Engine/Tech

Mermaid Engine - how it all came to be

When I decided to do a repro of the Mermaid car, I began by looking around for a good running 368 Lincoln motor. I bought a 56 Lincoln parts car from a guy in Rockford that had 40 some thousand miles on it but the motor seemed to run pretty well. I pulled it and sent it to the local machine shop for a freshening. We did a valve job, new rings, bearings, and cut the heads .040 to raise the compression a notch. I sent the stock cam to Chris Nielsen and he ground it to 230 @ .050 with .430 lift.

Once the machining was finished, I bolted everything back together, and added 56 Continental valve covers. Aftermarket intakes are scarce, and the best I had at the time was an old Edmunds 2x2 single plane. I modified 2 Rochester 2bbl’s and bolted them on. Ford Y block distributors fit, so I bought a late 292 unit and converted it to electronic. I bolted on the stock exhaust manifolds and headed for the dyno at R&R Performance are located in Spring Lake Park MN, which is a north suburb of St. Paul.

R&R Performance was great to work with. They have loads of patience and experience - which comes in handy with unusual applications like this. We were able to hook the motor to the dyno without too much hassle, as I had obtained a truck bellhousing and flywheel for the 332 version of this motor.

In my mind, I had hoped to equal or exceed the factory 2x4 335 hp version, and I certainly figured to at least exceed the 300 hp rating for the single 4bbl. WRONG ! The best I could obtain with the 2x2 manifold was 278 hp at 5200 rpm. I thought maybe the manifold and carbs were the problem so we tried the stock 4bbl and a 600 cfm Edelbrock. Lost 30 hp.. The stock manifold is a lousy design with the carb sitting lower than the runners. At this point I gave up. I was disappointed to say the least. However I was pleased that the motor ran well, with no problems, plenty of oil pressure, and a smooth idle. The folks at R&R made some suggestions, and I went home to contemplate power increases, and the expenditure of capital. (You know the old saying).

I began by learning as much about these engines as I could. Rick Martin was very helpful in this regard, as well as several left coast guys whose names escape me. You would be surprised what comes out of the woodwork from a wanted add in Hemmings! I decided the engine needed more of everything, compression, cam, fuel, and airflow. I learned that 57 heads were worth a point more compression so I obtained a set from a 368 Mercury Turnpike cruiser, then sent them to R&R for new valves (we used Caddilac 472/500), a street port job, and a .040 shave. Here lies one of the problems in making more power. Even the small 57 heads have 75cc chambers after milling, This limits compression with flat top pistons to about 9.5:1. The heads do however have excellent flow for a stock casting, and light porting helped a bunch especially on the exhaust side.

When it came time to select the cam, the old-timers all said Clay Smith ground the cams for the original Mermaid , so I sent them another stock cam to be reground. Cam blanks for these motors are made from unobtainium. I let them select the grind after explaining my needs. They recommended their 300x grind, which is: 240@.050 240@.050 with .420 lift.

Originally this motor used hydraulic lifters, but I went to solids since it uses the same blasted low ratio adjustable as the Ford Y. This is one reason for the low valve lift, you just can’t put enough lobe lift on a reground cam to overcome the low ratio rockerarm. On the first go around I just slid the cam in, lined up the timing marks and called it good. Second time I decided to degree it. AH HA! I found we were running 12 degrees RETARDED. Certainly enough explain part of our earlier poor performance. Of course there are no adjustable timing components available, so it necessitated a lot of head scratching and a couple of trips to a machinist before we solved the problem. I ended up about 2 degrees advanced which will leave us straight up with a little chain stretch figured in.

As for fuel delivery, the original 57Mermaid had Hilborn injection, and a Vertex Mag. The Mag proved easy to find, since I knew Ford Y would fit. I obtained a nice one from the Y-BLOCK MAGAZINE for sale adds. The Hilborn Injection proved a real challenge. In my conversations I had located 3 setups, but nobody was in a mood to sell. I nearly gave up and had resigned myself to just go with the 2x4 factory setup, when a guy told me he thought an early Olds injection unit could be adapted. I ran down to the parts store and bought an intake gasket. I held it up to the 368 head and low and behold, the intake ports LINED UP. Not only that, but so did two of the boltholes to attach it. I tracked down a sadly abused 303 Olds unit, and with some judicious grinding, welding and drilling I had a decent fitting and looking set-up. I sent the whole thing off to Kinsler in Mi. who totally rebuilt and calibrated it for my application. (Superb workmanship, great tech assistance, but pricey).

After making fuel delivery improvments, I wanted to improve the exhaust in some way. I felt the stock exhaust manifolds were hurting me, but I did not want to shell out extra money for custom headers just for dyno use. I fabricated a plate to fit the 368, then bought a sbc kit and fabricated a small adapter to use the chevy headers every dyno uses. I booked a day of dyno time and we headed out with great expectations, I figured we could do 375 hp.

It took a lot of time to get everything plumbed correctly and to work the glitches out of the FI. Finally we could make some pulls and we ended with a best of 370 hp at 5400 rpm, and VERY flat torque curve from 3000 on up. I wanted to run the 2x2 for comparison, but ran out of time. The motor still needs more cam and compression. I think it is easily capable of 400 hp, and the guys at R&R say the heads would easily support 450 hp as they are currently set up. I think my plan of attack is to use the current engine as is to get the Mermaid up and running, then build an all out motor later. I have talked Rick Martin out of a roller cam and a set of .125 over high compression pistons. Add a welded stroker crank, fully ported heads, roller rockers, and I can see 420 + cubes, and 500 + hp. The Lincoln Y is a better powerplant than most people give credit, especially when you consider it’s original iteration is in 1952. If you ask around you find that these motors were popular in racecars and boats in the late 50’s.

Here are some of the strengths and weaknesses as I see them:

STRENGTHS:
Superb oiling on the bottom end, just like a Ford Y. Very tall , thick block, lots of room to bore and stroke VERY long rods. 7.0625” This works well with current engine theory on maximizing dwell at TDC for torque at high rpm. Also leads to great longevity of bores and pistons, my 40,000 mile motor showed almost no wear. Excellent flowing heads, with decent size valves. 2.00 intake, 1.63 ex. (one of very few Fords with decent size ex valve). I had my heads flowed before and after porting. Before: intake 200 cfm@.400 cfm@ .400 221cfm@ .500 Exhaust 127 135 After: Intake 223@ .400 234@.500 234@.500 all at 28” water Exhaust 144 173. These are excellent numbers folks, very close to what my 428CJ heads flow, and only with minor clean-up and bowl work. The boys at R&R were very impressed saying they did not know of a stock brand X head that flowed that good. The ports, both intake and ex, are very chevy-like in appearance. Do you suppose the bowtie boys took a lesson? Forged cranks and gear drive cam can be pirated from the truck version of this engine series. I have been told a 4” stroker is no problem, which with an .125 overbore would give 431 cubes. The gear drive would also be nice, but may not be worth the hassle with reverse rotation cam and distributor. The stock timing chain is a VERY beefy piece

WEAKNESSES:
Lack of go fast goodies. You think you Y Ford guys have it tough? Almost no decent intakes are available. Factory cast iron stuff is aweful. The 2x4 M-335 intake is probably the best of everything, but rare and expensive. I have the 2x2 Edmunds which is fair, and also a 2X4 Edminds which looks identical design wise. It takes the small base wcfb chevy style carb, so I doubt it is much improvement over the 2x2. I also have an old Crower U-FAB log style that takes 4 Strombergs. Maybe Jerry Christianson can be talked into fabricating one similar to his Y Ford design. Heavy, wide block for the amount of cubes. This sucker weighs more than an FE Oddball bellhousing and crank flange bolt pattern. Y-Lincoln/Merc only Stick cars don’t exist for Lincoln, and are super rare on 57 Mercs. You are looking at truck parts unless you get lucky. (I did score an aluminum flywheel). You can however, easily put a Hydromatic behind them. Even today this is an excellent hotrod transmission, capable of absorbing gobs of power and giving you 4 speeds.

In addition, like the Y-Ford, the Lincoln heads have a funky combustion chamber shape that extends outside the cylinder of the bore. This can cause problems with high valve lift, and the edge of the bore impeding the valve. Large overbores help, but I suspect notching still needs to be done if lift is over .500. The combustion chambers are very large, and you need pop-up pistons to get good compression. Also, the valves are wide apart in the chamber and are shrouded by the combustion chamber wall, and prevent installing larger valves, a glitch in an otherwise excellent head. I have not experienced, but guys tell me that at high compression we have some of the same problems as Y-Ford, lack of decent gasket, and flexing of the combustion chamber roof. Rick Martin tells me he has some 57 heads that are posted by the factory. Mine are not, 56 or 57 While the rods are long, they are not very beefy. I suspect anything over 450 hp puts them at risk. The factory style piston design also sucks. The comp distance is huge, making the piston very tall and heavy. I have not done the math yet, but with a stroke job to 4” I am hoping I can find an off the shelf quality rod that I can use with a modern design piston to produce a really bulletproof bottom end.