Mercury in line 6 hop ups

[nitro_rat]

I know looks don't win races....

Going fast is ​looking good!

[delawarerick]

Dave S built me an inline 6 that was a hard runner. I never really learned all the mods he did but it was a bear. I only ran up to 6k for I wanted it to live and it did beat on it for 7 years now I have a v4 xflow 140 and this thing is a bear but I know not what has been done inside only the mods I have done and it is alot more than the inline I had. Cool factor I will give you W2F

[mrcrsr]

Prior to the introduction of the Merc V6 I was running some 1500J (same powerhead as 1500XS but without low water pickups) and Twister 2 stuff on a 15 Allison. I decided to send a 1500J powerhead to Orville Christner at Quincey Welding who had a legendary reputation in racing outboards INCLUDING building the inline 6 looper, pretty much from scratch. I got the powerhead back disassembled and the machine work was absolute art. The exhaust ports were re shaped and there was some work on the transfers on both ends. He had re shaped the windows in the pistons, which were 2 rings from an 850 and had completely re worked a new set of reed blocks, putting them in an end mill to open up the area in the middle, re shaping the rear of the holes and also re shaped the front half of the block behind the carbs. There was some work on the inner exhaust plates and other machine work that I can't remember over 40 years later. I was in awe over the quality and detail of the work. There was just one problem........................ It didn't put any speed on the boat. Somebody asked above, what was the restriction in the 1500's? It's a combination of the inefficient combustion chamber design with the deflector piston, the crossflow design itself and the way the reed blocks are configured. I've NEVER SEEN a 1500XS improved with internal modifications, but have seem many hurt by people that just can't accept the fact that they're not likely to help one by getting inside with the carbide bits. It's also worth mentioning that the factory port specs, as far as exhaust port height and transfer port height are the same between the 1500XS, the 650XS and the T2. Sam Cullis sent me the tech sheet that APBA used about 25 years ago and I still have it somewhere.

One other thing that the discussion on align boring to move crank up and raise compression fails to mention is that if you move the crank up in the block .010, you just lowered the port timing .010 at the same time. Would moving the crank that .010 and then raising the port timing .020 for a net gain of .010 help performance? I doubt it seriously but don't know for sure. What I do know for absolute certain is if you raise the port timing .020 on a standard XS you'll hurt the power from the bottom of the RPM range all the way to the top.

I've always said there's a lot more potential for hurt than there is for help in screwing with an inline 6 powerhead and if somebody's not happy with the output they'd be much better off to start with a Merc V6, all of which are loopers with a lot more potential for modification.

Jeff Griggs in S.C. who's a Formula V world Champ with tons of inline experience has said that even the 1500XS's in the last year or two have the low dome pistons from the factory. I presently have 14 1500XS's in various forms, from running to totally scattered, and haven't personally seen one with the low domes BUT I haven't measured most of mine either. Although I haven't bought any pistons for 2 or 3 years now, the last set I bought were 1500 high domes with 3 rings and were still available after market. Something makes me think the 2 rings from the 850 were no longer available in high dome. I think it's pretty safe to say that the extra tad of compression is more about acceleration than top end numbers and even there the difference is negligible.

Did he change anything with the combustion chamber in the block when he converted it to a looper? I remember it had a weird shape that was similar to the piston crown but reversed. It would be interesting to mill the existing head off and go with something like a hemi shape, but unsure if there is even enough meat in the block to install studs and have a gasket surface.

[Raceman]

Sam knows a lot more about the Quincey Loopers but I've always thought they started from scratch with a total redesign if the block.

[FMP]

The 6 carb motor with 3+3 exhaust tuning crank and finger ports was "capable" of 200+ The compression wasn't raised, and the rpm was only something a little over 7,000.

The 'customer' version of this motor was only a hair over 185.

That thread is somewhere but I cant even find it in my post lists??? Record wont pull up .It mention the wild compression , single ring etc , Hering maybe ? Also made ref. to the looper L6 in the thread, could be linked to Years of Merc thread.

[powerabout]

Sam knows a lot more about the Quincey Loopers but I've always thought they started from scratch with a total redesign if the block.

Yes the blocks are custom as they are looped charged as the brochure says.
Dick Austin has just made a completely new one ( t2 front half), he also has a few Quincys I think.
From drawing to pattern to casting to machining, ( his work) over on Rons site,

[FMP]

Not too long ago a video and description was posted, can't find it either. I liked and posted on these threads, can't find it.

[Capt.Insane-o]

The be all end all of inline 6's by Dick Austin

[FMP]

Beauty

[mrcrsr]

Yes the blocks are custom as they are looped charged as the brochure says.
Dick Austin has just made a completely new one ( t2 front half), he also has a few Quincys I think.
From drawing to pattern to casting to machining, ( his work) over on Rons site,

So they aren't using a factory block?

[FMP]

What's the biggest bore and stroke that fits in an L6, someone had to have made an attempt? Custom custom custom, maybe a prototype Lake X motor?

[Mark75H]

So they aren't using a factory block?

Not at all. All the Looper uses is a Merc crank and ignition. Early Loopers used Merc fronts, but later on they had their own dedicated front.

The Merc factory block has the cylinders spaced too close together to convert to loop charging, that's why Christner made his own blocks.

A hemi head on a cross flow is very dificult to pull off. McCulloch did it on their racers in 1963-64, but I have not seen any attempts more recently. You couldn't use Direct Charge pistons, you'd have to use pistons from a 125 and reshape them to agree with your custom hemi head.

On the smaller displacement 6's where they bolted a head on, I'm pretty certain they cut the block back to expose the cylinders, shaved the aluminum off, and fashioned a girdle base around the iron sleeves, then welded the girdle to the sleeves. This is what the head bolted to.

[Capt.Insane-o]

I know a few here followed Dicks build...incredible doesn't even come close.

[FMP]

Capt could you post the link, maybe the video is in the thread? I recall it running on a trailer, first start I think.

[Capt.Insane-o]

I have most of the build pics saved, when I get a minute I'll copy them back off of photof*cket