Piston Rings for 351w

[FirstEliminator]

   Hey guys,

    A mild 351w that I had put together in 2010 always had a shake to it at idle. I've tried moving around the initial timing. Tried different carbs---both Autolite 2100 going rich and lean with the mixture screws. Did a compression test to find cylinders were all very close. Then I had loosened all the rockers and put air pressure into the intake. There was a little bit of air coming out of the oil breather. So I resealed the intake. It was ever so slightly smoother. Or, just my brain playing tricks on me grasping for some improvement.  A couple weeks ago I pulled the engine, disassembled it to find a rough spot in the middle of cylinder 7. Like as if it were rusted. I had not pressure tested the block, but suspect there is either a very small crack or porosity pin hole. The piston has some scuffing in the ring land area, but the skirt looks untouched. The barrel finish of the top ring is worn flat from top to bottom where it rode over the rough spot. So, I need a set of rings. Pistons I think can be reused. Got another block and are having it bored to reuse my pistons.
   Here are the ring questions:
  1. Difference/benefit of moly versus plasma moly ring facings?
  2.  I'd like to use a "low tension" oil ring for improved efficiency. Is low tension a bad idea for a street cruiser? I've read the low tension oil ring has no problems when used with a Napier 2nd.  How about when used with a reverse twist taper ring or any non-Napier 2nd?
  3. Does anyone make a Napier style 2nd ring in 5/64?
  4. If there is no such thing as a 5/64" Napier, would it be a better choice to get another set of pistons that use thinner rings? Like 1.5mm, 1.5mm,  4.0mm are the stock style piston for the latest 351w in the Lightning truck. If I were to go this route of lower ring tensions, could I expect an improvement in gas mileage?

   The biggest problem I am having is I'm planning to take this car to Carlisle All Ford in 2 weeks.

   thanks,
     Mark

[IDOIT4SPEED]

 in my world I would rather have the block honed with deck plates, with about .005 to hone. and use sunnen an500 stones for finish. then brush 6 to 12 strokes . with 100 ft lbs of torque on the head bolts with a thin wall block, it is common to have .0015/003 bore distortion when the deck plates are installed.  if you must have trick rings call TotalSeal.

[machoneman]

   Hey guys,

  .
   Here are the ring questions:
  1. Difference/benefit of moly versus plasma moly ring facings?
 
-In a street car you will never know any difference.

2.  I'd like to use a "low tension" oil ring for improved efficiency. Is low tension a bad idea for a street cruiser? I've read the low tension oil ring has no problems when used with a Napier 2nd.  How about when used with a reverse twist taper ring or any non-Napier 2nd?

-waste of time, money and effort unless this s a 1.25 hp/per CID engine (or pure race).

  3. Does anyone make a Napier style 2nd ring in 5/64?

-yes, but.....see above.

  4. If there is no such thing as a 5/64" Napier, would it be a better choice to get another set of pistons that use thinner rings? Like 1.5mm, 1.5mm,  4.0mm are the stock style piston for the latest 351w in the Lightning truck. If I were to go this route of lower ring tensions, could I expect an improvement in gas  mileage?

-yes getting a new set with thin rings would be better yet I do think you'd need to order up a set of custom pistons. Once again, paying say $500 to $700 to merely get low compression (i.e. non-race) pistons iwht modern thin rings little sense to me. You'd never see enough mileage improvement in my book to pay off the increased cost. 

I agree that getting the block deck plate honed with your current pistons if they are in great shape is a far better investment with plasma or straight moly rings that fit the ring lands.

JMO!

[Falcon67]

1 - plasma moly is an application technique, usually provides a stronger attachment to the base ring.  So - whatever.  Any decent moly faced ring should work.
2. - Typically, yes - it's a bad idea.  You might get away with something at least 12 lbs tension or better with good PCV draw.  I used 11 lbs on the last 351C and not problems with oil control - but it was not a street cruizer.  95% open exhaust with header evac, not your street setup.
3. Have no idea.  I've run standard configuration rings in all my engines for 30 years and never had issues
4. If you'd like to drop $600 on a nice set of light Probes and re-balance the motor, sure.  Gas mileage?  I'd not think you'd be able to detect any improvements by using thin rings.  There are a zillion other thing that impact MPG.  The Probe set I have uses 1/16, 3mm oil.  Low tension rings makes for little friction - but they are going in a dragster, so not applicable.

IMHO - if you are running a 2100, then you need a set of Summit moly rings (Hastings is the OEM as I recall), get a decent cylinder wall finish for the rings - tell your block shop, deck the new block square, put it together and go.

[FirstEliminator]

    Thanks for the replies guys.

    Earlier today, I bought the Summit/Hastings ring set with the regular Moly top ring. A new set of Clevite main bearings and a few engine tools.  Which included a one-size-fits-one 4.030 solid ring compressor.
    The block is at the machinist and i dropped off my pistons today for him to mic.

   The 545 stroker 460 that I am putting together for a '79 F-350 crew cab has 1/16, 1/16 and 3/16 rings. I will try the Napier 2nd and low tension oil ring set up in hopes of retaining the term mileage instead of yardage. The E4OD will also help. Along with dropping from 4.10 to 3.73 gear set.

    Thanks for the help and now back to the regularly scheduled FE programming.


   Mark

   

[Falcon67]

Mileage?  F350 7.5L Gas?  Right, best of luck with that.  I pull the 24' box with a 1993 F350 extend cab 7.5L gas.  Trailer weighs about 7500lbs loaded.  I was pleased that we got 7 MPG average going to the bracket finals last year.  Total pull over 900 miles @ 65 MPH.

[FirstEliminator]

  A while back I had a decently built 460 with C-6 and 2.75 gear in my 78 F-150. I was checking mileage while pulling an empty open trailer across Ohio and Indiana on flat ground. Topping off then going 100 miles and topping off again the truck was getting 16.2 mpg. This was going by the mile markers on the side of the road, not by an optimistic odometer. It had an Edelbrock 750 that was leaned out until surging then richened up a step. The block had been decked for .040 quench. It had a 200/205 @ .050 cam with a 112 sep.  D3 heads with roller rockers. Stock intake and exhaust manifolds. The engine ran really good until one day turning onto a main road from a side street I heard a rattle and the engine stalled. What happened was the #8 piston shattered. Many miles before this failure a friend was driving the truck while helping me move from Florida to Massachusetts and the radiator let go. The engine got overheated really bad. I guess that started the ball rolling on a failure.

    When I say mileage, I don't expect 20 plus. 12 would be o-k when cruising at 65. The 545 will have the MSD Atomic EFI, mild cam picked by Scott at Reincarnation which has a 113 lobe separation. Performer RPM intake, FPA headers to 2 1/2 exhaust, Diamond pistons with a 38cc dish, ported D3VE heads.   Trans is E4OD with a 3.73 gear set.    I'm hoping for decent mileage from such a combination, but we'll find out what it really is once I get it together.

[machoneman]

Hyper-E pistons I take it. Forged would not do that.

[FirstEliminator]

Hyper-E pistons I take it. Forged would not do that.

 
    I don't remember if they were Hyper-E or plain cast. That is definitely why I went with forged in the 545. That 460 was a throw together of extra parts. Inconvenience and frustration for a little while, but not a big loss. In every attempt to build it right, the 545 is hopefully going to last the life of the truck. Which should last the rest of my life. It won't be driven daily and never in the winter. 
    But, then again, this 351w was supposed to be built that way------done and move onto the next thing. Oh well, perhaps this is the last time.

[Falcon67]

Our F350 DRW is a 4.10 gear unit, 7.5L injected AOD-E with overdrive .  Best it'll do totally empty one driver is around 10 MPG running 65-70 at steady throttle.  That's about 2000~2200 RPM on the highway.  The cat has been replaced with a high flow unit, but the rest is bone stock 103K miles.  It's fer pullin' not for cruzin'    Even the 2015 DRW 350s with a high zoot new tech 6.8L only get 12~14.

[FirstEliminator]

Well, 10 is double digits.  Perhaps single rear wheels and a 3.73 cruising at 60-65 might get me closer to 12. With my F-150 getting good mileage with a decently built 460 gives me hope on this F-350 getting near that.
    By the way, I replaced the decent 460 with the broken piston with a 460 that was pulled from a 76 Lincoln Towncar. The gas mileage immediately went from 16 with the trailer to 12 totally empty. Recently I took the F-150 on probably it's last long trip to pick up a Comp Green 70 Cougar Eliminator 351c 4 speed. The trip was from the northwest corner of Massachusetts to the Wisconsin/Minnesota boarder. It used $600 in gas. I didn't want to calculate the mileage---but it was terrible. Plus, the engine used 9 gallons of oil on the round trip. Definitely time for something fresh. Not too different, just fresh. The F-150 is a 1978 with tu-tone brown and tan. The 79 F-350 crew cab is also brown and tan. I like that color combo as I also have a 78 F-250 4x4 that is brown and tan.   Wow, gotta get this F-350 done. With two young kids, 2 more doors on the truck will be helpful. Since it's a summer truck, working A/C will be nice. Plus it has the capacity to tow my 28' enclosed trailer which my 150 certainly did not......well, pull yes----drive strait and stop, not so well.
   
   thanks,
     Mark

 p.s.  your trans is an E4OD, not AODE.

[Falcon67]

Oops, yes E not A.  We also pull with a 2004 F150 Super Crew 5.4L.  It's pretty good, averaged 11 with 5500 total (car+open trailer) last time we ran to Dallas and back.   Normally 18 ~20, not bad at all.  I imagine the 460 could be tweaked easily, maybe a bit torkier cam and/or diaiing in the stocker with a new chain.   But it runs well now, no time to mess with it.  I did bump the timing +2 and that seemed to help it a bit.   If I was going to fix anything, it'd be replacing the fuel pump assemblies because the front doesn't read and the truck has the "failed one way check valve" issue that requires care in how much you put in both tanks.   

[FirstEliminator]

   Well, it doesn't look too go in getting my 351w back together for Carlisle. I attempted to put the bottom end together this evening and I could turn the crank, it wouldn't budge. Took all the main caps off and tried just one. It created a significant amount of resistance. All in all, the main caps are off-set from the block.  The guy I bought the block from couldn't find the main caps at his house. We had to go across town to find the missing box of main caps in his friend's trailer. Apparently, these mains are not from this block. Where and when the mix-up happened, I have no idea. Highly unlikely that anyone will be able to align this caps to the block with enough time to get everything back together.

  It's a bummer. But oh well, life goes on. Guess I'll be taking a different car.

  Mark

[Falcon67]

Really sorry to hear that.  It's so simple to keep all those parts on the block, not sure why people like to scatter them around. 

[afret]

I use a low tension oil ring on my FE street car with no problems.  The ring set is just common standard 1/16, 1/16, 3/16.

If you want to use thinner rings on your pistons, you can get ring spacers from Total Seal to run whatever type ring you want.