Filler choice for MZ cylinder head

[lundtang]

We have been meddling with reduction of engine knocking of 300 ccm 2 stroke engines for the MZ, by filing small groves in the edge of the cylinder head. This disturbes the detonation wave starting from the spark plug.
Anyway as we do not have an endless supply of usable cylinder heads I would like to fill the groves again on some of the less successful attempts.

any guesses on tungsten type and filler for these old east german cast aluminium alloys ?

It is probably going to be a nightmare of cleaning and preheating.

I have pure argon, an AC tig and a footpedal.

I will get some pictures later

Thanks
Andreas

 

[rikrobson]

have you thought of hts2000 to fil the grooves?

 

[pedrobedro]

If the heads are cast then 4043 is usually recommended.

 

[lundtang]

Thanks
I give it a try with 4043 or filling material taken from an actual sample. Otherwise the HTS2000 looks interesting.

 

[CRB]

Some of us more enlightened members love MZs

No idea how to do what you ask though.

 

[eSCHEn]

Some of us more enlightened members love MZs

+1

 

[lundtang]

Yup, just started on a ts150 from 77 needs a total overhaul but is in reasonable shape. The current working cycle is a Saxon 250 with velorex sidecar.

 

[Mr shiney]

4043. I weld cylinder heads all the time. Usually doing fin repairs and thread repairs.

I would not use the HTS stuff on what you want to do.

 

[dannyp]

that aluminium solder brazeing stuff has no place in a cyl head

4043 every time

 

[Richard.]

Silicon based filler as the guys mention above. 4043 (5% Si) or 4047 (12% Si) has worked for me on Alu casting repairs in the past. The trick is to find as close a match to the material as pos. Alu cast is full of junk to be honest but usually contains quite a bit of Si as well as other rubbish. You'll want a good amount of cleaning on the balance ep% (40% plus) good luck.