470 piston ring questions

[natemoore]

But first, I still need some answers on my "crankcase installation thread" before I button it up. I'd appreciate you looking at that one too.

Now, piston rings.....

The Mercruiser manual and the Hastings instructions included with the rings contradict each other regarding the orientation of the bevel. Merc says bevel up. Hastings says bevel down/dot up. Which one is right?

My compression rings have one with a bevel and one with all square edges. Which is the top compression ring?

My ring gaps are running about .029-.030. Merc specs say .010-.025. Some here have suggested widening the gap above specs because of the hyper pistons. Do I need to lose any sleep over the slightly wider gap? And remember, I'm not building a racing engine.

Thanks.

 

[Don S]

Re: 470 piston ring questions

Since you don't have OEM rings, use the instructions that came with the rings.

 

[gettin'even]

Re: 470 piston ring questions

But first, I still need some answers on my "crankcase installation thread" before I button it up. I'd appreciate you looking at that one too.

Now, piston rings.....

The Mercruiser manual and the Hastings instructions included with the rings contradict each other regarding the orientation of the bevel. Merc says bevel up. Hastings says bevel down/dot up. Which one is right?

My compression rings have one with a bevel and one with all square edges. Which is the top compression ring?

My ring gaps are running about .029-.030. Merc specs say .010-.025. Some here have suggested widening the gap above specs because of the hyper pistons. Do I need to lose any sleep over the slightly wider gap? And remember, I'm not building a racing engine.

Thanks.

Ill check my piston ring box in a second (I still have it with the "other " four cylinders worth of rings in it) for the orientation.


I was told by the piston ring supplier than I wanted AT LEAST .016-.018 end gap. My machinist said he final hones the cylinders on a boat engine for a little extra gap as these engines are worked hard. My ring gap was .025-026" in all four holes, which was fine by the machinist.

The stock pistons are not hypers, so the Merc specs don't apply in this case.

 

[natemoore]

Re: 470 piston ring questions

The stock pistons are not hypers, so the Merc specs don't apply in this case.

Good point. :redface: Sounds like .030 will be okay. Now, just need to know which is the top ring and which is the bottom.

 

[natemoore]

Re: 470 piston ring questions

Since you don't have OEM rings, use the instructions that came with the rings.

Thanks. I was leaning that way.

 

[Don S]

Re: 470 piston ring questions

Merc recommends .010 to .020 for the ring gap, and I would bet they know the engines work hard too.

Gettin-even, don't try to compare your rings with his, unless you have the same rings. In the manual, the oem rings are bevel up and marks (pips as merc calls it) are both up. His Hastings rings have a dot that is supposed to be up and the bevel down. That is how the rings were designed. Don't start second guessing the specs on this stuff or you guys will always be asking why things don't work.

 

[natemoore]

Re: 470 piston ring questions

Merc recommends .010 to .020 for the ring gap, and I would bet they know the engines work hard too.

Gettin-even, don't try to compare your rings with his, unless you have the same rings. In the manual, the oem rings are bevel up and marks (pips as merc calls it) are both up. His Hastings rings have a dot that is supposed to be up and the bevel down. That is how the rings were designed. Don't start second guessing the specs on this stuff or you guys will always be asking why things don't work.

Duh! It's written on the flaps on the box Glad I didn't chunk the box. Thanks guys. Now, back to work.

 

[dr_bowtie]

Re: 470 piston ring questions

Regardless of the manual go with the specifications on the package of the manufacturer...

if they are Hasting's rings then use the Hastings specs on the box....

they come in th box separated 1st, 2nd and oil rings...

and I see no crank thread...?

 

[natemoore]

Re: 470 piston ring questions

Regardless of the manual go with the specifications on the package of the manufacturer...

if they are Hasting's rings then use the Hastings specs on the box....

they come in th box separated 1st, 2nd and oil rings...

and I see no crank thread...?

Guess I could make it easier for you guys:

http://forums.iboats.com/showthread.php?t=348898

 

[gettin'even]

Re: 470 piston ring questions

Merc recommends .010 to .020 for the ring gap, and I would bet they know the engines work hard too.

Gettin-even, don't try to compare your rings with his, unless you have the same rings. In the manual, the oem rings are bevel up and marks (pips as merc calls it) are both up. His Hastings rings have a dot that is supposed to be up and the bevel down. That is how the rings were designed. Don't start second guessing the specs on this stuff or you guys will always be asking why things don't work.

I guess I didn't specify that we have the style/type pistons and rings. Sealed power Hypers and the appropriate Hastings brand ring set.

The top rings (Hastings) are square-edged...so there is no real "up" to them. The second ring has a dot that faces up.

 

[natemoore]

Re: 470 piston ring questions

I guess I didn't specify that we have the style/type pistons and rings. Sealed power Hypers and the appropriate Hastings brand ring set.

The top rings (Hastings) are square-edged...so there is no real "up" to them. The second ring has a dot that faces up.

Thanks. Got a short block sitting in the garage. Relaxed in the hot tub, played some Rush on the guitar in my man cave, and am currently sipping a bourbon and coke. A good day all 'round.

Hey, I think I just tweeted!

 

[gettin'even]

Re: 470 piston ring questions

Thanks. Got a short block sitting in the garage. Relaxed in the hot tub, played some Rush on the guitar in my man cave, and am currently sipping a bourbon and coke. A good day all 'round.

Hey, I think I just tweeted!

Conrads on the progress. You'll be on the water soon.