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4 Valve DOHC 2-Stroke

General Tech Talk

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4 Valve DOHC 2-Stroke

Post by ISUZUROVER »

Not 4x4 tech, but tech nevertheless, and I though some people would be interested in this.

I was in italy on the weekend, and got to have a look around the workshop of a race engine builder. amongst heaps of really cool stuff, was this 4 Valve DOHC 2-STROKE single cylinder go cart engine. Since it is a 2-stroke, all 4 valves are exhaust!!! The intake ports are visible at the bottom of the bore.

Edit - who can guess what brand of piston is fitted and what the usual application for the piston is (first 2 letters are visible in the 2nd pic)???
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Post by droopypete »

motorlet, aviation
send me my steak knives :D
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Post by ISUZUROVER »

droopypete wrote:motorlet, aviation
send me my steak knives :D
Peter.
Sorry, wrong.

I bet everyone on here knows the brand though, but it's not the kind of application you would think of.
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Re: 4 Valve DOHC 2-Stroke

Post by Simo63 »

ISUZUROVER wrote:Not 4x4 tech, but tech nevertheless, and I though some people would be interested in this.

I was in italy on the weekend, and got to have a look around the workshop of a race engine builder. amongst heaps of really cool stuff, was this 4 Valve DOHC 2-STROKE single cylinder go cart engine. Since it is a 2-stroke, all 4 valves are exhaust!!! The intake ports are visible at the bottom of the bore.

Edit - who can guess what brand of piston is fitted and what the usual application for the piston is (first 2 letters are visible in the 2nd pic)???
I reckon it's a Mahle piston ..... maybe out of a motorcycle engine?

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Re: 4 Valve DOHC 2-Stroke

Post by Simo63 »

ISUZUROVER wrote:Not 4x4 tech, but tech nevertheless, and I though some people would be interested in this.

I was in italy on the weekend, and got to have a look around the workshop of a race engine builder. amongst heaps of really cool stuff, was this 4 Valve DOHC 2-STROKE single cylinder go cart engine. Since it is a 2-stroke, all 4 valves are exhaust!!! The intake ports are visible at the bottom of the bore.

Edit - who can guess what brand of piston is fitted and what the usual application for the piston is (first 2 letters are visible in the 2nd pic)???
Actually on second look it looks like Motorcraft??
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Post by jeep97tj »

So it only has the inlet port on one side and the exhaust port is missing from the other?

Good way to complicate a simple engine. The few extra HP created from getting more exhaust gasses out would surly be used up by all the extra gear hanging off of it?? But your right it is cool :cool: :cool:
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Post by scorched »

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Post by mico »

Motorcraft i'd say, probably out of some sort of ford (Falcon, light truck???)
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Post by ISUZUROVER »

jeep97tj wrote:So it only has the inlet port on one side and the exhaust port is missing from the other?
Yep, exactly.

Everyone is still wrong, not Mahle or Motorcraft.

Piston was made in the US though if that helps.
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Post by Spike_Sierra »

mopar?
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Post by droopypete »

Or maybe Motori Moderni F1?
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Post by droopypete »

Ok, as Motori Moderni is Italian and Morris is pommy I will have to try again :?
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Post by droopypete »

Mopar?
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Post by ISUZUROVER »

Still no on all counts... Here is another hint: The company that made the piston went bust AFAIK.

But here is something else to guess. Only 8 were ever made in the world (in italy), mid mounted V8, magnesium/aluminium monocoque chassis and fibreglass body. What is it:

EDIT - on the shelf behind the car are about 6 pairs of mid 70's Ferrari F1 engine heads, but don't think along those lines.
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Post by runnin4life »

duno who it is but do you care to just tell us lol
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Post by Nat84 »

in the second pic the box looks like a alfa one
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Post by ISUZUROVER »

Nat84 wrote:in the second pic the box looks like a alfa one
Well Done. It is an Alfa 33.2 race car - only 8 ever built in the world, and this one had to be completely rebuilt after a fire. This exact car will be competing in the Le Mans historic race this year.

Image
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Post by Nat84 »

i have owned 2 alfas and have broken my fair share of box
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Post by ISUZUROVER »

Now back to the piston...

some more hints: it is not from a car, motorbike or aeroplane engine.
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Post by Nat84 »

MOROSO
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Post by ISUZUROVER »

Nat84 wrote:MOROSO
No
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Post by Nat84 »

do we get any more hints?
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Post by ISUZUROVER »

Nat84 wrote:do we get any more hints?
You already have:
Made in the US by a company that went bust (in about 99/00).
Not from a motorbike, plane or car engine.

Last hint:
Piston is also made for a single cylinder engine.
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Post by droopypete »

Mc Cullock chainsaw :armsup:
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Post by ISUZUROVER »

droopypete wrote:Mc Cullock chainsaw :armsup:
Well done. Thought I had made it too easy now.

I would buy you (and Nat) a beer as a present, but you would have to come to Germany to drink it.
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Post by droopypete »

So I can go to bed now?
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Re: 4 Valve DOHC 2-Stroke

Post by Bush65 »

ISUZUROVER wrote:...The intake ports are visible at the bottom of the bore...
If they are the intake ports, this engine must have some form of forced induction.

With a conventional 2 stroke, the intake is into the crankcase and those ports into the cylinder would be transfer ports.

Any more info?
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Post by jeep97tj »

The inlet is still forced by the reducing crankcase volume but instead of the inlet gases forcing some of the exhaust gases out the port oppsite, the valves open up top allowing alot more of the exhaust gases to be flushed out.
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Re: 4 Valve DOHC 2-Stroke

Post by ISUZUROVER »

Bush65 wrote:
ISUZUROVER wrote:...The intake ports are visible at the bottom of the bore...
If they are the intake ports, this engine must have some form of forced induction.

With a conventional 2 stroke, the intake is into the crankcase and those ports into the cylinder would be transfer ports.

Any more info?
I think you are probably correct John, from memory the carby was on the opposite side to the ports. So air must be sucked into the crankcase, and then through the "transfer" ports into the cylinder.

The engine builder who showed it to me said it was a similar concept to 2-stroke diesels, but AFAIK all 2-stroke diesels have some form of forced induction??? I couldn't see any forced induction on this engine.
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Post by Bush65 »

jeep97tj wrote:The inlet is still forced by the reducing crankcase volume but instead of the inlet gases forcing some of the exhaust gases out the port oppsite, the valves open up top allowing alot more of the exhaust gases to be flushed out.
I think you are confusing the inlet with the transfer as well!

Inlet is into the crankcase, except with forced induction.

Inlet ports are usually, opened/closed by the bottom of the piston skirt, reed valves or disc valves.

As the inlet port closes, the transfer ports open and the descending piston displaces the air fuel mix into the cylinder through the transfer ports.
John
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