Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties valve seat inserts

valve seat inserts

Post Sat Apr 01, 2017 12:39 pm

Posts: 82
Location: Custer Wa.
the 42 was a little more wore out than we thought seats are gone any luck putting in hard inserts not much room

Post Sat Apr 01, 2017 3:16 pm

Posts: 3297
Location: Central Illinois, USA
T.Shoe!

The problem with hardened seats in a Flatty is that Flatties naturally run very close to the temperatures where a "tool steel" shrinks.
Even cooler OHVs have had disasters with hardened seats 'fall out', if advanced timing, crappy fuel, or a vacuum leak spikes the combustion.

The extreme press-fit spec'd for hardened seats would but them into the bore.

The age-old solution was cast iron seats, but they are nearly extinct.

....Cotten

Post Sat Apr 01, 2017 5:36 pm

Posts: 82
Location: Custer Wa.
I was thinking cast too just not shur what kind size ect. thank tshoe

Post Sat Apr 01, 2017 10:49 pm

Posts: 1189
Location: Ojo Caliente,NM,USA
Cotten,
Were the cast iron seats any special cast iron alloy? Just wondering if you could get a length of wonder bar or one of the similar continuous cast iron bars and whittle a few out. I've made my own valve guides out of wonder bar several times over the years. Also used Cat and Ford tractor guides as donors to turn down for Harleys.

I am planing to flame spray weld some rockwell c35 hard face on the seats in some Indian Scout cylinders that I don't want to sleeve. They certainly won't hold a seat without a sleeve. People I bought this batch of powder from said that they sold this powder to several specialty shops for valve seats. I guess I'll find out. I've used the flame spray on cranks and crane pins and sockets with great success, but this makes me a little nervous.

Dusty

Post Sun Apr 02, 2017 8:56 am

Posts: 3297
Location: Central Illinois, USA
Dusty!

The antique automotive seats I have are pretty soft.
But their expansion rate would be the same as the cylinder.

Not familar with "Wonder" bar, but I would advise determining the expansion rate of any seat by measuring it, and then putting it into an oven to measure again at temperature. It would be important, of course, to do the same with the cylinder to measure the counterbore for the seat.

I found with hardened steel seats and aluminum heads that a ~.006" interference was down to ~.0015".
Pans and Shovels lost so many seats because any unusual heat spike could shrink the hardened seat this much, just like welding out a race.

This is the same phenomenon that caused so many main races to spin.

....Cotten

Post Sun Apr 02, 2017 1:40 pm

Posts: 1189
Location: Ojo Caliente,NM,USA
Looked for the specs and it's Dura-Bar, memory is a little shaky anymore a continuously cast G2 grey iron. so should be pretty close to the cylinders. Since I don't own a Harley anymore I doubt I'll do any experimenting. Just throwing the idea out for those who own one.
Dusty

Post Sun Apr 02, 2017 2:44 pm

Posts: 3297
Location: Central Illinois, USA
Scouts are the same if not worse, Dusty!

(They have the evil head bolt right over the intake nipple).

....Cotten

Post Sun Apr 02, 2017 3:29 pm

Posts: 1189
Location: Ojo Caliente,NM,USA
Cotten,
Unless you sleeve a scout they always crack from the pressed in seat to the cylinder wall even if you make them slip fit and sweat them in they stand a good chance of cracking. That's why I plan to try Flame Spray Hardface on a few of the ones I'm going to race.
Dusty

Post Sun Apr 02, 2017 3:29 pm

Posts: 1189
Location: Ojo Caliente,NM,USA
Cotten,
Unless you sleeve a scout they always crack from the pressed in seat to the cylinder wall even if you make them slip fit and sweat them in they stand a good chance of cracking. That's why I plan to try Flame Spray Hardface on a few of the ones I'm going to race.
Dusty

Post Sun Apr 02, 2017 4:05 pm

Posts: 3297
Location: Central Illinois, USA
Spray-welding sounds great to me, Dusty!

But I have no experience with it..

...Cotten

Post Sun Apr 02, 2017 8:27 pm

Posts: 2717
Location: Los Angeles, CA
Take them to a good Cast Iron Welder. Weld them up, Flatten the surface. Then cut new seats. Raise them back up where they belong.

Post Sun Apr 02, 2017 9:41 pm

Posts: 1189
Location: Ojo Caliente,NM,USA
I am planing to raise the seats up with the spray weld. But since I'm running blown fuel I think a little harder will be good. Hopefully the spray weld will leave the metal between the seat and the cylinder wall (what little there is) relatively unstressed.
Dusty

Post Tue Apr 04, 2017 6:54 pm

Posts: 82
Location: Custer Wa.
Thanks for the info have made valve gides for sporters valves in my knuck will look at making cast seats

ride to lve T.shoe

Post Wed Apr 05, 2017 9:37 am

Posts: 1189
Location: Ojo Caliente,NM,USA
Chris Haynes wrote:
Take them to a good Cast Iron Welder. Weld them up, Flatten the surface. Then cut new seats. Raise them back up where they belong.

Chris,
Is there a reason to use cast iron instead of the harder powder? I can weld it with either one just thought that the hardface would be better for extreme use. After talking to several head shops I picked the not so hard powder but could go harder or softer if there is a valid reason.
Dusty

Post Wed Apr 05, 2017 9:53 am

Posts: 3297
Location: Central Illinois, USA
Dusty and Chris!

Most TIGmeisters I have known will only weld cast iron with some other filler rod, such as silicon bronze.

They scoffed at me for using a torch and old piston rings for filler, such as this repair:
IRNWELD2.jpg

Works great on Indian frame castings, too.

But I wouldn't suggest it for a valve seat, yet.
The greatest difficulty I have found with welding cast iron is that it "chills" incredibly hard. Maybe too hard.

Go for the spray weld, Dusty!

....Cotten
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Post Wed Apr 05, 2017 11:14 pm

Posts: 2717
Location: Los Angeles, CA
Dusty-Dave wrote:
Chris Haynes wrote:
Take them to a good Cast Iron Welder. Weld them up, Flatten the surface. Then cut new seats. Raise them back up where they belong.

Chris,
Is there a reason to use cast iron instead of the harder powder? I can weld it with either one just thought that the hardface would be better for extreme use. After talking to several head shops I picked the not so hard powder but could go harder or softer if there is a valid reason.
Dusty



I have no experience with spray weld and no nothing about it. I have no idea how thick it can be applied.
By Cast Iron I mean to find a welder with lots of experience welding cast iron. Long slow heating before welding. Keeping it hot while welding. long slow cool off when finished.

Post Thu Apr 06, 2017 1:03 pm

Posts: 3297
Location: Central Illinois, USA
Chris Haynes wrote:
I have no experience with spray weld and no nothing about it. I have no idea how thick it can be applied.
By Cast Iron I mean to find a welder with lots of experience welding cast iron. Long slow heating before welding. Keeping it hot while welding. long slow cool off when finished.


The critical question, Chris,..

...is: What filler rod did they use?

...Cotten

Post Thu Apr 06, 2017 2:38 pm
Pa Site Admin

Posts: 6036
Location: Ohio USA

Some welders in a machine shop I worked in used what I think was called Ni rod.

Post Thu Apr 06, 2017 2:55 pm

Posts: 3297
Location: Central Illinois, USA
Pa wrote:
Some welders in a machine shop I worked in used what I think was called Ni rod.

Ouch...

Ouch twice.

There's a place and time for everything, but not if you must re-machine it!

...Cotten

Post Thu Apr 06, 2017 9:08 pm

Posts: 1189
Location: Ojo Caliente,NM,USA
Guy I know knocks the flux off of Muggyweld an uses it for TIG rod. He says it stays machineable and by using the TIG he can control the thickness much better. The powder spray is even more controllable but dam it's slow, hot and uses lots of Oxy/ Acetylene. If I have a powder that matches what I am welding I can make the repair almost invisable, or limit the cutting or grinding to a few thousandths.
Dusty

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