Making a Chris-Craft flathead

I would love to make a 1/6th scale model of a Chris Craft boat engine. Flatheads (sidevalves) seem to sound so good and I am a model boat builder anyway, preferring the mahogany hotrods to any other.

Has anyone published plans of a flathead 6 cylinder engine in any scale, or even a four that could be extended by 2 cylinders?

I know of Westbury's Seal, but wondered if there is anything else that might be more suitable.

Cheers,
Martin

The old Chris Craft 6 cylinder was based on the Chrysler flathead 6, if that is any help.

Thanks, I wasn't aware of that. The Chrysler block looks simpler, so I could probably make it in brass, fabricated. I don't have the equipment for machining large lumps. Nobody makes kits of a straight six, as far as I know. And the Seal wouldn't do as a base for a 4 cylinder as the plugs are in the side of the head, oddly, for a sidevalve.
Cheers,
Martin

Chris Craft engine was designed and produced for them by Hercules.

So, are there any plans for the Hercules? Just a section or a cutaway would help.

Martin

Martin,

The Antique Boat Museum at Clayton, NY, has a wonderful collection of boat engines on display. They may have a Chris Craft six. I don't remember. If you are anywhere close, this might be a good source for external engine details.

Good luck with your project . Please keep us informed.

Chuck

This may not be of much help, but the September, 2018, issue of Hemmings Motor News ( A collector-car publication in the USA) contains an article about the Stokes Marine Supply Company which converted car engines for marine use before 1970. The article seems not to be available online. Googling "Stokes..." generates some hits, but nothing that quickly provides a lot of information.

Apparently, just about any popular engine could have ended up in a boat during that time, so you could probably choose something you believe you could build and go from there...

Best wishes for your build and I'm sure we would like to see a build thread.

--ShopShoe

Martin,

Another thought. If you can find a Motors Manual car repair book from the forties or early fifties, I suspect you'd find cross section drawings for various makes of flat head sixes along with photos of engine parts.

Chuck

Build has advanced since these pics were taken.
Get some tomorrow.
4 cylinder 4 stroke, water cooled, methanol/glow, single updraught carburettor, 25cc, working tacho built from picaxe micro and mini servo.
Tops out around 10,000 rpm though it won't be doing that in the water.
During tests it had a magnetic drive water pump to a heat exchanger but in the boat, conventional cooling off the prop (less chance of failure)
No plans as such, built on the go so-to-speak with many pencil drawings but they were all lost in the flood here in 2013. Had to re-build most of the boat and engine also.

Many thanks for your suggestions, chaps. I'm in eastern England, btw.
Bluejets, that's a lovely looking and sounding engine. Will you be making a rocker cover for it? I suppose making a 4 cylinder is sensible for a first job and I could always put it in a model of the Whippet single step hydro which used British 1.5 litre engines, like the Meadows Whippet engine, the Lea Francis, etc.
I will have to research what they looked like. There was also a British built hydro with a Bugatti 1500 cc, engine.
I will have to have a think. I do like the old sidevalves (flatheads).
But it'll have to be smaller than the Westbury engines or the boat would need to be huge and I don't have that space.
Cheers,
Martin

It seems that the Meadows engine in the Whippet hydro was a 4ED, a numerous and very basic OHV 1500. I'm wondering what happened to that website where the guy had fabricated everything from brass due to having no mill. That's something I could do as I also have no mill and only a Taig lathe, but I really want to make a working 4 cylinder engine and put it in a model boat.

Martin

4cyl. dimensions but it is a start.
http://www.woodyboater.com/wp-content/uploads/2013/04/1955-Model-B.jpg

That's very helpful. Many thanks. I can probably do something with that as it's quite basic. Sidevalve is easy too.

Cheers,

Martin

I would advise against a multi-cylinder as a first engine.
Many things to go wrong and any problems whatsoever will discourage attempts to finish.
Many will struggle with piston/cylinder but most problems will come from the sealing of the valves.
The method both George Punter ( Englishman also) and myself use is to turn the valves and the valve guide units without shifting the top cross slide.
One might think it would make no difference but it does. Once moved, it never goes back to the exact same position and these valve seats are REALLY small.
You could do the same whether side valve or overhead by using the machined valve guide/seat assembly as we do.

George made an engine here in Aus for his year 10 students when he was teaching called the "Simple Simon".
25cc, can have many variations such as poppet valve for intake or make up the twin cam for conventional.
He made castings etc. but not for sale. Can be manufactured from solid or built up.
He once gave permission for it to be freely used so I can find it and put it here for you if you like.
Can be water cooled or air cooled.

Also came up with a design of a 12v CDI ignition system using off-the-shelf parts for around $20.00.
Offered it to one of your magazines there about a year ago but they didn't seem interested for some reason or other.

Bluejets, I appreciate what you're saying about the difficulties of making a small 4 cylinder, although I don't really understand what you mean about the top slide.
I hadn't anticipated any problems with the valves, just the camshaft seemed to be the potential stalling point.
The reason I want to do the Chris Craft or a simple OHV is because they can go in a model boat and actually be used. I don't really need another single cylinder that merely apes any of the many available single cylinder 4 strokers available off the shelf.
But mainly I need to get straight to what I need at my time of life!

I still need to see if it'll all fit on my little Taig lathe any way. I'll draw up the Meadows and reprint that CC drawing to size and see if it's possible.
If I go ahead I would certainly be after your ignition system as I have no clue how all that lecktrickery works.
It doesn't surprise me that you got short shrift from mag. editors over here. I wrote an article for a high end model railway magazine as invited to do by the editor, then he changed to some one else and when I sent in the articles he told me that "nobody made anything anymore", which was the whole point of his particular rag. I told him where to get off and lit my woodburner with his articles! These days Model Engineer and the other one seem obsessed with CNC stuff, which all means nothing to me.

Many thanks for your concerns and help. I hope you can see why I can't really spend time going on the slow path through simpler stuff.

Cheers,
Martin

Seen many start out wanting to make a 4 cylinder or V8 ( Mustangs and Spitfire for r/c trainers too) and then find the complexities overwhelming and just plain give up and that's why I mentioned it.
The single cylinder does indeed have practical use and many have been fitted to boats and whatever in the past over here. Not bad for year 10 kids, and better than bending up a dustpan for metalwork prac.

The problem of the valves is, most will make the valves with the angle cut, then go off and do other things, then come back at some later date and do the guides and seats.
This is where they come unstuck.
You can get by on a sloppy piston fit or rings that are not yet bedded in by running up with a good starter but if the valves don't seal properly, no amount of high speed starter(or anything else) is going to help.

Never used a Taig but on my Myford, the top slide can be adjusted to any angle and used to cut both the seat and the valve face without moving the top slide angle whatsoever.
Guarantees same angle on both seats and valve face.
Taig if I remember are fairly small machines, are you sure it will be capable ?

For the cams I built a cam grinder machine, same for the crankshafts, purpose built machine BUT I have seen some do pretty good work with just a basic lathe and mill.
Plenty of good info out there by those who have done so.

Ignition has been bench tested and all seems ok .
Proof will be when George finishes off his 3 cylinder 4 stroke 50cc engine he built for a scale diesel loco in the coming months.

I'm sure you're right about giving up. I had to with a Westbury Sealion, but only because I got busy, required a smaller more accurate lathe than the Myford I had and ended up with the Taig, because it was cheap. Had it now for over 30 years! Flogged the castings to a bloke in Oxford who dealt with old model engineering stuff. Regretted it ever since as I can't afford the castings any more. When I bought them they came from a funny little man in the back room of a stationary shop in Oundle, Northants.

I have no interest in a V8 at all. Never been part of my life at all.

I see your point about the top slide now, thanks. I'll bear that in mind. There is a small top slide on my Taig that should just do valves and guides/seats. I take it guides/seats are a separate unit that gets heat shrinked into the head or is there some other method?

Whilst I would consider a single for an aeroplane, it really doesn't appeal for a boat at all. If I'm going to get flack from the Nazis for an IC engine, it might as well be for a big un as a single!

Cheers,
Martin

Yes, I see your point.
Guides/seats I usually make as a single unit to keep everything concentric and once again, so it seals when it should.
Pressing in is ok but it does not have to be an overwhelming great tight fit requiring heating/freezing or whatever.
The top lip holds all in place and a drop of loctite does the rest.
Same with cylinders, no need to have a massive great fit there either. Practice here is to make both the liner and the "hole" on a slight taper (not much) just enough.
Liner then slips in almost all the way and again with a drop of loctite and a small tap, they fit great.
Also, I might add, without resultant belly bulge that some have to deal with (very rarely successfully).
Again all seals down with a top lip "T" section.

Liner