View Full Version : the z engine

10-07-2008, 10:58 AM
hi all,

i've been fortunate enough to pick up some quincy z engines from francis latta, larry latta's widow. i've taken some pictures since i've not seen too many of them posted. the pictures are of a z 125, z175, z250 and 2 z rb. they are soooo much easier to work on than the loopers.

i have some questions for paul.... on the 2 z rb engines i have the carb is facing away from the boat and the plugs are facing inside the boat.... now on the 125, 175 and the 250 the carb is facing inside the boat and the plug is facing the 90 degrees from that. did you and your dad change the engineering on the smaller engines? also what do i need to do to convert one of the rbs to a regular 350 b?

right now the 125 is almost together and when it is i'll post pictures.


Original Looper 1
10-08-2008, 09:06 PM

As to what appears to be the power heads turned around on the RB engines, that was a deliberate evolution. We started with the Z pro B before the RB's, M's and the rest of the Z line. My father and I came to those reversed layouts because the pipe designs that worked best on the Z engines made the pipe length too long behind the back of the boat, which meant we had to use an extended length pipe support system, and the extra length pipe supports kept cracking and breaking. When we turned the powerheads around, similar to the FA Konig, it enabled us to use an 8 to 10 inch shorter pipe support bracket. This change gave us considerably less pipe bracket problems.

As to the design of your R&D M engines, when Chris closed down Quincy Welding/Precision Machine permanently in 1984, Jack Kugler & Larry Latta took over the racing program and went on in development. Chris and I were often in contact by phone with both Jack and Larry regarding the evolving development of the Quincy Z engines. As to who takes credit or blame for their performance or lack of from there on out is a good question, and everybody had an opinion. Most people that knew the late Larry Latta, knew that he was very educated and intelligent, but that didn't necessarily translate to water performance and speed on the race course most of the time.

As to converting your RB to a B pro engine -- obviously you would need 2 carbs instead of one and, my guess, 38 mm would be the correct size. The rest you can call me about, you know the number.

I especially like the opposed 2 cylinder A. One wonders how that would perform even today with a first class driver, boat, prop, test time and by someone that would use a clean fuel tank, clean fuel filter and fresh battery.

Frank, take good care of those engines as they are all one of a kind and collectable, historic and very likely still competitive in the right hands.

As to the origin of the name, the Quincy "Z" engine; let's see, we were in Quincy, Illinois, Zak was in Moline and we communicated frequently, starting in 1975 (although few knew that) when Chris and I restarted the Quincy racing engine program. Harry used to visit with Chris and me on many Saturday afternoons. It's truly an amazing story that after all these years, no one seems to have figured it out. Harry contributed to pro outboard racing in many more ways than most of you are aware. Think about that.

Look forward to seeing more photos.

Paul A Christner

10-13-2008, 06:51 PM
Sounds to me like a non effort on some parts of the organization, at that time anyways, or maybe there wasn't an org., at any rate Dieter didn't have that prob. and we went on and progressed.

Original Looper 1
10-13-2008, 09:13 PM
Mr. Z's influence traveled far.

10-14-2008, 04:40 AM
Paul, I have seen that device before and the other caption implied it belonged to the factory. I'm not surprised to learn it was really a Zak. Originally I thought it was 80 cubic inches ... now that there is info that it was actually raced, I'm more inclined to think 60 cubic inches for an F

What publication is that pic from?

John (Taylor) Gabrowski
10-14-2008, 06:00 PM
What a picture of that dual power headed Merc racing engine!

That is what that adapter and coupler here is all about except in this case the Merc engines are one front and one reversed. I can only suppose that was done to fit modified Quincy pipes where the picture must have exhaust blowing out the bottom out of some kind of dump through the base adapter plate for the engines.

Those racers then sure had imaginations they turned into results! :)

John (Taylor) Gabrowski
11-02-2008, 06:09 PM
I am sorry, I can offer no knowledge on the Quincy Z engines because of heavily being into stock outboard racing until 1983 aside from hearing about them. I was and still am of the feeling that the Flathead was not yet at its end when it was decided to go the Z route.

To me there are no other racing sounds that can compete with a Flathead 6 or on the other side a Quincy-Merc or equivilent Merc 6 Deflector on pipes! I mean nothing, no Indy car, no dragster, no nothing makes me shiver the way those Quincys and their padded block Deflector competitor 6s do when they run, they are so unique and so catching, they take your breath away, in my case always. Running a 44 Flathead is always impressive but the 6s!!!!!!!!!!!!!! :)

Tim Chance
11-03-2008, 06:44 AM
Paul, John, Frank or Gene,

I have a personal interest in the Quincy Z motor and have a bit of "sketchy" background regarding the development of the Z. Was it during the early 60's?

I drove the prototype B at Alexandria in 1975 or 76 for Quincy Welding. I shared the motor with Paul and unfortunately Paul was hurt quite badly when he blew over while in first place in B runabout coming out of the first turn. David Christner shared an A engine with Kay Harrison ( David on the same runabout as Paul and Kay with the same hydro as me (a Chance Craft, by the way). Barry Anderson also ran an A on a Chance Craft. Kay finished first in his elimination heat but was DQ'd for gun jumping.

Karen, there was also that motor that predated the Z that had the Yamaha crank that looked like a flathead on steroids. Same configuration, just bigger. Your Grandpa had one, but I don't know if he ever ran it.

12-05-2008, 12:26 PM
These are two pix of Stu Mill's [Windsor, ON] 125 'Z' as displayed at the OF Christner Memorial in 2003.

12-05-2008, 02:52 PM

nice pictures of the 125 z. the one i'm restoring has a different ignition on it, however i have a bunch of those ignitions with the blue distributor cap. larry latta went to an ignition module from a pioneer chainsaw. i was able to find some. i'm waiting for them to arrive and the 125 will be finished. my 125 tower is the same as the one you have posted. they clean up so nice.

i've got everything but the 2 carbs for the rb to b conversion. i had a second rb powerhead i'm converting, the other will stay an rb. i have to say that the z engines are a dream to work on. o f, paul and everyone else who developed it had the racer in mind. everything comes apart soooooo easy. i'll post pictures when all is finished.


12-05-2008, 04:09 PM
I found the floppy that I used on that visit to Ted Miller's shop.
Looks like it was the spring of 2004
Here is the two cylinder 'Z' that was there,
a 250 I presume.

12-05-2008, 04:19 PM
A single that Ted had.

Master Oil Racing Team
12-05-2008, 07:39 PM
I posted pictures of that crash on "Splash" David. I remember it too. Paul was as you described, on the other side of the race course on the backside, and started to blow over. Looking through the lens at races, I sometimes missed what else was going on. When I snapped the first frame, the runabout was perfectly parallel to the water. Having talked to Paul extensively on a couple of occassions about this, I think he was barrel rolling as the boat got airborne.

When the boat hit the water it exploded, which you can tell. Paul took the bottom of the boat out with his back and the weight of himself carried him down to where it was dark. Paul had thought his back was broken. He did not black out at this point, and you know how it is.....it's all in slow motion. With his breath knocked out at first, it's a wonder that his body didn't automatically try to breath when the sudden impact subsided. Then, as Paul began to try to take stock of himself, he was suddenly needing air badly since the blow had taken it away. His life jacket was taking him up, but he needed a breath now. Imagine as a kid falling from a tree, hitting flat on your back and getting momentarily paralyzed and unable to breath. You recover and soon you stand up and shake it off. When Paul's paralyzation quit, and his lungs screamed for air....he was still coming up.

Paul was a time in the hospital at Alexandria. Besides broken ribs, kidney bruises, and some other damage, I forget how long he was in there. He told me but I don't recall now. When I saw all the wood exploding through my lens and looking as if the boat fell on top of him, we dreaded the worst. It wasn't until a couple of years ago that Paul told me he took out the bottom. It was just too fast to see, but it looked very bad.

John (Taylor) Gabrowski
12-06-2008, 09:32 PM
That is the second 3 Holer Merc 650 with pipes I have seen anywhere else with another one he had with Quincy Flathead elbos parked on a stand. Both engines look like they ran a lot but how did they burn no one will know I suppose.

Neat Z engine pictures, it is too bad both they and the Flatheads did not continue in evolution. I would love to see a Flathead with a single exhaust port per cylinder with an expansion chamber parked on them. Computer modelling seems to show that all the 2s, 4s and 6s could have even been bigger horsepower makers than they were on megs but that is something I suppose we will never see unless someone makes a project of it just to make or break what calculations and simulations seem to indicate.

12-07-2008, 07:48 AM
would require a different crankshaft ... known as the Z

John (Taylor) Gabrowski
12-07-2008, 12:05 PM
Mark 75H, No it would not require a Flathead to have a Z crankshaft.

It would have required a revised block casting/machining to go from a twin port - 180 degree split exhaust which is the bane of using Expansion Chambers to a single port exhaust where most things are today to use expansion chambers properly. Two pipes with 180 degree twin exhaust ports were needed to service 2 ports servicing the same cylinder at the same time with sonic pulse effects effectively that did not work well where the design in the abscence of what expansion chambered exhausts are today relied upon bell megaphones, to a single exhaust port percylinder does lend itself to modern expansion chambers today.

From studying Flatheads extensively from restoring quite a few doing it, it would be as simple removing the liners using 180 degree split exhaust ports and putting in single exhaust port liners with minor remachining of each exhaust passage way to reflect the new liner situation.

The engine would look the same but obviously would sound different and run different reflecting the newer technology of the single port liner and single expansion chamber per cylinder. As Elmer Grade said it back in 2001, when we discussed that and the Quincy 6 banger they at times used, the Mercury crankshafts and rods where excellent and real hardy for the purpose then would still do the job. It is too bad not one tried it, meaning the single exhaust port cylinder concept turned into reality. He believed it would work. Then he launched into what was wrong with Konig cranks when your applied too much torque and horsepower to them. Before OF's death the same change was brought to him and he saw the merit to the single exhaust port concept in the Flatheads knowing technologies had changed since to what they are now. That was quite an acknowlegement.

There are some out there today restoring Quincy Flatheads too these days who could actually take a crack at the concept as it takes a machine shop, the spare time, the know how and a bit of the money too, to prove it all out. I am convinced that the Quincy Flathead could have gone further and longer than it did. With that technology Quincy would have gone on further with more American iron present in racing further in time than was. :)

12-07-2008, 12:42 PM
To make a Quincy with one single large exhaust port on one side would require farther cylinder spacing and a different crankshaft

Original Looper 1
12-07-2008, 01:30 PM
I've been following this thread and I'm concerned as to why you never appropriately brought up this debate after I previously posted these pictures on 1/06 & 1/08/07 with the explanation as to what they were - so let's do it again.

The 4 photos are of the Quinsky motor(not to be confused with Quincy). It was a creation by the late, great Stan Leavendusky aka Stan's Custom Pistons. A lot of people may not know it, but most Quincy Loopers used Leavendusky piston blanks as the building blocks for Quincy pistons. Stan was quite an innovator in the evolution of the Quincy Looper's success. His son, Butch, was also a top notch pro racer, especially in the runabout classes. Stan took it upon himself, with his son's help, to create and develop the Quinsky, based on the Konig internal specifications (porting wise and layout) with the conventional Looper Merc-Quincy exterior dimensions (stacked cylinders, not opposed) and crankshaft. The Quinsky was an experimental motor with a lot of good ideas.

Especially note: this engine had the single exhaust port. It was tried both with the Looper intake porting arrangement in conjuction with the single exhaust port and also with the Konig intake port layout with single exhaust.

Also notice the individual carbs per cylinder, along with individual external reed valves per cylinder. The horsepower of this engine was slightly less than the best Loopers of the day. This engine also ran a multitude of different expansion chambers.

We've been there and did that! Your theories are well meaning, but don't assume it hasn't been tried before. One of the major problems of the Loopers was the structural integrity of the crankshaft designs, both 2 & 4 cylinder. In other words, they were at the end of their intended design lifespan, and then some.

The Z engine was, what Chris & I thought, the best of all worlds. The 125 Z engine dominated 125cc racing for almost 20 years. What does that say about the design?

The main problem I see, looking back, was that I couldn't convince my dad to go the opposed route in 2, 4 and 6 cylinders with a new crankshaft. The opposed motors are silk smooth in comparison to tandem. The only regrets I have now is that we didn't somehow forge a meaningful relationship back then in B and C hydro with the caliber of racers such as Wayne & Baldy Baldwin to promote the Z engine as it should have been promoted. If we had done that back then, we might not be talking about Rossi and VRP now, which are quite similar to the Z engines with reed valves and similar porting but of opposed design.

Paul A Christner

Please note: these photos are for your enjoyment and are not to be copied or posted to any other web site without my written permission.

John (Taylor) Gabrowski
12-07-2008, 02:03 PM
Mark75H for a bigger exhaust port might require differences maybe in your view and concept?

I was always referring to a single exhaust port only within the confines of the existing Flathead block castings and exhaust port tunnel space allocated there already and not outside of that. From any engineering and machining standpoint working within the existing casting, it is doable without different rods or crankshafts in use.

Of course the Quincy Z is a departure that went in a good direction for a long time for Quincy. Its just hind sight at work in this technological period knowing the technology in previous periods only allowed them so much back then and technology has since changed that so one can look at what ifs even with computer simulation programs that did not exist back then, now.

To me this is a case of wishful thinking about what could have been had Quincy survived to these times and enjoyed what is technologically available now that was not available then.. Even should have that been the case it does not mean that Quincy would still have gone that direction with the Flatheads, it might not have. Its just wishful thinking here on my part as a admirier and supporter of Quincy Welding and what it accomplished for us all. Quincy Welding was "the amazing company" of its time and in everything that Quincy did from padded blocks Deflectors, to Flatheads to Z engines which is quite a record of achievement very much to be proud of, preserved and cherished. :)

I think we will always have arguments about what could have been! :)