I currently have a Kohler twin cylinder air cooled engine torn down on
the bench. It's not well supported by the factory, overpriced parts
ect. I'd like to put valve seat inserts in it. It's a cast iron
jug.. Thinking bore the hole using a mill and then turn the insert
to fit. Turn insert .003 under size, press fit. Any thoughts on
expedient material for insert, this is non critical lawn & garden
application. Anything else I'm missing here?

Also the jugs have worn a taper at the upper end, normal repair is
bore oversize, use new piston. No way am I paying $116 each for new
pistons on this beast. Old pistons are serviceable, looks like a dry
sleeve would bring it back to standard. The lower part of the bore
is not excessivly worn. Federal Mogul has a 9" sleeve that would
do the trick.
Do I bore .003 over the sleeve size,? Can just the tapered part be
sleeved and rebored/honed to spec?

Any words of wisdom appreciated.

DE

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From DE:

"Also the jugs have worn a taper at the upper end, normal repair is
bore oversize, use new piston. No way am I paying $116 each for new
pistons on this beast."

The old way is bore out most of that taper and knurl the pistons, isn't
it, to reestablish the fit?

I've never done this... I gas-ported a small engine piston once. You
can buy oversized rings cheaply and grind the gap with a gap grinder to
make them fit the new bore.

It has something to do with piston slap, I think.

--Doug

No way am I paying $116 each for new
pistons on this beast.

wow you can get new ones made for less. thats a real rip off.

I've rebored small outboard motor engines by mounting the block on a face
plate, indicate for runout, and then bore with a boring tool. Then hone with
a homemade emery cloth flapper mounted on a stick chucked in a power drill.

I've done a 4HP Evinrude two cylinder block on a Southbend 10L.

Tony

"DE" wrote in message
...


I currently have a Kohler twin cylinder air cooled engine torn down on
the bench. It's not well supported by the factory, overpriced parts
ect. I'd like to put valve seat inserts in it. It's a cast iron
jug.. Thinking bore the hole using a mill and then turn the insert
to fit. Turn insert .003 under size, press fit. Any thoughts on
expedient material for insert, this is non critical lawn & garden
application. Anything else I'm missing here?

Also the jugs have worn a taper at the upper end, normal repair is
bore oversize, use new piston. No way am I paying $116 each for new
pistons on this beast. Old pistons are serviceable, looks like a dry
sleeve would bring it back to standard. The lower part of the bore
is not excessivly worn. Federal Mogul has a 9" sleeve that would
do the trick.
Do I bore .003 over the sleeve size,? Can just the tapered part be
sleeved and rebored/honed to spec?

Any words of wisdom appreciated.

DE

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On Wed, 09 Feb 2005 15:01:38 -0700, DE
wrote:



I currently have a Kohler twin cylinder air cooled engine torn down on
the bench. It's not well supported by the factory, overpriced parts
ect. I'd like to put valve seat inserts in it. It's a cast iron
jug.. Thinking bore the hole using a mill and then turn the insert
to fit. Turn insert .003 under size, press fit. Any thoughts on
expedient material for insert, this is non critical lawn & garden
application. Anything else I'm missing here?

Also the jugs have worn a taper at the upper end, normal repair is
bore oversize, use new piston. No way am I paying $116 each for new
pistons on this beast. Old pistons are serviceable, looks like a dry
sleeve would bring it back to standard. The lower part of the bore
is not excessivly worn. Federal Mogul has a 9" sleeve that would
do the trick.
Do I bore .003 over the sleeve size,? Can just the tapered part be
sleeved and rebored/honed to spec?

Any words of wisdom appreciated.


What model engine is it. If it is a old model then there's a good
chance that aftermarket parts are available. I can look them up with
the model number.

As to the valve seats check the size of the valve OD and seat ID. I
might have some seats that will work.

Seats should be made from the hardest steel possible for long life
but softer steel will work for a while.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook

On Wed, 09 Feb 2005 23:38:37 GMT, Erik Litchy
wrote:

No way am I paying $116 each for new
pistons on this beast.

wow you can get new ones made for less. thats a real rip off.

That's pretty normal for OEM small engine parts. It's ridiculous but
there's not much that can be done in some cases.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook

On Wed, 09 Feb 2005 21:21:02 -0600, Wayne Cook
wrote:


What model engine is it. If it is a old model then there's a good
chance that aftermarket parts are available. I can look them up with
the model number.

It's a KT17QS, there were aftermarket parts until a year ago, now the
only thing available is rings in std. I've had this since '81 and
it's been a decent unit. I've been scrounging parts for the last year
off ebay. I've got a good extra sets of jugs w/pistons but they're
both for the left side. The only difference between the left and
right is the hardened seat in the exhaust valve. I figure to put a
seat in the
intake side and use it on the right side. It'll work fine. The
lower end is tight ,it just has excess blowby.

The other option is dry sleeve the old jugs, the taper is at the usual
area where it makes compression.


As to the valve seats check the size of the valve OD and seat ID. I
might have some seats that will work.

Seat ID measures 1.240 valve face 1.380 i've done this on auto
application years ago with a neway setup. I suppose it could be
farmed out but since I have this milling machine........


Seats should be made from the hardest steel possible for long life
but softer steel will work for a while.

I guess I could just use the cast seat and do valve job but I think
I would be sorry.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook


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On Wed, 09 Feb 2005 15:01:38 -0700, DE
wrote:



I currently have a Kohler twin cylinder air cooled engine torn down on
the bench. It's not well supported by the factory, overpriced parts
ect. I'd like to put valve seat inserts in it. It's a cast iron
jug.. Thinking bore the hole using a mill and then turn the insert
to fit. Turn insert .003 under size, press fit. Any thoughts on
expedient material for insert, this is non critical lawn & garden
application. Anything else I'm missing here?

Also the jugs have worn a taper at the upper end, normal repair is
bore oversize, use new piston. No way am I paying $116 each for new
pistons on this beast. Old pistons are serviceable, looks like a dry
sleeve would bring it back to standard. The lower part of the bore
is not excessivly worn. Federal Mogul has a 9" sleeve that would
do the trick.
Do I bore .003 over the sleeve size,? Can just the tapered part be
sleeved and rebored/honed to spec?

Any words of wisdom appreciated.

DE

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If you sleeve the engine the sleeve must be the length of the bore.
However, honing the bore straight is not a very expensive propsition.
Two methods are easily available. One, an automotive machine shop or
just a regular machine shop. With a Sunnen hone doing the work .004"
can be removed in less than 15 minutes. If you buy a 3 stone cylinder
hone and do it yourself, the second method, you can open the bore up
but it will take a long time. Cylinder hones don't put much pressure
on the stones. But it can be done. I honed out a brake cylinder with a
brake cylinder hone to remove some pits. I only removed about .003"
and it took a long time. And you need to be careful about honing a
taper.
ERS

On Wed, 09 Feb 2005 21:08:58 -0700, DE
wrote:

On Wed, 09 Feb 2005 21:21:02 -0600, Wayne Cook
wrote:


What model engine is it. If it is a old model then there's a good
chance that aftermarket parts are available. I can look them up with
the model number.

It's a KT17QS, there were aftermarket parts until a year ago, now the
only thing available is rings in std. I've had this since '81 and
it's been a decent unit. I've been scrounging parts for the last year
off ebay. I've got a good extra sets of jugs w/pistons but they're
both for the left side. The only difference between the left and
right is the hardened seat in the exhaust valve. I figure to put a
seat in the
intake side and use it on the right side. It'll work fine. The
lower end is tight ,it just has excess blowby.

Ok. I finally got a chance to check. That's not one of the old cast
iron engines so parts aren't as available. One company did show a
aftermarket standard sized piston assembly but it was expensive as
well.

The other option is dry sleeve the old jugs, the taper is at the usual
area where it makes compression.

Possible but a lot of work.

As to the valve seats check the size of the valve OD and seat ID. I
might have some seats that will work.

Seat ID measures 1.240 valve face 1.380 i've done this on auto
application years ago with a neway setup. I suppose it could be
farmed out but since I have this milling machine........

Ok. Unfortunately the seats I've got are to small. They're 1.125 ID
and 1.340 OD. I had hoped that they would work since I've got a bunch
of this size.


Seats should be made from the hardest steel possible for long life
but softer steel will work for a while.

I guess I could just use the cast seat and do valve job but I think
I would be sorry.

It would work just not as long as a good hard seat.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook

On Fri, 11 Feb 2005 11:34:25 -0600, Wayne Cook
wrote:
..

Ok. I finally got a chance to check. That's not one of the old cast
iron engines so parts aren't as available. One company did show a
aftermarket standard sized piston assembly but it was expensive as
well.


I appreciate the search, the long block is back together with the
salvaged parts. Left the exhaust valve on the cast seat, time will
tell on how it lasts.

DE





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