LMM: LMM with 222,000 tear down rebuild

[malibu795]

Been keeping up with what you have done to the hot shot truck over the past couple of years.

Would have been a good test (probably would have caused issues though) to have a standard piston in there to compare.

You ever think about bringing the compression ratio back up a bit? Wonder if bringing it up to about 18:1 would help with mileage?

Before I bought the FL60, I was strongly looking at building a 20:1 CR short block, current block is 17.5:1, mainly to chase efficiency/MPG.
To run same 400hp at 20:1 would probably bend stock rods and possibly cause problems with OEM main caps.

I know Dan Diesel performance ran 19:1 for couple seasons in a 2.6? Truck dropped a valve and took the engine out last year?
I've split stock LBZ/LMM pistons at ~275hp and 400rwhp.

I have also noticed and been my experience, stated earlier, ovals are less efficient than oem round bowls and run dirtier.. also to get same result one needs to add timing for ovals if everything else remains constant.
I also have never been able to match the mpg I got with OEM pistons with ovals while towing

Truck pulls 16-17mpg running 75-80 across the plains out west.. but loaded I avg solid 10mpg with ovals vs 11-12 with OEM even at 17.5:1

 

[M.A.M.]

Words couldn't begin to express, Adam... ROFL

Would you get yours recoated while they're out if you had it to do over again? (heaven forbid)

Looking forward to seeing what mine look like...

Definitely noticed an overall drop in economy as well, after I put in the ovals...

 

[malibu795]

Time permitting and someone local.. yes, I was rather disappointed to see the skirt coating was gone soo soon compared to the OEM at 222k

Thought I had a picture of used oval next to a used OEM but can't find it at this time.

 

[M.A.M.]

I've got an LML piston laying out in the shop with 170k on it, and one with 420k... I'll have to compare them both to the oval bowl piston...

 

[mebob2001]

Subed

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[Fingers]

The skirt wear and probably the shorter ring life is because of the higher compression ratio. Adam wanted to go higher and made an informed choice. I had recommended 16.5 : 1 . The ovals do not have the offset pin hole of the OEMs and work the piston skirts harder at higher CR. Even so, I am surprised at his wear. It is not typical. The offset from OEM also changes the timing of TDC. (tiny change)

The #1 priority for the oval piston design was, and is, strength. Adam wants to blame the pistons for all his drop in economy, when in fact his tuning and building skills are and have been suspect. Though I have respect for anyone that tries the path less traveled as he has.

I look forward to him moving on to the Freightliner so he can blame something else.

 

[malibu795]

5 years ~500,000 miles ~250,000 of those miles been running ovals, that's ~4x more miles than the avg forum member is going to put on their truck..

I lose a piston today, the question isn't who's piston do I get, it's what CR do I want my next of ovals.

I've been straight up and honest about them and you still get butt hurt about it. Get over it.

Avg person that puts 30-50k a year on their truck isn't going to feel the ~10% drop in MPG, like a person that puts 100,000+ miles down a year.

Between me beating them publicly and Mark beating them on the track, Definitely help moved your pistons.

I'm sure my overall positive experience lead to the choice of MAM putting them in his truck, which as he stated saw a drop in MPG compared to stock..

Nice jab at my wrenching skills..
Yes I have been unconventional in my wrenching, though that doesn't mean it's wrong.

Skirt wear could be different compound from what GM uses

And completely ignore the fact I'm running doctile iron rings when I should be running stainless steel rings

 

[Fingers]

Thank you for the stress test.

You would have done better with a lower CR.

 

[malibu795]

Ordered SS 42160 rings new bearings clevitte H for rods and mains.. clevitte P currently in it.
Everything should be in by Friday

 

[PureHybrid]

Uh oh

Any problems arise recently?

 

[malibu795]

Burning oil more, mpg dropped 1.5-2mpg.. blow bye getting substantually worse.
Boss asked today if I wanted to haul one of these to Idaho..said no..gut feeling says it would finish off the engine...2000 miles uphill with 20-30mph winds..
It's 10'6" tall on the deck.. catches more air than a box...

 

[six5creed]

Adam, how do y'all like those Kaufman gooseneck trailers? I bought a new one back in December and haven't used it much. Mines 20' with 4' dovetail.


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[malibu795]

It's not built well enough to do what I do.... That said...
Hauling vehicle to a track etc local stuff it's fine.
Thing to remember I was dragging it with 13-14k on the deck with tandem 8k axles

 

[Chevy1925]

atleast you will have the good rings going back in . post pics of the P bearings. im interested to see how they come out. ive heard tales they are stronger than stock GM bearings but just slightly.

 

[malibu795]

atleast you will have the good rings going back in . post pics of the P bearings. im interested to see how they come out. ive heard tales they are stronger than stock GM bearings but just slightly.

I'm pretty sure I didn't swap the main last time it was apart...
So that's mileage from Dec 2015 to now ... 160k? Miles... Noticed EOP changes 5psi pending on/off throttle.. couple weeks ago... That's at 2100 RPM and 60psi

 

[PureHybrid]

Higher oil pressure when off the throttle? I've seen that before, but it was a gasser. And the mains were TOAST

 

[WVRigrat05]

I'd just drop a cummins in it and call it good, pretty sure it'd last longer. I hate changing out power steering pumps let alone rings.

 

[malibu795]

Higher oil pressure when off the throttle? I've seen that before, but it was a gasser. And the mains were TOAST

Yep.. it's more noticeable above 220° EOT

I'd just drop a cummins in it and call it good, pretty sure it'd last longer. I hate changing out power steering pumps let alone rings.

This tear down is in short the cause of lack of knowledge when I did last time.. seams very few people knew that the cast Pistons came with SS rings vs the DI rings I put in.. I also didn't find out till after I fired the Engine.

So do I blame myself For not knowing enough to know I need to ask the question?
Realistically...I can't fault the engine..

 

[six5creed]

Yep.. it's more noticeable above 220° EOT





This tear down is in short the cause of lack of knowledge when I did last time.. seams very few people knew that the cast Pistons came with SS rings vs the DI rings I put in.. I also didn't find out till after I fired the Engine.



So do I blame myself For not knowing enough to know I need to ask the question?

Realistically...I can't fault the engine..

We live and learn Adam. It sucks it's costing you money to learn but it is what it is. Best of luck this time!



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[malibu795]

:thumb: