Groove Results - Tried & tested

Please post results of tried & 'tested' results and findings from grooved volvo heads. Although results /findings will be subjective, it will help to show the general beneits /shortfalls of grooving.

Please avoid general comments & discussions or questions in this thread.

Posts from actual Grooved users only please.

General Discussion can be done here -
http://forums.turbobricks.com/showthread.php?t=66779

Bump. Did you make a post in ^said thread^ to get people's attention to post their results in here?

EDIT: I see you did, nevermind...

Why i tried the grooves.

People are probably getting a bit fed up with my ramblings but here goes.

It's a bit hard to describe the affect the grooves have to someone else, sounds like a fairy tale, no wonder people think it's bs, you disfigure your pride and joy with a file and it works better, yeah right, to the people who think it's bs i don't really blame you, it pretty much goes against any "accepted practise", i'd have rejected it myself but for the fact it was free, i'm also disabled, 2 strokes, not important except i spend at least 2/3rds of my time in bed, and that doesn't count nights, so i've got plenty of thinking time, my "quality time" is spent on family stuff but that still leaves a proportion of time when i tend to get depressed and fret on how useless i am, daft projects that don't cost mucho cash keep me occupied and when they work lol, give me a feeling of accomplishment just for having done it myself, so if anybody was wondering why a fairly sensible (or as my wife puts it "senile") brit would be willing to destroy a perfectly good volvo head, now you know.

The 2 groove head i did was supposed to be text book somender singh, 1 groove pointed at the plug from the squish area aligned between the valves, i had a spare k-jet head that was no use to me so used it for test purposes, i tried a couple of powered ways of cutting the first groove with varying degrees of disaster, hence the triangular file, i realise it cut the grooves a couple of mm to wide at the top, the file is far bigger than i'd recomend a fit person to use but because it was large it meant i could slowly do the job myself, there seemed to be a sizeable squish area alongside the plug and on reflection decided to put a smaller one there as well, no scientific basis for it at all, it just looked right, a quick rub with a brass brush and on it went, i didn't even clean the plugs, if the grooves were going to work they'd do it in spite of me, not because of me.

First impressions were pretty underwhelming, what you don't realise is that you can now drive your car like a diesel but it takes a while before your brain registers the fact that 30 mph in 5th is quite normal for a grooved head, just the job for pootling around in traffic, that's one of the problems with it, your car won't sound the same or drive the same, it's much much smoother, it's quieter and sounds more like a six than a four, the volvo harshness has gone, it's somehow more refined.

I couldn't get it to ping/knock even at 30 degrees advance, i had to advance it that far with the engine running to get it to start, the kick back is wicked anything past around 23 degrees, we finally had some 90 degree weather and i got a slight low ve ping at 30 degrees, obviously i only advanced it that far to test knock prevention.

I had to lean the carb out after doing the grooves to get the tickover down, this made no difference to the actual running of the engine, the carb was brand new when i bought it 6 months ago and had new jets etc for a 2.3 as it was off a b18/b19?, i'd estimate, and i've run the grooves a good while now that fuel economy is up 10% at least.

My wife likes it, i'm in the process of teaching her to drive, the grooves make it virtually stall proof, great for a nervous learner or a bloke with a gammy leg.

the grooves actually call for having the c/r raised or turning the boost up to realise the full benefits, all my tests were done on 95 ron unleaded, i think thats about equivalent to 88 ish american, it's normal supermarket piss anyway nothing special.

Tickover = idle, there is no idle adjustment left on the carb so the only way i can get it down is by leaning the mixture.

95 ron is the europe wide standard for ordinary petrol, 98 ron is the better stuff and the race petrol is about 110 but thats also leaded.

Les said:

I had to lean the carb out after doing the grooves to get the tickover down,

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Probably a british English vs what the rest of us speak issue , but what do you mean buy ?tickover? or ?get the tickover down??

the grooves actually call for having the c/r raised or turning the boost up to realise the full benefits, all my tests were done on 95 ron unleaded, i think thats about equivalent to 88 ish american, it's normal supermarket piss anyway nothing special.

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They don?t really translate, since our rating is an average of 2 different ratings could be anything in a rather wide range over here and vice versa. Might be more useful if you guys do something like regular (87 R+M/2), plus (89 R+M/2) and premium or supreme (between 91 and 93 R+M/2 depending on area). In some places you can also buy an economy which is 86 R+M/2 (don?t know of anything that it is actually recommended for), and in some cases you can also buy 94 (getting rare), without getting into race gas

tickover=idle speed.

the lower the number for brit "piss" = lower number US. Piss

not bad!

Ok seems to work

Nice power from 2400 RPM

This is my efforts.
I you look closely, in laymans terms the grooves also coincide with the unburnt leftovers on the sides of the squish areas, that shows even after a head clean.
This then visually seems a sensible option!

My car was running great pre-mod, and now is also running and SOOOO quiet.
Fuel efficiency seems the same though, although I should have monitored it better pre mod.
Whos getting what fuel consumption in UK MPG?

you guys should index your plugs while the heads are off...

PetesDustyVolvo said:

you guys should index your plugs while the heads are off...

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You don't have to have the head off. If you want to waste your time indexing an enginen you mark the outside of the plug relative to the ground electrode. And it is only useful for race engines that would otherwise knock the gap closed.

mikep said:

You don't have to have the head off. If you want to waste your time indexing an enginen you mark the outside of the plug relative to the ground electrode. And it is only useful for race engines that would otherwise knock the gap closed.

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Can you explain "knock the gap closed"

xwave said:

Please post results of tried & 'tested' results and findings from grooved volvo heads....

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xwave, I haven’t grooved Volvo heads only because I don't know anybody that has one, but I'm looking. I couldn’t resist posting anyway.

Over the last two years I have grooved heads for more than twenty engines, I lost count. Most of these are performance or race only Generation I, II or III SBC. At first the results appeared to be rather vague, until I realized what was happening. The best way to describe it is: this modification improves the quality combustion to a point that it changes the characteristics of the engine. The limits of the engine are altered, the modification allows higher compression with out detonation, lean burn and ignition advance limits are changed and warm up periods are reduced. Fuel enrichment functionally can be reduced or eliminated completely.

Most of my work is on drag race engines designed to operate in 5000 to 7500 RPM range. The camshafts provide long overlap periods that can ruin idle quality and low RPM power. This modification restores the idle quality and power. This is a big plus for people that operate engines outside of there designed RPM range.

Additional benefits: oil & plugs runs cleaner, quit smooth engine operation under heavy loads at any RPM, engine runs cooler, reduced fuel consumption; I have seen reductions as high as 30%

Some little known facts:

The 2005 Western Canadian motorcycle championship was won using Somender’s multi groove cylinder head; the bike could not be beat leaving the starting line.

The driver winning the largest overall purse at No Problem Raceway in 2005 ran a set of heads grooved by me using Somender’s single groove layout.

Boris740 said:

Can you explain "knock the gap closed"

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On some race engines dome pistons are used to raise the compression, these domes are so close to the spark plug that reliefs are cut in the dome. The plugs are then indexed to prevent the piston from hitting the ground electrode.

The concave relief at the bottom of the piston is for the plug.

mikep said:

You don't have to have the head off. If you want to waste your time indexing an enginen you mark the outside of the plug relative to the ground electrode. And it is only useful for race engines that would otherwise knock the gap closed.

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good to know. it only takes a second when you have the head off... i've done it both ways and it doesnt take very much time.

I think what Mike's point was that indexing plugs is only worth doing if your engine's design will make the piston come into contact with the plug, should you NOT index them.

klr142 said:

I think what Mike's point was that indexing plugs is only worth doing if your engine's design will make the piston come into contact with the plug, should you NOT index them.

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and thats why I said "good to know"

Gotcha, . Now, with all this discussion, when I put on a head, I think I'm definitely going to be playing with these grooves...

automotivebreath said:

On some race engines dome pistons are used to raise the compression, these domes are so close to the spark plug that reliefs are cut in the dome. The plugs are then indexed to prevent the piston from hitting the ground electrode.

The concave relief at the bottom of the piston is for the plug.

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Ahhh.. I guess the screwing around with heat range could be troublesome.

Boris740 said:

Ahhh.. I guess the screwing around with heat range could be troublesome.

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Hard core race fanatics do what it takes, indexing plugs is just another pain they put up with. It has been realized the huge domes are a obstruction to flame travel, Somender?s grooves help to get the squish action over the dome.

The trend is to downsize combustion chamber volume, eliminating the need for the dome. With a flat top or dished piston, indexing the plugs is nothing more than "a good way to spend some time". Maybe a little something there but it's hardly worth the trouble.

Hi automotivebreath,

Thanks for your input.

Good to hear theres a few people who are willing not only to groove many heads, but are of the firm belief that its a positive move, and worthwhile in professional applications.

This thread was primarily to avoid questions from non groovers, but to give groovers and non groovers alike more 'hard' facts, +ve or otherwise to help them form their own conclusions, and decide whether they should get grooving! Thanks for your info.

xwave said:

...Good to hear theres a few people who are willing not only to groove many heads, but are of the firm belief that its a positive move, and worthwhile in professional applications....

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Not only has the modification worthwhile but it has proved to provide a fix to common problems of the the ineffecent design we call the internal combustion engine. Detonation, pore throttle response and lack of low RPM power are a thing of the past.


Here are details of one of my current projects.

I'm helping a good friend with his 1965 Corvette race car. It has a Generation II SCB from the late 90s, bored and stroked to 383 CI. Electronic fuel injection with a mix of production and aftermarket parts. The heads are a production piece ported and grooved.

The car has been 9.90ET in the 1/4 mile; it has reached the limits of the production intake manifold and valve sizes. Next step will be to fabricate a dual plane/dual throttle body intake manifold.