Ron, my autographed book arrived yesterday. Wonderful reading. As I thumbed through the pages I was saddened that your Dad could'nt read what you wrote.
My childhood was very much like yours doing...
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Ron, my autographed book arrived yesterday. Wonderful reading. As I thumbed through the pages I was saddened that your Dad could'nt read what you wrote.
My childhood was very much like yours doing...
Ron, put me on the list for a signed one. Thanks.
Mike, well written.
The 25 & 35 blocks are the same, 25 has thicker sleeve, smaller bore. You can bore out your 25 and install 35 pistons. Be sure to jet carb for 35. Glue joints in ports, especially finger ports, can...
Need some help. I am trying to finish up my Formula 1 race plane and need to find a replacement crankshaft for a Continental 0200A, 4-cylinder engine. Just learned that my crank has a cracked prop...
Excellent detective work, thank you Tana.
APBA has posted updated specification sheets for the OPC Classes. No rule changes but additional information and some corrected part numbers. A new "OPC-SST45 Reference Information" document as...
Lower unit ATF, we used Dexron II. Starter is standard OMC 12V with mounting tabs relocated for FR-31M. Most used 24V system for starting. Trim and lift are 12V. 18 deg good.
Yes, Roger Jenkins...
Congrats on finding two FR-31M's. Yes exhaust was put on right side for improved performance over earlier versions. A fuel-oil ratio of 24:1 using a premium blend of oil with Avgas will work. RPM...
Ron, tempting offer. When I last checked with Fred he said they were in Oshkosh, I would have been really jealous if he was back in California for the winter. He must be nuts! Still too cold in...
What an interesting post! WOW, is it great to get so much insider information. This is the stuff "Legends" are made of! Banned??? Too darn cold in Chicago.
Jeff Brown and Tom Ireland tested...
I think the Mirage was one of the best engines I did at OMC. The 25 and 35 share the same block and lower unit castings making all port passages and exhaust tuning the same between the two versions....
Fred, very accurate, excellent memory.
Sorry, the V6's raced were 2-litre - built as I explained in an earlier post. Maybe I will explain how the bores were done at a later time.
John. Yes, I gave Charlie that print. Truth is, we received a very very rudimentary drawing of the Merc V6 with a box of castings. One of the Johnson manufacturing engineers thought it interesting...
I had just started the production V6 project when it was decided (by Charlie) that we should enter a V6 at Paris. Clarence Blanchard, a brilliant designer who worked for Jack Leek, was given the...
Tim, very nice job on the 3-cylinder. First OMC with turbo that I am aware of was a V4 built by Jim Booe and Bob Thompson in 1972. Jack Leek, Jimbo and I went to test it on Bob's pond in...
Most, if not all, of the OMC V4 and early V6 twin pinion gearcases were built by Ward Cox who was a member of the race team. The pinion gear vertical location was shimmed based on the distance from...
Great picture of the OMC with single stack. That was the forerunner to the KC and later KR exhaust systems. The sound was unreal, made the V4 sound like it was running 10,000 RPM. We were never...
There are no words to describe the tragedy of losing a son and grandson. We will keep the Berghauer family in our thoughts and prayers.
The exhaust system Jimbo is running is a 4 into 1 system which was later designed as an aluminum casting that exited into the down housing on the KC and KR Race Engines. If you have never heard one...
The pressed sleeve die cast blocks were made by putting a special aluminum blank in the die, in place of the stock iron sleeves. After casting, the aluminum blank was carefully machined out leaving...
The carbs in the picture are OMC, for some reason Selva was never able to make their carbs work and would buy OMC Mod50 carbs for their engines. When Paul Kalb got wind of this he put a stop to the...
Lars, good to see you on the site. I am sure the group will enjoy your many stories.
Early Mod 50's with two port bridges did not have any special honing done to them when produced. Factory (OMC Race Group) modified motors had the bridge ground away from the piston. Not exactely...
We always tested with a KELLER. Each driver had his own and it was always kept in a safe secure place. When I completed my Invader Tunnel I asked Jack Leek if he had a KELLER I could borrow. He...
Fred,
The first time we used NOS we just shot it in front of the carb inlet. Ran a fuel line and NOS line. Ran this at St. Louis on the V6 the same year Mercury came with brakes. Later units were...
Fred,
The jet in the bottom of the main nozzle was an attempt to lean the carb out at higher RPM's to better follow the power curve. As RPM went up so did fuel flow to the point the engine would...
There is some misconception on the stuffer, color did not mean gas or alky. Early stuffers were one color later ones another, no more-no less. ABPA MOD 50 was a gasoline only class. UIM OE was Alky...
The alcohol kit was usually used in Europe for the OE Class. Kit included larger jets and "Gross-jet" needle seat assembly. Pump kit was just rubber material which would tolerate the alcohol. Best...
The twin V8 Molinari was raced at the Unlimited Gold Cup Race in Clear Lake, Texas. Jimbo ran the Second Effort four engine V8 tunnel at that race and finished second in the Gold Cup final. Jimbo...
Fred, they all got squese!
T2X brings up a very good point. We never had much luck putting V8's on boats designed for the V6. The additional weight and power changed the balance enought to make the boat handle poorly. I love...
Jim Booe, creator of the TURBO propeller line, built an OMC V4 with turbo-charger and mechanical fuel injection (Hilborn I believe) in the early 70's. He did this with Bob Thompson, Just-Add-Water...
Ron, this is insider information - the best blocks were always kept to build Evinrudes. Why do you think Jimbo was always so fast!!
Ron is right, in 1978 we were running V6 engines. The V8 did not come out until several years later. Depending on the history of your 1978 Molinari it would have most likely used a cross-flow V6...
No problem with removing the ring gear.
The exhaust was put on the other side to take advantage of the piston thrusting against that side on the downstroke for a better seal. This does not change the tuning effect due to firing order,...
JohnsonM50, the flywheels used on the OMC 25/30 are die castings which get most of their strength from the outermost layer of material. By cutting the wheel you took that material off. It always...
We tested just about every carb combination you could think of at the time. It was possible to see a few more horsepower with a larger carb but when tested on the race course lap times would always...
All the 3-cylinder race engines had stops. Mark 75 is correct on the function of the reed stop. Stop height and shape are very important. Early M50 engines used 0.010" thick stainless steel reeds,...
The spline on the 25/35 3-cylinder OMC is the same as the 25/35 hp twins. The gearcase was made by modifying one of the twin cylinder dies, all internal parts were the same. With a little work you...
Sam, you got it! Kind of like firing 1-3-2 rather than 1-2-3. Depending on the engine this can help performance.
Fred,
Thats a great looking exhaust but not what you want for the Mod 50. Port runners are going to be way too long. If you think about the systems used on the Mod 50 & Merc V6 they are very...
David,
Not sure if you have to exhaust through the midsection or can run an open stack. The motor Fred used for the Mod 50 record had the exhaust into the midsection because of the rules for Mod...
Fred, the block you show the picture of was modified that way because the port rib cracked and that was the only way to try to salvage the block. This is not an ideal situation and will most likely...