valve seats

[steinauge]

FWIW-I was browsing on the Kibblewhite site and found that they have bronze valve seat inserts in a variety of sizes! It would be interesting to try some in a panhead using the old factory procedure. I may do this,if so I will report my results.

[caschnd1]

I thought the factory seats were cast into the head. Did they have a bronze replacement that was pressed in?

[lowlife]

I've heard of bronze valve guides, but never bronze seats.

[caschnd1]

All panheads came from the factory with bronze seats.

[Cotten]

That's great news, Steinauge!

I hope they have huge, 'unfinished' blanks.

And yes folks,
The MOCO produced bronze replacement inserts.

panseats.jpg

....Cotten

[58flh]

Stienguage-----WAy to go! DEf. keep us posted,it should work good Ive heard of others that have done this!--probably half the bikes running the OEMs now / They could have been replaced years ago!---Richie

[JR JOHNSON]

cotten,the valve seat falling out has been talked about,many times,and i'm am one of the many sitting on the side of the road,and never will install valve seats in,don will do his magic,but my question is, did those facctory inserts stay in?or was there a prob with them?.....with respect......JR

[Cotten]

JR!

The OEM bronze inserts had no problems at all, and did not require the enormous press-fit that broke so many castings when the hardened seat fad came along.

The mystery is why the entire industry got so stupid.

....Cotten

[Hog54]

I had seats put in 16 years ago and never had a problem.But I had it done by somebody that knows what hes doing.Harley wouldnt sell the seats if they couldnt be put in.

[kitabel]

It's 18057-48, "valve insert", listed in the Parts book but not shown in the diagram.

How is it installed?

[Hog54]

You have to machine out the old one to a specified diameter and press the new one in.

[kitabel]

And the reason why this doesn't fall out, like everything else, is....?

[Hog54]

How could it fall out?The valve holds it in.

[Cotten]

And the reason why this doesn't fall out, like everything else, is....?

Kitabel!

Bronze seats can be cut'n'pressed at .0015" interference, as the thermal expansion coefficient is identical to the original seat; Often the repair was a seat-within-a-seat, and the aluminum was left un-touched.

And the coefficient of bronze is close enough to the aluminum casting itself if need be, whereas a hardened "tool steel" seat requires .006" interference, lest its interference be nil when at running temperatures.

And if a temperature spike occurs, such as from advanced timing, poor fuel, or an evil manifold leak,... etc,..
the steel can reach its critical temperature and shrink.

It occasionally happened to original OEM Shovel seats, even with their increased casting matrix around them, allowing more seat depth for more heat transfer.
So beware that a perfect hardened seat installation in a Pan can still suffer from a heat spike, too.

....Cotten

[JR JOHNSON]

thanks cotten,but 27 years to late.was there a shop dope,or a memo sent to the dealers on install...........thanks again.....with respect........JR...