Engine repair or swap to LDS?

[ldmack3]

These circular pits in the pistons. Are these normal or a result of excess EGT?
When I scrape the carbon off underneath it there is a whiteish deposit that looks like oxidation and scrapes off in a white powder.

 

[Mullaney]

These circular pits in the pistons. Are these normal or a result of excess EGT?
When I scrape the carbon off underneath it there is a whiteish deposit that looks like oxidation and scrapes off in a white powder.

View attachment 877173View attachment 877174

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Used to be that hitting those piston tops (NOT in the ring lands!) with a bead blaster was a good thing... Cleanliness is next to godliness in motor repairs.

 

[rustystud]

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Used to be that hitting those piston tops (NOT in the ring lands!) with a bead blaster was a good thing... Cleanliness is next to godliness in motor repairs.

If you use a softer media you can clean out the ring lands too. I've done this on really dirty hardened sludge ground into the ring lands.

 

[rustystud]

These circular pits in the pistons. Are these normal or a result of excess EGT?
When I scrape the carbon off underneath it there is a whiteish deposit that looks like oxidation and scrapes off in a white powder.

View attachment 877173View attachment 877174

Yes. Basically you were melting the piston tops at that point.

 

[ldmack3]

Does this alone require them to be replaced? Question for future.

 

[ldmack3]

Lots of piston confusion.
My pistons have 4 ring grooves PN 11668483 from inside the piston. I read a SS post from 2015 that discusses and apparently some LDS pistons are 4 ring and some are 3 ring. I can't find this PN anywhere. Are these LDS pistons?
If I can't find the 4 ring, must I replace all or can they be mixed? $$$
Only looking at NOS, not good take outs.

 

[Jbulach]

What do the liners look like? I wouldn’t replace the pistons due to minor pitting, but I’m cheap and somebody will probably be along to tell me I‘m wrong as well…

 

[Gypsyman]

I agree with Jbulach. Unless you want an "as new" engine build I wouldn't hesitate to run those after a good cleaning. If the pits were deeper and the edges could cause possible hot spots then maybe but I'm not seeing that.

That pitting is so minor that I don't see any reason to replace them.

 

[ldmack3]

These were already rejected due to cracking over the limit.
Also, my concern is what effect would a high enough temp do to the hardness if it got hot enough to begin melting.

 

[Gypsyman]

These were already rejected due to cracking over the limit.
Also, my concern is what effect would a high enough temp do to the hardness if it got hot enough to begin melting.

I'm sorry. I was away for a few days and missed that part.

 

[ldmack3]

I'm sorry. I was away for a few days and missed that part.

No worries! Advice always appreciated.

 

[rustystud]

These were already rejected due to cracking over the limit.
Also, my concern is what effect would a high enough temp do to the hardness if it got hot enough to begin melting.

If the pistons had not already been rejected I would have reused them. The pitting didn't go near the edges that I could see, and the lands I assume were Ok. As far as loosing it's hardness, Aluminum is a funny metal. It's not like steel which if overheated can lose its hardness. It's more a matter of the material makeup of the aluminum. How much tin, how much pure aluminum, how much other metal alloys that make up the hardness of the metal. True there is something to be said for the "Alignment" of the molecules, that is why "Freezing" the aluminum can help with hardness after it is formed. It's just over heating is not that vital to the integrity of the metal as in steel. I had a small foundry for several years and cast mostly aluminum. Fun metal to play with.
About the piston though. If this happened in my last shop, the pistons would be sandblasted and checked for further faults. If none were found, they would be reused.

 

[rustystud]

What do the liners look like? I wouldn’t replace the pistons due to minor pitting, but I’m cheap and somebody will probably be along to tell me I‘m wrong as well…

No, your right.

 

[rustystud]

Lots of piston confusion.
My pistons have 4 ring grooves PN 11668483 from inside the piston. I read a SS post from 2015 that discusses and apparently some LDS pistons are 4 ring and some are 3 ring. I can't find this PN anywhere. Are these LDS pistons?
If I can't find the 4 ring, must I replace all or can they be mixed? $$$
Only looking at NOS, not good take outs.

Yes, there are 4 ring (old style) and 3 ring (new style) pistons. Do not mix them though ! They have different weights and would put your engine out of balance.

 

[ldmack3]

Is this the newest style gasket?

 

[Welder1]

Is this the newest style gasket?



View attachment 877445

No that is the old style ones. The newer ones are black and don’t have those slots

 

[ldmack3]

Great! That's what came out of mine.
Do the new ones have fire rings?
I've read that you do not need to retorque them and in fact can be detrimental. True?
I've read a lot on here about retorquing, some do and some don't.

Edit: Do you install them dry or add a particular sealer?

 

[Welder1]

Great! That's what came out of mine.
Do the new ones have fire rings?
I've read that you do not need to retorque them and in fact can be detrimental. True?
I've read a lot on here about retorquing, some do and some don't.

Edit: Do you install them dry or add a particular sealer?

The fire rings are integral in the gasket. No sealer is used you install dry. You need to make sure the heads are flat and the block is clean. No re- torque is necessary. The torque on the studs depends if you have a TD block. That stands for thick deck. Those torque to 157 ft lbs. I used ARP ultra torque lube on the nuts and washers.

 

[ldmack3]

Not much different than a gas V8.
Heads are being milled at least .001" for a good sealing surface. It is a TD block. Think I'll use engine oil as the TM states.

Thanks for the info.

 

[rustystud]

Great! That's what came out of mine.
Do the new ones have fire rings?
I've read that you do not need to retorque them and in fact can be detrimental. True?
I've read a lot on here about retorquing, some do and some don't.

Edit: Do you install them dry or add a particular sealer?

You can use a "Loctite" or "FelPro" gasket sealer designed for heads. I've had good luck with the "Loctite" product. Though you shouldn't really need it if the block deck is finished nice and the heads are properly flat.