SO
I'm assembling my pistons. I am having a hard time with the pins and locks. I put some assembly lube on the pins & piston bores, but the wrist pins need to be massaged in with a rubber mallet and socket. Is this right?

 

I'm going to assume that these are floating type pins and not interference fit.

If so, then NO that is NOT normal. The clearance on my motor was tight. I can't remember off the top of my head but I believe it was something like .007". Still, the pins and bores in the pistons coated with some assembly lube and that was enough clearance for them to slide right in. They are called "floating" style pins for a reason. Because they should be able to move freely inside the piston bore without any type of interference holding them stationary.


Note that with tight clearances such as that. If the pin is cocked in the bore ever so slightly it will get stuck and not want to go through. Very common and I found a good way to minimize or prevent them from happening was to spin the pin while inserting it into the piston. I hope that this was not what your case was and you damaged the piston bore by forcing it in with a hammer. Hammer or press, anything besides your two bare hands to get a floating style pin in the piston/rod means something is not right.

Do you have a snap gauge and mic you can check clearances with?

 

The wrist pins move freely in the piston, but are not moving at all on the rod.

 

Do your rods have brass bushings in the small end or just all steel?

 

brass bushing.

 

Some is not right. The bronze bushed rods are meant to be floating style. I don't see anything wrong with an interference fit on the rod and floating fit on the piston (That's how the factory did it afterall) but the problem is they are not supposed to be doing it. You may have to take your rods to have the bushings honed.

You need to check the clearances to be sure. Are you blueprinting this motor or just throwing it together?

 

i agree with everything above. you could try freezing the pins for a few hours and see if they slide in better. if not i'd say you need the bushings honed.

 

OK,, I fixed my problem. I took some green scotchbrite and hand honed the wrist pin bushings down ever so slightly ans now they spin freely on the rod and in the piston. I feel happy now!

Is there any repercussions from doing it this way?

I spent the evening breaking everything down while listening to Roy D Mercer... I LAUGHED my butt off! Ended up with another cut on my finger too- These spiral locks should come with either a free box of bandaids or a coupon for some LOL

 

NO!

The wrist pin bores in the rods are now most likely out of round and stand a good chance of having EXCESSIVE clearance.

No offense, but did you not see where me and another indicated these needed a HONE by a MACHINE SHOP!?

There is a lot more to building a motor than just throwing everything together. I did countless research and have 8 hand written pages of blueprints on mine. Everything requires specific clearances and specific values.

I'd highly suggest STOPPING everything you're doing and reading some books if you don't want this thing flying apart on you. I have some very good suggestions if you care to take my advice.

 

I did't take any metal off- just all the parafin from shipping. everything is disassembled to be taken to the shop...

 

So many people have said that.

 

Key to installing spiro-locks: Stretch them out like a spring before install. Takes it from almost impossible to install to being able to do it with a small screwdriver EASILY. You can do all 8 in a matter of just a few minutes if you do it right.

I should make a YouTube video, but somebody's probably already done it and, of course, I would have to ask my 9 year old son how to upload a video to YouTube.

 

I could have used this advice before hand lol. The istructions say "Do not expand the spiral lock more than necessary"

 

I installed my spirolocks with nothing more than a small bladed screwdriver and bare hands. Removed them the same way too. Once you do a few you'll really get the hang of it. Like has been said, you need to stretch them out prior to installation. Not only does this make install/removal much easier, it gives them the tension they need to keep from wandering out of the piston groove.


I also installed my piston rings without aid, using nothing but either my thumbs or a heeman pinch grip on the ring ends with my pointers and thumbs, to get them on the pistons.


Obviously a ring compressor when installing them in the block wasn't an area I could take shortcuts on. Lol

 

i heat my pistons in a small oven to no more than 200 F . and i put my pins on dry ice. for about half an hour. everything just slides together . but note this is AFTER all measurements have been made.

 

^^ What he said. Back when we were poor and had to turn the head off in the shop at night, we could never get stuff to go together the next day.

-- Joe