pressed in pins (rod temperature)

[ProPower engines]

Is too hot a bad thing?

YES it is. Most shops I get stuff in from have turned the sm. end to purple or burnt black. Way too hot. the pin will get the
edge heated and stick part way through then its all over till you press it out and start again.

If you have any way to measure the small end it seems lots of rods have about .0025-.00358 press which is waaaaaaaaaaaaay too much.
I go .0015" max on stock rods and maybe .002" on good aftermarket stuff on the 1st go around.

If you can touch up the ID of the sm end then just carefully heat the rod till it turns a darker shade of light brown or a
wheat colour on the id then its ready to go in. The gas or elect.heaters are the same as using a small torch just easier you just have to watch what your doing and get the colour right before you install the pin.

[modok]

yeah, I know some people don't like to see blue spots.

remove them with a wire brush

[dwilliams]

Ford's factory manuals wanted the pins pressed in while cold. There were a number of different piston holding fixtures to keep from crushing the skirts while doing so. For OEM Ford pistons only, of course.

I was taught "bright red with the shop door closed", and never had any trouble. Though I did find out while trying to rush things, that "dull red" meant a high probability of the pin getting locked into place before it was in the correct position.

The old-timers did it all by eye and by hand; I made up an adjustable fixture so I could just slide the pin in until it hit the stop. Copied it from an ancient Goodson catalog, probably.

[rebelrouser]

Ford's factory manuals wanted the pins pressed in while cold. There were a number of different piston holding fixtures to keep from crushing the skirts while doing so. For OEM Ford pistons only, of course.

I was taught "bright red with the shop door closed", and never had any trouble. Though I did find out while trying to rush things, that "dull red" meant a high probability of the pin getting locked into place before it was in the correct position.

The old-timers did it all by eye and by hand; I made up an adjustable fixture so I could just slide the pin in until it hit the stop. Copied it from an ancient Goodson catalog, probably.

I like to cold press rods and pistons as well. Most older engines had fixtures to do this. I have an OTC fixture that works pretty good, only problem is a lot of the replacement pistons I am getting do not have room for the tool to fit inside the piston like the oem they replaced. I have tried making and modifying the shoes to fit, but with mixed results. Another nice thing is if you screw up and put a piston on wrong, pretty easy to press it out and back on, if it fits the fixture

[strokersix]

sm. end to purple or burnt black. Way too hot. the pin will get the
edge heated and stick part way through then its all over till you press it out and start again.

Interesting point about heat transfer to the pin

[Carnut1]

I have used a Sunnen rod oven and I own an old Dake press both work well. I always check for burrs and lube well. I was afraid to effect rod heat treat to do the propane torch method.

[ProPower engines]

yeah, I know some people don't like to see blue spots.

remove them with a wire brush

Kinda hard when rods and pistons are together. Walnut blast does a good job as well.

[ProPower engines]

I have used a Sunnen rod oven and I own an old Dake press both work well. I always check for burrs and lube well. I was afraid to effect rod heat treat to do the propane torch method.

Just think about using a Goodson LPG rod heater. Natural gas or propane its still about colour of the pin bore.
Most times I see guys do this they will over heat the rod and get 2-3 pins stuck part way and have to start over and thats a PITA.
If the rod bore is shiney clean then a dark wheat colour appearance in the pin bore will do 2 things for you.
When the colour is perfect it will give you enough time to push the pin through and have to hold still for about 5
seconds till the pin heats up to lock in the rod. All that with out sticking in the bore part way through

Regardless if its propane oxy/act torch or a bought rod heater system heat over time equals correct colour change it just
takes practice.

[modok]

yeah, right on.
Dark wheat color ok, brownish...maybe, blue....too hot!

How to reach with a wire brush? um, I use a small wire brush.

[ProPower engines]

yeah, right on.
Dark wheat color ok, brownish...maybe, blue....too hot!

How to reach with a wire brush? um, I use a small wire brush.

Really its not. When you get to blue thats too hot and beyond that junk rods.
The colour is a basic description to go by.It does take practice to get it right that how we learn but the fact is the same.
beyond the correct temp the pin bore changes to fast and at the right temp stays stable for longer then most believe but
if you spent alot of time doing various sizes of stock rods before the current offerings from the aftermarket you would
get where I am coming from.I can do about 200 rods sized and mounted in an afternoon with our power stroker machine and
sunnen heaters going. I can almost do it by sound blind folded but thats just me.

Just saying there are shops that send that stuff out to me. Not sure why they don't buy the heater and do it them self in house but there are those that don't.

They can learn with a simple fixture from Goodson for about $100 but like most they never measure the small end ID anyway
so I guess the likely hood of a screw up is much higher cause plastigauge can't check a pin fit that I have seen.

[modok]

I'm looking at a "job" today, DIY fail,
the piston is on backward, the piston does not move freely, there is a sizeable dent in the ring lands,
and the small end of the rod ....there is a line where it's cut 1/3 through with a cutoff wheel?? WTF!!!
Evidently, the pistons were CUT off with a die grinder and accidentally also cut part way through the rod, before mangling it together backward.

now THAT"S junk! ....after discussion both piston and rod it will be replaced.

But, between you and me.... I'd fix it and run that. I'd weld up the cut in the rod, hone the piston, fix the grooves, no sweat.
Things don't have to be perfect to work. I like Aiming for perfection as it's own art, and it's nice when you can, but I also like knowing what will fly and what won't.

I see lots of rods the LAST guy overheated when mounting, and usually they were doing OK and ready for more.
There is junk, and then there is junk, and then there is what will fly and what won't.

[KnightEngines]

Interesting that you lot seem to use lube when hot fitting pins.
I always found any lube transfers the heat to the pin faster & they're more likely to stick.
Dead dry for me, wash with thinners dry.
Oil the pin while it's still hot & it wicks in real fast.

On the odd occasion I do press fit pistons these days I bead blast the small end of the rod to get clean grey iron so I can see the colour easy.
Heat with oxy torch in a vice, straw colour with just a few flecks of blue starting to show & then move quick.

If it gets red it's definitely junk, if it gets blue all over it's maybe junk.

[modok]

Good idea.

I lube the far end of the piston bore, and the pin itself only.
so.... most of the oil is wiped off the pin as it slides into the piston.

[makin chips]

I use a Goodson rod heater set to 450 degrees, and a special marker that melts at 450 degrees to verify the temp. Oven has a temp setting, but the marker just backs it up. My big deal is that if the heating of the rod leaves a blue mark, my opinion is that the properties of the metal has been changed and I have seen rods break on such a blue line. I see lots of machine shops heat rods until they are blue to press in the pins, I will not accept a blue rod from a shop. At the 450 degree temp, have never seen it leave a blue mark.

That blue you see is an oxide layer that forms on the steel. It's not changing the properties of the steel or the rod itself to make that blue color. You're not going to cut that rod in half and find blue steel inside, either. It's on the surface. I doubt it's going to affect what's inside the rod.

[Dave Koehler]

I use the Sunnen electric machine.
I pre-oil the piston pin holes only.
None on the rod to avoid the oil leaving the visual effect of the rod being overheated.
How do I get away with this dry rod routine?
Careful planning.
As noted earlier.
Measuring the pin hole.
Then honing to size if it is too small and even when it is fine a quick swipe to remove any burrs or irregularities.
I also clean the rod of any residual oil before proceeding.
Spend a couple of minutes getting the pin stop set.

My machine has the heat settings the same for years. I snuck up on what works originally.
However, what works requires a preheat of the coils to keep from getting that overheated look.
I cycle the timers twice without any rod present.

Explanation of the preheat method.
IF I did not preheat the coils the first few rods might assemble just fine with whatever higher time setting I chose.
The coils heat soak hotter and hotter as I do the rest of the rods and they will get more and more of the overheated look.
Using the above methods I don't have any do overs with the exception of having brain fade and installing a piston on backwards. arrgh
I seldom have have any visible heating clues.

Once assembled and while the rod is not moving I squirt a little oil on the pin on each side of the rod.
Capillary action pulls the oil all around the pin and into the piston pin holes.
No dry starts that way.