Engine knocking LDS-456

Oerthedge21

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Gasket set came in today, along with the piston and sleeve set. Sleeve is a Z stamp and measures up exactly the same as the old one. The piston however, has me concerned. The new piston has the same # of rings and the same style solid wristpin. However, the inside is not the same. The new one doesn't have the oil cooling passage that the old one did, also has a differently milled bottom. I assume this means that this piston is not for my engine and cannot be used in it right?IMG_20190903_171027201.jpgIMG_20190903_171046160.jpg
 

Oerthedge21

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And if not, does anyone know somewhere I can get the style piston that my truck has? Or do I have to buy a full set of 6 and really hurt the wallet a bit?
 

davidb56

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Is there a hole drilled from the oil ring groove down to the wrist pin? thats how the wrist pin is lubed. Your old piston hole "could" be for cooling/oiling the wrist pin, but Id lean toward its there to remove excess oil from the oil rings. you need to check to make sure there is a passage drilled from the oil ring groove to the wrist pin and the weight of the two pistons are close in weight. And check the old piston to see how the wrist pin was lubed. I didn't see a oil channel cut in you con rod bearing, so the rod doesn't have a drilled passage for lube.
 

Oerthedge21

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The top of my rod has a hole drilled through the center. I'll take a better look at the holes and see exactly which way they go, as well as the weighs of the two pistons
 

davidb56

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So that old piston hole probably IS the lube port, lining up with the hole in the top of the rod. Im curious how the new piston lubes the pin.....
 

Oerthedge21

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I'm not sure. This engine has the single oil squirter. I had figured it shot up into that hole on the pistons to live and cool everything up there but that was little more than a guess, I don't know if the hole is on the same side of the piston that it sprays oil onto, I'll take a more in depth look tommorow in the light and report my findings. I don't know if I ever specifies but this engine is the LDS-465-1A
 

rustystud

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The Multifuel engine original design had oil cooling passages in the piston just like the MAN diesels do today. I'm not sure if they still make them though. If you cannot find some then you need to weigh this new piston and compare it to your old pistons. It needs to be the same, give or take a milligram here or there. A machine shop can tell you. If it is not the same then it will throw off your engine balance.
 

Oerthedge21

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Yes unfortunately I have been unable to locate an original style piston. I'll get it weighed and hope to God it's the same. Really don't wanna have to spend the money on a set of 6 but sadly I love this truck so I know if that's what it comes to I'll end up doing it
 

Katahdin

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Per TM 9-2815-210-34-2-1

The LDS-465-1A pistons have the oil cooling channel
The LDS-465-1 do not.
Seems like you bought pistons for the -1
 

frank8003

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lds ld 4-ring piston.jpg

lds ld pistons.jpg

I understand why you like your LDS 465-1A, 175HP & 425ft.lbs. torque with piston cooling and 22:1 compression ratio.
 
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Oerthedge21

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It's great, I'm confident this truck would've beat my M1010 had I ever raced the two. Another reason I bothered to spend this much money and time to fix it. That being said, anyone know a source for -1A pistons? I can only find them for the -1, and even saw one for a 427 but none for my truck
 

cattlerepairman

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From the diagram labels it appears that the pistons without the oil passage were used in production engines and the (later) model pistons with oil passage as replacements.

This would suggest that they are interchangeable.

The bottom of the piston is still oil cooled via the jet.

Weighing will provide more info.

Sent from my SM-G950W using Tapatalk
 

Oerthedge21

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I'll try to get them weighed today, after work I was gonna try to get over my friend's house and wash the heads down so I could out the valves back in, although this piston issue kinda takes priority now, I'll report back on what the two weigh
 

frank8003

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Not to discount the posters dilemma but one day in Germany two trucks were sent to get rockets.
1969, Me in a NEW M35AC-D turbo and Him in that dump truck.
150 miles to there and 150 miles back with a load of rockets.
I remember, because they loaded all the rockets with the noses pointing at Me.
I could not catch that dump no matter what I did.
Now I know what engine was in that dump compared to mine.

and this is from a long time agoa..................................

Folks, these topics have all been covered in depth. Please refer posters to existing threads when this sort of thing happens:

http://www.steelsoldiers.com/showthr...p?31284-Engine

http://www.steelsoldiers.com/showthr...he-best-choice

Those are just a couple of the threads out there.

If the links don't work then let me know, I think I can fix that.
 
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Oerthedge21

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It's amazing how much of a powerhouse the LDS is compared to an LDT. Even many if my friend's were surprised that a truck this size with only a 7.8L engine could accelerate in a gear higher than 3rd. And yes, unfortunately those links send me to a 404 error, however you can fix them would be great, the more info Ifind here the better
 

cattlerepairman

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I can fix the first one:
https://www.steelsoldiers.com/showthread.php?31284-Engine
Not too much useful info in that one.

There is a long thread on the multifuel differences. I remember that, in summary, the differences are in the IP/HH and the valve train, specifically the intake valve rocker arms. My personal impression from rebuilding an LDS was also that many other components appeared to be "better made" i.e. more care taken to balance/polish over what I saw in the LDT.

https://www.steelsoldiers.com/showthread.php?56041-LDS-VS-LDT-and-the-real-differences


I point out post #339 in this thread: "As for the oil passage in the pistons, I believe the internal memo that was linked way back said it offered a 100deg F decrease. While with 1950s lubes that were operating at the limits that might have been worth the effort, but modern oil would seem to minimize that advantage."

Post #340 says: " The continental literature claimed it was done to "eliminate the requirement for high additive oil to prevent excesssive ring groove carbon formation." Has anyone had ring sticking with modern oils? The piston bowl is cooled on all engines."

From this I think I would be comfortable running either set of pistons.
 
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