Board index Flathead Power-Technical Questions, Answers, and Suggestions Shovels 3-5/8 Cylinder repair

3-5/8 Cylinder repair

Post Mon Apr 20, 2020 8:28 am

Posts: 7
Location: Fort Lauderdale, FL
Hi all,

So here are my cylinders
IMG_20200420_101843.jpg
IMG_20200420_101843.jpg (140.88 KiB) Viewed 439 times


And they need to be re bored and re honed
IMG_20200420_101834.jpg
IMG_20200420_101834.jpg (39.47 KiB) Viewed 439 times


My measurements are:
2020-04-20 10_14_19-Window.jpg
2020-04-20 10_14_19-Window.jpg (63.17 KiB) Viewed 439 times


I'll have to create another post for my crankshaft...

I am missing the S&S pistons in the boxes (I have only the original ones).

My question is now:
Can I save those cylinders by machining them?
My plan would be to order S&S pistons and machine my cylinders to +0.0025"

Thanks for your help.
Quentin

Post Mon Apr 20, 2020 2:02 pm

Posts: 3458
Location: Central Illinois, USA
Quentin!

I would install each cylinder in "torque plates", and pass a hone through them a few times before inspection, and only then make a final verdict.

Big bore plates are rare, but I have them for both Pans and Shovels.
torqplat.jpg
torqplat.jpg (47.75 KiB) Viewed 432 times


(They haven't been used in decades.)

...Cotten

Post Tue Apr 21, 2020 1:09 pm

Posts: 7
Location: Fort Lauderdale, FL
Thanks Cotten.

I'll fabricate those and hone my cylinders.
I saw that it's also possible to sleeve the cylinders.

But I'll think before doing that because maybe it's just not worth it.

If they're toasted, I'll just buy a new cylinder and piston kit.
Quentin

Post Tue Apr 21, 2020 1:31 pm

Posts: 3458
Location: Central Illinois, USA
I fear, Bud,...

That even if you found sleeves, you would be boring the castings all the way to daylight.

Once upon a time, when I worked out of a "speed shop", such a job on common 80" cylinders was requested.
After performing the work, I pointed out to the boss exactly why they wouldn't "fly".

The customer paid anyway, and immediately sold the machine. The new owner came in to declare the front cylinder exploded into the frame like a cannon. Bossman told him he was screwed.

(Bossman later fired me; The only time in my life I was fired.)

...Cotten

Post Wed Apr 22, 2020 5:44 am
Pa Site Admin

Posts: 6212
Location: Ohio USA

Bossman was a prick !! :evil:

Post Wed Apr 22, 2020 3:20 pm

Posts: 3458
Location: Central Illinois, USA
Pa wrote:
Bossman was a prick !! :evil:
Sure, Pa,...

But I learned a lot from his mistakes.

....Cotten

Post Wed May 06, 2020 9:51 am

Posts: 7
Location: Fort Lauderdale, FL
Cotten wrote:
Quentin!

I would install each cylinder in "torque plates", and pass a hone through them a few times before inspection, and only then make a final verdict.

Big bore plates are rare, but I have them for both Pans and Shovels.
torqplat.jpg


(They haven't been used in decades.)

...Cotten


So I'm currently machining the plates.
I keep you posted when I'm done with the honing.
Quentin

Post Wed Jul 01, 2020 5:02 pm

Posts: 7
Location: Fort Lauderdale, FL
Soooooo...
I'm already +0.060 and those deep scratches are not coming off.
Cyl.jpg
Cyl.jpg (91.43 KiB) Viewed 201 times

I think I'm good for new cylinders.
Quentin

Post Wed Jul 29, 2020 1:39 pm

Posts: 3458
Location: Central Illinois, USA
Sorry for the late reply, Quentin,..

But I assume you have shopped for the largest available piston replacements?

You might want to consider having some made, as torque-plating allows for "unconventional" overbores; But first I would measure the remaining cylinder wall at the thinnest points over each base stud.
THINBORE.jpg
Caliper is set to wall thickness, and then measured with stacked feeler gauges. I have had successful rebuilds at only .070" remaining, but torque-plates were critical.
THINBORE.jpg (81.53 KiB) Viewed 95 times


....Cotten


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