pressed in pins (rod temperature)

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Dave Koehler
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Re: pressed in pins (rod temperature)

Post by 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.

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.

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.

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.
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Re: pressed in pins (rod temperature)

Post by ProPower engines »

Setting up and pre heating the rod heater is a big step guys seem to miss. They just turn it on and think they are heating.
I go 3 cycles on either of my heaters 1 pair takes about 2 min. longer to come to temp but its old as the hills from the
70's and 1 from the late 80's. but after the timer is set you just keep going.
A trick to getting consistent is I like to start heating 1 coil at a time then start the next about 45 sec.'s later and keep them all heating to that interval that way if there is a distraction you can keep rolling and not cook 1 more then the other beside it.
Appearance is also a bib issue as we all know when doing partial jobs and a delayed timing between rods keep them all the same.
And unless its an import rod I rarely change the timers as well. About 6 on the dial after a good pre heat seems best on
my heaters as well. =D>
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Re: pressed in pins (rod temperature)

Post by gn69z28 »

We have a set of 350 Chevy rods and pistons in the shop now that another shop attempted to install pistons on the rods. They only tried 3 and messed them up. Two rods had spun bearings and they still put the pistons on them. One piston is so tight on the pin it won't move. Another pin shows signs on marks where they were hitting it with a hammer. And all 3 pistons are scratched up and ring lands messed up from putting them in a vice. The owner,a young guy,said he took them to that shop because they had a race car parked out front and they said sure we can do that. Anyway we told the customer he needs 3 new rods and 3 new pistons. And one more thing. None of the rods have the caps on them and they aren't numbered.
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Re: pressed in pins (rod temperature)

Post by 4vpc »

rebelrouser wrote: Wed Aug 21, 2019 8:47 pm 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.
Yet factory engines have blue ended rods in them...
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Re: pressed in pins (rod temperature)

Post by dwilliams »

Dave Koehler wrote: Fri Aug 23, 2019 9:29 amUsing the above methods I don't have any do overs with the exception of having brain fade and installing a piston on backwards. arrgh
Un-possible! I thought I was the only one who did that...

I now use a large laundry marker color the correct sides of the rods and pistons in their matched pairs, matching up each handed rod with its appropriate handed piston as needed... and write the number each rod and piston so I don't mix them up.
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Re: pressed in pins (rod temperature)

Post by dwilliams »

4vpc wrote: Sun Aug 25, 2019 6:55 pmYet factory engines have blue ended rods in them...
Goodson used to sell some stuff you could dip the small ends into, that was supposed to remove the blue...
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