I need to reinstall a new piston on an existing rod. The wrist pin is
a shrink fit in the rod end. I pressed the wrist pin out of the rod
using my 30T press w/ no problems but I have been told that I need to
heat the rod end prior to attempting to insert the wrist pin. I have
been told to heat (w/ torch) to just the beginnig of "straw color".
How risky is this, am I better off dropping the parts off at a local
automotive machine shop for them to use an oven to heat the rod end?
TIA

How risky is this, am I better off dropping the parts off at a local
automotive machine shop for them to use an oven to heat the rod end?
TIA

i suppose its like anything. Once you've done it, piece of cake. If you want
to give yourself a bit more margin, put the pin in the freezer. if you do go
to the auto shop, they'll just use a torch.

Karl

No- Take it to a shop. The piston needs to go into a Sunnen heater that is a
heating unit designed exactly for this. Any other attempt could be a very
expensive mistake. Trust me...

Rob Fraser

Fraser Competition Engines
Chicago, IL.


"Karl Townsend" wrote in message
anews.com...

How risky is this, am I better off dropping the parts off at a local
automotive machine shop for them to use an oven to heat the rod end?
TIA

i suppose its like anything. Once you've done it, piece of cake. If you
want to give yourself a bit more margin, put the pin in the freezer. if
you do go to the auto shop, they'll just use a torch.

Karl

"Rob Fraser" wrote: (clip) The piston needs to go into a Sunnen heater that
is a
heating unit designed exactly for this. (clip)
^^^^^^^^^^^^^^^^^^^^^^^^
From your business name, I assume you know something about engines. So my
question is not a challenge, but a request for an explanation. The OP says
he pressed the wrist pin out of the rod end, and now needs to reinsert it.
You certainly can't have an interference fit in both the piston and the rod.
So why would you have to heat the piston?

Leo Lichtman wrote:
"Rob Fraser" wrote: (clip) The piston needs to go into a Sunnen heater that
is a
heating unit designed exactly for this. (clip)
^^^^^^^^^^^^^^^^^^^^^^^^
From your business name, I assume you know something about engines. So my
question is not a challenge, but a request for an explanation. The OP says
he pressed the wrist pin out of the rod end, and now needs to reinsert it.
You certainly can't have an interference fit in both the piston and the rod.
So why would you have to heat the piston?

He meant the rod, I bet.
Sunnen makes a small heater for rods

wrote in message
...
I need to reinstall a new piston on an existing rod. The wrist pin is
a shrink fit in the rod end. I pressed the wrist pin out of the rod
using my 30T press w/ no problems but I have been told that I need to
heat the rod end prior to attempting to insert the wrist pin. I have
been told to heat (w/ torch) to just the beginnig of "straw color".
How risky is this, am I better off dropping the parts off at a local
automotive machine shop for them to use an oven to heat the rod end?

No need to heat the rod if you use a good lubricant and properly support the
piston while pressing.

I use Goodson's lubricant when pressing pins:

http://www.goodson.com/store/templat...l.php?IID=5091

"John Kunkel" wrote:

No need to heat the rod if you use a good lubricant and properly support the
piston while pressing.

A bit of lube on an interferance fit can save one from disaster.

It is amazing how quick, the hot / cold thing seems to equalize and grip like a gorilla.
DAMHIKT.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

Wes wrote:

"John Kunkel" wrote:


No need to heat the rod if you use a good lubricant and properly support the
piston while pressing.


A bit of lube on an interferance fit can save one from disaster.

It is amazing how quick, the hot / cold thing seems to equalize and grip like a gorilla.
DAMHIKT.

Boiling water on a rag wrapped round the rod (to provide a resevoir of
heat), and plumbers pipe freezing spray for the pin (better still if its
hollow and you can stuff some rag down it to provide a resevoir of
freezing spray and you've got a fair chance it will just drop in. If
not, check how tight it feels and either apply more boiling water and
freezer spray and procede as advised above or farm it out to a pro if it
is not even starting to fit. At 100 deg C, there is no risk of
de-tempering anything. Just make sure its absolutely square ...

On Wed, 1 Oct 2008 12:14:20 -0500, the infamous "Rob Fraser"
FraserRacing"AT"RobFraser.Net scrawled the following:

No- Take it to a shop. The piston needs to go into a Sunnen heater that is a
heating unit designed exactly for this. Any other attempt could be a very
expensive mistake. Trust me...

Is this one of those DAMHIKT things, Rob? heh heh heh

-
If the gods had meant us to vote, they'd have given us candidates.
--------------

"RB" wrote in message
...
Leo Lichtman wrote:
"Rob Fraser" wrote: (clip) The piston needs to go into a Sunnen heater
that is a
heating unit designed exactly for this. (clip)
^^^^^^^^^^^^^^^^^^^^^^^^
From your business name, I assume you know something about engines. So
my question is not a challenge, but a request for an explanation. The OP
says he pressed the wrist pin out of the rod end, and now needs to
reinsert it. You certainly can't have an interference fit in both the
piston and the rod. So why would you have to heat the piston?

He meant the rod, I bet.
Sunnen makes a small heater for rods


Correct- it is a rod heater. I sometimes toss the wrist pins in the freezer
for a while too on a known tight fit. Like any Carrillo or Manley Hbeam rod.
I would never, ever, do it any other way. It's a lesson in disaster and I
have had engines with 2-3 passes from other assemblers shops who cheated it
and blew the top of the rod clear off. 15k engines destroyed because someone
took a shortcut. It takes a machine shop about 30 min to do a set of 8
properly. A little LPS or assembly lube on the pins is also a *Must-do* and
when priming the engine with a drill or if it's on a dry sump rotate it with
the plugs OUT for at least 30 min. by hand on the crank bolt or blower
pulley with a ratchet to get all that lubed up and that has no relevance to
the interference fit but your bearings and cam will thank you for a long
time. Another little trick is to fill the wrist pin with a few cc's of oil
before you put the piston in the compressor. That way when the engine is dry
cranking that oil will seep out and lube the rings and cylinder walls a
little extra.
If I ever saw a shop hit it with a torch I'd be finding a new shop fast.
If you can't find a shop to do it local. - mail them to my shop, I'll do it
no charge. Just cover the shipping. Don't let someone **** up your engine.

Rob


Fraser Competition Engines
Chicago, IL.

Correct- it is a rod heater.

Any idea what the target temp is? We do full-floaters only.
I used to do VW Porsche, we would put the timing gear in oil heated to
boiling on a hot plate before pressing it on the crank, torches were for
verboten.
--
Stupendous Man,
Defender of Freedom, Advocate of Liberty

"Stupendous Man" wrote in message
...
Correct- it is a rod heater.

Any idea what the target temp is? We do full-floaters only.
I used to do VW Porsche, we would put the timing gear in oil heated to
boiling on a hot plate before pressing it on the crank, torches were for
verboten.
--
Stupendous Man,
Defender of Freedom, Advocate of Liberty

Depends on the piston, (cast vs forged) the alloy and center taper of the
pin, the size micd' out .0001 increment, the rod( Alum, steel,ect. )
the heater has a knob on it to adjust target temps on both coils. To be
honest, I could not even tell you the temp. I am just so used to doing it
it's second nature I go by feel of the pin going in.

Rob


Fraser Competition Engines
Chicago, IL.

I have a local shop that does use a rod heater, I had already
contacted them prior to posting - I just did not want to spend money
on something that (in theory) I could do myself. Thanks for the
details in your posting. Reason that I asked this question in the
first place: http://i290.photobucket.com/albums/l...u/PB280023.jpg
I suspect a broken valve spring (never experienced one before) at 120K
miles on an engine that was on target for being a 200K to 250K mile
motor. THe head is now more of a modern art sculpture than a useable
head: http://i290.photobucket.com/albums/l...u/PB280018.jpg






On Oct 1, 10:21*pm, "Rob Fraser" FraserRacing"AT"RobFraser.Net
wrote:
"RB" wrote in message

...

Leo Lichtman wrote:
"Rob Fraser" wrote: *(clip) The piston needs to go into a Sunnen heater
that is a
heating unit designed exactly for this. (clip)
^^^^^^^^^^^^^^^^^^^^^^^^
From your business name, I assume you know something about engines. *So
my question is not a challenge, but a request for an explanation. *The OP
says he pressed the wrist pin out of the rod end, and now needs to
reinsert it. You certainly can't have an interference fit in both the
piston and the rod. So why would you have to heat the piston?

He meant the rod, I bet.
Sunnen makes a small heater for rods

Correct- it is a rod heater. I sometimes toss the wrist pins in the freezer
for a while too on a known tight fit. Like any Carrillo or Manley Hbeam rod.
I would never, ever, do it any other way. It's a lesson in disaster and I
have had engines with 2-3 passes from other assemblers shops who cheated it
and blew the top of the rod clear off. 15k engines destroyed because someone
took a shortcut. *It takes a machine shop about 30 min to do a set of 8
properly. A little LPS or assembly lube on the pins is also a *Must-do* and
when priming the engine with a drill or if it's on a dry sump rotate it with
the plugs OUT for at least 30 min. by hand on the crank bolt or blower
pulley with a ratchet to get all that lubed up and that has no relevance to
the interference fit but your bearings and cam will thank you for a long
time. Another little trick is to fill the wrist pin with a few cc's of oil
before you put the piston in the compressor. That way when the engine is dry
cranking that oil will seep out and lube the rings and cylinder walls a
little extra.
* * If I ever saw a shop hit it with a torch I'd be finding a new shop fast.
If you can't find a shop to do it local. - mail them to my shop, I'll do it
no charge. Just cover the shipping. Don't let someone **** up your engine..

* * * * *Rob

Fraser Competition Engines
Chicago, IL.

That reminds me of my VW Porsche days!.
I would weld that if it was something rare like a Lotus crossflow head.
--
Stupendous Man,
Defender of Freedom, Advocate of Liberty