I do detonation testing mainly at the race track with the aid of a lighted
magnifying glass designed for plug reading. I test with aviation fuel to
assure consistency. I started with too much compression for the fuel
in use and ended the testing when I could no longer get it to detonate.
Further testing will require either a lower grade fuel or more cylinder
pressure.

I don’t consider the impact the grooves have on air flow to be significant
enough to make a difference. Some high level people believe the grooves
may affect wet flow during the intake stroke; eventually wet flow testing
information will become public.

IMO one of the primary benefits comes from evacuating the squish zone
both ATDC compression and exhaust. One of the advantages of having
the grooves discharging towards the exhaust valve could possibly be
improved squish zone evacuation at the end on the exhaust stroke.

Curtis, Let me know if you need recommendations.

Yep, JimFulco is correct.
The square bosses in the chambers are used for machining setup. Also the round flat boss on the intake manifold side of the head.
If you look at a brand new set of heads you can see that the end cylinder's square bosses and the round flat on the intake side of head have a slightly burnished spot on them from being clamped onto.
That is the spot that the raw casting is clamped onto to begin the machining.
The older heads used that spot at the spark plug.
have fun,Smokey

Recommendations??? Heck, I'm gonna show up on your doorstep with the heads and bat my eyelashes to get you to do it

I will be picking your brain, thanks.

The old eyelash trick won't be needed, one day notice before arrival
would be great.

Regardless of how the square boss is used during the machining process, the
primary benefit is to move the spark plug to a more central location to
shorten burn duration.

The method GM used to relocate the plug with LT1 heads is more desirable.
This relocated the plug and increased the squish to bore ratio resulting in
reduced detonation tendencies and higher production compression ratios.

JimFulco and Yekoms

Thanks for the info. That is interesting.

More interesting is the fact that some of the turbo 4 cyls have similar notches and bumps for swirl.

Ricer 4s is not what I am used to seeing, and I bet you aren't either.

I bet I can actually learn something from those guys getting 600 hp out of 2.5 liters.

Yes, it is true. I sold cutting tools to all the engine plants and saw first hand that those squares are for location of the head while machining. Makes you wonder sometimes about all the little things we worry about when planning an engine and the factory does stuff like this.

Here's an article that states 5% power gain from increased turbulence as a direct result of piston crown alteration.

http://www.chevyhiperformance.com/t...learance_guide/

http://www.rbracing-rsr.com/Pistons.html

These links were posted by Hippie
http://www.hotrodders.com/forum/qui...ons-109550.html

Hi xntrik,
Yesterday Bart Jr. was running his dad's flat top 383 with these grooved
edelbrock rpm 64 cc heads in his Nova at the Mardi Grass drags. Best time
was 11.13 on Exxon 93 octane pump gas with a conservative tune up.

HI AB,

I was wondering how he was doing so far.

Did you and Larry at Abbeville get to do any dyno testing yet?

What ever happened to Putz-Jesse up in ND? Maybe too early, still snowed in. LOL 73* here.

x

xntrik,

I hear there is some groove testing going on on the west coast, they are saying
someone paid for a two week dyno session. I'm not involved so I don't have
details.

The reason I'm still heavily involved at home is people keep bringing heads
for me to groove. I'm working on a set tonight for a blown SBC. The heads on
Bart's engine are are of much interest to me because I developed the groove
layout and I what to see how much compression they can handle on pump junk.

I bought a 5.3L Chevy Pick up for my next project, something different. My goal
is 28 MPG. Hopefully I will be able to provide details this summer.

Hello Hotrodders. I'd like to contribute my experiences with the Singh grooves.

Recently I've modified an Opel Calibra motor. Engine is an EFI 2 litre (122 cid) inline four, SOHC two parallel valves per cylinder, bathtub chambers with a small dish in the piston below the spark plug. I got a scrapyard guinea-pig head, milled from 10.0:1 to 11.0:1 and cut three grooves per chamber aimed at the spark plug.









The results have been very positive. Engine started at first touch of key. Now sounds and behaves like an inline six of greater displacement, smooth and torquey. Acceleration time from 40 to 100 mph in fourth gear shortened from 21.5 secs to 19.0 . Can lug it uphill from low rpm in high gear and pulls firmly. Oil and plugs remain clean. No noticeable detonation with 98 RON/88 MON (~ 93 AKI) gasoline. Fuel consumption has been improved a 15-18%.

Hi Telvm,
It’s good to hear you are having success with your Opel, nice
tidy work!

A simple modification that results in improved acceleration combined
with a 15-18% reduction in fuel consumption is outstanding.
Especially when you consider the cost of fuel in Spain is double
what it costs here in the US!

Is 11:1 compression normally a problem with this engine design,
does this normally bring on detonation?

Another question I have is have you done any tuning after the
modification or rather are you running the stock tune?