Wow, I didn't know I would get such lengthy and informative posts! Very interesting!
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Wow, I didn't know I would get such lengthy and informative posts! Very interesting!
These guys here not only are knowledgeable, they SHARE their knowledge (except their most precious racing secrets!)
Jeff
There Are No "Secrets", but Unless You Ask, You May Never Find Out
My brother had one of the fastest A Hydros in America, 1949. He won the William Randolph Hearst Regatta (Hearst Newspaper, the company that vilified marijuana). The Hearst Regatta had 32 A Hydros in 1949. My brother, who was never a very good starter, started last the first heat and in five laps, he pasted everyone. Between heats while my dad filled his gas tank (with alcohol), my dad told him for CHRISSAKE don't start last again.Originally Posted by Fastjeff57
Well, my brother started just like he did the first heat, last that is, but again manged to pass everyone in the race. My brother pretty much out grew "A" as he was 14 in 1949, so when he turned 16 we sold his "A" and my brother started racing C Racing Runabout.
My brother got drafted in 1953, while he was in the Army, Jack Leek set a 61 MPH "A" Hydro record. Four years earlier, my brother won the biggest race in the USA going 51 MPH and Jack Leek went 61 MPH... MY brother thought the newspaper clipping we sent him must have been a misprint.
Jack Leek went on to run OMC Racing Division for many years. What few people would know is Jack and my dad exchanged letters for years, but, I'll admit, some questions were never answered. As in the 1950 my dad had figured out piston clearances and compression ratios that he didn't feel like sharing. Years later, my dad and Jack laughed about some of the questions my dad didn't answer.
Few people will just open up and tell you "SECRETS" but if the questions are asked, someone might answer them.
See, Sam posted that some early black block Mark 30's were higher compression.........I remember Don Pontius, John Meyers, Joe Schulte all having very fast MARK 30-H's that were DARK BLACK...I said, in 1977 I had one good black block MARK 30, but it wasn't a DEEP BLACK block. I held the C Runabout Kilo record for years, and won the 1966 Marathon Nationals. I seldom got better than 2nd or 3rd in C Runabout at the Nationals. I'm wondering, "IF" maybe I never had a high compression Mark 30....
What secrets do you want to know???? Funny thing about my prop business, when I started it, I could help front runners and Nationals Champion easier than back markers....because front runner could tell me what they needed. And they wouldn't just buy one prop, they'd buy a half dozen!
Clark Maloof beat me at the 1977 Nationals in DSH with my own three blade prop.
Last edited by Ron Hill; 01-29-2013 at 09:31 PM.
Actually the secret to a C Stock Merc block is very simple. Pull the intake port covers off all your 4 port cover blocks and pick out only the blocks that have the intake ports milled or drilled the highest into the top edge of the port passage. Then take those blocks and find the one with the lowest intake port height as measured from the crankcase split surface. You can find some with 0.007" or more below the mean dimension. And VOILA! you are in business and somehow the block most likely will be a dark block. And if you use the crank from it, it will be a small journal one as well- another nice part. There are other tricks with what reed cages to use and which of the carburetors seem better but the block part is pretty easy.
Black Blocks
So, what you are saying is: By looking at the location of the intake ports (holes), if they are toward the spark plug end, this is good. (Probably, this would increase the compression). But then, by measuring from the crank end, you want the ports that measure the lowest, even though the machined part of the port made them look high.
And you don't give a RATS *** about the exhaust ports????
I know you had some damn fast MARK 30-H'S BUT I JSUT ASSUMED IT WAS THE PROP!!!! LOL!!!!
It will have negligible effect on compression but will change the intake timing to a degree increasing top end with a higher port. The lowering of the port will increase the bottom end. So Hydroplay is saying, I believe, is you try to find a block with the highest port and lowest ports in one for the best performance. The whole thing is to get more charge into the cylinders. I am assuming that this is for a stock motor where machining is not permitted. For a mod motor, raising port height is common practice. Harry Brinkman's Manual "How to Modify your Mercury" is well worth the read even if you are not going to do one. Aeroliner Boats has it for sale and I believe it is being updated. The exhaust ports on a Mercury are more than enough to handle the gases from the expended charge. I tried doing a 30 Merc for Cmod a few years ago and didn't have a lot of success. Mainly the block I had was past it's prime and I was beating a dead horse and what few .015 over pistons I could find were way out of my price range. I bought a power head off ebay on a chance it might be good. It turned out to be a .015 over block with cross hatch still in the cylinders. I considered using it but decided to put my 30H back together as I had stolen everything out of it. As a side note the 30H I have was raced by John Landon in the 50's in the LA area. He stamped his name on the block and all the major components.
kk
Secrets??..........
Rumor was some of the best 30H's had 'crushed' heads.................that brought the cc's right to the minimum and folks didn't have to worry about scrounging for old 30H blocks...........
Of course that's just a rumor..........
You want both compression and low port timing in a st0ck powerhead. That is easier nowdays with line boring but back in the 70s and 80s it wasn't difficult to find a block that was factory machined with the crankshaft closer to the head for max factory compression. And then sort through those to get the lowest intake timing so the motor pulls great in the corner and more. Corner speed and acceleration have won more races than top speed on MOST courses. But motors with plenty of torque will pull bigger pitch props and go fast too.
Mercury may have had dynos but didn't know everything. Re Mark 55 vs MK55-H. The 55-H had higher ports both intake and exhaust but when finally approved for stock racing, the lower intake 55 blocks quickly took over. Even better would be one with 55 intakes and 55-H exhausts but that wasn't possible in stock. I think that answers Ron's question about exhaust port heights and why I didn't care about them. It is far more important to have the right intake height. Note that this applies only to the Merc stock deflector motors and not necessarily racing 2 strokes with more sophisticated exhaust systems.
Crushed heads for even lower ccs? Shocked! I'm truly shocked to hear that!
Location location location
LOL.............yea, i hear it was a West Coast thing!...........
Ted May Called It "Punch and Go"
My brother and I were talking the other day how he used to test props before a race. He'd run a diagonal course to see that TOP MPH. When the race come he'd be at the back of the pack. It was only after I started run hydros, did my brother start winning races. As my dad didn't like me racing hydros, maybe because it was against my brother, so my dad didn't buy me any hydro props. So, I ran my runabout props. In my first full season a D Hydro racing I had 9 firsts out of ten races.
When new racers are look for "Secrets" they sometime miss out not seeing a BIG SECRET. Hydroplay just agave one of the biggest secrets in racing, "Corner speed and acceleration have won more races than top speed on most courses." My two son sraced 45. Chad ran the 73 MPH, Broc ran the 64 MPH. I won't go into the details....But Chad ended up with the 64 MPH because he kept getting beat!
The SoCal boys never "CRUSHED" heads, but I would not be at all "SCHOCKED" to see some blocks like that out of Region 7.....AND I do know of line bored blocks out of Region 6...........And I do know about heads being welded in by Lon Steven in NorCal (Region 11).
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