Which JB Weld to use to seal the cam bung.

[Stevex]

After years of living with a small leak from the cam bung on the crank case rear face I'm prepping the bike for crabbing.
I don't ever want to visit this job again so got to get it right this time.
Is the standard JB Weld putty (Steelstick) up to the job or do I need a heat resistant option?
I've checked out amazon and noticed there is are HighHeat and ExtremeHeat versions.

[bigbikerrick]

I have sealed those successfully with regular JB weld, but if they make a higher heat product, it may be superior. I didnt use the stuff in a stick, but the two part tubes.  I think whats most important is scuffing up the area,and cleaning it very well with degreaser.
Rick.

[John A]

as you clean it Id use a heat gun to help get the oil out of the edges. sometimes after heat you'll notice the cam plug is loose. you can peen the edges over to help tighten it up before you seal it. I'd use the high temp stuff as well.

[Tom H]

As mentioned. Regular JB Weld will do just fine. I would NOT get the High Heat version for car headers and the like. Just make sure you have the cam plug clean. Brake clean and a paper towel does the job unless you have a really grimy one, then a wire brush as well.

Tom

[Antietam Classic Cycle]

My local powdercoater uses JB KwikWeld to fill dents and such before 'coating. He says it holds up to the heat better than regular JB Weld.

[Stevex]

Thanks for the info chaps. I have standard JB but have ordered some High Heat. The info says HH can be used on aluminium but Extreme heat says ferrous metals.

[Steph]

Has anybody ever had the JB weld come loose in there?

[bigbikerrick]

Has anybody ever had the JB weld come loose in there?

I think as long as you degrease the area well,and  roughen up the surface so the JB can get some "bite" , it will stick tenaciously.
Rick.

[Steph]

I think as long as you degrease the area well,and  roughen up the surface so the JB can get some "bite" , it will stick tenaciously.
Rick.

Thanks for that.
Just wondered, beyond the degreasing a roughing of the area, the JB weld will still subject to different metal heat expansion, vibration etc?
Im sure it’s fine but thought I’d ask as I’m considering doing it too

[jcctx]

Thread seal(er)??

[Don G]

I have always used a good quality RTV silicone like Permatex Ultra, been doing that to automotive engines since 1981, it will expand and contract better than epoxy.  DonG

[Antietam Classic Cycle]

JB Weld has been used successfully to repair cracks in diesel engine crankcases, so it must expand and contract some. I've applied it to every Guzzi engine I've rebuilt, as have many others. Never any reports of it failing.

[Stevex]

I have always used a good quality RTV silicone like Permatex Ultra, been doing that to automotive engines since 1981, it will expand and contract better than epoxy.  DonG

I used aircraft grade RTV about 10 years ago on the cam bung. This was before I became aware of JB Weld.
It didn't even last the first summer but I've lived with the leak until now.
The heat range of the High Heat JB Weld is higher than a Guzzi engine will get so hopefully it's sorted.
Getting the gearbox back on was a right chew due to not being able to nose the engine forward with the crabbed frame. I eventually got the splined hub into the clutch, then the push rod adaptor in the clutch went cockeyed and I had to remove the gearbox again to re seat it. Second time round the hub just slid in.