odonnell

At my wits end with trying to get my pistons in using my ARP tapered compressor - the oil rings are getting hung up on the transition point between the tool and the deck. The rings are gapped correctly and I've verified that everything else is in check. I just don't think it's compressing the rings tight enough (it's exactly a 100mm diameter at the exit).

Can anyone recommend a good compressor that's verified to work well? I don't want to do something stupid and scratch a bore.

Humboldtgrin

I use something similar to this.
https://www.ebay.com/itm/231745754422

weez58

I normally use the solid tapered ring style compressors, but I've had good luck with these: https://www.summitracing.com/parts/s...3900/overview/

944crazy

Are you holding the ring compressor down against the deck when you tap the piston down?

If you don't hold the ring compressor down, the rings will pop out the bottom before they go into the bore...no matter what compressor you use.

rlm328

I use this one.

http://www.oreillyauto.com/site/c/de...0717&ppt=C0374

Its easier if you can get a spare set of hands.

odonnell

Thanks for the links gents.

Yes, putting plenty of pressure on it. With a tapered compressor, are you really supposed to "tap" them in? All the videos I've seen show people smoothly sliding them in. That could be the issue. I'm just super paranoid about whacking it into the cylinder and boom, need a new block.

rlm328

I use the bottom end of the mallet to tap them into the block. The compressor is normally snug.

Tom M'Guinn

Assuming the ring compressor is the right size (with no step to overcome when the piston goes down) then it sounds like you need to use a little more force. If you are the type to get just the right tool for every job, they do make piston install hammers...

https://www.summitracing.com/parts/pro-67571/overview/

Porvair

I just used this one to install my pistons. It received some crappy reviews, but its been in my tool drawer for 10 years so I gave it a shot. I had to re-seat it twice on one piston, but the others went in fine as I made sure the tool was square to the block before tapping the pistons in. https://www.summitracing.com/parts/wmr-w80574

Dare

That's the one I used. I was nervous too, but it worked well. Be sure to soak the piston in lots of oil.



Also, here's a thread comparing ring compressors: Best Ring Compressors

odonnell

For posterity, I used that compressor (that Porvair and Dare posted) successfully for #1. For #4 it hung up on the bottom oil rail ring just like #1 did with my original tapered tool. Luckily, the tapered compressor actually worked perfectly for #4. Huh. Guess between these 2 tools, it'll get done.

Chris Prack

This one unless they were over 105mm then a compressor from Snap-On.

FRporscheman

I used a craftsman ring compressor, lots of oil, and a the rubber handle of my hammer.

http://www.sears.com/craftsman-pisto...p-00904716000P

kev951

I had my tapered ARP ring crompressor machined. works like a charm

Voith

I got this Hazet compressor, works good on other engines, hope it wont ruin 944 block.