Making a Chris-Craft flathead

[MrTin]

Oh that's a very useful drawing, bluejets, thanks.
In fact I meant to ask, is there a book about building engines generally from which I could take snippets of usefulness?
It would save me from searching out old ME articles by ETW, for instance.

Cheers,
Martin

 

[MrTin]

I will attempt to draw up the Whippet in overall dimensions and print that ChrisCraft 4 cylinder down to a workable size.
I was wondering about using proprietary cylinders and pistons from , say old Merco 61s, as I already have 2 that I bought for a tenner the pair at a dog show!
I'd like to make it a bit smaller than the liner drawing shows, but that is still useful for shape.

But a book that covers material choices, etc. would be very useful.

Martin

 

[Richard Carlstedt]

First , the 6 Cylinder flathead engine had a 230 Cubic Inch Displacement and was used in the 30 and 40"s up to 1959 ( IMHO) in their Plymouth and Dodge cars--- and ( I was told ) also in the Cris Craft boats, with the exhaust manifold being water cooled and the appropriate Intake manifold revisions. Chrysler also had a larger Flathead six (254 Cu In ?) used in some Chrysler Cars up to 1954 and those engines are easily identified by the word 'Spitfire" on the Flathead.
As a kid in the mid 50's ,it (230) was the first engine I learned to completely overhaul. A very reliable engine to say the least.
The Mariners Museum in Newport News Virginia has been designated as the head quarters for all Cris Craft history and data storage. They have a huge historical display of the boats and most likely all the drawings in their library . The librarian for the Chris Craft collection is Patti Hinson and you may wish to talk to her
https://www.marinersmuseum.org/library/plans-drawings/

Rich

For plans for a IC engine , you may want to look at the Panther Pup . I believe there are variations that are water cooled...but it is a OHV engine

https://littlemachineshop.com/products/product_view.php?ProductID=2341

Also you want to look up George Britnell who was recently named Metal Craftsman of the Year 2016 by the Craftsmanship Museum. George has done extensive engine building from scratch and his work should be a guiding light in your quest
https://www.craftsmanshipmuseum.com/britnell.htm

 

[MrTin]

Hi Rich,
I have a feeling the Panther Pub may be too big for my needs and I have no idea how to make it watercooled, but thanks for the thought.
I have those drawings above for a Chris Craft and they would be sufficient to design a nice flathead around.
At the moment, I am just assessing the options.
It all hinges around whether I can do the stuff on my Taig lathe and without a milling machine.

Cheers,
Martin

 

[Cogsy]

For valves I use press in cages but I don't use the lathe to cut the seat so I don't have issues with cross slide changes. When I turn up the valves (making sure to make a few extras just in case) I turn one valve blank into a valve seat cutter by milling some teeth into it. For brass valve cages a few turns of the cutter in the installed cage by hand is enough to create a seat, and the 'stem' of the valve cutter through the valve guide ensures it's concentric. I believe George Britnell came up with the idea (or at least popularised it). Works great and is very simple, plus eliminates any possibility of installation distortion being an issue.

I would agree that a quick single cylinder is the way to start though. It doesn't have to be a long build, certainly doesn't need castings, and doesn't need to be an aero engine either. A Webster or Upshur Farm Engine could be whipped up in 40 hours most likely and will teach you an enormous amount about constructing a working IC engine. I'd guess the experience would save you more time than that if you went straight into a complex multi-build, with remaking parts and diagnosing problems. Even simple things like getting orders of machining operations wrong can force a part to be scrapped and when it's something you've spent 5, 10 or 15 hours on it's a real pain. It is true that the vast majority of people that start a complex build as their first never finish it, though very experienced machinists sometimes do manage. Good luck!

 

[MrTin]

Cogsy,
I just don't have the need for or interest in a single. Just like I don't have the slightest interest in a V8, even if I could make one with ease. A twin cam 6 would be nice, but camshafts already frighten me so a twin cam is not on. I just want a realistic model in a suitable boat. I had thought of Ron Colonna's Offy in a 1/4 scale Miss Daytona, but I wasn't impressed with reports of the difficulties with his book and certain aspects of the engine.
So a very basic sidevalve would do in a suitable Chris Craft.

You mention brass valve cages. Wouldn't they be a bit soft on the seats?

Martin

 

[Charles Lamont]

A twin cam 6 would be nice, but camshafts already frighten me so a twin cam is not on.

Hey, if you can make three, you can make five! (I'm allowing for scrapage)

 

[MrTin]

Haha, if it took that many attempts, it really WOULD get left. I'd put an electric motor inside it!

Martin

 

[Cogsy]

Brass cages have been used in a lot of engines without issue. Spring force on model valves isn't overly high.

 

[bluejets]

Have a quick gander at the site link below on the construction details of a Seagull single cylinder.
Any of the sections would suffice and remembering if you are into a four cylinder , times 4 for almost everything.
Author has very kindly included the time spent on each part.

http://www.charleslamont.me.uk/Seagull/home.html

Built a single in a boat maybe 20 years ago, first ic engine, had done steam and other previously so was aware of the order of "machining steps".
Trip to the local boat pond with the grandkids used to end up in an almost all afternoon event as kids came from everywhere for a 2 minute "drive of the boat".
Tank is about 3oz from memory and so it was about a 15 minute turn-around, refuel, re-start and out again.
Boat is a scale neptune around 650mm length and engine is a 7.5cc side valve, 2 single cams, water cooled, glow ignition, methanol @4:1.
Allowance for spark ignition and a set of points at the rear, castings all made here.
Large flywheel to get idle down to a tick-over, works great.

Did have an old book from the 50's that had been reprinted many times, went in the flood here but I'll ask George about the name of it. Might be old but many things still apply.
Mostly used it before the internet became what it is today. Vast amounts of info freely available in model engineering sites, might take a bit to find sometimes but it's there. Just have to weed out good from bad ideas or to allow for your machining gear.
Mastiff marine engine might be worth a look also, 25cc side valve flat four.