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curtis73 said:
True, but in that context, EFI was around for about 15 years before it "caught on". Caddy, BMW, Jag, and some Japanese companies had EFI examples as early as 1974 and it was dismissed as complicated and that it wouldn't ever catch on.
And that 2 speed rear planetary of the 40s-50s,
and that overdrive transmission thingy of the 50s-60s that died out... called worthless because they "lugged" the engine.

Not to mention that 8-6-4 Caddy idea that resurfaced last year....... oh I did mention it. :spank:
 

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what peaked my interest in this subject was the claim that .50-070 quench was ideal for use with the grooves. this meant i could (i thought) use my heads without having to mill my block to get 040. which is ideal for non grooved engines. i.e. it was a fix: it would make me run better without spending money and use pump gas. i think that in the racing world, rather than try these grooves, people would be more inclined to do the machine work, match parts better, or just use higher octane race gas, change timing, and forget about detonation issues. i'm not saying grooves wouldnt work on a racetrack, because i believe autobreaths accounts of his work on racecars. but i do believe they work better at lower rpms (also illustrated by a-b's race results in a harder launching car), and will work to make less-than-ideal parts or specs for detonation better: as per EMC when he felt like his c.r. was too high for pump gas.

anybody think the same way on this?

(as for EMC using pistons out of the box, i would think the reasoning there is that the engine isnt going to be running long enough to get any carbon deposits just doing a few dyno pulls. and correct me if i'm wrong, but the guy in EMC who used the grooves placed second just a few points behind first. too bad he cant run w/o them and see if he wins or places third, we'd be done here)--hey wait! maybe he did? where's his number? right here:

BES Racing Engines
78 Harrison Brookville Road, Dept. PHR
West Harrison, IN 47060
(812) 637-5933 i called and LM. they are moving their shop. i asked if they dyno'd before and what improvement the grooves made. they may call back ... might not! they also are changing their number after the new year
 

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curtis73 said:
True, but in that context, EFI was around for about 15 years before it "caught on". Caddy, BMW, Jag, and some Japanese companies had EFI examples as early as 1974 and it was dismissed as complicated and that it wouldn't ever catch on.
This is true but EFI had to wait for the computer technology to advance to the point that is was feasible to control it in a manner that was mass-producable. The head-grooving thing, on the other hand, is a simple process that can easily be accomplished and tested.

tom
 

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The head grooving thing as a modification to existing engines should work... for some engines. It promotes turbulence which promotes better burning. I think we can all agree on the second statement anyway. On more efficient combustion chamber/head designs, there's already enough turbulence and the grooves will have less, and in a few cases no, effect. That's the plain and simple truth! It's not a mod that will increase efficiency enough on all designs to be worth the effort. That's why manufacturers haven't jumped on the band wagon -- they can improve chamber designs without grooves from the drawing board. Should be a great mod though. Just need to figure out which heads benefit the most from increased turbulence.

Obviously "older" heads will reap the most benefit, in most cases. But what's "older? Depends on the manufacturer for one thing. Pre LS-1 heads should benefit as far as GM, and maybe even LS-1. I doubt anything newer would benefit much, if any. Computer control makes a big difference too, as the computer fire the plug at just the right time compared to a distributor, which is more limited.
 

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bullheimer said:
(as for EMC using pistons out of the box, i would think the reasoning there is that the engine isnt going to be running long enough to get any carbon deposits

year

Dome contouring is not about "preventing" carbon buildup.

The carbon buildup is "caused" by incomplete or irregular burning....... which is what the grooving and contouring is trying to improve.

Radiusing domes/ contouring a similar purpose. Improving the flame propagation.

I would almost bet that if an EXACT repull could be done with contoured domes there would be a noticable power increase across the board. Maybe even a significant increase despite lowering of compression due to smaller domes.

If you look at the pistons shown, you will see that there is a significant and irregular carbon buildup for the short amount of hours on this experimental engine.
 

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farna said:
Obviously "older" heads will reap the most benefit, in most cases. But what's "older? Depends on the manufacturer for one thing. Pre LS-1 heads should benefit

.

Older engines that actually had some chamber quench area (closed chamber heads) usually had full dished pistons. Open chamber heads are moot.

Maximzing the quench between piston and head is the key. Any engine that has "some quench" should benefit. Those with reverse dome pistons should see benefits from grooving even though their maximized quenching is trying to acheive the same purpose = flame front turbulence to reduce detonation so higher compressions can be used.

If you study David Vizard about combustion chambers and turbulence, grooves absolutely have to help..... anytime.
 

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xntrik said:
In the second picture I see between that corresponding groove and the dome what appears to be a dimple that looks like someone with a hand held ball mill made an uh-oh. There also appears to be an irregularity in the edge of the high dome that might have been made by a "chuck" hitting the edge of the dome.

x
Looking more at these pictures and those available elsewhere, I see that the marks are there, but an optical illusion occurs and rather than that being a dome with the mark on the edge, that is actually the valve relief that has the irregularity. The valve relief is ajacent to the dimple, and a slip of the tool could have easily produced both.

I still can see no evidence that the piston was disintegrating.
 

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Quench If You Can

Quench It If You Can

.....the squish effect, wherein as the piston closes the gap in the quench portion of the head as it approaches TDC, the combustible mix in this portion of the chamber is rapidly displaced, creating combustion-promoting turbulence, speeding the burn.

.....as the propagating flame front expands, the pressure can get high enough to auto-ignite the end gas at the far side of the chamber. Since with a tight quench clearance,....the chances of auto-ignition (detonation) are greatly reduced.

.......An engine with effective quench will be more detonation resistant, and it is typical for surprisingly substantial improvements in torque to result from the more efficient combustion. Most builders consider .040 inch ...... to be an effectibve target for piston-to-quench-area clearance.......

Steve Dulcich
Winter 2006 (sic- Dec. 2006) Engine Masters Magazine p.23
 

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Discussion Starter #189
The cold of winter has limited my tinkering but I was able
to groove a couple of sets of BBC heads on the warm days.
The local track is open so hopefully I'll get some first
impressions from these soon.






[




 

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" If quench is so good at supressing detonation and allowing the use of higher CRs for more power and better mileage, why doesn't the factory make it tight to start with? In a nutshell the answer is emissions.

Tight quench..... causes unburned hydrocarbon emissions to go up.....
the trend has been to use a more open chamber with less quench area, but to make the quench action more active by tightening it up as necessary...

...optimizing quench clearance and quench area is something of a tight wire act done at the OE level and you may ask if we should worry about this (emissions) for our street machines? The answer is "no".

David Vizard, PHR magazine, June 2006, "Compression Comprehension", p. 85

spelling :rolleyes:
 

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I figured it's just cheaper for them to slap engines together as fast as they can, without having to worry about the pistons kissing the heads, so they spec everything so they won't even come close, except in the rare instance where the tolerance gods smile on some unwitting car buyer.
 

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okay so check this out: i have 8 eyebrow pistons. they have the usual four eyebrows on the top, but with a whole extra set above them. with all the highs and lows in these eight valve reliefs, should not, if this theory can imagine my valve reliefs as "grooves", my motor be able to get better combustion with these "always bad-mouthed" pistons? (and my open chamber heads). could be i'm sittin on a gold mine. buy the tooling for these monstrosities and sell the dog poop outta them.
 

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bullheimer said:
okay so check this out: i have 8 eyebrow pistons. they have the usual four eyebrows on the top, but with a whole extra set above them. with all the highs and lows in these eight valve reliefs, should not, if this theory can imagine my valve reliefs as "grooves", my motor be able to get better combustion with these "always bad-mouthed" pistons? (and my open chamber heads). could be i'm sittin on a gold mine. buy the tooling for these monstrosities and sell the dog poop outta them.
eight ????????
 

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71C10 said:
Yep... one for each cylinder. :p
He said........ i have 8 eyebrow pistons. they have the usual four eyebrows on the top, but with a whole extra set above them. with all the highs and lows in these eight valve reliefs,


OOOOOOOOOOOo......... :thumbup:
 

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71C10 said:
OK, OK, I'll admit this has been some interesting reading but...

I for one have a great interest in the theory of power production. Theory says this will improve combustion.



I'll miss ya buddy,,,,,,,, :(

send a note sometime....... let us know how you are...... sniffle
bye bye

:welcome:
 
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