Singh grooves in cylinder head

[Twinscrew]

I have seen several references here to Somender Singh and his work. http://somender-singh.com/ Does anyone have first hand experience with these modifications. How about some of the professional head designers/porters that post here frequently? Has anyone done any dyno tests for quantification?

[Unkl Ian]

Should be able to find some info here:
http://speedtalk.com/forum/search.php

[automotive breath]

I have seen several references here to Somender Singh and his work. http://somender-singh.com/ Does anyone have first hand experience with these modifications. How about some of the professional head designers/porters that post here frequently? Has anyone done any dyno tests for quantification?

Twinscrew,

I have been involved with this modification for a few years. Most of my work is with Generation 1, 2 & 3 SBC engines although I have done an occasional Ford and Mopar. I have done high compression race engines, street performance engines even the engine in my tow truck, all experiences have been very positive.

I’m a cylinder head porter, not professional; what started as a hobby for me more than 25 years ago has grown into a sideline job; I cover my racing expenses by modifying cylinder heads.

This modification changes the combustion characteristics of the engine, the burn is more complete. This is very evident in the modified engines.

Here’s an example, I can take good running 13:1 compression 23 degree SBC running a camshaft with 280 degrees duration at 0.050”. Idle quality is acceptable with current carburetor technology and CD ignition but requires high idle speed. Unburned fuel can be found in the oil. Groove the cylinder heads and the engine dries up, the burn is more complete, the oil runs clean after dozens of high RPM runs. Idle quality is unmatched; I have never before seen a race engine idle at 500 RPM.

Another benefit of the modification is the engine becomes more resistant to detonation. I have proven this with N/A engines and have read of others that have done so with turbo charged engines. This is possibly the most important benefit.

[Twinscrew]

Thanks, Automotive breath. Is a large quench clearance necessary? Or can .040" be maintained with positive results? Futhermore, how much would you estimate static compression could be raised in a typical application with Singh grooves and still run the same octane fuel as before the modification. A half point? A full point? Just trying to establish some generalizations here. Not hard numbers.

[automotive breath]

.... Is a large quench clearance necessary? Or can .040" be maintained with positive results? Futhermore, how much would you estimate static compression could be raised in a typical application with Singh grooves and still run the same octane fuel as before the modification. A half point? A full point?....

The large squish clearance is not necessary, the benefits will be realized with the 0.040” clearance, I have run them even tighter with the piston touching the head at RPM.

I’m convinced that the engine will be more detonation resistant with the grooves and a wider squish clearance. This goes against most current thinking with N/A engines. I recommend 0.050” to 0.055” with the engines I’m involved with. The interesting thing is we are seeing improved performance and increased engine reliability with the wide clearance. It appears the piston is more stable in the bore.

There are too many variables to recommend a specific increase in compression ratio. This much I will say, if an engine is running on the edge of detonation and the only changes made are the grooves and raising the compression; a full point would be stretching things. I’m testing several combinations that I have not discussed; this opinion will likely change.

Twinscrew; is that like two turbos?

[Twinscrew]

Thanks again, Automotive breath.

Twinscrew; is that like two turbos?

It's actually a generic term for a Lysholm type positive displacement supercharger.


Automotive breath; is that like being a huge Jethro Tull fan? That would make two of us.......

[automotive breath]

...automotive breath; is that like being a huge Jethro Tull fan? That would make two of us.......

...He feels the piston scraping --
steam breaking on his brow --
old Charlie stole the handle and
the train won't stop going --
no way to slow down...

[Twinscrew]

Right on...... Back on topic though, lest we go on smearing shabby clothes. Who else here has exprimented with grooved heads.

[automotive breath]

..... Back on topic though, who else here has exprimented with grooved heads.

This picture was sent from an active member from Australia, I hope he doesn't mind me posting it, may be he will tune in.

[#84Dave]

Could the grooves be placed in the flat-top pistons, versus the head, and serve the same function? Could 3 grooves, spaced at an angle with the angle exits pointed toward/between the intake/exhaust valves, improve the quench function further?

Dave

[mpgmike]

I've done several grooved heads, both NA and turbo applications. 2 Saturns were raised 1 point from 9.5 to 10.5:1, both running 87 octane, neither activating the knock sensor (checked with a scan gauge) even at 20 mph 1/2 throttle in 5th gear. Turbo applications seem to be good for about 4-5 psi extra boost on same fuel.

There was an engine challenge winner that grooved his pistons (not flat tops, but domed) just about how you described. When asked what they do, he said, "I don't know, just heard they worked".

[automotive breath]

... Could 3 grooves, spaced at an angle with the angle exits pointed toward/between the intake/exhaust valves, improve the quench function further?

I have a friend that did this to his 383 LT1, three groves coming together between the valves. He now changes the oil after X number of runs; it’s almost as clean as the day he put it in.

He recently won the 2006 foot brake championship at No Problem Raceway.

[ACE]

automotive breathe- I read on this sight about the grooves and somebody was going to do some dyno testing with it , and I never saw any results posted. Did anything ever happen with that? In what type of application do you see this most benificial? From the picture, it looks like you are doing this with a 3" cutoff wheel in a die grinder. Is there a required width and depth, to be effective? How close to the fire ring do you get? Looks like it could weaken the head deck surface. Have you had any cracks in heads develope that could be related to the groove? I think there are some heads that are to thin of deck for it, possibly 062 vortec sbc! I would really like to get to the bottom of this subject, and I have a complete engine machine shop facility with Superflow dyno and flow benches, and over 31 years experience, but very limited time to waste. I'm thinking about building a high compression 400plus cid sbc to test this. I also have magazine connections, and am confident that some independent testing would be of much interest. I have read Mr. Singh's article, and am skeptical, but with open mind enough to want to see it tested back to back to back properly on old style heads and newer modern combustion chamber style heads.

[automotive breath]

In what type of application do you see this most beneficial.

Hi ACE, I will answer your other questions but I like this question a lot and will focus on it first. I have given this plenty of thought over the last few years and will try to give a good response.

1. Any engine that runs with poor combustion conditions.

Most engens produced more than ten to fifteen years ago can be included here. An engine with a large bore, open chamber, dome piston and a long duration camshaft that is run for any length of time outside of the indented RPM range of the camshaft is a good example; this would produce the most pronounced results. I wish I would have known about this years ago when I ran my 468 BBC on the street.

2. When running ultra light weight pistons and a minimal ring pack.

I’m serious when I say this improves ring seal, this would solve the GM 6.0L slapper engine problem.

3. An engine that has detonation problems.

4. When fuel consumption is a concern

5. An engine that is running on kill looking for that last bit of efficiency.

Four and five could be grouped together; the people at the top level may likely already have secrets that allow then to extract that last ounce of power or efficiency to set them apart the rest of the pack.

[Twinscrew]

Ace, PM sent.