PRE-1975 MERCURY RACING ENGINES

[SpiritOfSelkirk]

This circa 1956 Mercury Mark 75H was the first in line six cylinder engine coming on to the racing scene in these earlier times. Used mainly on big cabover class F type hydros like those built by "Jones" as well on the big runabouts like those built by DeSilva they were remarkable and brought the outboard speed record back to North America where afterward the record was tossed back and forth between Mercury and OMC for years afterward in a game of one upsmanship. Quincy Welding made many pipe sets for these 60 degree firing order engines and converting many of them many of them into Alky (methanol) engines as well as their original specs were for running on gasoline. The British Anzani 322cc class B Alky engines by the later 1950s were giving both Mercury class D and class F Alky owners and drivers severe heartburn by hitting 90 miles per hour racing speeds by the late 1950s. Where Anzanis were entered to fill in on larger classes positions due to lack of entries in these larger classes could actually compete with them and at times beat these larger engines that are twice and three times the Anzani displacements. That was not lost on Quincy Welding who saw they had to change technologies on the long run to stay competitive some time in the future.

Enjoy the picture.

[SpiritOfSelkirk]

This one Mercury really qualifies for a look as it mirrors the efforts to pioneer expansion chamber exhausts in the earlies days in deflector piston aka crossflow engines when they were also being developed for loop engines where they had all the success. Indeed the battle still goes on for deflector aka crossflow to have them where loop engines have jumped ahead and never really looked back. The two sets of the these pipes are "gated" from each other and switchable on the go from one type of pipe to another coming from the same cylinder. The engine was twisted over from its normal orientation with carbs forward to sparkplugs rearward specifically to avaoid the use of long elbos from exhaust plate to first bell that cut down severly on the amount of welding that was still gross by any stretch of the imagination. Weight as also a consideration as longer elbos would have increased the overhanging weight making boat handling even more difficult and steering near impossible. Still these same principles were at one point even on Anzani loop no different with this Merc but with Anzani they found success with only using expansion chambers eventually where Mercurys have virtually still stayed with megaphone open pipes all due to what scavenging system each engine had.

Enjoy the picture though truly this test bed Mercury racing engine was anything but one could call pretty!

[SpiritOfSelkirk]

The following picture is of 2 class D (APBA) or E (AOF or NBRA) Modified 44 cubic inch Mercury powered hydroplanes (the red one a "kneeler hydro") (the yellow one a "laydown controlled" hydro) proped up and ready to run at an annual 8 class racing event at Selkirk, Manitoba, Canada on the Red River. These "Gasser" Modified Mercury powered hydros could attain speeds of near 90 miles per hour at the end of straightways before the corners came up using three blade propellers at this point in the 1970s where everything was 2 blade in the 1960s.

Enjoy the picture.

[puddleduck]

Hi S.O.S!
Thanks for showing us your fascinating series of incredible engines! Thought you might like to see my hydro, seeing she's a Canadian design! Thunderbolt III is an E.G.McCrea design 3 pointer, 121" built in the UK in 1956 to his plans. T3 was campaigned with a souped-up 1000cc Evinrude storm motor, modified with Pep Hubbell parts form the US, and was the 1957 X class champion in the UK. Sadly, the motor has long since disappeared and we found the boat as a heap of firewood back in 2004. I completely rebuilt the deck, port side coamings, transom and most of the hull, but her main frames, bulkheads and longitudinals are all original. I don't have a race engine, but have run her with a stock 1966 350 merc. This year I am using my '60 merc 300 with a racing prop, so we'll see how this set-up runs.

If you or any of your fellow collectors have a copy of McCrea's plans book I would dearly like to have copies of it if at all possible!

cheers,

Chris
(Chairman, Classic Motor Boat Association)

[SpiritOfSelkirk]

Puddleduck: You definitely need a Merc KG9 or 40H racing motor with pipes on it no different than what Steve is getting together. I am not saying don't use your family sports Merc engines for cruising as I do are doing myself too with a Merc 500 on a Chaparral class F 13.5 ft restored flatdeck wedge hydro. It would be nice to have some open piped closed course Merc engine to upset the local Formula 1 guys now and again and give the public a real treat to the ears few ever get used to! I am getting 55 to 57 mph on the Chaparral still using a 3 gallon tank that goes on forever once the hull is planed off.

I will see what I can do about getting what ever data or plans on your hydro are still available if someone has something out east as they were never in this area. Here in early conventional 3 point hydros it was generally Ogiers, Hedlunds, Swifts, Sidcrafts, Marchettis & Hal Kellys. When pickelfork hydros came along they were Butts Aerowings, Giles, Gordons, Byerscraft, Schumakers, Pughs, Yales etc. Lots of variety and great quality in terms of wood and construction though some will argue with me on that.

[SpiritOfSelkirk]

The following Mercury engine started its life as very much basic block wise a Mercury Mk30, Mk55, Mk55A, Mk58, Merc 300, Merc 350, Merc 400, Merc 450 and Merc 500 in two series of block castings, the older center of cylinder sparkplug standard dome with few improvements other than compression from the KF9, KG9 to Mark 40 days. Later into the late 1960s came the powerdome blocks with the offset to the intake side sparkplugs locations improving (plenty pro & con arguments to that) the engine. Original engines were developed around 80 octance marine gasoline where later powerdome blocks were developed for regular unleaded automotive fuel with older series of blocks making the original stock racing Mercury "H" engines (30H & 55H) and the newer leading to the famous Mercury and Mariner 44X stock racing engines. The offshoot is that all these various sized 4 cylinder engines from 30, 40 to 44 cubic inches all made great "Modified" gasoline catagory closed course racing engines though their technology is all deflector-crossflow. The following example picture is that of a typical Modified class Mercury engine that were stock racing, made into high compression moded Alkys and in the 1970s took off as serious Modifieds with modifications that look basically the same today. Prop and boat technologies have taken them faster since then with Modified Class C Modifieds (30 cubic inches) to 80 miles per hour, Class D Modifieds (40 cubic inches) to 90 miles per hour, Class E Modifieds (44 cubic inches) to 90+ miles per hour and Formula E Class engines where almost unlimited modifications to 44 cubic inches on what is developing as the Tim Kurz inspired "444" near unlimited Modified Mercs should get into the mid 90s around 95+ miles per hour ranges taking deflectors where they never envisioned Merc 44s to go. There are many variations of exhausts involved in very precision re-machined engines in these what started out as family ski, sport and fishing Mercs mostly coupled open twin pipe but also some expansion chambers systems too. Most 4 pipe systems are found these days are on the classics like KG0 and 40H.

Enjoy the picture.

[SpiritOfSelkirk]

Another example for the readers. The previous engine was a later model powerdome 44 cubic inch Mercury 500 Modified. The next picture is that of a Mark30 (30 cubic inch) non-powerdome un-compression padded early model.

Enjoy the picture.

[SpiritOfSelkirk]

The following is a Mercury Mk55H (40 cubic inch) Modified powerhead ready to mount on complete midsection, clamps and gearcase then ready to race.

Enjoy the picture.

[Healey75]

Brilliant...can't stop drooling and looking at the articles...thanks S.O.S

[Howstar]

They do look fantastic love one of them on my window ledge, or on a car