Moly vs Ducile Iron Rings

[jaluhn83]

How much real advantage is there to using moly rings?

I was planning to run moly rings and have a set on order, but apparently they're delayed and I need to get the motor back together asap. I have a set of ducile iron ring already and am considering just throwing those in. The set I have is an old sealed power set dating to 6/89 but new in box. I figure if they're good enough for OE use they can't be too bad, but on the other hand I want to do this one right and not have to mess with it for a while.

Thoughts?

 

[idiabuse]

The bore hone needs to match up the with the ring material if you want to get in the ball park.
If you already had the bore honed then you really have no clue what was done and used.

The stones and machine process used to hone the block can be used in so many different ways.
Just use the rings you have and forget about it.


Javier

 

[freebird01]

http://www.hastingsmfg.com/ServiceTips/ring_set_composition_recommendat.htm

this may help

 

[jaluhn83]

Good point. AFAIK, It was honed with a medium to high grit, something in the 400-600 range. I'll have to check.

 

[idiabuse]

Bored then honed? When boring a hole a lot of guys stop just a few thousands before finish hone.

Done right you stop .006 before finish size and hone with 3/4 different stones to smooth the bore.

I know an A$$ hole that he cuts the bore to .002 before final size and uses one stone to finish size
then hits it with the ball brush.
Those engines don't last 50,000 miles before they plume smoke, everyone he does.


Javier

 

[riotwarrior]

If you use moly rings you usually use a finer hone and take a bit longer to break in as I remember

Cast rings are a tad rougher hone and usually seat fairly quick but can eat bores quicker...more or less the quick standard rebuild.

In all likely hood you'ld be fine running those rings

JM2CW

 

[franklin2]

That's not what I have read in the rebuild books. From what I have read, the moly rings are more tolerant of the wrong finish on the bore, and you can actually get them to seat on a engine that you are doing surgery on. In other words, if you are going to replace a piston just to get the engine going, the moly rings will actually seat after awhile on a bore that is not even prepared. They are the most "dummy proof" rings you can buy.

 

[riotwarrior]

That's not what I have read in the rebuild books. From what I have read, the moly rings are more tolerant of the wrong finish on the bore, and you can actually get them to seat on a engine that you are doing surgery on. In other words, if you are going to replace a piston just to get the engine going, the moly rings will actually seat after awhile on a bore that is not even prepared. They are the most "dummy proof" rings you can buy.

If you swap out a piston on a worn bore, that's glazed, that's alot closer to a finer finnish than course hone. Kinda like I said. They do seal well right away but take time to seat fully.

The idea of plasma moly spray IIRC is a good face that is one self sealing and hold oil well. These are not tolerant to ***** from dirt and dust, etc that's why dirt bikes use cast or chrome rings which are more tolerant of harsh environments.

Yes the moly will seal in a used bore much better than a cast one but wow, does it take a while to seat.

The finer hone wears the moly face slower and being it holds oil better this takes more time to seat.

Maybe I'm wrong I dunno, I'm just going with what I learned some 35+ years ago.

Cast rings are a very GP ring in all honesty a best all around unit that's good in mildly harsh environments, seal ok off the hop but seats quicker as it's using a slightly courser hone.

Maybe I'm all backasswards and have forgotten this crap as I've not had to deal with this in like forever years...

Others will chime in with exp too.

These are my experiences and observations, others may have different results.

Al

 

[icanfixall]

Never ever use a ball type hone. Thats the worst thing to use on a bored cylinder of any kind. All your doing it making it "look right". Whats happening is the uneven ball are able to reach into all the undercut areas. A flat stone will show these bad bore areas better but you will be honing more to straighten up the bores too. But thats what we really want to do.. Not "make it look good" by balling it.Oh the humanity of it all...

 

[franklin2]

If you swap out a piston on a worn bore, that's glazed, that's alot closer to a finer finnish than course hone. Kinda like I said. They do seal well right away but take time to seat fully.

The idea of plasma moly spray IIRC is a good face that is one self sealing and hold oil well. These are not tolerant to ***** from dirt and dust, etc that's why dirt bikes use cast or chrome rings which are more tolerant of harsh environments.

Yes the moly will seal in a used bore much better than a cast one but wow, does it take a while to seat.

The finer hone wears the moly face slower and being it holds oil better this takes more time to seat.

Maybe I'm wrong I dunno, I'm just going with what I learned some 35+ years ago.

Cast rings are a very GP ring in all honesty a best all around unit that's good in mildly harsh environments, seal ok off the hop but seats quicker as it's using a slightly courser hone.

Maybe I'm all backasswards and have forgotten this crap as I've not had to deal with this in like forever years...

Others will chime in with exp too.

These are my experiences and observations, others may have different results.

Al

Looks like we read the same book(s) and had the same experiences.

 

[chris142]

So if you bore it you want a 3 stone hone and if your breaking a glaze on an old cylinder you can use a ball hone? I have had good luck with my ball hone on My backyard rebuilds.

 

[idiabuse]

At the race track with every car being the same, the guy with the best combination of ring material and hone process is usually the guy with the most power at the track that day.
Combustion engines are air pumps, rings and bore condition all affect how much air it pumps in a given amount of time.

Some racing engines use a .027 thick top piston ring due to a better seal on the bore.
I would never spend 5 seconds talking about a used bore and new parts, I become silent.

Javier

 

[jaluhn83]

Kind took off on a tangent here....

Going to use the moly rings, got enough other work to do today that I never got to where I needed rings.

From my research, the moly rings like a smoother finish, though I can't remember exactly why. I do recall them supposedly being usable in a glazed bore, but the machinists I've talked to have said it never really works out well.

Ball hones work fine for breaking the glaze. They woln't do anything to even out a bore or correct eccentricy, but if you're just trying to break up the glaze on an otherwise good cylinder to run new rings they work fine. The only way to really fix a messed up cylinder is a boring bar. A power hone (read machine shop) will be much more aggressive, but it's still not going to fix much.

I don't think I've ever heard anyone take 0.006" off with a hone.... 2-4 should be plenty. Shouldn't need more than one grit either - 2 for a plateau hone.

 

[OLDBULL8]

The angle of the dangle is proportionate to the heat of the meat.
If your going to hand hone the bore as apposed to machine honing, it really don't matter what grit stones your using. A machined hone produces a figure eight (8) at a 60* angle with a soft stone and plenty of mineral oil to wash the grit away. A production honed engine uses four (4) stones with four (4) fiber bars four (4) inches long. The metal removed is anywhere from four (4) to six (6) thousands, that's only two (2) to three (3) thousands per side. Each bore is measured with air and stamped A-B-C-D for piston size, there is only .00015 difference between each size.

Course, it's been 26 years since I was GF on the 460 block line, so I may be CRS.