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SportScout valve specs question

Post Thu May 02, 2002 2:00 pm

Posts: 3159
Location: Central Illinois, USA
I have no printed literature for SportScouts; Is the valvestem to guide tolerance smaller than Chiefs?

Since they are .340" stems instead of .375", I have been considering setting them up tight at .0035" on the intakes and .004" on the exhausts, mostly because there is enough meat in the new guides to do so.

Can anyone quote the Wigwam?
Thanks in advance.....

Post Thu May 02, 2002 3:39 pm

Posts: 1319
Location: State College, Pa.
Cotton

In the Q/A book, Indian 45 and 74 Military Models. Listed:

Valve stem diameter----------.339"
Valve guide hole diameter----.344"

.005" clearance

30.50 and the 841 show the same clearance

HOOT

Post Fri May 03, 2002 2:42 am

Posts: 108
Location: San Diego
My 741 Manual lists 0.338 and 0.343...dunno why Unkle Franks is different.

Post Fri May 03, 2002 3:04 am

Posts: 1038
Location: Ojo Caliente,NM,USA
Cotten:
TM-10-1485 as reprinted by Pierce motor company states stems should measure .338 and be replaced if worn smaller than .333 and guides should be .343 and replaced if over .350
Dusty

Post Fri May 03, 2002 4:55 am

Posts: 1319
Location: State College, Pa.
So regardless of discrepencies your aiming for .005" clearance for an as new dimension.

Post Fri May 03, 2002 2:33 pm

Posts: 3159
Location: Central Illinois, USA
Thanks for the clues.

The KIWI valves are nice and fat, probably the hardchrome, although it appears to be more than a "flash" of a thou.

If this were my own project, I would set it up tighter, just 'cos I could. I have come to beleive that lots of fits are spec'd as loose as a goose just for "idiot factor".

Post Fri May 03, 2002 4:32 pm

Posts: 896
Location: Bixby,OK, USA
I know what you mean Cotten, I hate to put something together that feels 1/2 worn out at the start. I'd set mine tighter, but on a customer bike I guess I'd have to know how he intended to ride it.

------------------
When you're riding lead--don't spit.

Post Fri May 03, 2002 8:57 pm

Posts: 108
Location: San Diego
so how tight do you guys think cast iron guides and chrome stems can be set (or other combos)?

Post Sat May 04, 2002 5:10 am

Posts: 896
Location: Bixby,OK, USA
I don't know, if it were mine and a sidevalve I'd probably go about.0035 on intake and exhaust, but that would be with honed guides (which hold lube better IMHO) and a good stainless or nitrided valve, and every thing right.....and no vacuum leaks! LOL

Post Sat May 04, 2002 6:14 am

Posts: 1319
Location: State College, Pa.
I,myself, would stay away from tight tolerances on the sidevalve mainly because the lubrcant has to go uphill instead of down hill as on an ohv engine. Honed guides can be fitted tighter because of their oil retention capability due to the cross hatch. But I wouldn't want to fit them any closer than a .001" lower than the stock specs. I would guenea pig it on my own engine before some one elses. At least if it doesn't work, the piston won't smack it if it sticks.

Never cared for the chromed stainless in castiron guides. Prefer the nitrided valves or if using uncoated valves. I bead blast and cook a moly coat on to them.

HOOT

Post Sat May 04, 2002 12:27 pm

Posts: 3159
Location: Central Illinois, USA
Hoot!
I agree that stainless valves in castiron guides is not optimum, but that's what the customer dropped off. At least there is some chrome in between.

My preference is Kibblewhites' for Chiefs, but I never asked them to make any SS valves yet.

Post Sat May 04, 2002 3:42 pm

Posts: 1319
Location: State College, Pa.
I'm adverse to using chrome plated stainless valves in iron because I've seen on numerous occasions where the chrome wore off and the stems had heavy galling. Probably because of angularity the valves are pushed by the rocker arm movement. Stainless galls easily so it needs a different wear surface.

I prefer Kibble's Black Diamond or Rowe's Black Melonite valves myself. I would only use the chrome valves with Ampco45 material guides if I had to use them.

Being that there are no side loads on the valve stem in a flathead and the demands that the customer just has to have this valve/guide combo. I would fit them at .005" minimum. And tell him no warrantry against valve seizure.

Aren't your Indian Kibblewhite valves impregnated stainless? Check them with a magnet.

HOOT

Post Sat May 04, 2002 6:16 pm

Posts: 896
Location: Bixby,OK, USA
When I port "the other" harley engines, I use kibblewhite guides if a lift of over .530 is involved. I really like the black diamond valves,which I think are nitrided stainless, are great. They will build your valves out of anything on request, and special order aren't that high. I have had them build oversize guides for me to repair wallowed out aluminum heads, this way the seats don't shift from the heat of welding.

Cotten, just for your info, Jim's just came out with their ovn line (Advanced Valve and Valvetrain) valves and guides.....I knew you would want to know....I'm ducking and running...jb


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