SQ4 main bearing

[Henning G]

Hello Everyone.. As you can clearly see, the casting where the outer rear main bearing fits on my 4G, has suffered some damage. I wonder if it will have any influence on oil escaping into the primary chain housing. I will fit the oil seal on the rear crank connecting sprocket behind the outer bearing. If it has, does anyone have the correct measurement on the hole?
Best Regards, Henning

[admin]

(Better off in 4-stroke technical - topic moved!)

SG

[paul.jameson]

I would be tempted to try it and see what happens. The oil seal wasn't originally fitted to the iron 4G models and my first one ran happily for years without one. My present 4G though, needed one straight away, possibly due to the badly worn pistons I had fitted initially.

Any weld repair may well distort the casting. These were originally matched individually to the crankcases as can be seen by the small number stamped on both casting and crankcase.

[Simon.Gardiner]

I've used glue (araldite, JB Weld etc) to patch up non-critical areas (mainly primary chaincases) and I don't think I've ever had a failure. Is this somewhere a suitably-shaped piece of thin sheet a aluminium could be glued in place?
(Obvious qualifications, I don't exactly know that area of a Square 4 intimately, and I don't know how hot it gets! )

SG

[Henning G]

Hi, THANKS for your great answers, I had the feeling that welding is of some risk, and the “lip” wasn’t there for fun. In the meantime, I found some “ALUTIGHT” in my soldering box. It’s a kind of alu soldering, only requires 380deg. Im renovating the engine with new pistons, and I will certainly look into the crankcase ventilating system. Thanks a lot for you help..
Regards
Henning

[JohnnyBeckett]

hi i have used JB weld for lots of repairs over the last 30 years it can withstand a lot of heat , i think it is the very good and never let me down with the jobs i have used it for

[Henning G]

I will give it a try, Thanks. Will let you know how it works…
Regards Henning

[Henning G]

So I finally got around to finish my little project. I made a tight fit aluminum disc, preheated the whole cover in my wife’s Owen to around 250 deg, and then soldered it with “alutight” by means of a soft gas flame. It only requires 380 deg. Thanks for all your comments..
Regards Henning

[allan.walker]

I bet Owen objected to being heated to 250 degrees....

A very nice repair, though!

[Henning G]

My wife did, owen can go to 300deg. Pretty east to solder with "alutight"