The crappest engine design ever? (flathead engines?)

The Original Tom · Post by **The Original Tom** » Fri Jul 20, 2007 3:54 pm

I've heard this term used a bit, but have no idea what it actually means? What's the difference between a flat head engine and a, well... non-flat headed one?!

Tom.

Post by **katanaman** » Fri Jul 20, 2007 3:58 pm

I think what your referring to is the heads on a side valve engine so there are no valves in the head? Its basically a lump of metal thats just there to keep the compression in.

The Original Tom · Post by **The Original Tom** » Fri Jul 20, 2007 4:15 pm

Ok, so the valves are in the block? Sounds like a much more logical arrangement to me - head gaskets would be damn easy to change, and even if one blew you'd not lose and water or oil - none of the traditional blown head problems. No need for tappets, or rockers either - much simpler!
Why don't more people run them?

Post by **katanaman** » Fri Jul 20, 2007 4:30 pm

its not as simple as just a flat bit metal that was just a generalisation. They still have water in them. Some links

http://www.flatheaddrag.com/flathead_basics.html
http://www.vanpeltsales.com/FH_web/flathead_home.htm
http://en.wikipedia.org/wiki/Ford_Flathead_engine

They dont use them because the performance is rubbish due to the poor gas flow routes.

sidecar · Post by **sidecar** » Fri Jul 20, 2007 4:33 pm

The Original Tom wrote:Ok, so the valves are in the block? Sounds like a much more logical arrangement to me - head gaskets would be damn easy to change, and even if one blew you'd not lose and water or oil - none of the traditional blown head problems. No need for tappets, or rockers either - much simpler!
Why don't more people run them?

The downside is that they have poor performance when compared to over head valve engines due to several factors, the main one being low compression and a poor combustion chamber shape which needs loads of igintion advance and is prone to detonation.

Push rod engines aren't much harder to work on than side valve lumps, it's double overhead cams that are a pain in the bum!

Suffolk punch lawn mower engines are side valves!

You could be talking about "heron head" engines where there is no combustion chamber at all in the head even though the valves are in the head. The chamber is machined or cast into the piston. Heron heads are the crappiest of crap! (At least in petrol engines).

Pete

kiwicar · Post by **kiwicar** » Fri Jul 20, 2007 6:07 pm

I think you are forgetting "inlet over exhaust" engines...... worst of all worlds, exhaust valves in block, exhaust exiting through the block, long inlet valve train, pushrod pinch, lowest compression ratio even with huge piston crowns, wierd shape combustion chamber, no logical place for the plug,water leaks because there is not enough gasket face, very under square engine, huge dedicated fan base with the stationary engine boys (yawn)!!!

Mike

The Original Tom · Post by **The Original Tom** » Fri Jul 20, 2007 6:24 pm

Ok well having seen the engine blocks they certainly look an... interesting design!!!
I think it's quite a good idea, but the fact that the exhausts exit through the block between the cylinders must make cooling interesting!!

I can see why they're no longer popular.

sidecar · Post by **sidecar** » Fri Jul 20, 2007 7:02 pm

This could catch on, who can come up with the crappiest engine design ever, or part of an engine design.

To get the ball rolling, how about "hot bulb" ignition. Or even worse I vaguely remember reading about engines that had a bit of file sticking out of the piston that ran across a lump of flint in the combuston chamber!

I mean where the hell to you connect the timing strobe?

Pete

Post by **katanaman** » Fri Jul 20, 2007 7:45 pm

No1 crap engine Honda CB900f engine comes with free glass crank and rods
No2 crap engine Honda VF750f Comes with none line bored cam tunnel and chocolate cam.

Ok not really in the spirit of things but at least most of the engines above lasted more than the first high rev gear change!!

I think some of the most unusual engines have to be in aviation. The radial engine for one. Not the one we are used to seeing but the original where the crank was stationary and the whole engine spun round it with the prop bolted on that.

kiwicar · Post by **kiwicar** » Fri Jul 20, 2007 7:55 pm

on the rotating cylinders theme my grandfarther was a ferry pilot in WW1, while taking a plane fitted with one of those things (i think it may have been a sopworth pup) over to france (about half way) he noticed he was loosing power and rapidly getting closer to the sea, he looked down to see the crank had come loose and had started to rotate, had to take off his boot and jam it in so the thing would stay still. I think is says how little power these things made that his boot would be enough to get it working again

If you want a really odd engine configuration look up the deltic loco engine

who ever thought that was a good idea was not a well person

Mike

kev_the_mole · Post by **kev_the_mole** » Fri Jul 20, 2007 8:09 pm

How about Diesel's coal dust engine or the Vietcong bus engines that ran on carbon monoxide.

The Original Tom · Post by **The Original Tom** » Fri Jul 20, 2007 8:32 pm

sidecar wrote:This could catch on, who can come up with the crappiest engine design ever, or part of an engine design.
Pete

I like that idea - thread name duly changed!

bill shurvinton · Post by **bill shurvinton** » Fri Jul 20, 2007 8:45 pm

One of those English vs Merkin things. We called them side valve, they called them flathead. In a T-bucket hot rod they do look the dogs, and they certainly have a low CoG, but powerful they aren't. The French were using them for military vehicles until the early 90s when a huge mil surplus warehouse of brand new engines got everyone over the other side of the pond very exited.

My Grandad had an Austin 7 and my mum remembers him doing a decoke on it, whih was whipping off the head and cleaning it up.

The sidevalve was a good design for the lubricants and fuels of the time, both of which were carp. For a bad engine...Hmmm. I would be pilloried if I said the triumph V8, so it might have to be the 2.6 straight 6 rover. The power of a 4 pot and heavier than a V8.

Post by **katanaman** » Fri Jul 20, 2007 9:04 pm

moved here as it pretty much general now

Deltic was an odd engine but so far as I know it was good at its job.

Does the engine ever have to have worked? If not then the gunpowder fuelled engine has to be a candidate. http://www.freepatentsonline.com/4301774.html for the patent.

The Original Tom · Post by **The Original Tom** » Fri Jul 20, 2007 9:15 pm

Yeah I heard the deltic was a fantastic engine at what it was meant to do. Even if they do take about 1/2 an hour to start up