Somender singhs groove theory tried.

There are some good photo's on somenders site that show the burn pattern extending right into the squish area, is this normal?, i'm out of my depth regarding burn patterns etc.

Wow!- I was waiting for somebody to do this. Mike H.(740ATL) and I were just talking about this yesterday. Keep us updated- I have a 530 head I wil try this on a B23ft.

Maybe a dyno run before and after would be in order.

this is awesome. I have been wanting to do this as well. Im glad someone took the plunge. Now... everybody get to cuttin!

I feel like picking up a spare 530 head now...

Volvo combustion chamber

I got this photo of a Volvo combustion chamber from a Bilsport article posted here. See those divots in the side of the chamber? Used to create turbulence for a better burn is what I was informed they are for by folks here on the board. Putting in a turbulence causing area is probably something manufacturers have used for a long time.

Hope the experiment works well for ya Les.

I'm wondering if these grooves will fill up with carbon-deposites...
anybody got info on that?
I'm curious to see what a combustionchamber will look like after lets say 100000miles of use.

Janspeed said:

I'm wondering if these grooves will fill up with carbon-deposites...
anybody got info on that?
I'm curious to see what a combustionchamber will look like after lets say 100000miles of use.

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Go read Somender's site. There is also a Popular Science article on this topic as well.

In short, the answer is no.

I wonder if the plugs should be indexed a certain way for this mod or maybe it doesn't make any difference how they end up.

Indexing is only necessary for piston clearance if the electrode would get damaged otherwise.

So this will improve flame traven into the quench areas, I understand that. BUT it also has the potential for creating hot spots on the flame ring of the HG. Also, were any of these heads you guys are grooving sonic checked first to be sure that you don't groove it and find out when you run it that you are too close to a water jacket?

It's a great idea, but I will let you guys be the guinea pigs. If it works, I will be doing it too.

There are pictures of modded heads after 6 months on somenders site, people who are interested should go and read the posts and look at the many photo's, i'm not treating this head gently, apart from a few runs up hill at 1000 rpm in 5th with stupidly advanced timing in a vain attempt to induce knock, don't forget theres no computer or knocksense on my car just a points centrifugal dizzy and a carb, if it knocks i have to lift my right foot to stop it.

As far as i'm concerned and for what i wanted to achieve, which was a reduction in detonation or better resistance to detonation, whatever you want to call it, it's a winner for me, i can't go the tight squish route because i simply can't justify spending that amount of money on machining etc for what is in essence an interesting project, i have no interest in driving my car really fast, with my level of disability it would be stupid and dangerous for me to try, i'll go to the concrete jungle (a grotty place but theres 14 salvage yards in 1 area ) and see if they've got a scrap 530 or 531 cheap and put a hacksaw through it to check the thickness ( well my 19 year old son will hacksaw it, handy things sons lol ) thinking about it, suterman has just changed to a 531, i'll pm him and see if he's still got the old head, can probably show the little un's the steam trains while there.

I just read Singh's website, i think the idea is good.

if I ever need to take the head of I'll put the grooves in. I might even do it this summer just for the fun of it.

Regarding the picture of the (530?)head:
- I think the grooves need to be at 1 certain continious width and depth over the total length, otherwise the squishjet will loose speed when the groove gets wider. (more space = pressuredrop)
- I also think the grooves should extend all the way to the edge of the cilinder(the projection of the bore on the head that is) so as to also pressurise the ringlands with the squishjet, improving sealing and blowing fuel out of these tight spots.

I don't know if uneven pressure on the ringlands would be really such a good idea. You'd be creating one pressure spot for each groove.

How long has this idea been around?

Long enough for car makers to buy/adopt it, if it were really any good?

badvlvo said:

BUT it also has the potential for creating hot spots on the flame ring of the HG.

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Well, you aren't the first to echo this concern, but so far that has proven to not be the case. And not talking about what Les has done, but others like mpgmike and automotivebreathe over on the mpgresearch board. Mpgmike is doing heads for customers (he's done a considerable number) on all kinds of things (even a VR6) and to this point the performance has been favorable.

badvlvo said:

It's a great idea, but I will let you guys be the guinea pigs. If it works, I will be doing it too.

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I was planning on doing some testing with it. It was going to include a dyno pull with the stock head and M cam to get a baseline as well as mileage info. Then a grooved head with an M cam and another mileage test. Hopefully one of us can post some more details of what we've found.

Cheers

I haven't looked at all reports, but the only slightly scientific dyno evidence (unskewed by a truckload of other mods done at the same time) I saw on the whole site shows fairly wild changes in power ; more down than up... and economy up only marginally.

http://somender-singh.com/content/view/12/37/

Now of course this isn't exactly your average car engine, but color me skeptical for now, however nice the story might sound. Eagerly awaiting BDKR's results.

Janspeed, my thinking was that the squishjet as you call it, would be a sort of progressive collection starting at the piston wall and collecting more or less the complete length of the groove,if the groove was 1 depth for it's whole length, wouldn't you get a faster but less sustainable jet, i can't see the point in going to the edge with the groove, the piston wall is a massive quench area, on the burn pattern photo's there is no burn at all next to the wall (i'd be worried if there was ) and after doing it i began to wonder if i should have made them shorter.

Anyone got any theories about how the combustion pattern is altered by the groove, maybe the jet hitting the plug area divides after hitting the wall so you get 2 burns, 1 each side of the jet, there are so many plausible sounding theories about combustion it's impossible to pick a clear winner.

If the thickness of the deck proves to be ok, i shall mod my other head and change them, so if anyone wants to try this, who's not too far from the midlands uk it'll only cost you a tenner for the head gasket, pointless fitting an expensive 1 for how long it'll be on, my advice to anyone is don't try this on your expensive ported etc head, you might not approve of the effects, try it on a throwaway head first, you can always pass it on afterwards and share the cost, it's great that theres so much genuine interest in this, there's not really a proper way to do a volvo head yet, we haven't got as much squish area as other heads so we are not going to see as "much" effect, trouble is our heads are a pretty efficient design to begin with, so i was very surprised and pleased to get such a noticeable transformation.
regards les.

web7 said:

I haven't looked at all reports, but the only slightly scientific dyno evidence (unskewed by a truckload of other mods done at the same time) I saw on the whole site shows fairly wild changes in power ; more down than up... and economy up only marginally.


http://somender-singh.com/content/view/12/37/

Click to expand...

You can't use only one or two of the examples and begin to get a complete picture. The majority are reporting big differences in idle quality, oil cleanliness, noticeable improvements in torque, and mild improvements in mileage. On that last point (mileage), most have not made the changes in ignition timing to really take advantage of this mod. Without doing what is at least recommended by the inventor, how can we arrive at a clear picture?

If you want more information, you really need to go to the mpgresearch board as there is more conversation over there on the topic.

If you notice also, some of the discussion in this thread has been about altering ignition timing. With any luck, Fred can pull something off for us non MS guys.

To be honest i think that anyone looking for this to be a "power" mod are not going to be pleased, it's a means to an end, yes you get more low end torque, i can now drive in traffic at 30 mph in 5th instead of waiting till i was doing 40-45, i have had to lean my mixture setting to get it to run the same, but as far as a difference in power goes, i haven't noticed a difference really, but then again it's a difference between a 531 that i'm used to and this modded 530, i won't know for sure until i mod the 531, and even then power is a subjective thing and i for 1 am not going to be making any claims unless they are obvious to me.

Your supposed to have the head skimmed at the same time as doing the mod, the better detonation resistance means you can run higher c/r without adverse effects, this is probably where the extra power comes from, sorry i'd forgotten as i did it for my +t so i can run more boost.

LOL, the power will take care of itself once boost is raised. Wouldn't really expect power gains from this.

Thanks for doing this Les. Good job.

Was pinging a problem for you much before the mod?

Quick someone try this on a boosted motor.

Pinging was not a problem below 16-17 degrees advance, i normally run 10, i saw that it was claimed to improve detonation resistance, i bought a 740 gle wagon/estate for the interior, trouble is the bloody missus preferred it to my old rusty gl w/e so now i've got to put my engine and box into that, that left me a good engine to mess with so i thought i'd have a go at the grooves, so far the claims made hold up pretty well. les

Edit Pinging was only a problem at high load low ve