Hypereutectic pistons and failures related..

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Its well worth a 1 1/2 hour drive if the shop does the job right the first time.

My builder is asking for chrome rings, says it take longer to break in but will last longer.
 
I've run chrome Hastings before with no problem, but switched to Speed Pro Ductile Molly. While talking to a friend who Road Races a late model Mustang, he had a bad engine experience similar to yours. Like you he felt his New engine was down on power and did a leak down test that came out only a little better than yours. He took it apart to find the valves were not sealing, so had them regound at a local speed shop. Anyway, he said to try Total Seal Rings because the leakdown is very small. I'll try them when I put my 340 together.
 
66fs said:
I've run chrome Hastings before with no problem, but switched to Speed Pro Ductile Molly. While talking to a friend who Road Races a late model Mustang, he had a bad engine experience similar to yours. Like you he felt his New engine was down on power and did a leak down test that came out only a little better than yours. He took it apart to find the valves were not sealing, so had them regound at a local speed shop. Anyway, he said to try Total Seal Rings because the leakdown is very small. I'll try them when I put my 340 together.
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yep just like mine, leaky exhaust valves...all of them.
finding the light scuffing was a by product there, if I did'nt see that I would have just dropped the heads back on.
 
oldkimmer said:
........Thats chromemoly i hope.........kim...
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There are iron rings, iron rings with hard chrome face and iron rings with a moly coating on the face. Chromemoly is a steel alloy and you will only find them in all out race engines like top fuel.

Chrome faced rings used to be popular in off road engines but you hardly ever seem used anymore. Plasma moly on a ductile iron ring is the current premium ring for street/strip engines.
 
My builder--who doesn't seem over 40 years old--was saying how the chrome rings would hold up to the heat and rpms more. True 20 years ago they were used more.

I do know Kieth Black does make them for their Hyper pistons. Looks like I be getting Hypers since forged 340 pistons that are .040 aren't like made anymore. If so I get the chrome rings to keep my builder happy. I had chrome rings on my 318 with 360 heads. For 8 years and no blowing smoke. 3.91 gears and the last few years with 360 heads shifting at 6,500 rpms. I drive 75 mph with traffic on the freeways--so what motor is buzzing around 4,000 rpms. Was ok back in 1969, lol.

It may had smoke a bit warming up but quickly went away in a minute or two. A smoky exhaust on the road is a great way to get a quick traffic ticket..so I get chrome rings again.
 
1wild&crazyguy said:
as for the finish...I run your basic hastings single moly top rings.
I was thinking too tight a wall moper, cause theres no sufficient oil there, thats a lot more swept and side thrust. jmo
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Looking (just eyeballing the wall finish in your pic) there is too much hone mark left. It's too rough for a moly faced top ring (normal Hastings "moly" ring). The pic I posted is with Hastings moly coated ring too. Note how little cross hatch is visible. What that means is the moly gets scrubbed off immediately... Like thin paint on steel being rubbed on sandpaper. At that point, the ring is plain iron face and will need the long break in period with light and moderate load, high vacuum perods, etc. However... The pistons on the 4" engines are short as compared to the stock ones, and the rings are narrower. Which means you have less ring surface area sealing on the wall, and less stability as the piston rocks around. The loser the piston on the wall, and the rougher the wall finish, the easier it is for oil to be cleared away and material to transfer between the piston and wall. Especially with the side loading of the long stroke. You've got low pressures, leakdown issues, and oil on top of the piston, plus possible material transfer on the bores. That all says to me the wall finish isnt right and the piston is wobbling around in the bore. Hypers dont expand. I would suggest if you are concerned with that, try measuring one at room temperature and then boiling one for an hour or so and re-measuring it. If it changes more than .0005 I'd be surprised. Keep after it. You have issues that will definately "find" more power when fixed.
 
Just the regular 5/64 rings on these hypers, the forged pistons take the skinny rings.

Yeah i wish I had time to stick another head on it and see if the rings were leaking too.
BUT there was no black crap on the skirts or bores, so no major/abnormal leaking.jmo

There was a lil bit on the exhaust stems, oil being pulled past the guides just a hair, more if there was no viton seal but not like the guides are crap just on the loose for the lift/pressure/rpm.

I know these don't grow like forgies, they send heat to the head and everywhere else though by design.

I will have the block looked at by multiple shops and get a verdict.
 
You said it yourself... Hypers dont absorb heat as well so the oil won't appear black on the skirts or ring lands. Sometimes it will leave some black soot in the machined grooves above the top ring. But mostly the dome, skirts, and ring lands will simply be wet with oil. I had a 383 I had to re-ring after the owner washed the rings of the new engine out. It wasnt sealing well but not smoking. The piston tops looked like yours. See if one of the shops does a lot of circle track stuff. Someone that can get you a report with a profilometer. Maybe ask the shop you're using what stones they use to hone. What do they finish with?
 
dodge freak said:
Quote from the K.B. web page I just posted the link.

"Excessive spark advance, lean fuel mixture or too much compression for the fuel and cam used will make heat sufficient to butt piston rings with as much as .060" ring end gap"
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initial timing-24* and 32* total.

no butted rings, piston skirts look brand spanking new.

somehow....someway...dirt/junk got into the motor.
I say this due to the fact that the skirts are bitchin, and when I pulled the #,3,5,7 rods I noticed # 3 cap side rod bearing lost about .100 off the side/edge-crank/radius side. The rod bearing are the clevite 'narrow' $80 or... the right ones for the type of journal [raised radius not filet style]
The crank checks to be right on and no polishing even needs to be done.
but something got in there...
so bearings,rings,gaskets, and the valve fix which is done.

I will be scribing each head/chamber using the bore as a guide, then I will open the all the chambers up to the scribed size, then I will re cc each chamber and correct if necessary to get all even and down to 60cc this time, then remill the intake side and the intake since at this point there will be plenty of milling going on.

The other way I might do this is to only scribe the side of the chamber where the quench pad comes up to/or the shallow side of the chamber opposite the spark plug, this way I can keep the mod uniform still, but end up having to mill less... that would only be 1/3 around.
also,
I think I might find a tiny sleeve to press into the rocker oiling feeds in the stands and do more finessing of the the straight walls...might even tube the head bolt holes and drill them back to 'bolt size'....

the other ponder I had was brazing up the exhaust floors...it's free...and I got the time being I have the 340 for now...hmmm
there is a decent amount of work to be done on the far side wall of the runner, before and as it transitions into the bowls.

....hmm ...good potential in what most call out dated.

[side note], I stuck the LD340 intake onto the 340 [pics], removing the weiand single plane...
I think it'll pick up a bit where I need it most with this particular cam/flow/gear/carb combo.
these x heads only flow [email protected] & [email protected] @28 depression
got about $600 into'em with hard seats, mancini ss valves, comp springs & 3 angle, but thats good fer 461'ish hp potential.
it works nice with the .528 solid thats in there.
I'd like to dyno it, chassis then flywheel...maybe.

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Maybe the bearing was damage before it went in and felled apart once it got hot and stressed? Maybe the bearing was taper and rubbed the crank on the edge. Quality control is not like it used to be. These companies scrape far less parts for higher profits.
 
To the guy who emailed me by the name of 'Bart Simpson'...

are we that worried about our identity?
or imbarrased to ask questions?

or just have no imagination for fake name?

sorry brah...it's just hard to take you seriously with stuff.

BUT 4 what it is worth...it's a milodon valley baffle and it keeps the hot oil splash from the cam off of the bottom of the intake which make more hp from a slightly cooler charge from a slightly colder intake, I also block the crossover passages.
AND yes it needs to be trimmed to fit properly and is held in place by those spring steel metal straps that are bolted to the baffle and have the threads flattened to keep the nuts from ever falling off by chance.

hope that helped you mr. oo7, oh I am sorry... I mean, 'Bart Simpson'

too funny...
 
16 years and still running.
6500 rpm shifts.
 
I was driving down a side street/back way home and last minute saw this massive dip at the intersection where I turning....well I slowed & went at an angle to avoid it but you could just feel it hit..

oh well,now it's a slightly 'clearanced' pan.

speaking of railroad tracks...I hit some so hard one time it ground the bell's lip pretty good and broke the trans mount while shifting into 3rd

I've bottomed out so hard in the past, trashing headers, k members, oil pans, sway bar clamps....just sparks flying everywhere.......lol live and learn.
 
Heres a hyper failure:

Not Mopar, but interesting:

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This is actually what they saw after pulling the head off, nothing has been moved.

Too much nitrous (maybe a 250 shot). Hypers are strong but when they go, the go everywhere. On this motor, the owner was pulling piston pieces out of the intake and carb.

Steve
 
Isn't that lifter valley baffle supposed to have the springs pressing against the bottom of the intake manifold? Although the way yours is/was installed sure would make installing the manifold muuuuch easier..
 
65TerrorCuda said:
Isn't that lifter valley baffle supposed to have the springs pressing against the bottom of the intake manifold? Although the way yours is/was installed sure would make installing the manifold muuuuch easier..
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No the springs go under the Heads. I thought the same thing until I installed one myself. You will need to do some trimming also to get it to fit like stated earlier in this post!
 
hardly relevant - but I thought I'd at least show you my only hyper failure after using them on many different makes/motors -

stock hyper piston on a 5.0L (94) - this is what happens with too much cam and stock valve springs (and happened only 75 miles after buying the car... lucky me) - EDIT - btw this is what happened when I pulled the head AFTER driving 20+ miles from the initial issue (on the hwy - still had 40+psi oil pressure the whole way)

I've ran hypers in several turbo cars (ceramic coating helps a ton btw) and in a few fords - so far 0 failures related to the pistons.

just so you don't think I'm trolling or anything I am finally returning to the world of mopar - I've had over a dozen darts/dusters/demons - all small block - the best being a GTS 340 - anyway - I'm prepping to start a 360 build - most likely gonna be a hyper setup so I'm doing research... couldn't help myself from showing damage photos :-D

Cleaning up 038.jpg
 
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