I've looked for a picture of the Michael May designed 1982 Jaguar "May Fireball" combustion chamber and haven't turned it up on the web yet??

Anybody know of a link to a picture of it that is online??

pdq67

Gee, I didn't spell the title very good.......

Sorry about that....

pdq67

I have never heard of it before. What makes you want to see a picture of it?

What is special about it is that it allowed compression in the 12:1(?) range on pump gas. Very efficient design. Sorry, no pics.

Thomas

Line drawing is the best I can do at least for now.

http://www.chevelles.com/showroom/Schurkey/JaguarFireball.jpg

Is it just me, or is the Jaguar head VERY similar to what "the old one" is doing with his "soft head":

http://theoldone.com/articles/The_Soft_Head_1999/

The part I don't understand about the Jaguar head: The original head was like the 348/409 Chevy-FLAT! The Jaguar 326 V-12 was a PIG for fuel economy, and quite frankly, wasn't that great for power, either. The "HE" High Efficiency (May Fireball) head upgrade in July '81 helped, but even with outstandingly high compression, fuel economy went from "ABYSMAL" to merely "BAD". Power improved, but not like you'd expect.

Man, I'd love to have one of them to play with!

Thanks for the pic again..

I have looked into this stuff out of curiousity a couple of times and have found that it seems the British were using some vertical valved and ported heads along with small diameter pistons that had only perimeter quench.

Seems for the times they worked pretty good but I don't know if it would be so today or not??

Now I can see why the old stock F-Head engine that was in my second '52, Willis Aero Eagle H/T car was said to have a very eff. head on it b/c it had the exhaust valve in the block and the intake valve in the head and they formed a combustion chamber like the May head has.

I think the three valve '89 Honda Accord head is kinda like it too.....

I always wanted to install a pair of 409 "W" motor flat combustion chambered heads on a 454/468 motor and then use pistons that have a figure-8 combustion chamber in them just to see what would happen??

Shouldn't be all that much of a hassle to try at least to me, that is....

pdq67

Ttt,

Try this link if you want to take the time to read about what Toyota, (TOO),has worked on in the past.

http://www.theoldone.com/archive/nitro_on_engine_techology.htm

This falls in line with my questions about the Michael May Jaguar heads combustion chamber design.

The part that gets me is the 16 to 1 CR. the chamber could operate at and not detonate!

The chamber had a flat, (i.e., perpendicular to the piston head), intake valve placement like the old 348/409 head, but had a regular combustion chambered exhaust valve and sparkplug so that all the air/fuel was squeezed from the intake side over to the exhaust sides combustion chamber!!

I have a sneaking suspicion(Sp?) that the old Chevy stovebolt 235 straight-6 head is kinda made this way but I can't find a pic. of it to verify it?? But the 235's head still has some combustion chamber under the flat intake valve.. I THINK??

Good reading to say the least..

pdq67

pdq67, I think the Fueling head with the figure 8 combustion chamber is sort of like what you are talking about. It has a very small, nearly flat chamber that gives you about 12-1 compression and will tolerate 87 octane gasoline and make decent power. I don't know if it still being produced since his death though.

Ok, I dug this one up from the Graveyard--but there's a great picture of the head and chamber as part of an auction on eBay right now.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=ADME%3AB%3ASS%3AUS%3A1&viewitem=&item=120085310612

I've always felt that the 348/409 pig motor head was under-utilized. It had the advantage of most of the combustion chamber being in the piston, thus allowing accurate sized and shaped chambers. The down side was heavy pistons. Still would make a good street engine, and possibly a good fuel engine if some of the quench was removed. (But it ain't a hemi) Dyno Don's 409 ran well. About 9 flat on gas in a 2400# car. Not competitive with a present day 350 SB, but Dyno's combo was conservative for obvious reasons.

Some did use the 409 heads, they put 454 cranks in the 409 block and came up with 482 or so I believe. Jahns made the pistons IIRC. Took a little machining but there were more than few of these ran by different people. Now the blocks and heads are worth more to originals than to hot rodding. Maybe PDQ remembers these.
Jeff

Schurkey,

GREAT PIC's!!

Thanks for digging this up!! And Smoke and Kirk too.............

The May head is zero angled!!! And I figure that it was PROBABLY the very first "fast-burn" head!!

Remember what I said about the Brit's using vertical valve heads with small bore cylinders and not much quench ring b/c the chamber was in the piston, well the opposite is found in the May head b/c it's chamber is right in front of the intake valve with i figure a flat-top piston OR one that has the dome right under the intake valve only!!

Neat to say the least!!!

Smoke,

About the old 409's, After I got my 409, I found out that our BB crank's could be cut down to fit so I picked up a used forged 396 crank w/ a bad pair. of rod journals for $10 to stroke my .060" over 409, but didn't have the money or know how to do it back in '73!! I still have that crank out in the garage..

If I had, I woulda had a 451.7"/409" engine...............

pdq67

Actually, the chamber is around the exhaust valve on those Jaguar heads. But your point is taken--the chamber is very small, produces very high compression ratio, and it's very "concentrated" so the flame front doesn't have to travel far.

Frankly, I think this should have worked better than it did. I wonder if Jaguar screwed the pooch on the ports or something. All I know is that folks complain about having terrible fuel mileage, and the published HP specs don't show anything special going on.

I suspect a hot rodder could find a lot of extra power in that engine.

Thanks for the pic again..

I have looked into this stuff out of curiousity a couple of times and have found that it seems the British were using some vertical valved and ported heads along with small diameter pistons that had only perimeter quench.

Seems for the times they worked pretty good but I don't know if it would be so today or not??

Now I can see why the old stock F-Head engine that was in my second '52, Willis Aero Eagle H/T car was said to have a very eff. head on it b/c it had the exhaust valve in the block and the intake valve in the head and they formed a combustion chamber like the May head has.

I think the three valve '89 Honda Accord head is kinda like it too.....

I always wanted to install a pair of 409 "W" motor flat combustion chambered heads on a 454/468 motor and then use pistons that have a figure-8 combustion chamber in them just to see what would happen??

Shouldn't be all that much of a hassle to try at least to me, that is....

pdq67 I really don't think it would work. The 409s block has an angled deck and the combustion chamber is in the piston. One side of the piston is thicker than the other and probably has balancing issues. The Rat motor has been a continual evolutionary engine and is better now than ever before with all the aftermarket stuff out there. Future better designs are coming in the form of the LSX engine platform.

Sorry Schurkey, I had the valves backwards in my pointy little head!!

And thinking about this a bit more, I have a funny feeling that the early MOPAR single rocker shaft Poly 318 type engines were somewhat like this BUT I again haven't been able to get a GOOD pic of their chamber shape???

I figure you are right and it probably is just a port angle deal is all that needs to be addressed by straightening them out so it flows better, in and out!!

I figure they both need to be at like at least a 45 degree angle if not a 60 degree at the bowl/port "corner" if you will vs probably their darn near a 90 degree corner/bend, BUT not holding a head in my hands, I am just guessing..

And right, my '52 Willis intake was in the head and it's exhaust in the block and it had the chamber around the exhaust with the intake flat against the piston top..

Thanks, Thanks, Thanks for this info...

Maybe somebody needs ta tool up a SB MODERN version of the May chambered head..................

pdq67

PS., I figure the terrible fuel mileage was just b/c it was a high rpm hi-po 12 cylinder engine is all...