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Problem intake nipple

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Post Tue Aug 25, 2020 2:08 pm

Posts: 1436
Location: Ojo Caliente,NM,USA
I've got the intake nipple out of a 36 sport scout cylinder and at some time in the past some tuner went crazy with a grinder and there is about 5/8" of the seal surface missing the one I removed had something resembling JB Weld on the threads and had passed a bubble test until recently. Any suggestions?
Dusty

Post Tue Aug 25, 2020 6:39 pm
don

Posts: 602
Location: Spokane WA USA
Dusty,
A board search of "xpando" will bring up a discussion on a possible cure, Including Cotton's opine.
Don

Post Wed Aug 26, 2020 11:41 am

Posts: 3539
Location: Central Illinois, USA
It ain't about the goober, Dusty!

Its about the P4gas.

If you can machine the surfaces for a real seal, you will be much better off for the long run.

...Cotten
PS: I am surprised how well Gorilla Glue has survived my soak tests...

Post Wed Aug 26, 2020 12:48 pm

Posts: 1436
Location: Ojo Caliente,NM,USA
There ain't nothing left to machine on the original seal area This cylinder has been sleeved so I don't want to weld in there if anything else will work. How bout a carefully sized cone washer trapping an O-ring on the outside and JB-Weld in the threads? What ever they had in the threads held for years until I cooked it.
Dusty

Post Wed Aug 26, 2020 1:19 pm

Posts: 1436
Location: Ojo Caliente,NM,USA
The gorilla glue I put on that Durable float probably 6 or 7 years ago is still holding when I managed to break it again this year it broke in new places and I Gorilla Glued it up while waiting for the new float and since it working I left it in there.I am carrying the new one in my saddle bag.
Dusty

Post Wed Aug 26, 2020 3:41 pm

Posts: 104
Maybe a photo?

Post Sun Aug 30, 2020 5:53 pm

Posts: 1436
Location: Ojo Caliente,NM,USA
I thought I described it but here 's a picture,
Image
Hopefully i'll get enough stuff paid off to get it a pair of new cylinders next spring. But for now I cut an o-ring grove in the nipple where it touches the head.
Image
Dusty

Post Mon Aug 31, 2020 9:09 am

Posts: 3539
Location: Central Illinois, USA
Its hard to focus on, Dusty!

When I cannot take the work to a machine, I take a machine to the work.

Consider making some sort of pilot to fit within the threads, so you can spin a grind stone or abrasive to level out the shoulder that the nipple should butt against.
If you get it reasonable and smooth, then I suggest a PEEK washer to make up the difference. Even inlaid within the nipple as an "0-ring", it would outlast a common gummyworm by far.

Isn't the rivet quite a concern as well?

....Cotten

Post Mon Aug 31, 2020 11:47 am

Posts: 1436
Location: Ojo Caliente,NM,USA
Bestest picture out of half a dozen. But anyway the ground area is above the threads all the way to where the port turns up to the valve pocket.
I had the viton o-ring don't have a piece of peek that large. Hopefully it's a Bandaid that will last a couple of seasons. I should have my mill back together by this winter, so I can weld and machine if I can't afford a pair of cylinders. Rather work on the racer.
Dusty

Post Mon Aug 31, 2020 12:32 pm

Posts: 3539
Location: Central Illinois, USA
Machining welded cast iron is a real trick, Dusty!

Can you guestimate how big o' piece o' PEEK you need? (You know I have gobs o' scrap..)

I'd rather you only fixed it once, and even Viton won't survive Flatty heat for long.

The rivet still bothers me.

...Cotten

Post Mon Aug 31, 2020 8:11 pm

Posts: 1436
Location: Ojo Caliente,NM,USA
The o-ring is already in it. I turned a pair of tapered rivets and used one to lap the hole.
Dusty


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