Floating piston pins vs Pressed piston pins

Hey Everybody,
This is a quick Q&A based on questions I have received from some of the younger viewers out there. All about full floating pistons and connecting rods, and how they compare to the standard press in style.
I hope you find the video informative, interesting and maybe inspirational.
As always practice your skills and turn them into craftsmanship. You never know how far they will take you.
Thanks for for watching.
Until next time....
This has been Fab Race Mod Repeat.

[@tree8761]

As someone going through school and studying piston related information at the moment, this is a perfect explanation of it all.

[@FabRaceModRepeat]

Glad you enjoyed it.

[@mariettasanchez9963]

love all the explanations of this guy, very informative

[@michaeldaugherty6826]

Thank you. It helped me understand full-floating Piston Pins for my Aviation class.

[@FabRaceModRepeat]

That’s great! Thanks for watching

[@tomsmith2361]

This was very informative and explained well. My Jeep dealer found two loose/worn wrist pins on my 2001 Cherokee xj 4x4 at 188 k miles. I've drove it another thousand with no change in sound or performance. Bought it with 187 and the sound was present then. Saving up for a rebuild.

[@FabRaceModRepeat]

Glad it helped Thanks for watching

[@OldSchoolNoe]

great explanation!

[@FabRaceModRepeat]

@@OldSchoolNoe Thanks!

[@benjamincoleman1210]

Simple and efficient explanation, thank you

[@FabRaceModRepeat]

Glad you enjoyed it. Thanks for the comment

[@abdikaniyussuf7206]

thank you very much for explaining. this was very helpful.

[@FabRaceModRepeat]

Thanks for watching glad I could help

[@danielgil-lubeiro4846]

nice video, clear explanation on fully floating piston pins. worth noting that press fit piston pins as shown in this video as also known as semi floating pins. fixed or stationary pins would be when the piston is fixed to the piston but is able to turn/spin in the connection rod.

[@FabRaceModRepeat]

Good morning, Thanks, glad you enjoyed the video. Yes that is the third type piston pin. I’ve seen that set up in very early engines and some industrial applications.

[@zachnuketown]

Thanks so much for the solid info!

[@FabRaceModRepeat]

Commie Killer Thanks for watching! Glad it helped.

[@BulliKid]

How can you physically tell the difference between pressed vs floating rod

[@FabRaceModRepeat]

Floating pins have a retaining device keeping the pin in the piston. Snap rings, spiro-locks bushings etc. if you take one end loose and you can slide the pin out then, you have floating pins

[@BulliKid]

@@FabRaceModRepeat I have a set of rods and pistons but the wrist pin does not slide into the rod. Even with some pressure with my hand. The pistons do have c clips with them. The rods do have 2 oil passages in the bottom of the small bore and the bronze/ copper insert. Im not sure if the small bore needs to get bored a bit or if they should come perfect and ready to go. Is it possible a rod can be press fit and the piston still have the c clips? Thanks. I appreciate your input im pretty stuck on this for a few days.

[@FabRaceModRepeat]

@Bullikid If they are new or the rods and pistons came from 2 different sources. It sounds like you need to have the bronze rod bushing honed to size. New ones are usually a bit tight.

[@BulliKid]

@@FabRaceModRepeat the rod and piston came together from the same company as a set. I micd the oem pin and new pin and new pin is .025 bigger. The oem pin floats nice and smooth with the new rod. So I’m not sure if I should heat and and try installing or go to machine shop to hone/ bore out to spec. Weird never thought this would be a issue. Building my first motor.

[@FabRaceModRepeat]

@BulliKid Use the pins that came with the pistons. Go to the machine shop it’s typically $50-80 to fit the pin. PS It’s money well spent

[@angrypepecancer5205]

Thank you sir

[@FabRaceModRepeat]

You’re very welcome. Thanks for watching.

[@nilla003]

Are the pins ever pressed into the piston and float in the small end of the rod?

[@FabRaceModRepeat]

Thanks for watching! In some industrial and early automotive applications, the pin is pressed in the piston with a floating rod.

[@1957mjk]

can I put gen 4 LS floating pistons on my gen 3 press fit rods?

[@dboser1]

Can you explain the installation for a press fit piston and floating rod installation? I have this arrangement on my Onan generator and I have the new rod ready for installation

[@FabRaceModRepeat]

Morning Don, Thanks for watching. I have only done that style once many years ago, on a hit an miss boat engine. The procedure for that on was: First clearance the rod bushing to fit the pin. The pin then pressed into the piston (without heating piston) to the specified depth. It used small cotter pins to insure the piston pins didn’t work back out. With all that said doing a google search for Onan piston installation would be worth while.

[@DELTRANIO99]

Great info vid ,,,I wonder if you can help me out ? If I keep my engine at a steady 2000 RPM and accelerate to like 2500 2700 RPM its like a hear a faint slight growl would that be the wrist pin ?,,, The engine is a 6.0 LQ9

[@FabRaceModRepeat]

Growling sound in the acceleration curve is usually a rocker trunion going bad.

[@DELTRANIO99]

@@FabRaceModRepeat Thank you for the reply ,,I was worried it was a wrist pin

[@murderedluv]

I’m going to use push in pins so should I use clips in order to prevent the pin from working it’s way to the side and scarring the cylinder? Or is it okay to not use a retaining clip if it is a press in pin.

[@FabRaceModRepeat]

The press pin set up doesn’t require a retaining clip. I never really thought about adding a clip to a press setup. If I was going to have the added weight of the clips I’d go full floating pins.

[@dawsonmacie6984]

So in the full floating type the pin can move freely in the piston and around the pin?

[@FabRaceModRepeat]

Yes The pin spins freely in both the piston and the rod. It can also walk right left a bit in most cases.

[@kennethconole9990]

I have sum d16a1. High Compression piston I'm trying to put on my d16y7 rods how can I remove the rods to put my high compression piston on ???

[@FabRaceModRepeat]

I believe you have a Honda?

[@interst8erj968]

What the difference in the from a pin that floats and one that's pressed? ...other than how they are assembled and work. Can the same pin be used as floater or pressed?

[@FabRaceModRepeat]

Great question. How they’re retained is the main differences. The same pin can be used for both application (Varys by manufacture). The floating pins are usually a bit shorter than press in.

[@interst8erj968]

@@FabRaceModRepeat thanks

[@erkopihlak]

What do you think is a better solution? Floating or heated?

[@FabRaceModRepeat]

I go for the floating setup on 99% of my builds.

[@Michael-jp4oh]

Very informational, thank you. I had my pistons ceramic coated but during the process, the wrist pins were not marked to each piston. Does it matter which piston the wrist pins go back in? They are full floating.

[@FabRaceModRepeat]

Michael Matagrano Thanks for watching. If you have not had the pins fit yet it doesn’t matter. If they have been fit, either at the factory or by the engine builder it most likely does matter. This would be a good time to do some clearance checking.

[@Michael-jp4oh]

@@FabRaceModRepeat They are the original pins and rods (LS 5.3 Gen IV) and the pins slide in just fine with no binding. They were all fine before the rebuild and have about 160,000 miles on them.

[@FabRaceModRepeat]

Michael Matagrano As a general rule it’s best to keep used parts together and in the same orientation. If you have the measuring equipment, I would check the clearance of both the pins and the hole in the pistons. It’s cheap insurance. Then put the pins in the piston they fit best.

[@michaeldaugherty6826]

If you ask me, I would say, Yes, it does matter. Every part of an engine has been warn to its specific place. This is what happens when you break -in an engine for the first time. The piston pins will be worn to the specific piston and connecting rod. So it's important to put them back into the same place and direction where they came out of the piston and connecting rod.

[@Davisme1]

301st subscriber here 🎉

[@FabRaceModRepeat]

Davis John Happy New Year! Welcome to the channel

[@robertsiefker4440]

I got new pistons and going to reuse stock rods stock is pressed and the new pistons are floating ones they come with the wrist pin am I ok to use the new ones

[@FabRaceModRepeat]

Great question. I have seen this done. However, If I were doing the build; I would have the rods bushed and make it a full floating set up.

[@chief1972]

I'm working on a '56 Pontiac with full floating pistons.I want to reuse my pistons but I noticed on one piston the wrist pin won't rotate on the rod and on another one it won't rotate in the piston.I tried soaking them with lube,letting them sit and then working them again but they won't budge.What do you suggest?

[@FabRaceModRepeat]

Chief 1 Sounds like your going to have to press them out.

[@ianw9171]

gudgeon pin

[@FabRaceModRepeat]

What is another name for wrist pin?

[@michaelcuffee6393]

Good video

[@FabRaceModRepeat]

Michael Cuffee Thanks for watching.

[@michaelcuffee6393]

@@FabRaceModRepeat not a problem,very useful cause im getting into racing myself.

[@FabRaceModRepeat]

Michael Cuffee Glad to hear it! It’s a great and fun sport.

[@joealfaro9862]

Can you use a press for press fit wrist pins also

[@FabRaceModRepeat]

Joe Alfaro Good morning and great question, It’s not recommended because a “cold” press is not as tight as a “hot press”.

[@RideWithTheWolf]

Can the pin be a little loose when cold, in my motorcycle?

[@FabRaceModRepeat]

Loose as in pin wiggles in the hole?

[@RideWithTheWolf]

@@FabRaceModRepeat yes there is a little play and wear.

[@FabRaceModRepeat]

I’d replace it. It’ll start to pin knock, and that will tear up the piston

[@micthegreasemonkey2918]

R the 52 series wrist pins any good?

[@FabRaceModRepeat]

Morning By “52 series” I assume you mean JE Piston, wrist pins. With that said JE makes a great product. I would check their website or call the tech line about the best pin for the application. Pins vary greatly between applications, for example: a very lite rotating assembly in a 2bbl late model stock car and a BIG power adder outlaw 10.5. car.

[@mondude9754]

I have an engine with a floating wrist pin setup however the con rod is severely scored and uneven so the wrist pin just binds in it, making the only pivot point in the piston. Do you think it’s okay to run like that?

[@FabRaceModRepeat]

@mondude9754 Thanks for watching however, NO do not run your engine with a rod in that condition!

[@kevinhumphrey932]

Looks like a stroker piston

[@FabRaceModRepeat]

Kevin Humphrey Yes indeed. 347, customer ended up going big block instead.

[@tylerfehr889]

It's spelt groove not grove

[@FabRaceModRepeat]

The occasional fat finger happens, it’s been out there this long. It’ll be ok Thanks for watching