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RickG61
08-14-2017, 11:30 AM
Searched the forums about powder coating and Sportster cam cover bearings, found a few threads, but none that answered my question. So, anyone with experience having this done? Here's my question.

Will the heat from the powder coat oven expand my housing enough that the pressed in bearings are gonna fall out? I routinely use heat at work to remove stuck parts, INCLUDING pressed in sleeve bearings. Not on shit like this though. I don't want to go through the hassle of having bearings pressed back in or replaced, and the reaming shit that needs to be done afterwards. Not tearing down the rest of the motor, just having the covers on each side and the valve covers powder coated. The engine is low miles, existing bearings look great, cams look great. I understand that after the coating, there's gonna be some clean up to get rid of dust/dirt/ etc in the bearing area, but I'm wanting to avoid the time and expense of replacing if I don't need to.

So, anyone have a Sportster cam cover powdered and have bearings fall out during the baking?

Dragstews
08-14-2017, 11:51 AM
They can fall out ...
The cure heat of powder is 400 degrees for a good 20 minutes.....

RickG61
08-14-2017, 12:57 PM
They can fall out ...
The cure heat of powder is 400 degrees for a good 20 minutes.....

Reusable without reaming if pressed back in? Have you ever tried that if its happened to you?

humancertainty
08-14-2017, 2:23 PM
I've heard of it happening but had no problems when I powdered mine.

tzienlee
08-14-2017, 2:51 PM
if you clean it real well & de-grease it with carb or brake cleaner
then use high temp powder coating masking tape (available on Ebay) so no powder can get to the inside or on the gasket faces.
then get your powder coater to hang it virticaly when he powders & bakes it.
the bush's shouldn't fall out as they will be in a horizontal position........

Tattooo
08-14-2017, 3:02 PM
Everything heats at the same rate so I don't see how they will fall out..... But if it should happen, They should be replaced as they weren't in there properly in the first place.....

jimboh
08-14-2017, 6:43 PM
My powdercoater did mine with no problems. Still no problems 2 years later.

RickG61
08-15-2017, 9:14 AM
if you clean it real well & de-grease it with carb or brake cleaner
then use high temp powder coating masking tape (available on Ebay) so no powder can get to the inside or on the gasket faces.
then get your powder coater to hang it virticaly when he powders & bakes it.
the bush's shouldn't fall out as they will be in a horizontal position........

I like that vertical idea. Something I'll push for when he does them. Thanks.

RickG61
08-15-2017, 9:26 AM
Everything heats at the same rate so I don't see how they will fall out..... But if it should happen, They should be replaced as they weren't in there properly in the first place.....

Thanks a lot Tattoo. I blame you for the time I just wasted looking at thermal expansion rates comparing aluminum and brass/bronze. I understood very little of it, other than they expand differently at the same temperatures. LOL Damned engineers. Why can't they speak English instead of math formulas. LOL

My job involves rebuilding pumps. Many of them have bronze bearings installed in housings of dissimilar material. Small parts we toss in an oven to heat it up. Granted, I don't heat them to 400 degrees, usually in the 275 to 300 degree area, but those bearings come out a whole lot easier at that temp, which tells me the housings expanded more than the bearing even tho they were heated equally. I guess I was applying that logic to my covers and worrying that those small bearings would drop out if the aluminum expanded quicker and further than the bronze.

I need to stay away from websites that make me think to much. Look at more sites with nekkid women. LOL

Dragstews
08-15-2017, 9:39 AM
Those bushings are dowel pin-ed in....
That's a plus to keep them from falling out ....

RickG61
08-15-2017, 10:01 AM
Those bushings are dowel pin-ed in....
That's a plus to keep them from falling out ....
I think the factory installed ones are without the dowels, but the manual says when replacing them, you have to drill and install dowels. After reading the service manual, I looked at mine last night, no dowels there.

RickG61
08-15-2017, 10:03 AM
I suppose I COULD dowel mine in before the powder coating as some added insurance.

tzienlee
08-15-2017, 11:29 AM
from the factory they were drilled and pinned to prevent the bush's spinning in the cover and causing greater damage,...
if your's are not pinned in they are probably new to the motor & whoever fitted them only did 1/2 the job.
a drilling jig is needed (see thumbnail pic)

PS... Thinking about it,...what year is yours??...
I don't work on anything later than 84 and it might be later sportsters (the evo things) didn't pin the bushes,.... Ironheads & earlier did however

Tattooo
08-15-2017, 12:26 PM
Thanks a lot Tattoo. I blame you for the time I just wasted looking at thermal expansion rates comparing aluminum and brass/bronze. I understood very little of it, other than they expand differently at the same temperatures. LOL Damned engineers. Why can't they speak English instead of math formulas. LOL
LOL

I know what your talking about... Hell that's one of the reasons why I quite school in the 10 grade..... Well that and I needed to get a job to be able to eat...... But anyway, I didn't understand why I needed to learn Latin names for animals.... Hell you shoot and eat a squirrel it's still a squirrel to me and it was good.......... LOL

RickG61
08-15-2017, 2:06 PM
I know what your talking about... Hell that's one of the reasons why I quite school in the 10 grade..... Well that and I needed to get a job to be able to eat...... But anyway, I didn't understand why I needed to learn Latin names for animals.... Hell you shoot and eat a squirrel it's still a squirrel to me and it was good.......... LOL

Ratimus maximus? LOL

RickG61
08-15-2017, 2:09 PM
from the factory they were drilled and pinned to prevent the bush's spinning in the cover and causing greater damage,...
if your's are not pinned in they are probably new to the motor & whoever fitted them only did 1/2 the job.
a drilling jig is needed (see thumbnail pic)

PS... Thinking about it,...what year is yours??...
I don't work on anything later than 84 and it might be later sportsters (the evo things) didn't pin the bushes,.... Ironheads & earlier did however


86. Yeah EVO, per the factory manual, it says they were not pinned from the factory, but that they needed to be pinned if replaced. Mines low miles, so I'm guessing never apart.