Expansion Chambers for DMH

[PETEG]

PAUL
In the 70's Quincy built me a set of 3 pipes for my 60 in 6 cyl deflector merc which used water injection, but did not slide. I thought they worked in an absolutely fantastic way. This seems to be contrary to your dissertations. Am I dreaming when I say "they worked" ? Please straighten me out!
PeteG

[Morris85C]

Take your chamberd moter an go test it get a speed reading an a tach reading then put aset of L.S PIPES on and do the same thing with them and you will find out the answer. THE CHAMBER ARE SLOWER.

[sam]

Lon's pipes are the only ones I've tried that made me do a significant jet change

I wonder if he still has the tooling and if someone (like Ron Hill maybe) could charm it away from him to make some more ...

Otherwise I'd have to give Ron an elbow and let him cut it in half and make copies

[Morris85C]

Dcrabtree bring your 40ci boat with chambers to the nats in 2008 i will bring my dmod rig and we will see who is faster. If you win i will buy you dinner.

[Bob Dunlap]

Nothing is better than the sound of a 6 cylinder Merc with Megaphones. BUT It only takes ONE resident living on a lake who doesn't like noise to stop boat racing if they complain. I have been to city council meetings where one resident complained and we had 20 people there who supported boat racing and that one resident out weighted our support because they were resident property owners.

The chambers are definitely faster if you take time to get them right, a chamber that doesn't work is no good. When I was running the Hot Rods I had to make 21 chambers for my Hot Rod before I got it exactly right and then it was great. I have the Turner program and have memorized Gordon Blairs book and other books on chambers but they are not always exact for the deflector motors. It takes a lot of hard work and testing.

[nbass]

The chambers are definitely faster if you take time to get them right, a chamber that doesn't work is no good. When I was running the Hot Rods I had to make 21 chambers for my Hot Rod before I got it exactly right and then it was great. I have the Turner program and have memorized Gordon Blairs book and other books on chambers but they are not always exact for the deflector motors. It takes a lot of hard work and testing.

Care to share what you discovered worked and why?
Neil

[mr2boats]

Another book available if you can find

There is a book out there it is called "Whatever makes your 2 stroke stoke" I have looked for the copy that Bob Thornton gave me when he used Expansion Chambers on his Jamaha (Antique Johnson PR nad Yamaha Motorcycle Cylinders with the fins cut off with a pair of chambers on it,I can remember alot of reading on where exactly you want the sound reversion in the tailcone to reflect waves back to the cylinder to burn any unburned residue to make more power,the Johnson PR was on the same wave length as the Mercury with a Deflector Piston of course i makes you wonder if Mr.Christner wasnt way ahead of his game by padding the mercury blocks with a very close squish area.
Good luck guys
Tim Lee

[Larry Mac]

Merc 44 chambers

I was at the Pro Nationals this year as a spectator and was looking around at the trailers and equipment and saw this old picture of this Mod Merc which had chambers on it. I talked to the guy ( I can't remember his name) and he said that they were made by Quincy welding. I asked him how they ran and he told me they ran great. He said he won the APBA Mod National with them ( in the early to mid 70's) . He told me he was the fastest there by far and won both heats. Also these chambers didn't slid.

Do they work, a very few people have made them work on the Merc I have made a few but I didn't do any good.
Larry Mac

[Dave M]

Why Bother is another Point

If someone has to make 21 pairs of chambers for a 44mod to find one that works adequate, why bother ?

Back in the day the 44mercs (MOD) were no where near what they are today in speed. We have found new ways to make them go fast since the 70's. Back then chambers worked okay, and when someone found a set that worked okay they did okay. Today, you will not get as lucky. Chambers on a deflector can give you more top end, that is right. But, top end is NOT what wins races. We all know that. You take a big course, say over a mile, and the chambers will work great. Slide them and they work okay on short course, but will still lack the acceleration. A deflector is not designed to use chambers. It is a good motor for what it was, and it was built in 1969... even further back if you want to toy with the Mark 58 blocks. When OF Christner padded the blocks this made the chamber work better, obviously. It also took him several tries to get it right on a gas engine.

Now then, if you mandate porting on every model of the 500 block Merc Made, get everyone ot the same port height mandate what years blocks can be used, and then say go for it with chambers it might work. They would be slower than todays lap times though. But you would have chambered quit engines.

I love the sounds of the Mercs and I also see a need to quiet them down. However in the past this has been tried, it is like trying to get the stockers to eliminate AXSH, not gonna happen easily.

Paul F, you have a point, but I think your calcs are off on the pro equivilents. Cubic inch wise you are close. Not sure what would happen if one simply changed jets and ran methanol in a Mod. I bet we would find that the speeds would not change to much. How does one cut the head down on a Merc 44 block ? I think OF Christner answered that many, many years ago... Then the speeds would begin increasing.

And for the record Paul, the Quincy 6 loopers are the best sounding race engine out there period. Keep up your six banger as I always look forward to hearing it run.

I think eventually the mods will convert to pro like status. They almost have to with four strokes coming. However, I truly think the divisions need to remain seperate. USTS has all the classes they want now, and so does Mod. Combine them and the day gets long again.

[alky6]

From tales of Old.....

I suppose I need to review my definition of expansion chambers “working” on deflector engines. “Working” on a racing engine to me means as good, or better, than the current technology. Can they (expansion chambers) be added to a deflector engine, sure. Have we made ok power with expansion chambers? If you consider 20-30% less power than one of today’s best 44’s (and a very steep horsepower curve) then yes, they work. Further, we are making about 25% more power today than we were back in the 80’s with 44’s (yes we have dyno results on the same dyno going back to1960’s). FER was very strong on the west coast and the engines my father raced at that time were very competitive. So, with that logic, “back in the day” expansion chambers were probably competitive. But if they were so competitive, where are they today? Why isn’t everyone running them on Mercs? Fact is they are not. There is a reason why all the manufacturers (Quincy and Konig included) shifted from the economical deflector crossflow scavenged engine to the more expensive to manufacture loop scavenged. It is nearly impossible to get enough port area to get the air in and out of the cylinder effectively in a deflector engine (Mercury). Further, compound that with a piece of aluminum sticking up inside the cylinder and one cannot put as much heat in the cylinder as you can with the domed style piston of a looper (too many exposed edges) without melting the corners off of the deflector. The smaller diameter bore engines like the 30, 40, and 60 inch Mercs are better suited to expansion chambers (they are all the same block, just different diameter cylinders which leaves more room to add and widen ports). The area available for ports as compared to the volume in the cylinder is much higher (even in stock configuration) as compared to the 44 block. So, in the 70’s where a 40 inch D was predominant one could expect to see some expansion chambers running. Today we don’t run 40inch Mercs (none available parts or blocks) we run 44 inch blocks.

If everyone would be happy with 20-30% less power than they are running today, then, by all means, mandate expansion chambers in MOD. I for one could never go backwards and would rather choose a class/engine that was conducive to quenching my thirst for more power.
-Paul Fuchslin

[alky6]

...

Paul F, you have a point, but I think your calcs are off on the pro equivilents. Cubic inch wise you are close. Not sure what would happen if one simply changed jets and ran methanol in a Mod. I bet we would find that the speeds would not change to much. How does one cut the head down on a Merc 44 block ? I think OF Christner answered that many, many years ago... Then the speeds would begin increasing.

And for the record Paul, the Quincy 6 loopers are the best sounding race engine out there period. Keep up your six banger as I always look forward to hearing it run...

.

DaveM - On the comparisons - I was referring to speed. Not step downs. Basically my point was to choose an alky class that had about the same average lap speed and abandon the Mercs and convert totally to the alky class, boat and motor entirely. Not creating more classes just more participants in an existing alky class.

Agree with you hole heartedly: the Loop 6 is the best sounding out there!

As to converting to alcohol on the Mercs, without doing anything else, you would see a slight increase in acceleration and same top end. That is what we have found at least.

-Paul Fuchslin

[Morris85C]

Im still waiting for some one to tell were i can buy a set of these fast chamber for my dmod. Im like neil bass give us some Imfo so we are not noise poluters.

[Skoontz]

In Southern Cal

There is a rash of geniouses who move onto areas, knowing full well of the events that go on in that area, or next to an airport for example, and ***** piss and moan about noise.

Longbeach Marine Stadium for example built in the 30's, updated with an actual clubhouse and beaches in the 60's was built for boat racing, which, as I'm told, used to happen every weekend. It has dwindled down to one, maybe two events a year, with very strict limits on time, i.e. 9AM til 5 or 6PM. Some genious sits home on his balcony and instead of enjoying the time, or taking a weekend away, he invested in a decibelomoter to attempt to show town council how loud and disturbing the event was.....

The key, common sense, which I feel there is very little left in the world....If you know you are moving next to a drag strip, marine stadium, airport, stock car track, or for that matter a gravel pit with loaders and back up alarms going off, you need to realize it was there first, so you should enjoy the situation, keep your mouth shut, or move. On the legal side, judges need to look at the grandfather act and stick to it. If the site was there before you were, you ain't got no say in the matter....It would save alot of taxpeyer time and money....