Hi Dave,

I have an almost new DZ 140 which runs very well in all respects. However there are fuel leaks from many places on the engine, e.g. pump (top and bottom). cam gear housing, backplate assembly, rocker box cover etc. This isn't just restricted to my engine, I was at a team selection event yesterday here in the UK and a number of pilots running DZ's had the same problem. As I said the leaks are not catastrophic and all the DZ's ran very well yesterday in the howling crosswinds, but the leakage does get all over the place. Needless to say I've gone round the engine checking that all the screws were tight, but did not over tighten them as I've seen a previous comment not to do this as the castings distort.

Apart from the generic green leak-free gaskets that are curently marketed, are there any other products that can be used to beef up the seals between this engine parts?

Regards

Keith

Wow Keith,

You must be psychic! - I looked up this forum to post just the same question!

Regards

Malcolm H

Here are the things we've seen with the DZ's.

Pump gasket not installed properly or not installed at all.

Cylinder head shim improperly installed and crushed when the head was put on.

This had been in only a very small number of engines which were all from the first shipment of DZ's we received. Problems have since been corrected in production.

Hope this helps.

Dave

Could the leak from the head shim look as if it was coming out of the carb?

Does this affect performance any?

At any rate, my first motor (from the first shipment I think) is a messy sucker No problems with power (16x13 APC at 8400 the other day, 30% nitro/3500'asl) or overall running, just messy.

Think that might be the culprit? I have never been too concerned since the motor ran so well. My other one doesnt seem to be as bad.

Hi Dave,

Thanks for the reply about the various problems encountered but I was more interested in the possible use of jointing compounds or perhaps other OEM gaskets that might be available to be used in place of the YS gaskets. In the past I've smeared a very thin layer of silicone over the YS gskets and this in large seemed to work, but its quite messy to do this.

Any suggestions would be a great help.

Thanks


Keith Jackson

UK F3A Team member 2003

PS.

Great link to the Canadian Team web page Chad; wish we had sponsors here in the UK like those!

The head shim leak makes them run poorly. It's easy to check, just run some oil under the head and see if it blows bubbles when you turn the prop.

We really aren't having any big issues with the DZ's. Quique has one with over 500 flights and never had it apart. There are several others in the 300 plus range that I know of.

As far as after market gaskets, I don't think there are any for the DZ, and I can't personally recommend any kind of sealer since I've never used any.