Webra 1.5cc

1960s Webra Rekord 1.5cc.

Put it into a hot oven to free it up. Don't dismantle it. Be gentle with it when hot, use gloves.

1/3 castor oil, 1/3 lamp oil/kerosene/JetA1 and 1/3 ether will run it. Suggest a 9X4 prop. to get it started.

Competition fuel is 30% castor, 30% kero, 40% ether and either an 8X4 prop. or 7X4 for maximum revs.

1966 advert

Here is a photo of the manual, they are pretty much like any other diesel engine. To find the correct compression ratio prime the side of the piston only and flip. Gradually increase the compression ratio while flipping until it fires, this can be done with one hand on the compression screw while flipping with the other. This ensure that you can quickly release the compression too if the engine fires and sounds laboured. Once you have mastered the priming and starting, then connect a tank and run it.

It's a good sport engine.

You can find it stunt or RC,

Hey thanks guys for the tips and ID I won't take it apart, just put it in the oven first to see if it is enough to free the compression setting. Then, a good cleanup, some oil to the bearings and we're good to go.

I'll let y'all know how it turns out. Please be patient, this may take a while

OK... With some heat, penetrating oil and gentle persuation I was able to get the compression setting locking lever and the screw itself loose. But the screw is not attached to the "contra piston" I am pretty sure that nothing snapped while I loosened the screw, and the end of the screw looks machined, not broken.

Should the contra- or counter piston just float in the cylinder or should it be attached to the setting screw? If it should be attached, can it be repaired somehow or do I have a new paperweight?

The counter piston does not move and the engine won't turn past the tdc. I have not put a wrench on it, just tried to turn it by the drive plate using fingers only but it feels kinda solid. Now it is soaking in penetrating oil.

The contra piston is not attached to the adjustment screw. In a quality engine as the Webra, the fit is quite snug. Unfortunately when sitting for a log time, it really gets frozen. Heat, oil, and patience will free it. Run the screw down until you feel it touch, then back it out 1/2 turn or so. Than way you'll insure the contra can move up under compression when you finally get the piston free.

The best way to unfreeze a frozen counter piston is to take off the cylinder and gently press the counter piston higher up in the bore. Use a vice or similar to do this.

To get the cylinder off, just warm it up using a heating gun.

Thanks Gwillie, I was a bit worried about the screw and contra piston thing. More heat and oil (and time) it is then. I did mount a prop on it, loosened the compression screw, and gently turned the prop back and forth near the tdc until it turned over. I put some penetrating oil into the cylinder and again turned the crank gently back and forth, hoping that the pressure would force-feed the oil between the cylinder wall and the contra piston. It is still stuck but maybe over time it will break loose.

Kris, I would like to take the engine apart but the cylinder threads are most likely very stuck, and the construction is so thin at the ports level that I am worried about distorting it. So I'll try to un-freeze it first with other methods. But when I heat it the next time, now that it has soaked in penetrating oil for a few days, who knows, maybe I can get it apart. I guess I am still a bit traumatized because of the TeeDee cylinder that I mangled (with my two hands and a pair of cox wrenches), so I want to be careful. Especially as the parts support for Webra is nowhere near as good as it is for Cox engines.

Anyone have a cut-away drawing or an exploded view pic of this engine?

If you can turn the engine through TDC then you could always try to run it on a prime. Set the compression screw loose (half a turn or more from where it engages the counter piston) and then when the engine fires it will push the contra piston back up towards the compression screw.

I haven't seen any exploded views for the Webra but they are made pretty much just like any other engines from that time.

My engine comes apart quite easily so here are a few pictures.

The cylinder is quite interesting, it doesn't have but three transfer channels but six in total.

The center bore through the crank is very small though and there is no counter weight on the crank either, so there is room for improvement

One reason for taking taking the engine apart is to check that the gudgeon pin is not frozen onto the conrod, if it is run like that it will wear on the piston...

Removing the backplate can be enough to check for that.

Surfer_kris wrote:If you can turn the engine through TDC then you could always try to run it on a prime. Set the compression screw loose (half a turn or more from where it engages the counter piston) and then when the engine fires it will push the contra piston back up towards the compression screw.

I haven't seen any exploded views for the Webra but they are made pretty much just like any other engines from that time.

As Surfer Kris says, with a prime of diesel fuel, the contra piston will be blown upward. You need to get a copy of Eric Clutton's Dr. Diesel's Diary; it is full of diesel expertise. http://www.cafes.net/doctordiesel/

Webras are among the very best engines you can find.

Surfer_kris wrote:If you can turn the engine through TDC then you could always try to run it on a prime. Set the compression screw loose (half a turn or more from where it engages the counter piston) and then when the engine fires it will push the contra piston back up towards the compression screw.

I concur. "If" it goes past TDC there is little chance you will damage the rod unless flooded. Prime the side of the piston with the exhaust port closed & give it a flip with the comp screw 1/2 a turn loose. Even if it doesn't go over TDC it may still fire and drive the contra piston up. (Get you fingers quickly out of the way, and never use a starter) You may hear a significant "clack" as it strikes the compression screw. If it does so, check the screw & see if the clearence is still there. If you can make it fire a few times, this may heat & expand the contra piston slightly more than the cylinder, and when it cools it may be a little looser. Never force it over TDC hoping to move the contra piston. Many rods have been bent this way.
Rod.