Finish on 20H Conversion LU

[zul8tr]

As evidenced by the debates about chamfering, where to measure etc, inspection would be a problem. All is sidestepped with bolt-on parts. Back in 1960, there were a lot more racers that never saw the inside of a motor; having to disassemble and do the work or send it out to be done would have reeked to high hell of alky racing.

Good point, agreed!

What about those 20H drivers when the conversion came out and the detailed work of R&R and grind inside the gear case for the 16:21 etc? Bet that caused some bitching?

[Aeroliner]

Having done a number of 16:21 changes that David and I have done the amount of material removal was minor. I will dig up my old documents and get them posted. Not all the cases needed this step in that some already had enough clearance.

Alan

[Allen J. Lang]

Hi Alan, my old 20-H I ran in EORC back in the 60s was converted to 16:21 and did not need to be clearanced. I did not have the toilet bowl conversion. Did have the Carter carb. It did run pretty well until I snapped rolled it at the starting line and blew it wide open from flywheel to gear case.
Al

[MTECHMARINE]

In reference to John Alden - - My friend Stu Lowe from Mercer Island WA gave him a run for the $$ in BOH. It was a crap shoot as to who would win. We blew up a bunch of Hot rods doing this. We had to put steel rods around the crankcase with flat bar on the head to keep the block from blowing off! Rods were the downfall, followed by broken cranks.

I have one Alden prop in my old props box - -

Good times!

[champ20B]

In reference to John Alden - - My friend Stu Lowe from Mercer Island WA gave him a run for the $$ in BOH. It was a crap shoot as to who would win. We blew up a bunch of Hot rods doing this. We had to put steel rods around the crankcase with flat bar on the head to keep the block from blowing off! Rods were the downfall, followed by broken cranks.

I have one Alden prop in my old props box - -

Good times!

I can certainly believe it...I was messing around with my 6NHR and as I looked over it, I could see tiny squiggly cracks all over the cylinder block around a 1/4" long and shaped like wool strands every inch or so apart. The cylinder block actually looks like some possible later casting because it is bare aluminum and super clean (not a grease stain anywhere). The engine was built by Cooper Jess several years ago, and I sold an old 20H (not running) to buy it from another collector. It will start up in one pull every time and has 160lbs compression. The only thing is that there are little wrinkles in the casting and water actually seeps through one on the upper side of the block. Its not a stress crack at all, and poses no concern as such, as it turned out to be a common casting imperfection found on some hotrods. What I wonder is if this is found on the original versions or if this flaw results from later reproduction blocks.

[Ron Hill]

In reference to John Alden - - My friend Stu Lowe from Mercer Island WA gave him a run for the $$ in BOH. It was a crap shoot as to who would win. We blew up a bunch of Hot rods doing this. We had to put steel rods around the crankcase with flat bar on the head to keep the block from blowing off! Rods were the downfall, followed by broken cranks.

I have one Alden prop in my old props box - -

Good times!

Was Jeff Lowe, Stu Lowe's kid? Seems Jeff was fast as hell in B Stock Hydro in the 1960's

[MTECHMARINE]

Was Jeff Lowe, Stu Lowe's kid? Seems Jeff was fast as hell in B Stock Hydro in the 1960's

Jeff is Stu's younger brother.

[champ20B]

When the 20H popper kit was fixed into B-stock, were there guys running real 20H motors that abandoned racing because of this? I have heard that it was that they didn't want to go spending more money modifying their motors just to stay in the game, but I wonder if it was the principle of fair play that played a role as well. After all, the idea of the hotrod having a tuned exhaust was a dubious claim to say the least....fact is, when the cover was removed running as just "open" the engine was faster and that's a fact. With an actual tuned exhaust, it would be slower after removing the exhaust cover! That's a physical fact....

Caution: you are entering a "NO SPIN ZONE"!!!

[Aeroliner]

Having played with 20-H's since 1955 I don't believe that a lot of folks left racing because of it. My 20-H cost $411.00 with bar and prop which was a lot of money. The guys with the KG-7's were mad in that the had to buy a whole new engine to race B. In order to make them happy Mercury introduced a kit to convert the engine to a 15 inch A unit. If I remember correctly it also came with a S/N tag with the new block and pistons. The HR engine were beating the Merc's hands down with there higher HP and lower weight so the conversion was what was needed to keep you in the game. Now here is where the turn comes in. Shortly after the conversions were out Mercury started testing the lower unit for the new B engine which was going to be the 25-H. Although the a few towers and lower units were produced and tested no real power heads ever were assembled with the 12 reed valve setup. The new lower unit and tower proved to be very fast running under a Mark 20-H power head. I have posted photos of the 25-H foot I own but can do it again if folks want to see it.

Racer were really upset with having to look at the new B engine so Mercury dropped the idea.

Alan

[Fastjeff57]

..."no real power heads ever were assembled with the 12 reed valve setup."

Any idea what that set up looked like?

Jeff