When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
Well about a year ago I had some bronze in my oil, checked the run out and I was at .011 The camplate, oil pump, cams and lifters are toast and Im assuming the crank
This NOS crank ended up in my lap which Im going to true. Ive seen people plug and weld the ends which increases the press fit for the fly wheel. In my mind, that still relies on the press fit which can fail.
What about drilling between the pin and the wheel, pressing a dowel and tack welding? I understand the crank wont be serviceable after this
That is, by definition, "plugging" "pinning" the crank pin. Attached is a picture of a plugged and welded crank pin. IIRC, the plug is stainless and installed with a interference fit of .0045"-.006". This is a DIY project by a forum member I pulled up from a few years back. He was concerned that the heat from the TIG welding would tweak the crank out of true but it did not. He could touch the wheels after welding. I think the heavy assembly absorbed the heat like a big heat sink?
@djlI think the OP is referring to just pining the crank pin and welding, not plugging..
I think you are correct; thanks. Slip of the tongue on "plugging" vs "pinning"; they are two different procedures; my bad. I need to edit my post to be clear.
Well about a year ago I had some bronze in my oil, checked the run out and I was at .011 The camplate, oil pump, cams and lifters are toast and Im assuming the crank
This NOS crank ended up in my lap which Im going to true. Ive seen people plug and weld the ends which increases the press fit for the fly wheel. In my mind, that still relies on the press fit which can fail.
What about drilling between the pin and the wheel, pressing a dowel and tack welding? I understand the crank wont be serviceable after this
Thoughts?
I'm not a machinist but I would imagine two very high carbon steel pins (heat treated) with a tight press fit and at least a 1/4" weld, 2 on each wheel will help.. I would think the hard part would be trueing..
21984002[/url]]That is, by definition, "plugging" "pinning" the crank pin. Attached is a picture of a plugged and welded crank pin. IIRC, the plug is stainless and installed with a interference fit of .0045"-.006". This is a DIY project by a forum member I pulled up from a few years back. He was concerned that the heat from the TIG welding would tweak the crank out of true but it did not. He could touch the wheels after welding. I think the heavy assembly absorbed the heat like a big heat sink?
EDIT: Strike thru correction.
I saw this post and its what gave me motivation to give it a go. Im going to plug mine like this but I didnt know if putting a pin in there as well would be beneficial.
Originally Posted by 98hotrodfatboy;[url=tel:21984050
21984050[/url]]@djl
I wonder how much reciprocating mass that puts on the wheels. I imagine rebalancing would be critical..
I think the OP is referring to just pining the crank pin and welding, not plugging..
Good point. Those pins dont weigh much but it does add a little mass. I was planning on plugging the crank as well but maybe this is a better alternative? Just curious if anyone has done it this way.
do you stress the machine?
if normal rider, all of that is moot.
i do say this, be careful doing anything to the crank, they are not a piece of non destructible steel and in a way fragile. stress induce fracturing is a possibility.
i doubt that small welds will affect the balance that much, where it is more important is the piston assy.
on diff machines, sometimes a small hole is drilled and tapped and a allen is thread locked between the matting surface.
not dragging??? spend the money on beer. how many stock cranks are there merrily spinning on over the decades living happily ever after. shoot i ran 170+k miles on one and only went to s&s because bird in hand, had the engine out for frame restoration and upped the ponies.
do you stress the machine?
if normal rider, all of that is moot.
i do say this, be careful doing anything to the crank, they are not a piece of non destructible steel and in a way fragile. stress induce fracturing is a possibility.
i doubt that small welds will affect the balance that much, where it is more important is the piston assy.
on diff machines, sometimes a small hole is drilled and tapped and a allen is thread locked between the matting surface.
not dragging??? spend the money on beer. how many stock cranks are there merrily spinning on over the decades living happily ever after. shoot i ran 170+k miles on one and only went to s&s because bird in hand, had the engine out for frame restoration and upped the ponies.
On my well built stock crank 110"er there has been no run out change in 13k miles. Yes, I measured it because I do a lot of cam changes looking for more power. For now I' back down to my Stage II heads with a TW-888 @11.16:1 comp.. No issues.
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.
Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.
Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.
Crank pin bullet proofing.
