Kmot

My Feedback: (24)

Like most of my engines in my collection, this was purchased second hand many years ago.

This engine looked to be new, never used. However it did have some fuel residue and was gummed up a bit. But I found out by running it that it certainly had never been broken in. As I ran the engine the top RPM slowly increased and the idle RPM slowly was reduced and more reliable. I put about 90 minutes on the engine today.

Prop is a Rev-Up 12x5W 4-cycle, glow plug is a Thunderbolt standard long, fuel is Powermaster 15%, temperature outside was in the mid 90's.

Max RPM achieved was 8000, and lowest idle speed was 3000.

The engine is VERY quiet, and even rivals the HP VT-21 I ran yesterday!

This is an interesting piece of engineering. Cast crankcase, billet head, billet carb, belt drive for the valve drum, ball raced, two needle carb. It's marvelous to look at, and it runs sweet.

[youtube]http://www.youtube.com/watch?v=LqBv3LQ6spI[/youtube]

pe reivers

sweet, but not powerful. I had one. It would be a nice engine for a small cub.

Kmot

My Feedback: (24)

Definitely not powerful.

I was thinking of some sort of a floater, like an old time free flight converted to r/c.

gkamysz

My Feedback: (19)

The strangest thing is the T4-40 I have has intake in back and exhaust out the side. I don't think I've ever seen another one with this arrangement. They are neat engines. I have a new spare head for one, but have never checked to see if it's the same arrangement as the engine I have.

pe reivers

Intake is the at the end of the hollow rotary drum. Exhaust uses a cross-over pathway inside the valve.
Reworking this rotary valve for better gas flow can bring a gain of about 500 rpm IIRC.

gkamysz

My Feedback: (19)

Pe, look at Tom's engine. The intake is in the side. I just checked the spare head and it's timed so the rear port opens first and then the cross port, opposite of the engine I have.

Kmot

My Feedback: (24)

Greg, if you do an image search on Google, or even look at Webra lit. they all have the carb on the side. Maybe you have a prototype??

http://images.rcuniverse.com/forum/u...02/Om33348.jpg

gkamysz

My Feedback: (19)

Nothing about the way it looks says it's not production.

Here's mine.


I found one more on google images. http://www.modell-motoren-archiv.de/...viertWEBRA.htm

pe reivers

Old age is playing tricks on me.
Now I am unsure of carb location!
I am sure of the carb being bolted directly to the head, and the trumpet valve shape of the rotor. My engine was a 6.5cc. Rotor axial backlash could be adjusted by (carb or exhaust stack, dang!)

gkamysz

My Feedback: (19)

I always thought it would be tough to put a tank at spray bar center with the common carb on head arrangement. So I thought those were the odd ones!

earlwb

I would agree that on the T4-40 engines they mounted the carb directly off the intake port on the engine. But with the larger T4-60 and T4-80, etc engines they mounted the carb down lower and used a short length of bent tubing as a intake manifold tube for it. That allowed for easier fuel tank placement.  I do not remember seeing a T4-40 with a carb mounted down lower before like they did on the larger engines. But it would make sense to do so for the fuel tank placement. But maybe they were thinking people were going to side mount the engines or something.

Motorboy

I saw at the difference at timing belt cover and carburator/exhaust location between T4-40 and T4-60/T4-80. Kmot own Webra is a T4-40 since it is same form at timing belt cover while other Webra T4-40 has black timing belt cover. It can be a first and second version T4-40 in production line with changing og location of carburator with long intake pipe or direct mounted carburator at cylinder head/exhaust and paintet/unpaintet timing cover. Difficult to learn out which of these T4-40 came first in production line...

jetpack

My Feedback: (1)

Thaks Kmot for the restoration and video. I always wanted one of those and almost bought one just to take it apart out of curiousity. Your resto pics and writings were great and its nice to see your having good luck with its running!

Kmot

My Feedback: (24)

Thanks Jetpack!

I did not restore the T4-40. But I am restoring a T4-60 in another thread.

jetpack

My Feedback: (1)

YOUR PAINTING YOUR ENGINE? WHY? AINT IT GOING TO COME OFF? DOESNT IT RUN ANYMORE?? ....lol...thats the questions I get, how about you?

Yes, I got confused with the engines you've been working on. Both are super-cool. The rotory valve of the Webra 4's really interest me. I like your beagle btw.

The sound of that engine is great.

Kmot

My Feedback: (24)

"Well, no, actually. The paint doesn't come off. And yes, the engines are still run. "

That's what I would tell them.

JP, another Webra four stroke had another style of valve, it was cone shaped and also spun with a gear.

Greg, I was surfing the web last night and came across another reference to your version of the T4-40 head on a French forum. It was called the "T4-40 'R' Series" according to the gentleman there.

gkamysz

My Feedback: (19)

I have a used crankcase and crank for a T4-40. I might try to make the rest and use the spare head when I find belts.

JimmyZep

I have a RCM mag from Oct 84 with a review of this eng.

Jimmy

Kmot

My Feedback: (24)

Scan it and post it!

gkamysz

My Feedback: (19)

It's also in Lee's "The RC Four Stroke Engine" published by RCM. Chinn's "Model Four-Stroke Engines" has a small blurb in the back.

maxtenet

I think we need a shootout between the WebraT4-40 and the HP VT .49!

Max

gkamysz

My Feedback: (19)

Max, both engines with tests are in each of the above mentioned books. Any four stroke enthusiast without these books owes it to themselves to track down a copy.

Reginald

The first Webra T-4's did have the arrangement like the engine from my collection. Later a conversion set was available from Webra so you could put the carb in the head.

Reginald

earlwb

Nice pics of the T4 engines Reginald. I think you have the most ultimate collection of engines that I know that anyone has.

If I remember correctly, the T4-40 with the carb mounted directly on the head was for RC cars or trucks. Years ago, there was a push to get people to use 4 stroke engines in cars and trucks. For RC cars and trucks, OS marketed a .26, MECOA had a special VT-21 or 25, and Webra had the T4-40.