mini dome pistons that brought the compression near 11:1, performance improved, times in the low 11’s at 119. (no grooves)

After reading about Somender Singh I found his email address and asked him how to groove the AFR heads, the pictures are the result. One groove in each combustion chamber lowered the compression slightly, each groove measures 1cc. The result is something I have never seen before, an engine that struggled to idle before the modification at 1100 RPM now idles at 800 RPM cold. Fuel consumption is down, the plugs and oil run clean and the engine runs stronger than ever. High 10’s at over 122mph in my 67 and 10.65 at 124 in my lighter 68.

Over one year later I have grooved more than 15 sets of heads and have been contacted by numerous people from around the world. Still most people think it’s some kind of scam and don’t give it a second thought. I spent much of my time grooving more heads and figuring out what is happening inside of my engine.

To understand what’s happening it’s best to think of the negative effects of compression and squish. We know the benefits of the two but what about the negative effects. When air/fuel is compressed and pressures are rising due to the approaching flame front bad things can begin to happen. Fuel starts to separate from the air as it is squished tighter in between the piston and the head, under the right temperature and pressure it can explode uncontrollably. The solution has been lower compression or higher octane fuel.

When thinking about the effect of the grooves I read some one comparing it to the grooves on a tire. Run a slick tire on a dry surface and everything is OK. Add water and it gets caught between the tire and the road. The solution is to add grooves to let the water out.

So what does this do to my engine? The piston is coming up to the cylinder head and the flame is quickly approaching. With out grooves some of the air/fuel mixture is trapped in the squish area and goes unburned and is pushed past the rings (or explodes if conditions are right) Add grooves and the air fuel mixture is routed into the approaching flame front.

Can someone explain lump porting to me, the 300 head I pictured earlier is the first 6 cylender head I ported so I have little experience with them?

Twisted 6 (Larry) is the Inliners resident "Lump port expert" and moderator of this forum which is why I chose to use the Lump port mod to illustrate my point.

There are excellent cut-away pictures as well as discriptions of the "Bolt in" Lump Port modification on his "Twisted 6 Racing" website.

Here's a direct link to the article on his site:

http://www.t6racing.org/id2.html

Lump Porting has been discussed at great length on this site so do a search and you'll find info on several different types of Lump porting.

Enjoyed this thread Automotivebreath, I first read about the "Grooved" head mod on the AutoRacing message board. I believe you had input in that thread also. Very interesting subject.

Yes I understand what you're saying It's having the same effect (pretty much) as cutting the groove into a domed piston to get the flame to the fuel and induce the swirl in the combustion chamber. after going back over the other sites I see there is a guy here in Lake city, not really that far from me who has done it to his head.I was
trying to knock the topic. Just trying to understand it better. as for it only taking 1 cc thats not much at all or at least it doen't sound like anyway The groove in most cases I'm guessing isn't much more then that of a spark plug gap.
And as bad as Our L6 chevy head bolt pattern is It has me woundering If it could have any benfit in keeping the Head gasket in place Better while running the higher compression rates??????


AB.
as to the Lump port( I don't claim to be no Expert but thanks just the same) the idea is to Get the air thats not moving into a area which that is and ( the port also becomes smaller)And to change the way the air goes around the short turn radius.Which in turn also Speeds up the air Increasing the over all CFMs going into the combustion chamber even with the Stock size valve.
This is the effect it has on our chevyL6s as to what it would or could do for the Ford & Mopars I have no clue at this time. I have been how ever looking around my area for Donor heads (cracked, toasted BAD) to cut up and to look at to see where the water jackets are and to see if this is something that can be used for them as well.
but like most thigs it takes time and Testing. And as for myself Still learning and always will.
So maybe when I put my Old motor back together maybe this is something I will try just for the Learning if nothing else.Seeing all i realy need to put the Old combo back to gether is the Pistons
I still have the cam, Head Many Blocks (hehe)It would be intersting to see How differently it would run.
as for Less fuel Heck I'm all for that LOL seeing Racing fuel has now hit the 7.00 buck mark Over the Norm of 4.50 for who knows How many years.
but hey it's all good I have to hard feelings over any of this

I’d like to know if the gasket always blows out in the same area. Is it in the squish area?

As for cutting grooves an a head that has a deck thickness of 0.100” it’s out of the question, a failed deck is sure to follow.

On my suburban I shaved 0.050” off the head to get the compression to 10:1, the deck thickness was still 0.210”.

I cut the grooves 0.040” deep; meaning at the bottom of the groove the deck is 0.170” thick.

Suburban

Yeah AB it is always 99.9% of the time on that side due to the way the bolt pattern is. and for what i have seen it's mostly close to being Dead center. Because of this bolt pattern The head you could say seems to Float/Pushed up due to the HIGH compression Esp. If the block has not had studs Put in it. and even then after a certain
point/compression 13-1. O ringing the block is pretty much a Must do, This helps.

Have you tried this groove Less then.040 to see if it still works as it should?? Or is .040 pretty much the Min.

It looks like GM put the head bolts too far from the bore, well there’s not much you can do about that. You say “The head seems to Float/Pushed up due to the HIGH compression”. I wonder if it’s pressure, detonation or rather liquid fuel being trapped in the squish area that floats the head.

What ever it is I’ll tell you what I would do. Most people will tell you I don’t know what I’m talking about when I say this so take it like you want.

What I would do is to put a groove right in the middle of the squish pad all the way to the gasket to relieve the pressure. In addition I would open the piston to head clearance to 0.060” to 0.070” to keep from building pressure in the squish area. Compression will be lower but performance will improve.

With a 0.100” thick deck you have no choice but to put the groove in the piston, this you said you already did so you may have begun to solve the head gasket problem.

With the SBC we don’t see many head gasket problems, the condition you describe exists but with five head bolts close to the gasket it holds up.

I tried the groove with tight squish clearance < 0.040” and wide squish clearance > 0.050” and it works best with the wider clearance despite the compression being lower.

With the grooves we change the oil by counting the number of runs because it never gets black.

Well i see you have been to the web site. But Yeah it's a wide gap between Our Head bolts.
Part of the main reason I did teh fire slot/groove in the piston is to get the spark/flame front to the other side of the dome easier. I used to do this all the time On my Big&small blocks with pop-up pistons.
Well the first time i ran into this personaly I Burned .010 right out of the head ,Never hurt the block Only the gasket and the .010 groove into the head. much later after that I had changed the head from the 194 to a 250 bring the compression back under the 13-1 plus mark to around 12-1 Because at the time i didn't feel like Oringing the head.

I agree with T6, you can argue combination does X but how do you know the benefits of the groove, unless you test the concept?

Yea, I really like the lump porting, I have never seen anything like it. I think all of the older style heads could benifit from this modification. The factory didn't do a good job with the short turn in the old days.

Nope they sure didn't and OUR siamesed ports didn't help matters any either or having the Bolt Boss dead center in the ports. Pretty much anything beyond street use it really needs to go.

Inline 300 said:
I also have agreed with T6 that testing one thing at a time is usually the best way to test something . . . just not ALWAYS the best way.

I also provided examples of why testing and judging modifications individually does not always give the whole story or more importantly does not reveal it's greater potential.


Automotivebreath has claimed to have tested the groove modification "by itself" and found improvements. He has also supported my position that it will enhance other modifications.

As for "Arguing combination" there is no arguing combination . . . . . just ask ANY racer or engine builder anywhere. It's always about "The Combination"

Its always about the combination, the question is, should the groove be part of the recipe.


You have to test things individually, there is no way around it, unless you like spending money. Lets say you build X engine with the fire groove and X engine without, now if it shows no gains by adding the groove, your not gonna go to the time or trouble to do it again. Testing is a must.


You said it, not me.

O.K. . . . here goes

Inline 300 said:

And I have said:

So we are generally in agreement there.

Inline 300 also said:

So we are in agreement there also.


Although I beleive you intended it as a slight, you posted this:

Which only proves that once again we both agree on something: that Automotivebreaths claims should not be taken totally on his word, hence my intentional use of the word "claim".

We are in agreement on that issue also . . .


You continued by saying:

Here's where I disagree:

Maybe experience is the difference in our thinking.
A closed minded or inexperienced person would deduce that no gain (or negative gain . . . remember the race fuel example?) when tested individually means it's not a worth while modification and abandon further testing.

An experienced or open minded person would continue testing (Yes, at the expense of time and money) in combination with other modifications to thoroughly explore all the variables before rendering judgement . . . .

This is the whole point I have been trying to make throughout this entire thread !

Testing ALWAYS cost time and money so you better be prepared to spend alot of both before you even start. Unfortunately much of testing proves to be a waste of time in regard to positive results. If you're going to test some thing you have to be prepared to give it a fair chance to prove it's worth (at least that's the optimists veiw). I suppose if you're trying to knock something and quickly disprove it, you would give it a cursory test, proclaim it junk and bash it's developer.(this happens quite frequently)

If were not arguing "Combination" then apperently we're arguing for the sake of arguing. Since we seem generally to be in agreement on the issue of testing and I think I have supported and clarified my position on doing additional testing, I wonder what you hope to gain by being argumentative ?

Your veiws are welcome and it's certainly not my forum, that's not my point, but I don't think you've added anything to the thread. The point you made has already been agreed on by all of us including you . . . . .

I have been involved with this for over a year. First I had to prove the it work to myself using traditional “seat of the pants”, time slip & fuel consumption methods. Once I proved the value to myself; I went further by proving it to others by modifying their cars (just to be sure I wasn’t illusional). Convinced of the benefits I set out to determine how to document the value, I don’t expect people to believe me a virtual nobody. Like I said earlier:

“ If things go as planned I will be able to provide scientific evidence later this year”

This will come at a cost, before I jump in I will know exactly what I want to do and how it should be done.

Ok Before this does start to get out of hand And into any kinda bashing Or arguing . I'll lock the topic So lets Keep it clean OK??

Point taken T6, sorry things have gotten a little heated.

If we can get back on topic I would also like an answer to a question you asked in regards to carbon build up in the "Groove" itself.

Have you experienced carbon build up in the slot on your slotted pistons Larry ?

I would speculate that the velocity of the gasses moving through the groove might prohibit the carbon from building up.

Any observations on this from your experience Automotivebreath ?

No problem i just wanted to make sure we stay on Track here ( no pun)
As for the groove in my Pistons. I have Not had a problem with that in the past on any of the Vthings I've built But again Those were not daily drivers So They never got to see That Kinda Build up of carbon. Also The Groove On the pistons is Much wider then that AB is doing to the Head.
This will be the First time I have tried doing this to the L6 But it shouldn't perform any diferently. But It may. Reason I say that it may is because The High compression On the L6(I'll say on MY L6 anyway.)Is when i had my Big Blocks Built with 12-1 or more They Wouldn't Fire Up if the octane wasn't high enough. Were as when I was Pushing OVER 13-1 on my L6 it would fire up with just a Bump of the KEY But Don't ever try to turn it off Cause it wasn't going to Happen with Out Loading up the clutch and turning the key off.

Ever get the feeling your reply went over someones head?

Ah, never mind, you'll figure it out...

Best of luck

Crocket, First I would like to let you know that I appreciate your level headed approach.

My opinion is; preventing carbon build up in the groove depends on the groove design itself.

If you cut the groove too narrow [< 0.060”] wide it becomes crevice space, too small to support combustion, this groove will carbon up.

If you cut the groove too wide [> 0.125”] the squish velocity in the groove goes down allowing more carbon build up.

With my limited experience, I have not had a problem with carbon and I consider my old Holley nothing more than an organized leak.

O.K. Gentlemen, let`s get serious

Here is a overhauled 484 head that will go on my new 261.


Would this make any sense or is the chamber design too wierd?

The engine will not have that much compression (maybe 8.5:1) will I see benefits anyways?

Thanks, Frank

Man Talk about crouding the Valves. It's no surprize why that didn't flow very well to start with. What the piston look like??? is it a flat top? My biggest concern would be How thick is the deck surface of that head??

Serious, you bet.

What does the piston top look like?
How thick is the head deck?
What is the distance between the piston and head with gasket in place ATDC?

Pistons are flat top (can`t find 0.060 over dome pistons for a 261 and can`t aford to have them custom made)

Surface is about 0.59" where I painted the blue line.

What do you mean "crouding" (sorry I´m German)

@AB I go and check the piston distance when I have the crank back from the machine shop. But I think it`s about 0.40. The deck was milled just enough to make everything square.

The 0.40 is just a guess. Maybe somebody here knows the standard distance.

Frank

[ Larry and I must think alike, we ask the same questions.

Frank, don’t go by standard piston to head clearance, when you get the crank installed; install a piston rod assembly and measure to be sure.

What is the head gasket thickness, are other thickness available?

With over ½” head deck thickness you have options. Any reason why you wouldn’t consider milling the head to raise the compression to 9 or 9.5:1?

I like your proposed groove location, how are you planning to cut the initial groove?

How I do planning to cut the groove

I thought you would tell me that

I was thinking about a Dremel.

I had the head and the block just from the machine shop and they did milled the head and the block but not much and they charged me big for that.

I´m running out of budged for this project soon.
It already was more than I calculated.

So taking it back to the shop is no option.

I was only thinking because you said the grooves alone improve the engine.

Frank

How to Groove?

Mr. Singh claims a jeweler's saw and finished with a thin triangular file.

Must be some curious mech with a milling machine in your area if the sawblade sounds too risky.

Go for it!

What method do you use?

Frank,
I cut the initial groove depth parallel with the deck surface using a 0.080” ball end mill in a high speed grinder. The trick is to cut it in a straight line. I fabricated a crude fixture that assures a straight line is cut. As groover explained, Somender cuts the groove with a hack saw blade. I have seen others use a cut off wheel.

Once the initial groove is cut; the finishing is best done by hand. I have a set of small files to get the finished shape and size like I want it.

Frank,
The 235/261 are natorious for cracking in the rounded over area between the intake valve and the chamber. While your proposed groove location doesn't go directly through there, it is right at the edge of that area, so cracking may be more of a possibility than you think.

Second, it would seem to me that for this groove thing to be affective, it needs to be relatively centered in the squish area, but that isn't possible on these heads. Your groove is about 3/4 of the way over to one side of the piston, so I'm not sure how much is to be gained from it.

Lastly, how are you going to know if its done any good?